Ceftaroline as Salvage Monotherapy for Persistent MRSA Bacteremia.

PubMed

Burnett, Yvonne J; Echevarria, Kelly; Traugott, Kristi A

2016-12-01

To summarize published data regarding the use of ceftaroline as salvage monotherapy for persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. PubMed (January 1980-June 2016) was searched using combinations of the search terms methicillin-resistant Staphylococcus aureus, MRSA, bacteremia, ceftaroline, refractory, and persistent Supplemental references were generated through review of identified literature citations. Available English-language, full-text articles pertaining to the use of ceftaroline for persistent MRSA bacteremia (MRSAB) were included. The PubMed search yielded 23 articles for evaluation. There are no randomized controlled trials to date-only case series and reports. Four retrospective case series detailing the use of ceftaroline as monotherapy for persistent MRSAB were included. Most patients received at least 4 days of an appropriate anti-MRSA antimicrobial prior to ceftaroline and were able to clear bacteremia within 3 days. The most common rationales for ceftaroline use were progression of disease or nonresponse to current therapy. Higher off-label dosing of ceftaroline is often utilized to achieve optimal pharmacokinetic/pharmacodynamic parameters. Adverse events are not well described due to lack of follow-up; however, neutropenia has been associated with prolonged use. Treatment options for persistent MRSAB remain few and far between. Ceftaroline is an effective agent for the salvage treatment of MRSAB. Off-label doses up to 600 mg every 8 hours are often used to achieve optimal pharmacokinetic/pharmacodynamic parameters. Because of lack of follow-up in these reports, the incidence of adverse effects of prolonged use of ceftaroline is not well defined. © The Author(s) 2016.

Antimicrobial activity of ceftaroline against methicillin-resistant Staphylococcus aureus (MRSA) isolates collected in 2013-2014 at the Geneva University Hospitals.

PubMed

Andrey, D O; François, P; Manzano, C; Bonetti, E J; Harbarth, S; Schrenzel, J; Kelley, W L; Renzoni, A

2017-02-01

Ceftaroline is a broad-spectrum antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA) strains. Ceftaroline susceptibility of an MRSA set archived between 1994 and 2003 in the Geneva University Hospitals detected a high percentage (66 %) of ceftaroline resistance in clonotypes ST228 and ST247 and correlated with mutations in PBP2a. The ceftaroline mechanism of action is based on the inhibition of PBP2a; thus, the identification of PBP2a mutations of recently circulating clonotypes in our institution was investigated. We analyzed ceftaroline susceptibility in MRSA isolates (2013 and 2014) and established that resistant strains correlated with PBP2a mutations and specific clonotypes. Ninety-six MRSA strains were analyzed from independent patients and were isolated from blood cultures (23 %), deep infections (38.5 %), and superficial (skin or wound) infections (38.5 %). This sample showed a ceftaroline minimum inhibitory concentration (MIC) range between 0.25 and 2 μg/ml and disk diameters ranging from 10 to 30 mm, with a majority of strains showing diameters ≥20 mm. Based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, 76 % (73/96) of isolates showed susceptibility to ceftaroline. Nevertheless, we still observed 24 % (23/96) of resistant isolates (MIC = 2 μg/ml). All resistant isolates were assigned to clonotype ST228 and carried the N146K mutation in PBP2a. Only two ST228 isolates showed ceftaroline susceptibility. The decreasing percentage of ceftaroline-resistant isolates in our hospital can be explained by the decline of ST228 clonotype circulating in our hospital since 2008. We present evidence that ceftaroline is active against recent MRSA strains from our hospital; however, the presence of PBP2a variants in particular clonotypes may affect ceftaroline efficacy.

In vitro activity of ceftaroline against 623 diverse strains of anaerobic bacteria.

PubMed

Citron, D M; Tyrrell, K L; Merriam, C V; Goldstein, E J C

2010-04-01

The in vitro activities of ceftaroline, a novel, parenteral, broad-spectrum cephalosporin, and four comparator antimicrobials were determined against anaerobic bacteria. Against Gram-positive strains, the activity of ceftaroline was similar to that of amoxicillin-clavulanate and four to eight times greater than that of ceftriaxone. Against Gram-negative organisms, ceftaroline showed good activity against beta-lactamase-negative strains but not against the members of the Bacteroides fragilis group. Ceftaroline showed potent activity against a broad spectrum of anaerobes encountered in respiratory, skin, and soft tissue infections.

Ceftaroline Injection

MedlinePlus

... infections and pneumonia (lung infection) caused by certain bacteria. Ceftaroline is in a class of medications called cephalosporin antibiotics. It works by killing bacteria.Antibiotics such as ceftaroline injection will not work ...

Antimicrobial activity of ceftaroline and other anti-infective agents against microbial pathogens recovered from the surgical intensive care patient population: a prevalence analysis.

PubMed

Edmiston, Charles E; Krepel, Candace J; Leaper, David; Ledeboer, Nathan A; Mackey, Tami-Lea; Graham, Mary Beth; Lee, Cheong; Rossi, Peter J; Brown, Kellie R; Lewis, Brian D; Seabrook, Gary R

2014-12-01

Ceftaroline is a new parenteral cephalosporin agent with excellent activity against methicillin-sensitive (MSSA) and resistant strains of Staphylococcus aureus (MRSA). Critically ill surgical patients are susceptible to infection, often by multi-drug-resistant pathogens. The activity of ceftaroline against such pathogens has not been described. Three hundred thirty-five consecutive microbial isolates were collected from surgical wounds or abscesses, respiratory, urine, and blood cultures from patients in the surgical intensive care unit (SICU) of a major tertiary medical center. Using Clinical and Laboratory Standards Institute (CLSI) standard methodology and published breakpoints, all aerobic, facultative anaerobic isolates were tested against ceftaroline and selected comparative antimicrobial agents. All staphylococcal isolates were susceptible to ceftaroline at a breakpoint of ≤1.0 mcg/mL. In addition, ceftaroline exhibited excellent activity against all streptococcal clinical isolates and non-ESBL-producing strains of Enterobacteriaceae (93.5%) recovered from SICU patients. Ceftaroline was inactive against ESBL-producing Enterobacteriaceae, Pseudomonas aeruginosa, vancomycin-resistant enterococci, and selective gram-negative anaerobic bacteria. At present, ceftaroline is the only cephalosporin agent that is active against community and healthcare-associated MRSA. Further studies are needed to validate the benefit of this novel broad-spectrum anti-infective agent for the treatment of susceptible serious infections in the SICU patient population.

A multicentre study of meticillin-resistant Staphylococcus aureus in acute bacterial skin and skin-structure infections in China: susceptibility to ceftaroline and molecular epidemiology.

PubMed

Zhang, Hui; Xiao, Meng; Kong, Fanrong; O'Sullivan, Matthew V N; Mao, Lei-Li; Zhao, Hao-Ran; Zhao, Ying; Wang, He; Xu, Ying-Chun

2015-04-01

Ceftaroline is a novel cephalosporin with activity against Gram-positive organisms, including meticillin-resistant Staphylococcus aureus (MRSA). The objective of this study was to investigate the susceptibility to ceftaroline of hospital-associated MRSA (HA-MRSA) isolates causing acute bacterial skin and skin-structure infections (ABSSSIs) in China and to examine their relationship by genotyping. A total of 251 HA-MRSA isolates causing ABSSSIs were collected from a multicentre study involving 56 hospitals in 38 large cities across 26 provinces in mainland China. All isolates were characterised by multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, spa typing and detection of the Panton-Valentine leukocidin locus (lukS-PV and lukF-PV). Minimum inhibitory concentrations (MICs) of 14 antimicrobial agents, including ceftaroline, were determined by broth microdilution and were interpreted using Clinical and Laboratory Standards Institute breakpoints. The ceftaroline MIC50 and MIC90 values (MICs that inhibit 50% and 90% of the isolates, respectively) were 1 μg/mL and 2 μg/mL, respectively; 33.5% (n=84) of the isolates studied were ceftaroline-non-susceptible, with MICs of 2 μg/mL, but no isolate exhibited ceftaroline resistance (MIC>2 μg/mL). All of the ceftaroline-non-susceptible isolates belonged to the predominant HA-MRSA clones: 95.2% (n=80) from MLST clonal complex 8 (CC8), with the remaining 4.8% (n=4) from CC5. The high rate of non-susceptibility to ceftaroline amongst HA-MRSA causing ABSSSIs in China is concerning. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

In vitro pharmacodynamics of human simulated exposures of ceftaroline and daptomycin against MRSA, hVISA, and VISA with and without prior vancomycin exposure.

PubMed

Bhalodi, Amira A; Hagihara, Mao; Nicolau, David P; Kuti, Joseph L

2014-01-01

The effects of prior vancomycin exposure on ceftaroline and daptomycin therapy against methicillin-resistant Staphylococcus aureus (MRSA) have not been widely studied. Humanized free-drug exposures of vancomycin at 1 g every 12 h (q12h), ceftaroline at 600 mg q12h, and daptomycin at 10 mg/kg of body weight q24h were simulated in a 96-h in vitro pharmacodynamic model against three MRSA isolates, including one heteroresistant vancomycin-intermediate S. aureus (hVISA) isolate and one VISA isolate. A total of five regimens were tested: vancomycin, ceftaroline, and daptomycin alone for the entire 96 h, and then sequential therapy with vancomycin for 48 h followed by ceftaroline or daptomycin for 48 h. Microbiological responses were measured by the changes in log10 CFU during 96 h from baseline. Control isolates grew to 9.16 ± 0.32, 9.13 ± 0.14, and 8.69 ± 0.28 log10 CFU for MRSA, hVISA, and VISA, respectively. Vancomycin initially achieved ≥3 log10 CFU reductions against the MRSA and hVISA isolates, followed by regrowth beginning at 48 h; minimal activity was observed against VISA. The change in 96-h log10 CFU was largest for sequential therapy with vancomycin followed by ceftaroline (-5.22 ± 1.2, P = 0.010 versus ceftaroline) and for sequential therapy with vancomycin followed by ceftaroline (-3.60 ± 0.6, P = 0.037 versus daptomycin), compared with daptomycin (-2.24 ± 1.0), vancomycin (-1.40 ± 1.8), and sequential therapy with vancomycin followed by daptomycin (-1.32 ± 1.0, P > 0.5 for the last three regimens). Prior exposure of vancomycin at 1 g q12h reduced the initial microbiological response of daptomycin, particularly for hVISA and VISA isolates, but did not affect the response of ceftaroline. In the scenario of poor vancomycin response for high-inoculum MRSA infection, a ceftaroline-containing regimen may be preferred.

In vitro activity of ceftaroline against staphylococci from prosthetic joint infection.

PubMed

Park, Kyung-Hwa; Greenwood-Quaintance, Kerryl E; Patel, Robin

2016-02-01

We tested the in vitro activity of ceftaroline by Etest against staphylococci recovered from patients with prosthetic joint infection, including 97 Staphylococcus aureus isolates (36%, oxacillin resistant) and 74 Staphylococcus epidermidis isolates (74%, oxacillin resistant). Ceftaroline inhibited all staphylococci at ≤0.5 μg/mL. The ceftaroline MIC(90/50) values for methicillin-susceptible S. aureus, methicillin-susceptible S. epidermidis, methicillin-resistant S. aureus, and methicillin-resistant S. epidermidis were 0.19/0.125, 0.094/0.047, 0.5/0.38, and 0.38/0.19 μg/mL, respectively. Based on these in vitro findings, ceftaroline should be further evaluated as a potential therapeutic option for the treatment of prosthetic joint infection caused by methicillin-susceptible and methicillin-resistant S. aureus and S. epidermidis. Copyright © 2016 Elsevier Inc. All rights reserved.

Neutropenia Associated with Long-Term Ceftaroline Use.

PubMed

LaVie, Katherine W; Anderson, Scott W; O'Neal, Hollis R; Rice, Todd W; Saavedra, Tatiana C; O'Neal, Catherine S

2016-01-01

Ceftaroline is a fifth-generation cephalosporin with potent antimicrobial activity against Gram-positive and Gram-negative pathogens. Neutropenia is a rare serious adverse event for the class of cephalosporins; however, we observed several cases of severe neutropenia in our outpatient infectious disease practice believed to be associated with ceftaroline use. The aim of this study was to determine the incidence of neutropenia among patients receiving ceftaroline therapy for more than 7 days. We conducted a retrospective cohort analysis of patients admitted to an 800-bed regional medical center between June 2012 and December 2014 who received ceftaroline for more than 7 days to assess the incidence of developing clinically significant neutropenia. Demographic and patient care data points as well as underlying admitting and chronic diagnoses were retrospectively collected from the medical record. Clinically significant neutropenia was defined as an absolute neutrophil count (ANC) less than 1,500 cells/mm(3). Analysis was performed to determine the incidence, severity, and outcome of neutropenia following ceftaroline administration. A total of 39 patients were included in the cohort. The median duration of therapy was 27 days. Seven patients (18%) developed neutropenia while on ceftaroline therapy. Four (10%) of the neutropenic patients had an ANC of <500 cells/mm(3). The median first neutropenic day was day 17, with the median ANC nadir of 432 cells/mm(3) on day 24. We determined that extended ceftaroline infusion is associated with the development of neutropenia. We recommend obtaining a complete blood count (CBC) with differential at the onset of therapy and weekly thereafter. Should the ANC fall below 2,500 cells/mm(3), then twice-weekly CBCs should be monitored for the duration of ceftaroline therapy, and therapy should be discontinued if the ANC falls to 1,500 cells/mm(3) or less. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Avibactam and Class C β-Lactamases: Mechanism of Inhibition, Conservation of the Binding Pocket, and Implications for Resistance

PubMed Central

Johnstone, M. R.; Ross, P. L.; McLaughlin, R. E.; Olivier, N. B.

2014-01-01

Avibactam is a novel non-β-lactam β-lactamase inhibitor that inhibits a wide range of β-lactamases. These include class A, class C, and some class D enzymes, which erode the activity of β-lactam drugs in multidrug-resistant pathogens like Pseudomonas aeruginosa and Enterobacteriaceae spp. Avibactam is currently in clinical development in combination with the β-lactam antibiotics ceftazidime, ceftaroline fosamil, and aztreonam. Avibactam has the potential to be the first β-lactamase inhibitor that might provide activity against class C-mediated resistance, which represents a growing concern in both hospital- and community-acquired infections. Avibactam has an unusual mechanism of action: it is a covalent inhibitor that acts via ring opening, but in contrast to other currently used β-lactamase inhibitors, this reaction is reversible. Here, we present a high-resolution structure of avibactam bound to a class C β-lactamase, AmpC, from P. aeruginosa that provided insight into the mechanism of both acylation and recyclization in this enzyme class and highlighted the differences observed between class A and class C inhibition. Furthermore, variants resistant to avibactam that identified the residues important for inhibition were isolated. Finally, the structural information was used to predict effective inhibition by sequence analysis and functional studies of class C β-lactamases from a large and diverse set of contemporary clinical isolates (P. aeruginosa and several Enterobacteriaceae spp.) obtained from recent infections to understand any preexisting variability in the binding pocket that might affect inhibition by avibactam. PMID:25022578

In Vitro Activity of Ceftaroline against Staphylococcus aureus Isolates Collected in 2012 from Latin American Countries as Part of the AWARE Surveillance Program.

PubMed

Biedenbach, Douglas J; Hoban, Daryl J; Reiszner, Edina; Lahiri, Sushmita D; Alm, Richard A; Sahm, Daniel F; Bouchillon, Samuel K; Ambler, Jane E

2015-12-01

The in vitro activities of ceftaroline and comparators, using broth microdilution, were determined against 1,066 Staphylococcus aureus isolates from hospitalized patients. Seventeen medical centers from Latin American countries contributed isolates. Methicillin-resistant S. aureus (MRSA) percentages ranged from 46% (Brazil) to 62% (Argentina). All methicillin-susceptible S. aureus (MSSA) isolates were susceptible to ceftaroline. Ceftaroline activity against MRSA varied with MIC90s of 0.5 (Venezuela) to 2 (Brazil, Chile, and Colombia) μg/ml, which was the highest MIC value. ST-5 was the most common sequence type. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Antimicrobial activity of ceftaroline and comparator agents when tested against numerous species of coagulase-negative Staphylococcus causing infection in US hospitals.

PubMed

Sader, Helio S; Farrell, David J; Flamm, Robert K; Streit, Jennifer M; Mendes, Rodrigo E; Jones, Ronald N

2016-05-01

A total of 1593 coagulase-negative staphylococci (CoNS) considered clinically significant were collected from 71 US medical centers in 2013-2014 and tested for susceptibility by CLSI broth microdilution methods. Species identification was performed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Overall, 59.7% of isolates were oxacillin resistant (MRCoNS). Ceftaroline (MIC50/90, 0.25/0.5μg/mL) inhibited 99.2% of CoNS at ≤1μg/mL (susceptible breakpoint for Staphylococcus aureus), including 98.7% of MRCoNS, and the highest ceftaroline MIC value was 2μg/mL (13 isolates). Staphylococcus epidermidis represented 60.3% of the CoNS collection and was highly susceptible to ceftaroline (MIC50/90, 0.25/0.5μg/mL, 99.9% inhibited at ≤1μg/mL). All isolates of Staphylococcus capitis, Staphylococcus caprae, Staphylococcus hominis, Staphylococcus lugdunensis, Staphylococcus pettenkoferi, Staphylococcus simulans, and Staphylococcus warneri (MIC50/90, 0.06-0.25/0.25-0.5μg/mL) were inhibited at ceftaroline MIC of ≤1μg/mL. Staphylococcus haemolyticus represented only 4.8%, was atypically less susceptible to ceftaroline (MIC50/90, 0.5/2μg/mL, 87.0% inhibited at ≤1μg/mL), and accounted for 76.9% (10/13) of isolates with ceftaroline MIC >1μg/mL. Copyright © 2016 Elsevier Inc. All rights reserved.

A resurgence of β-lactamase inhibitor combinations effective against multidrug-resistant Gram-negative pathogens.

PubMed

Bush, Karen

2015-11-01

β-Lactamase inhibitors (BLIs) have played an important role in combatting β-lactam resistance in Gram-negative bacteria, but their effectiveness has diminished with the evolution of diverse and deleterious varieties of β-lactamases. In this review, a new generation of BLIs and inhibitor combinations is presented, describing epidemiological information, pharmacodynamic studies, resistance identification and current clinical status. Novel serine BLIs of major interest include the non-β-lactams of the diazabicyclo[3.2.1]octanone (DBO) series. The DBOs avibactam, relebactam and RG6080 inhibit most class A and class C β-lactamases, with selected inhibition of class D enzymes by avibactam. The novel boronic acid inhibitor RPX7009 has a similar inhibitory profile. All of these inhibitors are being developed in combinations that are targeting primarily carbapenemase-producing Gram-negative pathogens. Two BLI combinations (ceftolozane/tazobactam and ceftazidime/avibactam) were recently approved by the US Food and Drug Administration (FDA) under the designation of a Qualified Infectious Disease Product (QIDP). Other inhibitor combinations that have at least completed phase 1 clinical trials are ceftaroline fosamil/avibactam, aztreonam/avibactam, imipenem/relebactam, meropenem/RPX7009 and cefepime/AAI101. Although effective inhibitor combinations are in development for the treatment of infections caused by Gram-negative bacteria with serine carbapenemases, better options are still necessary for pathogens that produce metallo-β-lactamases (MBLs). The aztreonam/avibactam combination demonstrates inhibitory activity against MBL-producing enteric bacteria owing to the stability of the monobactam to these enzymes, but resistance is still an issue for MBL-producing non-fermentative bacteria. Because all of the inhibitor combinations are being developed as parenteral drugs, an orally bioavailable combination would also be of interest. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

A combination of ceftaroline and daptomycin has synergistic and bactericidal activity in vitro against daptomycin nonsusceptible methicillin-resistant Staphylococcus aureus (MRSA).

PubMed

Shafiq, Iffat; Bulman, Zackery P; Spitznogle, Sarah L; Osorio, Justin E; Reilly, Irene S; Lesse, Alan J; Parameswaran, Ganapathi I; Mergenhagen, Kari A; Tsuji, Brian T

2017-05-01

There is an urgent need to optimize therapeutic options in patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia who have failed conventional therapy. Two clinical isolates were obtained from a 68-year-old male with persistent MRSA bacteremia before and after the development of daptomycin nonsusceptibility. The pharmacodynamic activity of monotherapies and combinations of ceftaroline, daptomycin, cefoxitin, nafcillin and vancomycin were evaluated in time-kill experiments versus 10 8 CFU/mL of the pre- and post-daptomycin nonsusceptible MRSA isolates. Cefoxitin, nafcillin and vancomycin alone or in combination with ceftaroline failed to generate prolonged bactericidal activity against the post-daptomycin nonsusceptible isolate whereas a ceftaroline-daptomycin combination resulted in 6, 24 and 48 h log 10 (CFU/mL) reductions of 3.90, 4.40 and 6.32. Population analysis profiles revealed a daptomycin heteroresistant subpopulation of the pre-daptomycin nonsusceptible MRSA isolate that expanded by >10,000× on daptomycin agar containing 2-16 mg/L in the post-daptomycin nonsusceptible isolate. Daptomycin and ceftaroline combinations may be promising against persistent MRSA bacteremia.

Ceftaroline modulates the innate immune and host defense responses of immunocompetent cells exposed to cigarette smoke.

PubMed

Bruno, A; Cipollina, C; Di Vincenzo, S; Siena, L; Dino, P; Di Gaudio, F; Gjomarkaj, M; Pace, E

2017-09-05

Cigarette smoke, the principal risk factor for chronic obstructive pulmonary disease (COPD), negatively influences the effectiveness of the immune system's response to a pathogen. The antibiotic ceftaroline exerts immune-modulatory effects in bronchial epithelial cells exposed to cigarette smoke. The present study aims to assess the effects of ceftaroline on TLR2 and TLR4 expression, LPS binding and TNF-α and human beta defensin (HBD2) release in an undifferentiated and PMA-differentiated human monocyte cell line (THP-1) exposed or not to cigarette smoke extracts (CSE). TLR2, TLR4, and LPS binding were assessed by flow cytometry, TNF-α and HBD2 release were evaluated by ELISA. The constitutive expression of TLR2 and TLR4 and LPS binding were higher in differentiated compared to undifferentiated THP-1 cells. In undifferentiated THP-1 cells, CSE increased TLR2 and TLR4 protein levels, LPS binding and TNF-α release and reduced HBD2 release and ceftaroline counteracted all these effects. In differentiated THP-1, CSE did not significantly affect TLR2 and TLR4 expression and LPS binding but reduced HBD2 release and increased TNF-α release. Ceftaroline counteracted the effects of CSE on HBD2 release in differentiated THP-1. Ceftaroline counteracts the effect of CSE in immune cells by increasing the effectiveness of the innate immune system. This effect may also assist in reducing pathogen activity and recurrent exacerbations in COPD patients. Copyright © 2017 Elsevier B.V. All rights reserved.

In vitro activity of novel anti-MRSA cephalosporins and comparator antimicrobial agents against staphylococci involved in prosthetic joint infections.

PubMed

Isnard, Christophe; Dhalluin, Anne; Malandain, Damasie; Bruey, Quentin; Auzou, Michel; Michon, Jocelyn; Giard, Jean-Christophe; Guérin, François; Cattoir, Vincent

2018-02-05

Ceftaroline and ceftobiprole are new parenteral cephalosporins with potent activity against methicillin-resistant (MR) staphylococci, which are the leading cause of prosthetic joint infections (PJIs). The aim of this study was to determine and compare the in vitro activities of both molecules against staphylococcal isolates recovered from clinically documented PJIs. A collection of 200 non-duplicate clinical isolates [100 Staphylococcus aureus and 100 coagulase-negative staphylococci (CoNS), including 19 and 27 MR isolates, respectively] was studied. Minimum inhibitory concentrations (MICs) of oxacillin, ceftaroline, ceftobiprole, vancomycin, teicoplanin, clindamycin, levofloxacin, linezolid and daptomycin were determined by the broth microdilution method. Bactericidal activity (at 4× MIC) of ceftaroline, ceftobiprole, vancomycin, teicoplanin, linezolid and daptomycin was assessed by time-kill assay. Among the S. aureus isolates, 100% were susceptible to ceftaroline (MIC 50/90 , 0.25/0.5μg/mL) and 98% were susceptible to ceftobiprole (MIC 50/90 , 0.5/1μg/mL), regardless of their methicillin resistance. The two ceftobiprole-non-susceptible strains (including one MRSA) showed MICs at 4mg/L. Against CoNS isolates, ceftaroline and ceftobiprole exhibited in vitro potency with MIC 50/90 values at 0.06/0.25μg/mL and 0.25/1μg/mL, respectively. At 4× MIC, ceftaroline and ceftobiprole showed rapid and marked bactericidal activity against both S. aureus and CoNS (after 24/12h and 12/6h of incubation, respectively), whilst none of the other molecules tested had a bactericidal effect by 24h. This study showed that ceftaroline and ceftobiprole have excellent in vitro activity against clinical isolates of staphylococci involved in PJIs. These molecules may therefore represent promising alternatives for the treatment of such infections. Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

In vitro activity of Ceftaroline against bacterial pathogens isolated from patients with skin and soft tissue and respiratory tract infections in African and Middle Eastern countries: AWARE global surveillance program 2012-2014.

PubMed

Karlowsky, James A; Biedenbach, Douglas J; Bouchillon, Samuel K; Hackel, Meredith; Iaconis, Joseph P; Sahm, Daniel F

2016-10-01

The objective of this report was to document antimicrobial susceptibility testing surveillance data for ceftaroline and comparative agents from the AWARE (Assessing Worldwide Antimicrobial Resistance Evaluation) global surveillance program for bacterial pathogens causing skin and soft tissue and respiratory tract infections in African and Middle Eastern countries from 2012 through 2014. Pathogen identities were confirmed by MALDI-TOF and antimicrobial susceptibility testing performed by CLSI broth microdilution methodology in a central laboratory. All methicillin-susceptible Staphylococcus aureus (MSSA) (n= 923; MIC90, 0.25 μg/mL) and 91.8% of methicillin-resistant S. aureus (MRSA) (n= 1161; MIC90, 1 μg/mL) tested were susceptible to ceftaroline. The maximum ceftaroline MIC observed for isolates of MRSA was 2 μg/mL. All Streptococcus pyogenes (n= 174; MIC90, 0.008 μg/mL), Streptococcus agalactiae (n= 44; MIC90, 0.015 μg/mL), Streptococcus pneumoniae (n= 351; MIC90, 0.25 μg/mL), and Haemophilus influenzae (n= 84; MIC90, ≤0.015 μg/mL) were susceptible to ceftaroline. Rates of susceptibility to ceftaroline among ESBL-negative Escherichia coli (n= 338), Klebsiella pneumoniae (n= 241), and Klebsiella oxytoca (n= 97) were 89.1% (MIC90, 1 μg/mL), 94.2% (MIC90, 0.5 μg/mL), and 99.0% (MIC90, 0.5 μg/mL), respectively. Copyright © 2016. Published by Elsevier Inc.

Ceftaroline: A New Cephalosporin with Activity against Methicillin-Resistant Staphylococcus aureus (MRSA)

PubMed Central

Duplessis, Christopher; Crum-Cianflone, Nancy F.

2011-01-01

Microbial resistance has reached alarming levels, threatening to outpace the ability to counter with more potent antimicrobial agents. In particular, methicillin-resistant Staphylococcus aureus (MRSA) has become a leading cause of skin and soft-tissue infections and PVL-positive strains have been associated with necrotizing pneumonia. Increasing reports of growing resistance to glycopeptides have been noted, further limiting the efficacy of standard antibiotics, such as vancomycin. Ceftaroline is a novel fifth-generation cephalosporin, which exhibits broad-spectrum activity against Gram-positive bacteria, including MRSA and extensively-resistant strains, such as vancomycin-intermediate S. aureus (VISA), heteroresistant VISA (hVISA), and vancomycin-resistant S. aureus (VRSA). In addition to being an exciting new agent in the anti-MRSA armamentarium, ceftaroline provides efficacy against many respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Ceftaroline (600 mg intravenously every 12 hours) has been shown effective in phase III studies in the treatment of complicated skin and soft tissue infections and community-acquired pneumonia. To date, this unique antibiotic exhibits a low propensity for inducing resistance and has a good safety profile, although further post-marketing data and clinical experience are needed. In summary, ceftaroline provides an additional option for the management of complex multidrug resistant infections, including MRSA. PMID:21785568

Pathogens of skin and skin-structure infections in the UK and their susceptibility to antibiotics, including ceftaroline.

PubMed

Livermore, David M; Mushtaq, Shazad; Warner, Marina; James, Dorothy; Kearns, Angela; Woodford, Neil

2015-10-01

Bacterial skin and skin-structure infections (SSSIs) are frequent settings for antibiotic use. We surveyed their UK aetiology and pathogen susceptibility, including susceptibility to ceftaroline. Consecutive SSSI isolates were collected at 35 UK hospitals, to a maximum of 60/site, together with 15 'supplementary' MRSA/site. Isolates were re-identified and BSAC susceptibility testing was performed, with parallel CLSI agar testing for ceftaroline. Isolates (n = 1908) were collected from 1756 hospitalized patients, predominantly with surgical and traumatic infections, abscesses and infected ulcers and largely from general medicine and general surgery patients. They included 1271 Staphylococcus aureus (201 MRSA), 162 β-haemolytic streptococci, 269 Enterobacteriaceae, 138 Pseudomonas aeruginosa and 37 enterococci. Most (944/1756) patients had monomicrobial MSSA infections. Rates of resistance to quinolones, gentamicin and cephalosporins were <20% in Enterobacteriaceae and <10% in P. aeruginosa. MRSA rates varied greatly among hospitals and were 2.5-fold higher in general medicine than in general surgery patients. At breakpoint, ceftaroline inhibited: (i) all MSSA and 97.6% of MRSA, with MICs of 2 mg/L for the few resistant MRSA; (ii) all β-haemolytic streptococci; and (iii) 83% of Enterobacteriaceae. High-level ceftaroline resistance in Enterobacteriaceae involved ESBLs or AmpC enzymes. Ceftaroline MICs by CLSI methodology generally equalled those by BSAC or were 2-fold higher, but this differential was 4-16-fold for P. aeruginosa. Irrespective of patient group, SSSIs were dominated by S. aureus. Most pathogens were susceptible, but 15.8% of S. aureus were MRSA, with locally higher prevalence. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Activity of Ceftaroline and Epidemiologic Trends in Staphylococcus aureus Isolates Collected from 43 Medical Centers in the United States in 2009▿

PubMed Central

Richter, Sandra S.; Heilmann, Kristopher P.; Dohrn, Cassie L.; Riahi, Fathollah; Costello, Andrew J.; Kroeger, Jennifer S.; Biek, Donald; Critchley, Ian A.; Diekema, Daniel J.; Doern, Gary V.

2011-01-01

A Staphylococcus aureus surveillance program was initiated in the United States to examine the in vitro activity of ceftaroline and epidemiologic trends. Susceptibility testing by Clinical and Laboratory Standards Institute broth microdilution was performed on 4,210 clinically significant isolates collected in 2009 from 43 medical centers. All isolates were screened for mecA by PCR and evaluated by pulsed-field gel electrophoresis. Methicillin-resistant S. aureus (MRSA) were analyzed for Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosome mec (SCCmec) type. All isolates had ceftaroline MICs of ≤2 μg/ml with an MIC50 of 0.5 and an MIC90 of 1 μg/ml. The overall resistance rates, expressed as the percentages of isolates that were intermediate and resistant (or nonsusceptible), were as follows: ceftaroline, 1.0%; clindamycin, 30.2% (17.4% MIC ≥ 4 μg/ml; 12.8% inducible); daptomycin, 0.2%; erythromycin, 65.5%; levofloxacin, 39.9%; linezolid, 0.02%; oxacillin, 53.4%; tetracycline, 4.4%; tigecycline, 0%; trimethoprim-sulfamethoxazole, 1.6%; vancomycin, 0%; and high-level mupirocin, 2.2%. The mecA PCR was positive for 53.4% of the isolates. The ceftaroline MIC90s were 0.25 μg/ml for methicillin-susceptible S. aureus and 1 μg/ml for MRSA. Among the 2,247 MRSA isolates, 51% were USA300 (96.9% PVL positive, 99.7% SCCmec type IV) and 17% were USA100 (93.4% SCCmec type II). The resistance rates for the 1,137 USA300 MRSA isolates were as follows: erythromycin, 90.9%; levofloxacin, 49.1%; clindamycin, 7.6% (6.2% MIC ≥ 4 μg/ml; 1.4% inducible); tetracycline, 3.3%; trimethoprim-sulfamethoxazole, 0.8%; high-level mupirocin, 2.7%; daptomycin, 0.4%; and ceftaroline and linezolid, 0%. USA300 is the dominant clone causing MRSA infections in the United States. Ceftaroline demonstrated potent in vitro activity against recent S. aureus clinical isolates, including MRSA, daptomycin-nonsusceptible, and linezolid-resistant strains. PMID:21709080

Postantibiotic effect of ceftaroline against gram-positive organisms.

PubMed

Pankuch, G A; Appelbaum, P C

2009-10-01

The postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects (SMEs) of ceftaroline, a novel injectable cephalosporin, were determined for 15 gram-positive organisms. The pneumococcal, staphylococcal, and enterococcal PAEs were 0.8 to 1.8 h, 0.7 to 2.2 h, and 0.2 to 1.1 h, respectively. The corresponding PA-SMEs (0.4 times the MIC) were 2.5 to 6.7 h, 2.9 to >0.0 h, and 7.9 to >10.3 h, respectively. The PA-SMEs were longer than the PAEs, suggesting that sub-MIC levels extend the PAE of ceftaroline against gram-positive cocci.

Ceftaroline--An Anti-MRSA Cephalosporin and Its Implications for Singapore.

PubMed

Chen, Hui Hiong; Hon, Pei Yun; Hsu, Li Yang

2014-03-01

Ceftaroline is a fifth-generation cephalosporin with activity against methicillin-resistant Staphylococcus aureus (MRSA) that was recently launched in Singapore. It received approval from the United States (US) Food Drug Administration (FDA) and European Commission for the treatment of adult patients with community-acquired pneumonia (CAP) and complicated skin and soft tissue infections (cSSTI). This study aimed to review current published data and determine its clinical role, particularly in the local setting. A literature review on published articles in English on ceftaroline, focusing in particular on clinical trials and other clinical reports. Susceptibility testing was also performed on a limited sample of local MRSA and Streptococcus pneumoniae isolates. Ceftaroline has an extensive spectrum of activity, including coverage of MRSA and multidrug-resistant S. pneumoniae. However, it has limited activity against non-fermenting Gram-negative bacteria and is susceptible to hydrolysis by extended spectrum beta-lactamases. It is only available for intravenous delivery, with a reconstituted stability of just 6 hours, rendering it unavailable for use for outpatient antibiotic therapy. Clinical trials demonstrate non-inferiority compared to first-line comparators in the treatment of CAP and cSSTI. Published case reports/series suggest a potential greater role in the treatment of MRSA bacteremia and endocarditis. No resistance was found among local archived MRSA and S. pneumoniae isolates. We believe ceftaroline will occupy primarily niche roles for culture-directed treatment of various infections--in particular those caused by MRSA--until further clinical trial data become available. A variety of factors render it less useful or appealing for empirical treatment of CAP or healthcare-associated infections.

The potential role of newer gram-positive antibiotics in the setting of osteomyelitis of adults.

PubMed

Moenster, Ryan P; Linneman, Travis W; Call, William B; Kay, Chad L; McEvoy, Theresa A; Sanders, Jamie L

2013-04-01

To summarize available literature regarding the potential role of linezolid, daptomycin, telavancin, tigecycline and ceftaroline for the treatment of osteomyelitis caused by resistant gram-positive organisms. Literature was obtained through PubMed searches from January 1980 to October 2011 using the terms osteomyelitis, bone, linezolid, daptomycin, telavancin, tigecycline and ceftaroline. Results were limited to those published in English. All articles identified from the PubMed searches were evaluated. Any published data related to bone penetration (animal or human) or clinical outcomes in adult osteomyelitis of these agents were included in the review. Animal models report bone concentrations of 2·3 mcg/dL (vertebral) for linezolid, 0·45 mcg/mL (tibiae) for daptomycin, 0·78 mcg/mL (tibiae) for tigecycline and 0·27 mcg/mL (tibiae) for telavancin; no data are available for ceftaroline. Human studies demonstrate bone concentrations of 4·6, 17·0 and 3·9 mcg/mL (sternal, metatarsal and cancellous bone respectively) for linezolid, 4·7 mcg/mL (metatarsal) for daptomycin and 0·078 mcg/mL (unspecified) for tigecycline; no data are available for telavancin and ceftaroline. Retrospective cohort data, and prospective/retrospective case series support the use of linezolid in this setting; however, side-effects may limit use. Retrospective and prospective cohort data support daptomycin use. A retrospective case series is available supporting the use of telavancin. No data are available supporting clinical effectiveness for ceftaroline or tigecycline in the setting of osteomyelitis. Limited data are available evaluating the safety and efficacy of these agents in osteomyelitis in adults. Daptomycin and telavancin may be potential alternatives or second-line agents to vancomycin in selected patients. Linezolid, because of an increase in clinically important ADRs with prolonged use, should be reserved as a second- or third-line agent. Due to a lack of clinical data and poor bone penetration, along with concerns regarding outcomes in severe infections, tigecycline's potential is limited. Little data exist regarding ceftaroline use in osteomyelitis. © 2013 Blackwell Publishing Ltd.

[New antibiotics - standstill or progress].

PubMed

Rademacher, J; Welte, T

2017-04-01

The development of resistance to antibiotics has been ignored for a long time. But nowadays, increasing resistance is an important topic. For a decade no new antibiotics had been developed and it is not possible to quickly close this gap of new resistance and no new drugs. This work presents six new antibiotics (ceftaroline, ceftobiprole, solithromycin, tedizolid, ceftolozane/tazobactam, ceftazidime/avibactam). In part, only expert opinions are given due to lack of study results.The two 5th generation cephalosporins ceftaroline and ceftobiprole have beside their equivalent efficacy to ceftriaxone (ceftaroline) and cefipim (ceftobiprole) high activity against MRSA. The fluoroketolide solithromycin should help against macrolide-resistant pathogens and has been shown to be noninferior to the fluorochinolones. The oxazolidinone tedizolid is effective against linezolid-resistant MRSA. The two cephalosporins ceftolozane/tazobactam and ceftazidime/avibactam are not only effective against gram-negative pathogens, but they have a very broad spectrum. Due to the efficacy against extended-spectrum β‑lactamases, they can relieve the selection pressure of the carbapenems. We benefit from all new antibiotics which can take the selection pressure from other often used antibiotics. The increasing number of resistant gram-negative pathogens worldwide is alarming. Thus, focusing on the development of new drugs is extremely important.

Novel combinations of vancomycin plus ceftaroline or oxacillin against methicillin-resistant vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA.

PubMed

Werth, B J; Vidaillac, C; Murray, K P; Newton, K L; Sakoulas, G; Nonejuie, P; Pogliano, J; Rybak, M J

2013-05-01

We demonstrated a significant inverse correlation between vancomycin and beta-lactam susceptibilities in vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) isolates. Using time-kill assays, vancomycin plus oxacillin or ceftaroline was synergistic against 3 of 5 VISA and 1 of 5 hVISA isolates or 5 of 5 VISA and 4 of 5 hVISA isolates, respectively. Beta-lactam exposure reduced overall vancomycin-Bodipy (dipyrromethene boron difluoride [4,4-difluoro-4-bora-3a,4a-diaza-s-indacene] fluorescent dye) binding but may have improved vancomycin-cell wall interactions to improve vancomycin activity. Further research is warranted to elucidate the mechanism behind vancomycin and beta-lactam synergy.

Improving known classes of antibiotics: an optimistic approach for the future.

PubMed

Bush, Karen

2012-10-01

New antibiotic agents are desperately needed to treat the multidrug-resistant pathogens that continue to emerge at alarming rates. Many of the agents that have entered full clinical development since 1995 have been members of previously accepted classes of antibiotics. Among these are a new aminoglycoside (plazomicin), anti-MRSA cephalosporins (ceftobiprole and ceftaroline), a monocyclic β-lactam (BAL30072), the β-lactamase inhibitor combination of tazobactam with the anti-pseudomonal cephalosporin ceftolozane, β-lactam combinations with new non-β-lactam inhibitors (MK-7655 with imipenem, and avibactam with ceftazidime and ceftaroline), new macrolides (cethromycin and solithromycin), oxazolidinones (tedizolid phosphate and radezolid), and quinolones (delafloxacin, nemonoxacin and JNJ-Q2). Resistance and safety issues have been circumvented by some of these new agents that have well-established mechanisms of action and defined pathways leading toward regulatory approval. Copyright © 2012 Elsevier Ltd. All rights reserved.

Theranostic reduction-sensitive gemcitabine prodrug micelles for near-infrared imaging and pancreatic cancer therapy

NASA Astrophysics Data System (ADS)

Han, Haijie; Wang, Haibo; Chen, Yangjun; Li, Zuhong; Wang, Yin; Jin, Qiao; Ji, Jian

2015-12-01

A biodegradable and reduction-cleavable gemcitabine (GEM) polymeric prodrug with in vivo near-infrared (NIR) imaging ability was reported. This theranostic GEM prodrug PEG-b-[PLA-co-PMAC-graft-(IR820-co-GEM)] was synthesized by ring-opening polymerization and ``click'' reaction. The as-prepared reduction-sensitive prodrug could self-assemble into prodrug micelles in aqueous solution confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In vitro drug release studies showed that these prodrug micelles were able to release GEM in an intracellular-mimicking reductive environment. These prodrug micelles could be effectively internalized by BxPC-3 pancreatic cancer cells, which were observed by confocal laser scanning microscopy (CLSM). Meanwhile, a methyl thiazolyl tetrazolium (MTT) assay demonstrated that this prodrug exhibited high cytotoxicity against BxPC-3 cells. The in vivo whole-animal near-infrared (NIR) imaging results showed that these prodrug micelles could be effectively accumulated in tumor tissue and had a longer blood circulation time than IR820-COOH. The endogenous reduction-sensitive gemcitabine prodrug micelles with the in vivo NIR imaging ability might have great potential in image-guided pancreatic cancer therapy.A biodegradable and reduction-cleavable gemcitabine (GEM) polymeric prodrug with in vivo near-infrared (NIR) imaging ability was reported. This theranostic GEM prodrug PEG-b-[PLA-co-PMAC-graft-(IR820-co-GEM)] was synthesized by ring-opening polymerization and ``click'' reaction. The as-prepared reduction-sensitive prodrug could self-assemble into prodrug micelles in aqueous solution confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In vitro drug release studies showed that these prodrug micelles were able to release GEM in an intracellular-mimicking reductive environment. These prodrug micelles could be effectively internalized by BxPC-3 pancreatic cancer cells, which were observed by confocal laser scanning microscopy (CLSM). Meanwhile, a methyl thiazolyl tetrazolium (MTT) assay demonstrated that this prodrug exhibited high cytotoxicity against BxPC-3 cells. The in vivo whole-animal near-infrared (NIR) imaging results showed that these prodrug micelles could be effectively accumulated in tumor tissue and had a longer blood circulation time than IR820-COOH. The endogenous reduction-sensitive gemcitabine prodrug micelles with the in vivo NIR imaging ability might have great potential in image-guided pancreatic cancer therapy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06734k

Modern prodrug design for targeted oral drug delivery.

PubMed

Dahan, Arik; Zimmermann, Ellen M; Ben-Shabat, Shimon

2014-10-14

The molecular information that became available over the past two decades significantly influenced the field of drug design and delivery at large, and the prodrug approach in particular. While the traditional prodrug approach was aimed at altering various physiochemical parameters, e.g., lipophilicity and charge state, the modern approach to prodrug design considers molecular/cellular factors, e.g., membrane influx/efflux transporters and cellular protein expression and distribution. This novel targeted-prodrug approach is aimed to exploit carrier-mediated transport for enhanced intestinal permeability, as well as specific enzymes to promote activation of the prodrug and liberation of the free parent drug. The purpose of this article is to provide a concise overview of this modern prodrug approach, with useful successful examples for its utilization. In the past the prodrug approach used to be viewed as a last option strategy, after all other possible solutions were exhausted; nowadays this is no longer the case, and in fact, the prodrug approach should be considered already in the very earliest development stages. Indeed, the prodrug approach becomes more and more popular and successful. A mechanistic prodrug design that aims to allow intestinal permeability by specific transporters, as well as activation by specific enzymes, may greatly improve the prodrug efficiency, and allow for novel oral treatment options.

Effects of vehicles and prodrug properties and their interactions on the delivery of 6-mercaptopurine through skin: bisacyloxymethyl-6-mercaptopurine prodrugs.

PubMed

Waranis, R P; Sloan, K B

1987-08-01

A series of S6,9-bisacyloxymethyl-6-mercaptopurine (6,9-bis-6-MP) prodrug derivatives was synthesized and characterized. The solubilities of the derivatives in solvents (vehicles), which exhibited a wide range of polarities from water to oleic acid, were measured. The abilities of the prodrugs to deliver 6-mercaptopurine (6-MP) from the vehicles have also been determined, and experimental fluxes and permeability coefficients (Kp) have been calculated for a large number of prodrug: vehicle combinations. Generally the best prodrugs of the series in terms of delivering 6-MP, regardless of the vehicle, were the first two members--the bisacetyl- and the bispropionyloxymethyl-6-mercaptopurine prodrugs. This result has been attributed mainly to the increased water solubility of these two prodrugs compared with that of 6-MP and the other prodrugs, since all of the prodrugs are much more lipid soluble than 6-MP. For three vehicles--isopropyl myristate, propylene glycol, and water--there was a good correlation between log experimental Kp for the delivery of 6-MP by the prodrugs from those vehicles and the theoretical solubility parameters of the prodrugs. The stabilities of the bisacetyl-(2), bisproprionyl-(3), and bisbutyryloxymethyl-6-mercaptopurine (4) derivatives were determined in buffer and in buffer containing enzymes leached from the dermis. Prodrug 2 was more stable than 3 or 4 in the buffer containing the enzymes, while 4 was more stable than 2 or 3 in the plain buffer.

Effects of vehicles and prodrug properties and their interactions on the delivery of 6-mercaptopurine through skin: S6-acyloxymethyl-6-mercaptopurine prodrugs.

PubMed

Waranis, R P; Sloan, K B

1988-03-01

A homologous series of S6-acyloxymethyl-6-mercaptopurine (6-mono-6-MP) and two 9-acyloxymethyl-6-mercaptopurine (9-mono-6-MP) prodrugs have been synthesized and characterized. The ability of the 6-mono-6-MP prodrugs to deliver 6-mercaptopurine (6-MP) through hairless mouse skin from isopropyl myristate (IPM) and propylene glycol (PG) has been evaluated. There was a good correlation between the log experimental permeability coefficients from the diffusion data and calculated solubility parameters of the prodrugs. Although there was no statistical difference between the rates of delivery of 6-MP by the acetyl through valeryl 6-mono-6-MP prodrugs from IPM, the butyryl and valeryl prodrugs were significantly better at delivering 6-MP from PG. For a given solubility parameter value, the 6-mono-6-MP prodrugs were less soluble in water and IPM, and more soluble in PG than the previously studied S6,9-bisacyloxymethyl-6-MP (6,9-bis-6-MP) prodrugs. On the other hand, for a given solubility parameter, the 6,9-bis-6-MP prodrugs were generally more effective at delivering 6-MP from IPM and PG. The single 9-mono-6-MP prodrug that was evaluated was much less effective at delivering 6-MP than either the 6-mono- or 6,9-bis-6-MP prodrugs. Thus, it is much less important to mask the imidazole than the thionamide functional group in 6-MP to enhance the topical delivery of 6-MP using a prodrug approach.

Reduction of in-source collision-induced dissociation and thermolysis of sulopenem prodrugs for quantitative liquid chromatography/electrospray ionization mass spectrometric analysis by promoting sodium adduct formation.

PubMed

Wujcik, Chad E; Kadar, Eugene P

2008-10-01

Six chromatographically resolved sulopenem prodrugs were monitored for their potential to undergo both in-source collision-induced dissociation (CID) and thermolysis. Initial Q1 scans for each prodrug revealed the formation of intense [Prodrug2 + H]+, [Prodrug2 + Na]+, [Prodrug + Na]+, and [Sulopenem + Na]+ ions. Non-adduct-associated sulopenem ([Sulopenem + H]+) along with several additional lower mass ions were also observed. Product ion scans of [Prodrug3 + Na]+ showed the retention of the sodium adduct in the collision cell continuing down to opening of the beta-lactam ring. In-source CID and temperature experiments were conducted under chromatographic conditions while monitoring several of the latter ion transitions (i.e., adducts, dimers and degradants/fragments) for a given prodrug. The resulting ion profiles indicated the regions of greatest stability for temperature and declustering potential (DP) that provided the highest signal intensity for each prodrug and minimized in-source degradation. The heightened stability of adduct ions, relative to their appropriate counterpart (i.e., dimer to dimer adduct and prodrug to prodrug adduct ions), was observed under elevated temperature and DP conditions. The addition of 100 microM sodium to the mobile phase further enhanced the formation of these more stable adduct ions, yielding an optimal [Prodrug + Na]+ ion signal at temperatures from 400 to 600 degrees C. A clinical liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay for sulopenem prodrug PF-04064900 in buffered whole blood was successfully validated using sodium-fortified mobile phase and the [PF-04064900 + Na]+ ion for quantitation. A conservative five-fold increase in sensitivity from previously validated preclinical assays using the [PF-04064900 + H]+ precursor ion was achieved.

Folate Receptor-Mediated Enhanced and Specific Delivery of Far-Red Light-Activatable Prodrugs of Combretastatin A-4 to FR-Positive Tumor

PubMed Central

2015-01-01

We examined the concept of a novel prodrug strategy in which anticancer drug can be locally released by visible/near IR light, taking advantage of the photodynamic process and photo-unclick chemistry. Our most recently formulated prodrug of combretastatin A-4, Pc-(L-CA4)2, showed multifunctionality for fluorescence imaging, light-activated drug release, and the combined effects of PDT and local chemotherapy. In this formulation, L is a singlet oxygen cleavable linker. Here, we advanced this multifunctional prodrug by adding a tumor-targeting group, folic acid (FA). We designed and prepared four FA-conjugated prodrugs 1–4 (CA4-L-Pc-PEGn-FA: n = 0, 2, 18, ∼45) and one non-FA-conjugated prodrug 5 (CA4-L-Pc-PEG18-boc). Prodrugs 3 and 4 had a longer PEG spacer and showed higher hydrophilicity, enhanced uptake to colon 26 cells via FR-mediated mechanisms, and more specific localization to SC colon 26 tumors in Balb/c mice than prodrugs 1 and 2. Prodrug 4 also showed higher and more specific uptake to tumors, resulting in selective tumor damage and more effective antitumor efficacy than non-FA-conjugated prodrug 5. FR-mediated targeting seemed to be an effective strategy to spare normal tissues surrounding tumors in the illuminated area during treatment with this prodrug. PMID:25351441

Activation of multiple chemotherapeutic prodrugs by the natural enzymolome of tumour-localised probiotic bacteria.

PubMed

Lehouritis, Panos; Stanton, Michael; McCarthy, Florence O; Jeavons, Matthieu; Tangney, Mark

2016-01-28

Some chemotherapeutic drugs (prodrugs) require activation by an enzyme for efficacy. We and others have demonstrated the ability of probiotic bacteria to grow specifically within solid tumours following systemic administration, and we hypothesised that the natural enzymatic activity of these tumour-localised bacteria may be suitable for activation of certain such chemotherapeutic drugs. Several wild-type probiotic bacteria; Escherichia coli Nissle, Bifidobacterium breve, Lactococcus lactis and Lactobacillus species, were screened against a panel of popular prodrugs. All strains were capable of activating at least one prodrug. E. coli Nissle 1917 was selected for further studies because of its ability to activate numerous prodrugs and its resistance to prodrug toxicity. HPLC data confirmed biochemical transformation of prodrugs to their toxic counterparts. Further analysis demonstrated that different enzymes can complement prodrug activation, while simultaneous activation of multiple prodrugs (CB1954, 5-FC, AQ4N and Fludarabine phosphate) by E. coli was confirmed, resulting in significant efficacy improvement. Experiments in mice harbouring murine tumours validated in vitro findings, with significant reduction in tumour growth and increase in survival of mice treated with probiotic bacteria and a combination of prodrugs. These findings demonstrate the ability of probiotic bacteria, without the requirement for genetic modification, to enable high-level activation of multiple prodrugs specifically at the site of action. Copyright © 2015 Elsevier B.V. All rights reserved.

Esterase-sensitive prodrugs with tunable release rates and direct generation of hydrogen sulfidea

PubMed Central

Zheng, Yueqin; Yu, Bingchen; Ji, Kaili; Pan, Zhixiang; Chittavong, Vayou

2016-01-01

Prodrugs that release hydrogen sulfide upon esterase-mediated cleavage of an ester group followed by lactonization are described herein. By modifying the ester group and thus its susceptibility to esterase, and structural features critical to the lactonization rate, H2S release rates can be tuned. Such prodrugs directly release hydrogen sulfide without the involvement of perthiol species, which are commonly encountered with existing H2S donors. Additionally, such prodrugs can easily be conjugated to another non-steroidal anti-inflammatory agent, leading to easy synthesis of hybrid prodrugs. As a biological validation of the H2S prodrugs, the anti-inflammatory effects of one such prodrug were examined by studying its ability to inhibit LPS-induced TNF-α production in RAW 264.7 cells. This type of H2S prodrugs shows great potential as both research tools and therapeutic agents. PMID:26822005

Anticancer activities of emetine prodrugs that are proteolytically activated by the prostate specific antigen (PSA) and evaluation of in vivo toxicity of emetine derivatives.

PubMed

Akinboye, Emmanuel S; Rosen, Marc D; Bakare, Oladapo; Denmeade, Samuel R

2017-12-15

Emetine is a small molecule protein synthesis inhibitor that is toxic to all cell types and therefore suitable for complete killing of all types of heterogeneous cancer cells within a tumor. It becomes significantly inactive (non-toxic) when derivatized at its N-2' secondary amine. This provides a strategy for targeting emetine to cancerous tumor without killing normal cells. In this report, PSA activatable peptide prodrugs of emetine were synthesized. To overcome steric hindrances and enhance protease specific cleavage, a 2-stage prodrug activation process was needed to release emetine in cancer cells. In this 2-stage process, emetine prodrug intermediates are coupled to PSA peptide substrate (Ac-His-Ser-Ser-Lys-Leu-Gln) to obtain the full prodrug. Both prodrug intermediates 10 (Ala-Pro-PABC-Emetine) and 14 (Ser-Leu-PABC-Emetine) were evaluated for kinetics of hydrolysis to emetine and potency [Where PABC = p-aminobenzyloxycarbonyl]. While both intermediates quantitatively liberate emetine when incubated under appropriate conditions, upon coupling of PSA substrate to give the full prodrugs, only prodrug 16, the prodrug obtained from 14 was hydrolyzable by PSA. Cytotoxicity studies in PSA producing LNCaP and CWR22Rv1 confirm the activation of the prodrug by PSA with an IC 50 of 75 nM and 59 nM respectively. The cytotoxicity of 16 is significantly reduced in cell lines that do not produce PSA. Further, in vivo toxicity studies are done on these prodrugs and other derivatives of emetine. The results show the significance of conformational modulation in obtaining safe emetine prodrugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorzoxazone esters of some non-steroidal anti-inflammatory (NSAI) carboxylic acids as mutual prodrugs: design, synthesis, pharmacological investigations and docking studies.

PubMed

Abdel-Azeem, Ahmed Z; Abdel-Hafez, Atef A; El-Karamany, Gamal S; Farag, Hassan H

2009-05-15

The discovery of the inducible isoform of cyclooxygenase enzyme (COX-2) spurred the search for anti-inflammatory agents devoid of the undesirable effects associated with classical NSAIDs. New chlorzoxazone ester prodrugs (6-8) of some acidic NSAIDs (1-3) were designed, synthesized and evaluated as mutual prodrugs with the aim of improving the therapeutic potency and retard the adverse effects of gastrointestinal origin. The structure of the synthesized mutual ester prodrugs (6-8) were confirmed by IR, (1)H NMR, mass spectroscopy (MS) and their purity was ascertained by TLC and elemental analyses. In vitro chemical stability revealed that the synthesized ester prodrugs (6-8) are chemically stable in hydrochloric acid buffer pH 1.2 as a non-enzymatic simulated gastric fluid (SGF) and in phosphate buffer pH 7.4 as non-enzymatic simulated intestinal fluid (SIF). In 80% human plasma, the mutual prodrugs were found to be susceptible to enzymatic hydrolysis at relatively faster rate (t(1/2) approximately 37 and 34 min for prodrugs 6 and 7, respectively). Mutual ester prodrugs (6-8) were evaluated for their anti-inflammatory and muscle relaxation activities. Scanning electromicrographs of the stomach showed that the ester prodrugs induced very little irritancy in the gastric mucosa of rats after oral administration for 4days. In addition, docking of the mutual ester prodrugs (6-8) into COX-2 active site was conducted in order to predict the affinity and orientation of these prodrugs at the enzyme active site.

Amino acids as promoieties in prodrug design and development.

PubMed

Vig, Balvinder S; Huttunen, Kristiina M; Laine, Krista; Rautio, Jarkko

2013-10-01

Prodrugs are biologically inactive agents that upon biotransformation in vivo result in active drug molecules. Since prodrugs might alter the tissue distribution, efficacy and the toxicity of the parent drug, prodrug design should be considered at the early stages of preclinical development. In this regard, natural and synthetic amino acids offer wide structural diversity and physicochemical properties. This review covers the use of amino acid prodrugs to improve poor solubility, poor permeability, sustained release, intravenous delivery, drug targeting, and metabolic stability of the parent drug. In addition, practical considerations and challenges associated with the development of amino acid prodrugs are also covered. Copyright © 2012 Elsevier B.V. All rights reserved.

Discovery and Characterization of a Water-Soluble Prodrug of a Dual Inhibitor of Bacterial DNA Gyrase and Topoisomerase IV.

PubMed

O'Dowd, Hardwin; Shannon, Dean E; Chandupatla, Kishan R; Dixit, Vaishali; Engtrakul, Juntyma J; Ye, Zhengqi; Jones, Steven M; O'Brien, Colleen F; Nicolau, David P; Tessier, Pamela R; Crandon, Jared L; Song, Bin; Macikenas, Dainius; Hanzelka, Brian L; Le Tiran, Arnaud; Bennani, Youssef L; Charifson, Paul S; Grillot, Anne-Laure

2015-07-09

Benzimidazole 1 is the lead compound resulting from an antibacterial program targeting dual inhibitors of bacterial DNA gyrase and topoisomerase IV. With the goal of improving key drug-like properties, namely, the solubility and the formulability of 1, an effort to identify prodrugs was undertaken. This has led to the discovery of a phosphate ester prodrug 2. This prodrug is rapidly cleaved to the parent drug molecule upon both oral and intravenous administration. The prodrug achieved equivalent exposure of 1 compared to dosing the parent in multiple species. The prodrug 2 has improved aqueous solubility, simplifying both intravenous and oral formulation.

Targeted enzyme prodrug therapies.

PubMed

Schellmann, N; Deckert, P M; Bachran, D; Fuchs, H; Bachran, C

2010-09-01

The cure of cancer is still a formidable challenge in medical science. Long-known modalities including surgery, chemotherapy and radiotherapy are successful in a number of cases; however, invasive, metastasized and inaccessible tumors still pose an unresolved and ongoing problem. Targeted therapies designed to locate, detect and specifically kill tumor cells have been developed in the past three decades as an alternative to treat troublesome cancers. Most of these therapies are either based on antibody-dependent cellular cytotoxicity, targeted delivery of cytotoxic drugs or tumor site-specific activation of prodrugs. The latter is a two-step procedure. In the first step, a selected enzyme is accumulated in the tumor by guiding the enzyme or its gene to the neoplastic cells. In the second step, a harmless prodrug is applied and specifically converted by this enzyme into a cytotoxic drug only at the tumor site. A number of targeting systems, enzymes and prodrugs were investigated and improved since the concept was first envisioned in 1974. This review presents a concise overview on the history and latest developments in targeted therapies for cancer treatment. We cover the relevant technologies such as antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT) as well as related therapies such as clostridial- (CDEPT) and polymer-directed enzyme prodrug therapy (PDEPT) with emphasis on prodrug-converting enzymes, prodrugs and drugs.

Modulating lipophilicity of rohitukine via prodrug approach: Preparation, characterization, and in vitro enzymatic hydrolysis in biorelevant media.

PubMed

Kumar, Vikas; Bharate, Sonali S; Vishwakarma, Ram A

2016-09-20

Rohitukine is a medicinally important natural product which has inspired the discovery of two anticancer clinical candidates. Rohitukine is highly hydrophilic in nature which hampers its oral bioavailability. Thus, herein our objective was to improve the drug-like properties of rohitukine via prodrug-strategy. Various ester prodrugs were synthesized and studied for solubility, lipophilicity, chemical stability and enzymatic hydrolysis in plasma/esterase. All prodrugs displayed lower aqueous solubility and improved lipophilicity compared with rohitukine, which was in accordance with the criteria of compounds in drug-discovery. The stability of synthesized prodrugs was evaluated in buffers at different pH, SGF, SIF, rat plasma and in esterase enzyme. The rate of hydrolysis in all incubation media was dependent primarily on the acyl promoieties. Hexanoyl ester prodrug of rohitukine, 3d, was stable under chemical conditions; however it was completely hydrolyzed to rohitukine, in plasma and in esterase in 4h. Hexanoate ester 3d appeared to be the most promising prodrug as it remained intact at gastric/intestinal pH and was completely transformed to the parent compound in plasma as desired for an ideal prodrug. The data presented herein, will help in designing prodrugs with desired physicochemical properties in future in structurally similar chemotypes. Copyright © 2016 Elsevier B.V. All rights reserved.

Flurbiprofen–antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling

PubMed Central

Ashraf, Zaman; Alamgeer; Kanwal, Munazza; Hassan, Mubashir; Abdullah, Sahar; Waheed, Mamuna; Ahsan, Haseeb; Kim, Song Ja

2016-01-01

Flurbiprofen–antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI) effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (–COOH) was temporarily masked by esterification with phenolic –OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (P<0.001) reduced the inflammation against carrageenan and egg albumin-induced paw edema at 4 hours of study. The reduction in the size of the inflamed paw showed that most of the compounds inhibited the later phase of inflammation. The prodrug 2-oxo-2H-chromen-7-yl-2-(2-fluorobiphenyl-4-yl)propanoate (4b) showed significant reduction in paw licking with percentage inhibition of 58%. It also exhibited higher analgesic activity, reducing the number of writhes with a percentage of 75%, whereas flurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer’s yeast-induced pyrexia model, and significant (P<0.001) reduction in rectal temperature was shown by all prodrugs at all times of assessment. The results of ulcerogenic activity showed that all prodrugs produced less GI irritation than flurbiprofen. Molecular docking and simulation studies were carried out with cyclooxygenase (COX-1 and COX-2) proteins, and it was observed that our prodrugs have more potential to selectively bind to COX-2 than to COX-1. It is concluded that the synthesized prodrugs have promising pharmacological activities with reduced GI adverse effects than the parent drug. PMID:27555750

Flurbiprofen-antioxidant mutual prodrugs as safer nonsteroidal anti-inflammatory drugs: synthesis, pharmacological investigation, and computational molecular modeling.

PubMed

Ashraf, Zaman; Alamgeer; Kanwal, Munazza; Hassan, Mubashir; Abdullah, Sahar; Waheed, Mamuna; Ahsan, Haseeb; Kim, Song Ja

2016-01-01

Flurbiprofen-antioxidant mutual prodrugs were synthesized to reduce the gastrointestinal (GI) effects associated with flurbiprofen. For reducing the GI toxicity, the free carboxylic group (-COOH) was temporarily masked by esterification with phenolic -OH of natural antioxidants vanillin, thymol, umbelliferone, and sesamol. The in vitro hydrolysis of synthesized prodrugs showed that they were stable in buffer solution at pH 1.2, indicating their stability in the stomach. The synthesized prodrugs undergo significant hydrolysis in 80% human plasma and thus release free flurbiprofen. The minimum reversion was observed at pH 1.2, suggesting that prodrugs are less irritating to the stomach than flurbiprofen. The anti-inflammatory, analgesic, antipyretic, and ulcerogenic activities of prodrugs were evaluated. All the synthesized prodrugs significantly (P<0.001) reduced the inflammation against carrageenan and egg albumin-induced paw edema at 4 hours of study. The reduction in the size of the inflamed paw showed that most of the compounds inhibited the later phase of inflammation. The prodrug 2-oxo-2H-chromen-7-yl-2-(2-fluorobiphenyl-4-yl)propanoate (4b) showed significant reduction in paw licking with percentage inhibition of 58%. It also exhibited higher analgesic activity, reducing the number of writhes with a percentage of 75%, whereas flurbiprofen showed 69% inhibition. Antipyretic activity was investigated using brewer's yeast-induced pyrexia model, and significant (P<0.001) reduction in rectal temperature was shown by all prodrugs at all times of assessment. The results of ulcerogenic activity showed that all prodrugs produced less GI irritation than flurbiprofen. Molecular docking and simulation studies were carried out with cyclooxygenase (COX-1 and COX-2) proteins, and it was observed that our prodrugs have more potential to selectively bind to COX-2 than to COX-1. It is concluded that the synthesized prodrugs have promising pharmacological activities with reduced GI adverse effects than the parent drug.

Prodrugs for Gene-Directed Enzyme-Prodrug Therapy (Suicide Gene Therapy)

PubMed Central

2003-01-01

This review focuses on the prodrugs used in suicide gene therapy. These prodrugs need to satisfy a number of criteria. They must be efficient and selective substrates for the activating enzyme, and be metabolized to potent cytotoxins preferably able to kill cells at all stages of the cell cycle. Both prodrugs and their activated species should have good distributive properties, so that the resulting bystander effects can maximize the effectiveness of the therapy, since gene transduction efficiencies are generally low. A total of 42 prodrugs explored for use in suicide gene therapy with 12 different enzymes are discussed, particularly in terms of their physiocochemical properties. An important parameter in determining bystander effects generated by passive diffusion is the lipophilicity of the activated form, a property conveniently compared by diffusion coefficients (log P for nonionizable compounds and log D7 for compounds containing an ionizable centre). Many of the early antimetabolite-based prodrugs provide very polar activated forms that have limited abilities to diffuse across cell membranes, and rely on gap junctions between cells for their bystander effects. Several later studies have shown that more lipophilic, neutral compounds have superior diffusion-based bystander effects. Prodrugs of DNA alkylating agents, that are less cell cycle-specific than antimetabolites and more effective against noncycling tumor cells, appear in general to be more active prodrugs, requiring less prolonged dosing schedules to be effective. It is expected that continued studies to optimize the bystander effects and other properties of prodrugs and the activated species they generate will contribute to improvements in the effectiveness of suicide gene therapy. PMID:12686722

Mutual Amide Prodrug of Etodolac-glucosamine: Synthesis, Characterization and Pharmacological Screening

PubMed Central

Pandey, Preeti; Pandey, S.; Dubey, Shaifali

2013-01-01

Etodolac, a nonsteroidal antiinflammatory drug, widely used in arthritis is associated with gastric ulceration and irritation due to presence of free carboxylic group. The current investigation reports synthesis of mutual amide prodrug of etodolac by masking free carboxylic group with glucosamine, a nutritional supplement for treatment of arthritis. Confirmation and characterization of the structure of the synthesized prodrug done by elemental and spectroscopy analysis, melting point, determination of migration parameters (Rf, RM, and Rt) by using thin layer chromatography and high performance liquid chromatography, respectively. Partition coefficient and solubility study confirms its lipophilic character so can be suitable candidate for controlled release delivery. In vitro hydrolytic studies of prodrug confirms good rate of hydrolysis in blood plasma, fecal matter, and simulated intestinal fluid while stable in gastric simulated fluid. In vivo pharmacological screening performed on animals. Prodrug with respect to etodolac shows good analgesic, antiinflammatory, and antiarthritic activity. The prodrug was assessed for their probable damaging effects by ulcerogeniticity and histopathological analysis. The histopathological studies showed less ulceration in the gastric region when treated with prodrug, thereby proving the prodrug to be better in action as compared to etodolac and are advantageous in having less gastrointestinal side effects. PMID:24302794

Design and Synthesis of Phosphotyrosine Peptidomimetic Prodrugs

PubMed Central

Garrido-Hernandez, Hugo; Moon, Kyung D.; Geahlen, Robert L.; Borch, Richard F.

2008-01-01

A novel approach to the intracellular delivery of aryl phosphates has been developed that utilizes a phosphoramidate-based prodrug approach. The prodrugs contain an ester group that undergoes reductive activation intracellularly with concomitant expulsion of a phosphoramidate anion. This anion undergoes intramolecular cyclization and hydrolysis to generate aryl phosphate exclusively with a t1/2 = ∼ 20 min. Phosphoramidate prodrugs (8-10) of phosphate-containing peptidomimetics that target the SH2 domain were synthesized. Evaluation of these peptidomimetic prodrugs in a growth inhibition assay and, in a cell-based transcriptional assay, demonstrated that the prodrugs had IC50 values in the low micromolar range. Synthesis of phosphorodiamidate analogs containing a P-NH-Ar linker (16 – 18) was also carried out in the hope that the phosphoramidates released might be phosphatase-resistant. Comparable activation rates and cell-based activities were observed for these prodrugs, but the intermediate phosphoramidate dianion underwent spontaneous hydrolysis with a t1/2 = ∼ 30 min. PMID:16722656

Macrocyclic Prodrugs of a Selective Nonpeptidic Direct Thrombin Inhibitor Display High Permeability, Efficient Bioconversion but Low Bioavailability.

PubMed

Andersson, Vincent; Bergström, Fredrik; Brånalt, Jonas; Grönberg, Gunnar; Gustafsson, David; Karlsson, Staffan; Polla, Magnus; Bergman, Joakim; Kihlberg, Jan

2016-07-28

The only oral direct thrombin inhibitors that have reached the market, ximelagatran and dabigatran etexilat, are double prodrugs with low bioavailability in humans. We have evaluated an alternative strategy: the preparation of a nonpeptidic, polar direct thrombin inhibitor as a single, macrocyclic esterase-cleavable (acyloxy)alkoxy prodrug. Two homologous prodrugs were synthesized and displayed high solubilities and Caco-2 cell permeabilities, suggesting high absorption from the intestine. In addition, they were rapidly and completely converted to the active zwitterionic thrombin inhibitor in human hepatocytes. Unexpectedly, the most promising prodrug displayed only moderately higher oral bioavailability in rat than the polar direct thrombin inhibitor, most likely due to rapid metabolism in the intestine or the intestinal wall. To the best of our knowledge, this is the first in vivo ADME study of macrocyclic (acyloxy)alkoxy prodrugs, and it remains to be established if the modest increase in bioavailability is a general feature of this category of prodrugs or not.

Prodrugs as self-assembled hydrogels: a new paradigm for biomaterials.

PubMed

Vemula, Praveen Kumar; Wiradharma, Nikken; Ankrum, James A; Miranda, Oscar R; John, George; Karp, Jeffrey M

2013-12-01

Prodrug-based self-assembled hydrogels represent a new class of active biomaterials that can be harnessed for medical applications, in particular the design of stimuli responsive drug delivery devices. In this approach, a promoiety is chemically conjugated to a known-drug to generate an amphiphilic prodrug that is capable of forming self-assembled hydrogels. Prodrug-based self-assembled hydrogels are advantageous as they alter the solubility of the drug, enhance drug loading, and eliminate the use of harmful excipients. In addition, self-assembled prodrug hydrogels can be designed to undergo controlled drug release or tailored degradation in response to biological cues. Herein we review the development of prodrug-based self-assembled hydrogels as an emerging class of biomaterials that overcome several common limitations encountered in conventional drug delivery. Published by Elsevier Ltd.

Iterative design of emetine-based prodrug targeting fibroblast activation protein (FAP) and dipeptidyl peptidase IV DPPIV using a tandem enzymatic activation strategy.

PubMed

Akinboye, Emmanuel S; Brennen, W Nathaniel; Rosen, D Marc; Bakare, Oladapo; Denmeade, Samuel R

2016-06-01

There is an urgent need to develop new agents for treating metastatic prostate cancer to overcome multiple drug resistance to the current standard targeted cancer therapy. Emetine is a highly cytotoxic natural product protein synthesis inhibitor, which is toxic to all cell types. Its cytotoxicity can be blocked by derivatizing its N-2' position. Thus emetine can be selectively delivered to cancer cells in the region of metastatic cancer as a prodrug that will be activated by an enzyme selectively overexpressed within the metastatic tumor microenvironment. In this work, we convert emetine to a prodrug activatable by the fibroblast activation protein (FAP), a serine protease overexpressed by the carcinoma associated fibroblasts. By using an iterative structure-activity relationship strategy, several peptidyl emetine prodrug analogs (1-11) were synthesized by chemical derivatization of emetine at its N-2' position and tested for in-vitro activation by FAP. The lead prodrug 11 is made up of a DPPIV activatable prodrug precursor 10 (Ala-Pro-PABC-Emetine) coupled to FAP substrate (Ala-Ser-Gly-Pro-Ala-Gly-Pro). Activation assays of the prodrugs were performed in purified FAP, DPPIV, FBS, and human serum and were analyzed by LCMS. In vitro cytotoxicity assays of these prodrugs are carried out in prostate (LNCaP, PC3) and breast (MCF7 and MDA-MB-231) cancer cell lines. The prodrugs are also tested in normal immortalized human prostatic epithelial cell line (PrEC). The lead FAP activated emetine prodrug 11 is activated to emetine in tandem by FAP and DPPIV in about 70% conversion within 24 hr. In prostate and breast cancer cell lines treated with prodrug 11, it is found to be equipotent with emetine in the presence of FAP and DPPIV. However, in the PrEC cell line grown in serum free media, prodrug 11 is more than 200-fold less cytotoxic than emetine in the absence of FAP and DPPIV. This FAP activated prodrug of cytotoxic agent emetine further shows the crucial role of the N-2' position of emetine in controlling its cytotoxicity. Significantly reduced toxicity observed in the PrEC cell line in the absence of FAP and DPPIV shows that prodrug 11 could be systemically delivered to regions of metastatic prostate cancer or other solid tumor for activation by cancer selective enzymes within the cancer microenvironment, such as FAP that is overexpressed by the carcinoma-associated fibroblasts. The two-step tandem enzymatic activation of prodrug 11 by FAP and DPPIV is a strategy for overcoming steric hindrance. © 2016 Wiley Periodicals, Inc.

Acid-activatable prodrug nanogels for efficient intracellular doxorubicin release.

PubMed

Zhan, Fuxing; Chen, Wei; Wang, Zhongjuan; Lu, Wentao; Cheng, Ru; Deng, Chao; Meng, Fenghua; Liu, Haiyan; Zhong, Zhiyuan

2011-10-10

Endosomal pH-activatable doxorubicin (DOX) prodrug nanogels were designed, prepared, and investigated for triggered intracellular drug release in cancer cells. DOX prodrugs with drug grafting contents of 3.9, 5.7, and 11.7 wt % (denoted as prodrugs 1, 2, and 3, respectively) were conveniently obtained by sequential treatment of poly(ethylene glycol)-b-poly(2-hydroxyethyl methacrylate-co-ethyl glycinate methacrylamide) (PEG-b-P(HEMA-co-EGMA)) copolymers with hydrazine and doxorubicin hydrochloride. Notably, prodrugs 1, 2, and 3 formed monodispersed nanogels with average sizes of 114.4, 75.3, and 66.3 nm, respectively, in phosphate buffer (PB, 10 mM, pH 7.4). The in vitro release results showed that DOX was released rapidly and nearly quantitatively from DOX prodrug nanogels at endosomal pH and 37 °C in 48 h, whereas only a minor amount (ca. 20% or less) of drug was released at pH 7.4 under otherwise the same conditions. Confocal laser scanning microscope (CLSM) observations revealed that DOX prodrug nanogels delivered and released DOX into the cytosols as well as cell nuclei of RAW 264.7 cells following 24 h incubation. MTT assays demonstrated that prodrug 3 had pronounced cytotoxic effects to tumor cells following 72 h incubation with IC(50) data determined to be 2.0 and 3.4 μg DOX equiv/mL for RAW 264.7 and MCF-7 tumor cells, respectively. The corresponding polymer carrier, PEG-b-P(HEMA-co-GMA-hydrazide), was shown to be nontoxic up to a tested concentration of 1.32 mg/mL. These endosomal pH-activatable DOX prodrug nanogels uniquely combining features of water-soluble macromolecular prodrugs and nanogels offer a promising platform for targeted cancer therapy.

Pharmacokinetics and Toxicology of a Fibroblast Activation Protein (FAP)-activated Prodrug in Murine Xenograft Models of Human Cancer

PubMed Central

Brennen, W. Nathaniel; Rosen, D. Marc; Chaux, Alcides; Netto, George J.; Isaacs, John T.; Denmeade, Samuel R.

2014-01-01

Background As carcinoma progresses, the stroma undergoes a variety of phenotypic changes, including the presence of carcinoma-associated fibroblasts (CAFs) that express fibroblast activation protein (FAP). FAP is a post-prolyl endopeptidase whose expression in a healthy adult is largely restricted to the cancer-associated stroma. FAP-targeted prodrugs with a 100-fold greater therapeutic window over the parent compound were previously generated. Methods Prodrugs and non-cleavable controls were incubated in the presence of FAP. Plasma and tumor half-lives (t1/2) of the full-length and active forms of the prodrugs were determined using LCMS. Biodistribution studies of prodrug activation were performed. Histopathological analysis of tissues from treated animals were compared to vehicle-treated controls. Toxicity and efficacy studies were performed in human breast (MDA-MB-231 and MCF-7) and prostate (LNCaP) cancer xenografts models. Results These FAP-activated prodrugs have a significantly slower clearance from tumor tissue than the circulation (~12 vs. ~4.5 hrs). Micromolar concentrations of active drug persist in the tumor. Active drug is detected in non-target tissues; however, histopathologic evaluation reveals no evidence of drug-induced toxicity. A FAP-activated prodrug (ERGETGP-S12ADT) inhibits tumor growth in multiple human breast and prostate cancer xenograft models. The anti-tumor effect is comparable to that observed with docetaxel, but results in significantly less toxicity. Conclusion FAP-activated prodrugs are a viable strategy for the management of prostate and other cancers. These prodrugs exhibit less toxicity than a commonly used chemotherapeutic agent. Further refinement of the FAP cleavage site for greater specificity may reduce prodrug activation in non-target tissues and enhance clinical benefit. PMID:25053236

Pharmacokinetics and toxicology of a fibroblast activation protein (FAP)-activated prodrug in murine xenograft models of human cancer.

PubMed

Brennen, W Nathaniel; Rosen, D Marc; Chaux, Alcides; Netto, George J; Isaacs, John T; Denmeade, Samuel R

2014-09-01

As carcinoma progresses, the stroma undergoes a variety of phenotypic changes, including the presence of carcinoma-associated fibroblasts (CAFs) that express fibroblast activation protein (FAP). FAP is a post-prolyl endopeptidase whose expression in a healthy adult is largely restricted to the cancer-associated stroma. FAP-targeted prodrugs with a 100-fold greater therapeutic window over the parent compound were previously generated. Prodrugs and non-cleavable controls were incubated in the presence of FAP. Plasma and tumor half-lives (t1/2) of the full-length and active forms of the prodrugs were determined using LCMS. Biodistribution studies of prodrug activation were performed. Histopathological analysis of tissues from treated animals were compared to vehicle-treated controls. Toxicity and efficacy studies were performed in human breast (MDA-MB-231 and MCF-7) and prostate (LNCaP) cancer xenografts models. These FAP-activated prodrugs have a significantly slower clearance from tumor tissue than the circulation (∼12 vs. ∼4.5 hr). Micromolar concentrations of active drug persist in the tumor. Active drug is detected in non-target tissues; however, histopathologic evaluation reveals no evidence of drug-induced toxicity. A FAP-activated prodrug (ERGETGP-S12ADT) inhibits tumor growth in multiple human breast and prostate cancer xenograft models. The anti-tumor effect is comparable to that observed with docetaxel, but results in significantly less toxicity. FAP-activated prodrugs are a viable strategy for the management of prostate and other cancers. These prodrugs exhibit less toxicity than a commonly used chemotherapeutic agent. Further refinement of the FAP cleavage site for greater specificity may reduce prodrug activation in non-target tissues and enhance clinical benefit. © 2014 Wiley Periodicals, Inc.

1-Arylsulfonyl-2-(Pyridylmethylsulfinyl) Benzimidazoles as New Proton Pump Inhibitor Prodrugs

PubMed Central

Shin, Jai Moo; Sachs, George; Cho, Young-moon; Garst, Michael

2010-01-01

New arylsulfonyl proton pump inhibitor (PPI) prodrug forms were synthesized. These prodrugs provided longer residence time of an effective PPI plasma concentration, resulting in better gastric acid inhibition. PMID:20032890

A Smart Europium-Ruthenium Complex as Anticancer Prodrug: Controllable Drug Release and Real-Time Monitoring under Different Light Excitations.

PubMed

Li, Hongguang; Xie, Chen; Lan, Rongfeng; Zha, Shuai; Chan, Chi-Fai; Wong, Wing-Yan; Ho, Ka-Lok; Chan, Brandon Dow; Luo, Yuxia; Zhang, Jing-Xiang; Law, Ga-Lai; Tai, William C S; Bünzli, Jean-Claude G; Wong, Ka-Leung

2017-11-09

A unique, dual-function, photoactivatable anticancer prodrug, RuEuL, has been tailored that features a ruthenium(II) complex linked to a cyclen-europium chelate via a π-conjugated bridge. Under irradiation at 488 nm, the dark-inactive prodrug undergoes photodissociation, releasing the DNA-damaging ruthenium species. Under evaluation-window irradiation (λ irr = one-photon 350 nm or two-photon 700 nm), the drug delivery process can be quantitatively monitored in real-time because of the long-lived red europium emission. Linear relationships between released drug concentration and ESI-MS or luminescence responses are established. Finally, the efficiency of the new prodrug is demonstrated both in vitro RuEuL anticancer prodrug over some existing ones and open the way for decisive improvements in multipurpose prodrugs.

Prodrugs for transdermal drug delivery - trends and challenges.

PubMed

Ita, Kevin B

2016-09-01

Prodrugs continue to attract significant interest in the transdermal drug delivery field. These moieties can confer favorable physicochemical properties on transdermal drug delivery candidates. Alkyl chain lengthening, pegylation are some of the strategies used for prodrug synthesis. It is usually important to optimize partition coefficient, water and oil solubilities of drugs. In this review, progress made in the field of prodrugs for percutaneous penetration is highlighted and the challenges discussed.

Direct Real-Time Monitoring of Prodrug Activation by Chemiluminescence.

PubMed

Gnaim, Samer; Scomparin, Anna; Das, Sayantan; Blau, Rachel; Satchi-Fainaro, Ronit; Shabat, Doron

2018-05-22

The majority of theranostic prodrugs reported so far relay information through a fluorogenic response generated upon release of the active chemotherapeutic agent. A chemiluminescence detection mode offers significant advantages over fluorescence, mainly due to the superior signal-to-noise ratio of chemiluminescence. Here we report the design and synthesis of the first theranostic prodrug monitored by a chemiluminescence diagnostic mode. As a representative model, we prepared a prodrug from the chemotherapeutic monomethyl auristatin E, which was modified for activation by β-galactosidase. The activation of the prodrug in the presence of β-galactosidase is accompanied by emission of a green photon. Light emission intensities, which increase with increasing concentration of the prodrug, were linearly correlated with a decrease in the viability of a human cell line that stably expresses β-galactosidase. We obtained sharp intravital chemiluminescent images of endogenous enzymatic activity in β-galactosidase-overexpressing tumor-bearing mice. The exceptional sensitivity achieved with the chemiluminescence diagnostic mode should allow the exploitation of theranostic prodrugs for personalized cancer treatment. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A polymeric colchicinoid prodrug with reduced toxicity and improved efficacy for vascular disruption in cancer therapy

PubMed Central

Crielaard, Bart J; van der Wal, Steffen; Lammers, Twan; Le, Huong Thu; Hennink, Wim E; Schiffelers, Raymond M; Storm, Gert; Fens, Marcel HAM

2011-01-01

Colchicinoids are very potent tubulin-binding compounds, which interfere with microtubule formation, giving them strong cytotoxic properties, such as cell mitosis inhibition and induction of microcytoskeleton depolymerization. While this makes them promising vascular disrupting agents (VDAs) in cancer therapy, their dose-limiting toxicity has prevented any clinical application for this purpose. Therefore, colchicinoids are considered attractive lead molecules for the development of novel vascular disrupting nanomedicine. In a previous study, a polymeric colchicinoid prodrug that showed favorable hydrolysis characteristics at physiological conditions was developed. In the current study, this polymeric colchicinoid prodrug was evaluated in vitro and in vivo for its toxicity and vascular disrupting potential. Cell viability studies with human umbilical vein endothelial cells, as an in vitro measure for colchicine activity, reflected the degradation kinetics of the prodrug accordingly. Upon intravenous treatment, in vivo, of B16F10 melanoma-bearing mice with colchicine or with the polymeric colchicinoid prodrug, apparent vascular disruption and consequent tumor necrosis was observed for the prodrug but not for free colchicine at an equivalent dose. Moreover, a five-times-higher dose of the prodrug was well tolerated, indicating reduced toxicity. These findings demonstrate that the polymeric colchicinoid prodrug has a substantially improved efficacy/toxicity ratio compared with that of colchicine, making it a promising VDA for cancer therapy. PMID:22114500

Targeted prodrugs in oral drug delivery: the modern molecular biopharmaceutical approach.

PubMed

Dahan, Arik; Khamis, Mustafa; Agbaria, Riad; Karaman, Rafik

2012-08-01

The molecular revolution greatly impacted the field of drug design and delivery in general, and the utilization of the prodrug approach in particular. The increasing understanding of membrane transporters has promoted a novel 'targeted-prodrug' approach utilizing carrier-mediated transport to increase intestinal permeability, as well as specific enzymes to promote activation to the parent drug. This article provides the reader with a concise overview of this modern approach to prodrug design. Targeting the oligopeptide transporter PEPT1 for absorption and the serine hydrolase valacyclovirase for activation will be presented as examples for the successful utilization of this approach. Additionally, the use of computational approaches, such as DFT and ab initio molecular orbital methods, in modern prodrugs design will be discussed. Overall, in the coming years, more and more information will undoubtedly become available regarding intestinal transporters and potential enzymes that may be exploited for the targeted modern prodrug approach. Hence, the concept of prodrug design can no longer be viewed as merely a chemical modification to solve problems associated with parent compounds. Rather, it opens promising opportunities for precise and efficient drug delivery, as well as enhancement of treatment options and therapeutic efficacy.

Metronidazole prodrugs: synthesis, physicochemical properties, stability, and ex vivo release studies.

PubMed

Mura, Carla; Valenti, Donatella; Floris, Costantino; Sanna, Roberta; De Luca, Maria Antonietta; Fadda, Anna Maria; Loy, Giuseppe

2011-09-01

The aim of the present study was to develop a colon targeted delivery system for metronidazole using polymeric prodrug formulation. Two chitosan amide conjugates of metronidazole were prepared by using two different spacers to covalently link the drug to the amino group of the chitosan glucosamine units. Glutaric and succinic hemiesters of metronidazole were thus prepared and then coupled to chitosan to obtain metronidazole-glutaryl- and metronidazole-succinyl-chitosan conjugates. Polymeric prodrugs were characterized by solid state NMR method, namely carbon 13 cross polarization magic angle spinning ((13)C NMR CPMAS). Prodrug stability study was carried out in acid (pH = 1.2) and in alkaline (pH = 7.4) buffers in a thermostatic bath at 37 °C. Drug release from the two prodrugs was studied by incubating each of them with 10% w/v cecal and colonic content of rats. Obtained results showed that both prodrugs were adequately stable in acid environment, while the succinyl conjugate was more stable than the glutaryl one in alkaline buffer. Both the prodrugs released the drug in cecal and colonic content, showing that the two systems could serve as colon specific delivery systems of metronidazole. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Ocular Sustained Release Nanoparticles Containing Stereoisomeric Dipeptide Prodrugs of Acyclovir

PubMed Central

Jwala, Jwala; Boddu, Sai H.S.; Shah, Sujay; Sirimulla, Suman; Pal, Dhananjay

2011-01-01

Abstract Purpose The objective of this study was to develop and characterize polymeric nanoparticles of appropriate stereoisomeric dipeptide prodrugs of acyclovir (L-valine-L-valine-ACV, L-valine-D-valine-ACV, D-valine-L-valine-ACV, and D-valine-D-valine-ACV) for the treatment of ocular herpes keratitis. Methods Stereoisomeric dipeptide prodrugs of acyclovir (ACV) were screened for bioreversion in various ocular tissues, cell proliferation, and uptake across the rabbit primary corneal epithelial cell line. Docking studies were carried out to examine the affinity of prodrugs to the peptide transporter protein. Prodrugs with optimum characteristics were selected for the preparation of nanoparticles using various grades of poly (lactic-co-glycolic acid) (PLGA). Nanoparticles were characterized for the entrapment efficiency, surface morphology, size distribution, and in vitro release. Further, the effect of thermosensitive gels on the release of prodrugs from nanoparticles was also studied. Results L-valine-L-valine-ACV and L-valine-D-valine-ACV were considered to be optimum in terms of enzymatic stability, uptake, and cytotoxicity. Docking results indicated that L-valine in the terminal position increases the affinity of the prodrugs to the peptide transporter protein. Entrapment efficiency values of L-valine-L-valine-ACV and L-valine-D-valine-ACV were found to be optimal with PLGA 75:25 and PLGA 65:35 polymers, respectively. In vitro release of prodrugs from nanoparticles exhibited a biphasic release behavior with initial burst phase followed by sustained release. Dispersion of nanoparticles in thermosensitive gels completely eliminated the burst release phase. Conclusion Novel nanoparticulate systems of dipeptide prodrugs of ACV suspended in thermosensitive gels may provide sustained delivery after topical administration. PMID:21500985

Pharmacokinetics of amino acid ester prodrugs of Acyclovir after oral administration: Interaction with the transporters on Caco-2 cells

PubMed Central

Katragadda, Suresh; Jain, Ritesh; Kwatra, Deep; Hariharan, Sudharshan; Mitra, Ashim K.

2008-01-01

In vivo systemic absorption of the amino acid prodrugs of acyclovir (ACV) after oral administration was evaluated in rats. Stability of the prodrugs, L-Alanine-ACV (AACV), L-Serine-ACV (SACV), L-Isoleucine-ACV (IACV), γ-Glutamate-ACV (EACV) and L-Valine-ACV (VACV) was evaluated in various tissues. Interaction of these prodrugs with the transporters on Caco-2 cells was studied. In vivo systemic bioavailability of these prodrugs upon oral administration was evaluated in jugular vein cannulated rats. The amino acid ester prodrugs showed affinity towards various amino acid transporters as well as the peptide transporter on the Caco-2 cells. In terms of stability, EACV was most enzymatically stable compared to other prodrugs especially in liver homogenate. In oral absorption studies, ACV and AACV showed high terminal elimination rate constants (λz). SACV and VACV exhibited approximately five fold increase in area under the curve (AUC) values relative to ACV (p<0.05). Cmax(T) (maximum concentration) of SACV was observed to be 39 ± 22 µM in plasma which is 2 times better than VACV and 15 times better than ACV. Clast(T) (concentration at the last time point) of SACV was observed to be 0.18 ± 0.06 µM in plasma which is 2 times better than VACV and 3 times better than ACV. Amino acid ester prodrugs of ACV were absorbed at varying amounts (Cmax) and eliminated at varying rates (λz) thereby leading to varying extents (AUC). The amino acid ester prodrug SACV owing to its enhanced stability, higher AUC and better concentration at last time point seems to be a promising candidate for the oral treatment of herpes infections. PMID:18638532

Synthesis and anti-cancer efficacy of rapid hydrolysed water-soluble paclitaxel pro-drugs.

PubMed

Ryu, Beom-Young; Sohn, Jeong-Sun; Hess, Michael; Choi, Soo-Kyung; Choi, Jae-Kon; Jo, Byung-Wook

2008-01-01

A new series of poly(ethylene glycol)(PEG)-paclitaxel conjugates that increases water solubility of paclitaxel was synthesized. We developed well-designed self-immolating linkers between a drug and a water-soluble polymer moiety which gave an extremely rapid hydrolysis rate to convert a pro-drug into a parent drug without any reduction in drug efficacy. The self-immolating spacer groups were introduced between the solubilizing PEG and C7-OH of paclitaxel in order to control the rate of enzymatic hydrolysis. All these pro-drugs had a water-solubility of 400 mg/ml or more compared with a solubility of about 0.01 mg/ml. The rate of hydrolysis for the pro-drugs in rat plasma showed considerable variation of t((1/2)) ranging from 0.94 min to 42.7 min. To evaluate the anti-tumor efficacy of the pro-drug which had the fastest enzymatic hydrolysis rate, the growth inhibitory effect (IC(50)), the anti-tumor activity and the anti-metastatic potential of the pro-drug were examined. The pro-drug was potent to inhibit the growth of various cancer cell lines, such as human lung, ovarian, colon and melanoma cancer cells. On the development of melanoma lung colonies in C57B/6 mice following intravenous administration of metastatic murine B16/F10 melanoma cells, the pro-drug seems to be more efficacious than paclitaxel. The reduction of the number of melanoma lung colonies was 46.9% (dose: 5 mg/kg) with pure paclitaxel, and 24.5%, and 40.0% with the pro-drug in the dose of 0.71 mg paclitaxel equivalent/kg and 1.42 mg paclitaxel equivalent/kg, respectively.

Prodrug strategy for cancer cell-specific targeting: A recent overview.

PubMed

Zhang, Xian; Li, Xiang; You, Qidong; Zhang, Xiaojin

2017-10-20

The increasing development of targeted cancer therapy provides extensive possibilities in clinical trials, and numerous strategies have been explored. The prodrug is one of the most promising strategies in targeted cancer therapy to improve the selectivity and efficacy of cytotoxic compounds. Compared with normal tissues, cancer cells are characterized by unique aberrant markers, thus inactive prodrugs targeting these markers are excellent therapeutics to release active drugs, killing cancer cells without damaging normal tissues. In this review, we explore an integrated view of potential prodrugs applied in targeted cancer therapy based on aberrant cancer specific markers and some examples are provided for inspiring new ideas of prodrug strategy for cancer cell-specific targeting. Copyright © 2017. Published by Elsevier Masson SAS.

Prodrugs for Improving Tumor Targetability and Efficiency

PubMed Central

Mahato, Rubi; Tai, Wanyi; Cheng, Kun

2011-01-01

As the mainstay in the treatment of various cancers for several decades, chemotherapy is successful but still faces challenges including non-selectivity and high toxicity. Improving the selectivity is therefore a critical step to improve the therapeutic efficacy of chemotherapy. Prodrug is one of the most promising approaches to increase the selectivity and efficacy of a chemotherapy drug. The classical prodrug approach is to improve the pharmaceutical properties (solubility, stability, permeability, irritation, distribution, etc.) via a simple chemical modification. This review will focus on various targeted prodrug designs that have been developed to increase the selectivity of chemotherapy drugs. Various tumor-targeting ligands, transporter-associated ligands, and polymers can be incorporated in a prodrug to enhance the tumor uptake. Prodrugs can also be activated by enzymes that are specifically expressed at a higher level in tumors, leading to a selective anti-tumor effect. This can be achieved by conjugating the enzyme to a tumor-specific antibody, or delivering a vector expressing the enzyme into tumor cells. PMID:21333700

Analgesic Prodrugs for Combating their Side-Effects: Rational Approach.

PubMed

Ruchita; Sucheta; Nanda, Sanju; Pathak, Dharampal

2017-01-01

Analgesics are the drugs which bring insensibility to pain without loosing consciousness. Treatment strategy is generally based on the type of pain. Most of the analgesics are associated with serious side effects, such as NSAIDS can cause severe GI disturbance and opioids can cause addiction. There are various ways to reduce their side effects The analgesic prodrug approach is one of the several strategies used to attain the required pharmacological response with a considerable decrease in side effects. The aim of this paper is to introduce in depth the rational behind the use of the analgesic prodrug approach from past to present. Data is collected from online as well as from extensive literature survey which have appeared on this subject during the last decades. This review will map the origins and development of the most important of the analgesic prodrugs to date. This review indicates that, designing analgesic prodrugs represent successful strategy to gain the required pharmacological activity with a considerable decrease in side effects. However thorough knowledge of diverse biological phenomena is needed which enables scientists to invent and design superior, nontoxic and better-targeted prodrugs. The newly synthesized chemical entity or prodrugs may or may not have intrinsic pharmacological activity and also synthesizing novel molecules consume a lot of time and money than developing prodrugs of existing clinically used analgesic drugs which is surely an attractive and promising area of research now a days. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Enhancement of Curcumin Bioavailability Via the Prodrug Approach: Challenges and Prospects.

PubMed

Ratnatilaka Na Bhuket, Pahweenvaj; El-Magboub, Asma; Haworth, Ian S; Rojsitthisak, Pornchai

2017-06-01

Curcumin is a natural product with many interesting pharmacological properties. However, these are offset by the particularly poor biopharmaceutical properties. The oral bioavailability of curcumin in humans is very low, mainly due to low solubility, poor stability, and extensive metabolism. This has led to multiple approaches to improve bioavailability, including administration of curcumin with metabolism inhibitors, formulation into nanoparticles, modification of the curcumin structure, and development of curcumin prodrugs. In this paper, we focus on the pharmacokinetic outcomes of these approaches. Pharmacokinetic parameters of curcumin after release from prodrugs are dependent on the linker between curcumin and the promoiety, and the release itself may depend on the physiological and enzymatic environment at the site of cleavage. This is an area in which more data are required for rational design of improved linkers. Cytotoxicity of curcumin prodrugs seems to correlate well with cellular uptake in vitro, but the in vivo relevance is uncertain. We conclude that improved experimental and theoretical models of absorption of curcumin prodrugs, development of accurate analytical methods for simultaneous measurement of plasma levels of prodrug and released curcumin, and acquisition of more pharmacokinetic data in animal models for dose prediction in humans are required to facilitate movement of curcumin prodrugs into clinical trials.

Tailoring acyclovir prodrugs with enhanced antiviral activity: rational design, synthesis, human plasma stability and in vitro evaluation.

PubMed

Chayrov, Radoslav L; Stylos, Evgenios K; Chatziathanasiadou, Maria V; Chuchkov, Kiril N; Tencheva, Aleksandra I; Kostagianni, Androniki D; Milkova, Tsenka S; Angelova, Assia L; Galabov, Angel S; Shishkov, Stoyan A; Todorov, Daniel G; Tzakos, Andreas G; Stankova, Ivanka G

2018-05-19

Bile acid prodrugs have served as a viable strategy for refining the pharmaceutical profile of parent drugs through utilizing bile acid transporters. A series of three ester prodrugs of the antiherpetic drug acyclovir (ACV) with the bile acids cholic, chenodeoxycholic and deoxycholic were synthesized and evaluated along with valacyclovir for their in vitro antiviral activity against herpes simplex viruses type 1 and type 2 (HSV-1, HSV-2). The in vitro antiviral activity of the three bile acid prodrugs was also evaluated against Epstein-Barr virus (EBV). Plasma stability assays, utilizing ultra-high performance liquid chromatography coupled with tandem mass spectrometry, in vitro cytotoxicity and inhibitory experiments were conducted in order to establish the biological profile of ACV prodrugs. The antiviral assays demonstrated that ACV-cholate had slightly better antiviral activity than ACV against HSV-1, while it presented an eight-fold higher activity with respect to ACV against HSV-2. ACV-chenodeoxycholate presented a six-fold higher antiviral activity against HSV-2 with respect to ACV. Concerning EBV, the highest antiviral effect was demonstrated by ACV-chenodeoxycholate. Human plasma stability assays revealed that ACV-deoxycholate was more stable than the other two prodrugs. These results suggest that decorating the core structure of ACV with bile acids could deliver prodrugs with amplified antiviral activity.

New prodrugs of two pyrimidine acyclic nucleoside phosphonates: Synthesis and antiviral activity.

PubMed

Krečmerová, Marcela; Dračínský, Martin; Snoeck, Robert; Balzarini, Jan; Pomeisl, Karel; Andrei, Graciela

2017-09-01

New 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy]pyrimidine (PMEO-DAPy) and 1-[2-(phosphonomethoxy)ethyl]-5-azacytosine (PME-5-azaC) prodrugs were prepared with a pro-moiety consisting of carbonyloxymethyl esters (POM, POC), alkoxyalkyl esters, amino acid phosphoramidates and/or tyrosine. The activity of the prodrugs was evaluated in vitro against different virus families. None of the synthesized prodrugs demonstrated activity against RNA viruses but some of them proved active against herpesviruses [including herpes simplex virus (HSV), varicella-zoster virus (VZV), and human cytomegalovirus (HCMV)]. The bis(POC) and the bis(amino acid) phosphoramidate prodrugs of PMEO-DAPy inhibited herpesvirus replication at lower doses than the parent compound although the selectivity against HSV and VZV was only slightly improved compared to PMEO-DAPy. The mono-octadecyl ester of PME-5-azaC emerged as the most potent and selective PME-5-azaC prodrug against HSV, VZV and HCMV with EC 50 's of 0.15-1.12µM while PME-5-azaC only had marginal anti-herpesvirus activity. Although the bis(hexadecylamido-l-tyrosyl) and the bis(POM) esters of PME-5-azaC were also very potent anti-herpesvirus drugs, these were less selective than the mono-octadecyl ester prodrug. Copyright © 2017 Elsevier Ltd. All rights reserved.

Glutathione- and pH-responsive nonporous silica prodrug nanoparticles for controlled release and cancer therapy

NASA Astrophysics Data System (ADS)

Xu, Zhigang; Liu, Shiying; Kang, Yuejun; Wang, Mingfeng

2015-03-01

A myriad of drug delivery systems such as liposomes, micelles, polymers and inorganic nanoparticles (NPs) have been developed for cancer therapy. Very few of them, however, have the ability to integrate multiple functionalities such as specific delivery, high circulation stability, controllable release and good biocompatibility and biodegradability in a single system to improve the therapeutic efficacy. Herein, we report two types of stimuli-responsive nonporous silica prodrug NPs towards this goal for controlled release of anticancer drugs and efficient combinatorial cancer therapy. As a proof of concept, anticancer drugs camptothecin (CPT) and doxorubicin (DOX) were covalently encapsulated into silica matrices through glutathione (GSH)-responsive disulfide and pH-responsive hydrazone bonds, respectively, resulting in NPs with sizes tunable in the range of 50-200 nm. Both silica prodrug NPs showed stimuli-responsive controlled release upon exposure to a GSH-rich or acidic environment, resulting in improved anticancer efficacy. Notably, two prodrug NPs simultaneously taken up by HeLa cells showed a remarkable combinatorial efficacy compared to free drug pairs. These results suggest that the stimuli-responsive silica prodrug NPs are promising anticancer drug carriers for efficient cancer therapy.A myriad of drug delivery systems such as liposomes, micelles, polymers and inorganic nanoparticles (NPs) have been developed for cancer therapy. Very few of them, however, have the ability to integrate multiple functionalities such as specific delivery, high circulation stability, controllable release and good biocompatibility and biodegradability in a single system to improve the therapeutic efficacy. Herein, we report two types of stimuli-responsive nonporous silica prodrug NPs towards this goal for controlled release of anticancer drugs and efficient combinatorial cancer therapy. As a proof of concept, anticancer drugs camptothecin (CPT) and doxorubicin (DOX) were covalently encapsulated into silica matrices through glutathione (GSH)-responsive disulfide and pH-responsive hydrazone bonds, respectively, resulting in NPs with sizes tunable in the range of 50-200 nm. Both silica prodrug NPs showed stimuli-responsive controlled release upon exposure to a GSH-rich or acidic environment, resulting in improved anticancer efficacy. Notably, two prodrug NPs simultaneously taken up by HeLa cells showed a remarkable combinatorial efficacy compared to free drug pairs. These results suggest that the stimuli-responsive silica prodrug NPs are promising anticancer drug carriers for efficient cancer therapy. Electronic supplementary information (ESI) available: Experimental details of SSP-CPT and SSP-DOX; 1H NMR and FT-IR spectra; DLS, TEM and SEM images of prodrug NPs; the TEM image, UV-vis absorption and photoluminescence spectra of CPT/DOX NPs; the TEM images of prodrug NPs incubated under physiological conditions; the reaction conditions and structure information of size-controlled prodrug NPs; the IC50 value of free drug and prodrug NPs at different times. See DOI: 10.1039/c5nr00297d

Synthesis and Characterization of a Phosphate Prodrug of Isoliquiritigenin.

PubMed

Boyapelly, Kumaraswamy; Bonin, Marc-André; Traboulsi, Hussein; Cloutier, Alexandre; Phaneuf, Samuel C; Fortin, Daniel; Cantin, André M; Richter, Martin V; Marsault, Eric

2017-04-28

Isoliquiritigenin (1) possesses a variety of biological activities in vitro. However, its poor aqueous solubility limits its use for subsequent in vivo experimentation. In order to enable the use of 1 for in vivo studies without the use of toxic carriers or cosolvents, a phosphate prodrug strategy was implemented relying on the availability of phenol groups in the molecule. In this study, a phosphate group was added to position C-4 of 1, leading to the more water-soluble prodrug 2 and its ammonium salt 3, which possesses increased stability compared to 2. Herein are reported the synthesis, characterization, solubility, and stability of phosphate prodrug 3 in biological medium in comparison to 1, as well as new results on its anti-inflammatory properties in vivo. As designed, the solubility of prodrug 3 was superior to that of the parent natural product 1 (9.6 mg/mL as opposed to 3.9 μg/mL). Prodrug 3 as an ammonium salt was also found to possess excellent stability as a solid and in aqueous solution, as opposed to its phosphoric acid precursor 2.

Discovery, identification and mitigation of isobaric sulfate metabolite interference to a phosphate prodrug in LC-MS/MS bioanalysis: Critical role of method development in ensuring assay quality.

PubMed

Yuan, Long; Ji, Qin C

2018-06-05

Metabolite interferences represent a major risk of inaccurate quantification when using LC-MS/MS bioanalytical assays. During LC-MS/MS bioanalysis of BMS-919194, a phosphate ester prodrug, in plasma samples from rat and monkey GLP toxicology studies, an unknown peak was detected in the MRM channel of the prodrug. This peak was not observed in previous discovery toxicology studies, in which a fast gradient LC-MS/MS method was used. We found out that this unknown peak would co-elute with the prodrug peak when the discovery method was used, therefore, causing significant overestimation of the exposure of the prodrug in the discovery toxicology studies. To understand the nature of this interfering peak and its impact to bioanalytical assay, we further investigated its formation and identification. The interfering compound and the prodrug were found to be isobaric and to have the same major product ions in electrospray ionization positive mode, thus, could not be differentiated using a triple quadrupole mass spectrometer. By using high-resolution mass spectrometry (HRMS), the interfering metabolite was successfully identified to be an isobaric sulfate metabolite of BMS-919194. To the best of our knowledge, this is the first report that a phosphate prodrug was metabolized in vivo to an isobaric sulfate metabolite, and this metabolite caused significant interference to the analysis of the prodrug. This work demonstrated the presence of the interference risk from isobaric sulfate metabolites to the bioanalysis of phosphate prodrugs in real samples. It is critical to evaluate and mitigate potential metabolite interferences during method development, therefore, minimize the related bioanalytical risks and ensure assay quality. Our work also showed the unique advantages of HRMS in identifying potential metabolite interference during LC-MS/MS bioanalysis. Copyright © 2018 Elsevier B.V. All rights reserved.

In vitro optimization of non-small cell lung cancer activity with troxacitabine, L-1,3-dioxolane-cytidine, prodrugs.

PubMed

Radi, Marco; Adema, Auke D; Daft, Jonathan R; Cho, Jong H; Hoebe, Eveline K; Alexander, Lou-Ella M M; Peters, Godefridus J; Chu, Chung K

2007-05-03

l-1,3-Dioxolane-cytidine, a potent anticancer agent against leukemia, has limited efficacy against solid tumors, perhaps due to its hydrophilicity. Herein, a library of prodrugs were synthesized to optimize in vitro antitumor activity against non-small cell lung cancer. N4-Substituted fatty acid amide prodrugs of 10-16 carbon chain length demonstrated significantly improved antitumor activity over l-1,3-dioxolane-cytidine. These in vitro results suggest that the in vivo therapeutic efficacy of l-1,3-dioxolane-cytidine against solid tumors may be improved with prodrug strategies.

Novel prodrugs of tegafur that display improved anticancer activity and antiangiogenic properties.

PubMed

Engel, Dikla; Nudelman, Abraham; Tarasenko, Nataly; Levovich, Inesa; Makarovsky, Igor; Sochotnikov, Segev; Tarasenko, Igor; Rephaeli, Ada

2008-01-24

New and more potent prodrugs of the 5-fluorouracyl family derived by hydroxymethylation or acyloxymethylation of 5-fluoro-1-(tetrahydro-2-furanyl)-2,4(1H,3H)-pyrimidinedione (tegafur, 1) are described. The anticancer activity of the butyroyloxymethyl-tegafur derivative 3 and not that of tegafur was attenuated by the antioxidant N-acetylcysteine, suggesting that the increased activity of the prodrug is in part mediated by an increase of reactive oxygen species. Compound 3 in an in vitro matrigel assay was found to be a more potent antiangiogenic agent than tegafur. In vivo 3 was significantly more potent than tegafur in inhibiting 4T1 breast carcinoma lung metastases and growth of HT-29 human colon carcinoma tumors in a mouse xenograft. In summary, the multifunctional prodrugs of tegafur display selectivity toward cancer cells, antiangiogenic activity, and anticancer activities in vitro and in vivo, superior to those of tegafur. 5-fluoro-1-(tetrahydro-2-furanyl)-2,4(1 H,3 H)-pyrimidinedione (tegafur, 1), the oral prodrug of 5-FU, has been widely used for treatment of gastrointestinal malignancies with modest efficacy. The aim of this study was to develop and characterize new and more potent prodrugs of the 5-FU family derived by hydroxymethylation or acyloxymethylation of tegafur. Comparison between the effect of tegafur and the new prodrugs on the viability of a variety of cancer cell lines showed that the IC50 and IC90 values of the novel prodrugs were 5-10-fold lower than those of tegafur. While significant differences between the IC50 values of tegafur were observed between the sensitive HT-29 and the resistant LS-1034 colon cancer cell lines, the prodrugs affected them to a similar degree, suggesting that they overcame drug resistance. The increased potency of the prodrugs could be attributed to the antiproliferative contribution imparted by formaldehyde and butyric acid, released upon metabolic degradation. The anticancer activity of the butyroyloxymethyl-tegafur derivative 3 and not that of tegafur was attenuated by the antioxidant N-acetylcysteine, suggesting that the increased activity of the prodrug is in part mediated by an increase of reactive oxygen species. Compound 3 in an in vitro matrigel assay was found to be a more potent antiangiogenic agent than tegafur. In vivo 3 was significantly more potent than tegafur in inhibiting 4T1 breast carcinoma lung metastases and growth of HT-29 human colon carcinoma tumors in a mouse xenograft. In summary, the multifunctional prodrugs of tegafur display selectivity toward cancer cells, antiangiogenic activity and anticancer activities in vitro and in vivo, superior to those of tegafur.

Use of enzyme inhibitors to evaluate the conversion pathways of ester and amide prodrugs: a case study example with the prodrug ceftobiprole medocaril.

PubMed

Eichenbaum, Gary; Skibbe, Jennifer; Parkinson, Andrew; Johnson, Mark D; Baumgardner, Dawn; Ogilvie, Brian; Usuki, Etsuko; Tonelli, Fred; Holsapple, Jeff; Schmitt-Hoffmann, Anne

2012-03-01

An approach was developed that uses enzyme inhibitors to support the assessment of the pathways that are responsible for the conversion of intravenously administered ester and amide prodrugs in different biological matrices. The methodology was applied to ceftobiprole medocaril (BAL5788), the prodrug of the cephalosporin antibiotic, ceftobiprole. The prodrug was incubated in plasma, postmitochondrial supernatant fractions from human liver (impaired and nonimpaired), kidney, and intestine as well as erythrocytes, in the presence and absence of different enzyme inhibitors (acetylcholinesterase, pseudocholinesterase, retinyl palmitoyl hydrolase, serine esterases, amidases, and cholinesterase). Hydrolysis was rapid, extensive, and not dependent on the presence of β-nicotinamide-adenine dinucleotide phosphate (reduced form) in all matrices tested, suggesting the involvement of carboxylesterases but not P450 enzymes. Hydrolysis in healthy human plasma was rapid and complete and only partially inhibited in the presence of paraoxonase inhibitors or in liver from hepatic impaired patients, suggesting involvement of nonparaoxonase pathways. The results demonstrate the utility of this approach in confirming the presence of multiple conversion pathways of intravenously administered prodrugs and in the case of BAL5788 demonstrated that this prodrug is unlikely to be affected by genetic polymorphisms, drug interactions, or other environmental factors that might inhibit or induce the enzymes involved in its conversion. Copyright © 2011 Wiley Periodicals, Inc.

Targeting Carcinoma-Associated Fibroblasts Within the Tumor Stroma With a Fibroblast Activation Protein-Activated Prodrug

PubMed Central

2012-01-01

Background Fibroblasts undergo a morphological transformation to a reactive phenotype in the tumor microenvironment characterized by the expression of proteins such as fibroblast activation protein (FAP), a post-prolyl endopeptidase with expression largely restricted to carcinoma-associated fibroblasts. Thapsigargin (TG) is a highly toxic natural plant product that triggers a rise in intracellular calcium levels and apoptosis. FAP is therefore a provocative target for the activation of prodrugs consisting of a FAP-specific peptide coupled to a potent cytotoxic analog of TG. Methods The efficacy of FAP-activated peptidyl-TG prodrugs was tested in vitro in cell proliferation assays and effects on intracellular calcium in human cancer cell lines. The effects of FAP-activated prodrugs on tumor growth and host toxicity were tested in Balb-C nude MCF-7 and LNCaP xenograft mice (n = 9–11 per group). P values were calculated using permutation tests based on 50 000 permutations. Mixed effects models were used to account for correlations among replicate measures. All statistical tests were two-sided. Results FAP-activated prodrugs killed human cancer cells at low nanomolar concentrations (MCF-7 cells: IC50 = 3.5nM). Amino acid-12ADT analogs from FAP-cleaved prodrugs, but not uncleaved prodrugs, produced a rapid rise in intracellular calcium within minutes of exposure. Immunohistochemical analysis of xenografts exposed to FAP-prodrugs documented stromal-selective cell death of fibroblasts, pericytes, and endothelial cells of sufficient magnitude to inhibit growth of MCF-7 and LNCaP xenografts with minimal systemic toxicity, whereas non-FAP cleavable prodrugs were inactive. MCF-7 and LNCaP xenografts treated with a FAP-activated prodrug had maximal treated-to-control tumor volume ratios of 0.36 (treated: mean = 0.206mm3, 95% CI = 0.068 to 0.344mm3; control: mean = 0.580mm3, 95% CI = 0.267 to 0.893mm3) and 0.24 (treated: mean = 0.131mm3, 95% CI = 0.09 to 0.180mm3; control: mean = 0.543mm3, 95% CI = 0.173 to 0.913mm3), respectively, on day 21 after therapy. Conclusions This study validates the proteolytic activity of FAP as a target for the activation of a systemically delivered cytotoxic prodrug and demonstrates that targeted killing of cells within the stromal compartment of the tumor microenvironment can produce a therapeutic response. PMID:22911669

Combined enzyme/prodrug treatment by genetically engineered AT-MSC exerts synergy and inhibits growth of MDA-MB-231 induced lung metastases.

PubMed

Matuskova, Miroslava; Kozovska, Zuzana; Toro, Lenka; Durinikova, Erika; Tyciakova, Silvia; Cierna, Zuzana; Bohovic, Roman; Kucerova, Lucia

2015-04-09

Metastatic spread of tumor cells remains a serious problem in cancer treatment. Gene-directed enzyme/prodrug therapy mediated by tumor-homing genetically engineered mesenchymal stromal cells (MSC) represents a promising therapeutic modality for elimination of disseminated cells. Efficacy of gene-directed enzyme/prodrug therapy can be improved by combination of individual systems. We aimed to define the combination effect of two systems of gene therapy mediated by MSC, and evaluate the ability of systemically administered genetically engineered mesenchymal stromal cells to inhibit the growth of experimental metastases derived from human breast adenocarcinoma cells MDA-MB-231/EGFP. Human adipose tissue-derived mesenchymal stromal cells (AT-MSC) were retrovirally transduced with fusion yeast cytosine deaminase::uracil phosphoribosyltransferase (CD::UPRT) or with Herpes simplex virus thymidine kinase (HSVtk). Engineered MSC were cocultured with tumor cells in the presence of prodrugs 5-fluorocytosin (5-FC) and ganciclovir (GCV). Combination effect of these enzyme/prodrug approaches was calculated. SCID/bg mice bearing experimental lung metastases were treated with CD::UPRT-MSC, HSVtk-MSC or both in combination in the presence of respective prodrug(s). Treatment efficiency was evaluated by EGFP-positive cell detection by flow cytometry combined with real-time PCR quantification of human cells in mouse organs. Results were confirmed by histological and immunohistochemical examination. We demonstrated various extent of synergy depending on tested cell line and experimental setup. The strongest synergism was observed on breast cancer-derived cell line MDA-MB-231/EGFP. Systemic administration of CD::UPRT-MSC and HSVtk-MSC in combination with 5-FC and GCV inhibited growth of MDA-MB-231 induced lung metastases. Combined gene-directed enzyme/prodrug therapy mediated by MSC exerted synergic cytotoxic effect and resulted in high therapeutic efficacy in vivo.

Polyphosphoester-Camptothecin Prodrug with Reduction-Response Prepared via Michael Addition Polymerization and Click Reaction.

PubMed

Du, Xueqiong; Sun, Yue; Zhang, Mingzu; He, Jinlin; Ni, Peihong

2017-04-26

Polyphosphoesters (PPEs), as potential candidates for biocompatible and biodegradable polymers, play an important role in material science. Various synthetic methods have been employed in the preparation of PPEs such as polycondensation, polyaddition, ring-opening polymerization, and olefin metathesis polymerization. In this study, a series of linear PPEs has been prepared via one-step Michael addition polymerization. Subsequently, camptothecin (CPT) derivatives containing disulfide bonds and azido groups were linked onto the side chain of the PPE through Cu(I)-catalyzed azidealkyne cyclo-addition "click" chemistry to yield a reduction-responsive polymeric prodrug P(EAEP-PPA)-g-ss-CPT. The chemical structures were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared, ultraviolet-visible spectrophotometer, and high performance liquid chromatograph analyses, respectively. The amphiphilic prodrug could self-assemble into micelles in aqueous solution. The average particle size and morphology of the prodrug micelles were measured by dynamic light scattering and transmission electron microscopy, respectively. The results of size change under different conditions indicate that the micelles possess a favorable stability in physiological conditions and can be degraded in reductive medium. Moreover, the studies of in vitro drug release behavior confirm the reduction-responsive degradation of the prodrug micelles. A methyl thiazolyl tetrazolium assay verifies the good biocompatibility of P(EAEP-PPA) not only for normal cells, but also for tumor cells. The results of cytotoxicity and the intracellular uptake about prodrug micelles further demonstrate that the prodrug micelles can efficiently release CPT into 4T1 or HepG2 cells to inhibit the cell proliferation. All these results show that the polyphosphoester-based prodrug can be used for triggered drug delivery system in cancer treatment.

Bi-functional prodrugs of 5-aminolevulinic acid and butyric acid increase erythropoiesis in anemic mice in an erythropoietin-independent manner.

PubMed

Rephaeli, Ada; Tarasenko, Nataly; Fibach, Eitan; Rozic, Gabriela; Lubin, Ido; Lipovetsky, Julia; Furman, Svetlana; Malik, Zvi; Nudelman, Abraham

2016-08-25

Anemia is a major cause of morbidity and mortality worldwide resulting from a wide variety of pathological conditions. In severe cases it is treated by blood transfusions or injection of erythroid stimulating agents, e.g., erythropoietin (Epo), which can be associated with serious adverse effects. Therefore, there is a need to develop new treatment modalities. We recently reported that treatment of erythroleukemic cells with the novel the bi-functional prodrugs of 5-aminolevulinic acid (ALA) and butyric acid (BA), AN233 and AN908, enhanced hemoglobin (Hb) synthesis to a substantially higher level than did ALA and BA individually or their mixture. Herein, we describe that these prodrugs when given orally to mice induced histone deacetylase inhibition in the kidneys, bone marrow and spleen, thus, indicating good penetrability to the tissues. In mice where anemia was chemically induced, treatment with the prodrugs increased the Hb, the number of red blood cells (RBCs) and the percentage of reticulocytes to normal levels. The prodrugs had no adverse effects even after repeated treatment at 100-200mg/kg for 50days. The lack of increased levels of Epo in the blood of mice that were treated with the prodrugs suggests that AN233 and AN908 affected the Hb and RBC levels in an Epo-independent manner. Taken together with our previous studies, we propose that the prodrugs increase globin expression by BA inhibition of histone deacetylase and elevation heme synthesis by ALA. These results support an Epo-independent approach for treating anemia with these prodrugs. Copyright © 2016 Elsevier B.V. All rights reserved.

Nanostructured nanoparticles of self-assembled lipid pro-drugs as a route to improved chemotherapeutic agents.

PubMed

Sagnella, Sharon M; Gong, Xiaojuan; Moghaddam, Minoo J; Conn, Charlotte E; Kimpton, Kathleen; Waddington, Lynne J; Krodkiewska, Irena; Drummond, Calum J

2011-03-01

We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipid prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation.

Preclinical studies of dendrimer prodrugs.

PubMed

Kojima, Chie

2015-01-01

Dendrimers are synthetic macromolecules with well-defined structures bearing a wide variety of functional groups on their periphery. These groups can be used to conjugate bioactive molecules such as drugs, ligands and imaging agents. Dendrimer prodrugs can be used to improve the water solubility and pharmacokinetic properties of the corresponding free drugs. This article summarizes preclinical studies pertaining to the use of drug-dendrimer conjugates as dendrimer prodrugs for the treatments of various diseases, including cancer and inflammatory diseases. A wide range of anticancer drugs have been conjugated to dendrimers via biodegradable linkers. The side effects of the parent drugs can be markedly reduced using dendrimer prodrugs, with some drugs showing improved efficacy. Anti-inflammatory agents have also been conjugated to dendrimers and used to treat a number of inflammatory diseases. Drug-dendrimer conjugates are preferable to drug-dendrimer complexes, where the use of degradable linkers is critical to the release of the drug. Polyethylene glycol and/or ligands can be added to a dendrimer prodrug, which is useful for the targeting of affected tissues. Imaging probes can also be incorporated into dendrimer prodrugs for the simultaneous delivery of therapeutic and diagnostic agents as 'theranostics.'

Design of a targeted peptide nucleic acid prodrug to inhibit hepatic human microsomal triglyceride transfer protein expression in hepatocytes.

PubMed

Biessen, Erik A L; Sliedregt-Bol, Karen; 'T Hoen, Peter A Chr; Prince, Perry; Van der Bilt, Erica; Valentijn, A Rob P M; Meeuwenoord, Nico J; Princen, Hans; Bijsterbosch, Martin K; Van der Marel, Gijs A; Van Boom, Jacques H; Van Berkel, Theo J C

2002-01-01

In this study, we present the design and synthesis of an antisense peptide nucleic acid (asPNA) prodrug, which displays an improved biodistribution profile and an equally improved capacity to reduce the levels of target mRNA. The prodrug, K(GalNAc)(2)-asPNA, comprised of a 14-mer sequence complementary to the human microsomal triglyceride transfer protein (huMTP) gene, conjugated to a high-affinity tag for the hepatic asialoglycoprotein receptor (K(GalNAc)(2)). The prodrug was avidly bound and rapidly internalized by HepG2s. After iv injection into mice, K(GalNAc)(2)-asPNA accumulated in the parenchymal liver cells to a much greater extent than nonconjugated PNA (46% +/- 1% vs 3.1% +/- 0.5% of the injected dose, respectively). The prodrug was able to reduce MTP mRNA levels in HepG2 cells by 35-40% (P < 0.02) at 100 nM in an asialoglycoprotein receptor- and sequence-dependent fashion. In conclusion, hepatocyte-targeted PNA prodrugs combine a greatly improved tropism with an enhanced local intracellular availability and activity, making them attractive therapeutics to lower the expression level of hepatic target genes such as MTP.

Suppression of inflammation in a mouse model of rheumatoid arthritis using targeted lipase-labile fumagillin prodrug nanoparticles.

PubMed

Zhou, Hui-Fang; Yan, Huimin; Senpan, Angana; Wickline, Samuel A; Pan, Dipanjan; Lanza, Gregory M; Pham, Christine T N

2012-11-01

Nanoparticle-based therapeutics are emerging technologies that have the potential to greatly impact the treatment of many human diseases. However, drug instability and premature release from the nanoparticles during circulation currently preclude clinical translation. Herein, we use a lipase-labile (Sn 2) fumagillin prodrug platform coupled with a unique lipid surface-to-surface targeted delivery mechanism, termed contact-facilitated drug delivery, to counter the premature drug release and overcome the inherent photo-instability of fumagillin, an established anti-angiogenic agent. We show that α(v)β(3)-integrin targeted fumagillin prodrug nanoparticles, administered at 0.3 mg of fumagillin prodrug/kg of body weight suppress the clinical disease indices of KRN serum-mediated arthritis in a dose-dependent manner when compared to treatment with the control nanoparticles with no drug. This study demonstrates the effectiveness of this lipase-labile prodrug nanocarrier in a relevant preclinical model that approximates human rheumatoid arthritis. The lipase-labile prodrug paradigm offers a translatable approach that is broadly applicable to many targeted nanosystems and increases the translational potential of this platform for many diseases. Copyright © 2012 Elsevier Ltd. All rights reserved.

Quantitative modeling of the dynamics and intracellular trafficking of far-red light-activatable prodrugs: implications in stimuli-responsive drug delivery system.

PubMed

Li, Mengjie; Thapa, Pritam; Rajaputra, Pallavi; Bio, Moses; Peer, Cody J; Figg, William D; You, Youngjae; Woo, Sukyung

2017-12-01

The combination of photodynamic therapy (PDT) with anti-tumor agents is a complimentary strategy to treat local cancers. We developed a unique photosensitizer (PS)-conjugated paclitaxel (PTX) prodrug in which a PS is excited by near-infrared wavelength light to site-specifically release PTX while generating singlet oxygen (SO) to effectively kill cancer cells with both PTX and SO. The aim of the present study was to identify the determinants influencing the combined efficacy of this light-activatable prodrug, especially the bystander killing effects from released PTX. Using PS-conjugated PTX as a model system, we developed a quantitative mathematical model describing the intracellular trafficking. Dynamics of the prodrug and the model predictions were verified with experimental data using human cancer cells in vitro. The sensitivity analysis suggested that parameters related to extracellular concentration of released PTX, prodrug uptake, target engagement, and target abundance are critical in determining the combined killing efficacy of the prodrug. We found that released PTX cytotoxicity was most sensitive to the retention time of the drug in extracellular space. Modulating drug internalization and conjugating the agents targeted to abundant receptors may provide a new strategy for maximizing the killing capacity of the far-red light-activatable prodrug system. These results provide guidance for the design of the PDT combination study in vivo and have implications for other stimuli-responsive drug delivery systems.

What's new in the treatment of serious MRSA infection?

PubMed

Holmes, Natasha E; Howden, Benjamin P

2014-12-01

Vancomycin has been the cornerstone of treatment for methicillin-resistant Staphylococcus aureus (MRSA) infections. This review describes new MRSA-active antibiotics that have recently been introduced and highlights emerging resistance. Elevations in the vancomycin minimum inhibitory concentration within the susceptible range are associated with treatment failure and mortality in the treatment of MRSA infections. Ceftaroline and ceftobiprole are anti-MRSA cephalosporins and are noninferior to comparator agents in the treatment of acute bacterial skin and skin structure infections (ABSSSIs) and pneumonia. Tedizolid is more potent than linezolid, has improved pharmacokinetics and reduced toxicity and is active against cfr-containing S. aureus. Telavancin now has approval for treatment of hospital-acquired pneumonia, and recent phase 2 trial data showed similar cure rates in S. aureus bacteremia. Dalbavancin and oritavancin are administered once weekly and are noninferior to comparators for acute bacterial skin and skin structure infections. Resistance has emerged against many new anti-MRSA antimicrobials including ceftaroline. Combination therapy of β-lactams with vancomycin or daptomycin is increasing. Several new MRSA-active agents are now approved for use, although much of the data is derived from treatment of acute bacterial skin and skin structure infections or pneumonia. Further studies are required for more invasive infections, such as bacteremia and endocarditis.

Transporter targeted gatifloxacin prodrugs: Synthesis, permeability, and topical ocular delivery

PubMed Central

Vooturi, Sunil K.; Kadam, Rajendra S.; Kompella, Uday B.

2013-01-01

Purpose To design and synthesize prodrugs of gatifloxacin targeting OCT, MCT, and ATB (0, +) transporters and to identify a prodrug with enhanced delivery to the back of the eye. Method Dimethylamino-propyl, carboxy-propyl, and amino-propyl(2-methyl) derivatives of gatifloxacin (GFX), DMAP-GFX, CP-GFX, and APM-GFX, were designed and synthesized to target OCT, MCT, and ATB (0, +) transporters, respectively. LC-MS method was developed to analyze drug and prodrug levels in various studies. Solubility and Log D (pH 7.4) were measured for prodrugs and the parent drug. Permeability of the prodrugs was determined in cornea, conjunctiva, and sclera-choroidretinal pigment epitheluim (SCRPE) and compared with gatifloxacin using Ussing chamber assembly. Permeability mechanisms were elucidated by determining the transport in the presence of transporter specific inhibitors. 1-Methyl-4-phenylpyridinium iodide (MPP+), nicotinic acid sodium salt, and α-methyl-DL-tryptophan were used to inhibit OCT, MCT, and ATB (0, +) transporters, respectively. A prodrug selected based on in vitro studies was administered as an eye drop to pigmented rabbits and the delivery to various eye tissues including vitreous humor was compared with gatifloxacin dosing. Results DMAP-GFX exhibited 12.8-fold greater solubility than GFX. All prodrugs were more lipophilic, with the measured Log D (pH 7.4) values ranging from 0.05 to 1.04, when compared to GFX (Log D: -1.15). DMAP-GFX showed 1.4-, 1.8-, and 1.9-fold improvement in permeability across cornea, conjunctiva, as well as SCRPE when compared to GFX. Moreover, it exhibited reduced permeability in the presence of MPP+ (competitive inhibitor of OCT), indicating OCT-mediated transport. CP-GFX showed 1.2-, 2.3- and 2.5-fold improvement in permeability across cornea, conjunctiva and SCRPE, respectively. In the presence of nicotinic acid (competitive inhibitor of MCT), permeability of CP-GFX was reduced across conjunctiva. However, cornea and SCRPE permeability of CP-GFX was not affected by nicotinic acid. APM-GFX did not show any improvement in permeability when compared to GFX across cornea, conjunctiva, and SCRPE. Based on solubility and permeability, DMAP-GFX was selected for in vivo studies. DMAP-GFX showed 3.6- and 1.95-fold higher levels in vitreous humor and CRPE compared to that of GFX at 1 hour after topical dosing. In vivo conversion of DMAP-GFX prodrug to GFX was quantified in tissues isolated at 1 hour after dosing. Prodrug-to-parent drug ratio was 8, 70, 24, 21, 29, 13, 55, and 60 % in cornea, conjunctiva, iris-ciliary body, aqueous humor, sclera, CRPE, retina, and vitreous humor, respectively. Conclusions DMAP-GFX prodrug enhanced solubility, Log D, as well as OCT mediated delivery of gatifloxacin to the back of the eye. PMID:23003105

Development and characterization of nanoparticulate formulation of a water soluble prodrug of dexamethasone by HIP complexation.

PubMed

Gaudana, Ripal; Parenky, Ashwin; Vaishya, Ravi; Samanta, Swapan K; Mitra, Ashim K

2011-01-01

The objective of this study was to develop and characterize a nanoparticulate-based sustained release formulation of a water soluble dipeptide prodrug of dexamethasone, valine-valine-dexamethasone (VVD). Being hydrophilic in nature, it readily leaches out in the external aqueous medium and hence partitions poorly into the polymeric matrix resulting in minimal entrapment in nanoparticles. Hence, hydrophobic ion pairing (HIP) complexation of the prodrug was employed with dextran sulphate as a complexing polymer. A novel, solid in oil in water emulsion method was employed to encapsulate the prodrug in HIP complex form in poly(lactic-co-glycolic acid) matrix. Nanoparticles were characterized with respect to size, zeta potential, crystallinity of entrapped drug and surface morphology. A significant enhancement in the entrapment of the prodrug in nanoparticles was achieved. Finally, a simple yet novel method was developed which can also be applicable to encapsulate other charged hydrophilic molecules, such as peptides and proteins.

Utilization of peptide carrier system to improve intestinal absorption: targeting prolidase as a prodrug-converting enzyme

NASA Technical Reports Server (NTRS)

Bai, J. P.; Hu, M.; Subramanian, P.; Mosberg, H. I.; Amidon, G. L.

1992-01-01

The feasibility of targeting prolidase as a peptide prodrug-converting enzyme has been examined. The enzymatic hydrolysis by prolidase of substrates for the peptide transporter L-alpha-methyldopa-pro and several dipeptide analogues without an N-terminal alpha-amino group (phenylpropionylproline, phenylacetylproline, N-benzoylproline, and N-acetylproline) was investigated. The Michaelis-Menten parameters Km and Vmax for L-alpha-methyldopa-pro are 0.09 +/- 0.02 mM and 3.98 +/- 0.25 mumol/min/mg protein, respectively. However, no hydrolysis of the dipeptide analogues without an N-terminal alpha-amino group is observed, suggesting that an N-terminal alpha-amino group is required for prolidase activity. These results demonstrate that prolidase may serve as a prodrug-converting enzyme for the dipeptide-type prodrugs, utilizing the peptide carrier for transport of prodrugs into the mucosal cells and prolidase, a cytosolic enzyme, to release the drug. However, a free alpha-amino group appears to be necessary for prolidase hydrolysis.

ROS-activated anticancer prodrugs: a new strategy for tumor-specific damage

PubMed Central

Peng, Xiaohua; Gandhi, Varsha

2013-01-01

Targeting tumor cells is an important strategy to improve the selectivity of cancer therapies. With the advanced studies in cancer biology, we know that cancer cells are usually under increased oxidative stress. The high level of reactive oxygen species in cancer cells has been exploited for developing novel therapeutic strategies to preferentially kill cancer cells. Our group, amongst others, have used boronic acids/esters as triggers for developing ROS-activated anticancer prodrugs that target cancer cells. The selectivity was achieved by combining a specific reaction between boronates and H2O2 with the efficient masking of drug toxicity in the prodrug via boronates. Prodrugs activated via ferrocene-mediated oxidation have also been developed to improve the selectivity of anticancer drugs. We describe how the strategies of ROS-activation can be used for further development of new ROS-targeting prodrugs, eventually leading to novel approaches and/or combined technology for more efficient and selective treatment of cancers. PMID:22900465

Development and characterization of nanoparticulate formulation of a water soluble prodrug of dexamethasone by HIP complexation

PubMed Central

Gaudana, Ripal; Parenky, Ashwin; Vaishya, Ravi; Samanta, Swapan K.; Mitra, Ashim K.

2015-01-01

The objective of this study was to develop and characterize a nanoparticulate-based sustained release formulation of a water soluble dipeptide prodrug of dexamethasone, valine–valine-dexamethasone (VVD). Being hydrophilic in nature, it readily leaches out in the external aqueous medium and hence partitions poorly into the polymeric matrix resulting in minimal entrapment in nanoparticles. Hence, hydrophobic ion pairing (HIP) complexation of the prodrug was employed with dextran sulphate as a complexing polymer. A novel, solid in oil in water emulsion method was employed to encapsulate the prodrug in HIP complex form in poly(lactic-co-glycolic acid) matrix. Nanoparticles were characterized with respect to size, zeta potential, crystallinity of entrapped drug and surface morphology. A significant enhancement in the entrapment of the prodrug in nanoparticles was achieved. Finally, a simple yet novel method was developed which can also be applicable to encapsulate other charged hydrophilic molecules, such as peptides and proteins. PMID:20939702

Nanostructured nanoparticles of self-assembled lipid pro-drugs as a route to improved chemotherapeutic agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagnella, Sharon M.; Gong, Xiaojuan; Moghaddam, Minoo J.

2014-09-24

We demonstrate that oral delivery of self-assembled nanostructured nanoparticles consisting of 5-fluorouracil (5-FU) lipid prodrugs results in a highly effective, target-activated, chemotherapeutic agent, and offers significantly enhanced efficacy over a commercially available alternative that does not self-assemble. The lipid prodrug nanoparticles have been found to significantly slow the growth of a highly aggressive mouse 4T1 breast tumour, and essentially halt the growth of a human MDA-MB-231 breast tumour in mouse xenografts. Systemic toxicity is avoided as prodrug activation requires a three-step, enzymatic conversion to 5-FU, with the third step occurring preferentially at the tumour site. Additionally, differences in the lipidmore » prodrug chemical structure and internal nanostructure of the nanoparticle dictate the enzymatic conversion rate and can be used to control sustained release profiles. Thus, we have developed novel oral nanomedicines that combine sustained release properties with target-selective activation.« less

Enhanced Cell-Specific Ablation in Zebrafish Using a Triple Mutant of Escherichia Coli Nitroreductase

PubMed Central

Mathias, Jonathan R.; Zhang, Zhanying; Saxena, Meera T.

2014-01-01

Abstract Transgenic expression of bacterial nitroreductase (NTR) facilitates chemically-inducible targeted cell ablation. In zebrafish, the NTR system enables studies of cell function and cellular regeneration. Metronidazole (MTZ) has become the most commonly used prodrug substrate for eliciting cell loss in NTR-expressing transgenic zebrafish due to the cell-specific nature of its cytotoxic derivatives. Unfortunately, MTZ treatments required for effective cell ablation border toxic effects, and, thus, likely incur undesirable nonspecific effects. Here, we tested whether a triple mutant variant of NTR, previously shown to display improved activity in bacterial assays, can solve this issue by promoting cell ablation in zebrafish using reduced prodrug treatment regimens. We generated several complementary transgenic zebrafish lines expressing either wild-type or mutant NTR (mutNTR) in specific neural cell types, and assayed prodrug-induced cell ablation kinetics using confocal time series imaging and plate reader-based quantification of fluorescent reporters expressed in targeted cell types. The results show that cell ablation can be achieved in mutNTR expressing transgenic lines with markedly shortened prodrug exposure times and/or at lower prodrug concentrations. The mutNTR variant characterized here can circumvent problematic nonspecific/toxic effects arising from low prodrug conversion efficiency, thus increasing the effectiveness and versatility of this selective cell ablation methodology. PMID:24428354

Enhanced cell-specific ablation in zebrafish using a triple mutant of Escherichia coli nitroreductase.

PubMed

Mathias, Jonathan R; Zhang, Zhanying; Saxena, Meera T; Mumm, Jeff S

2014-04-01

Transgenic expression of bacterial nitroreductase (NTR) facilitates chemically-inducible targeted cell ablation. In zebrafish, the NTR system enables studies of cell function and cellular regeneration. Metronidazole (MTZ) has become the most commonly used prodrug substrate for eliciting cell loss in NTR-expressing transgenic zebrafish due to the cell-specific nature of its cytotoxic derivatives. Unfortunately, MTZ treatments required for effective cell ablation border toxic effects, and, thus, likely incur undesirable nonspecific effects. Here, we tested whether a triple mutant variant of NTR, previously shown to display improved activity in bacterial assays, can solve this issue by promoting cell ablation in zebrafish using reduced prodrug treatment regimens. We generated several complementary transgenic zebrafish lines expressing either wild-type or mutant NTR (mutNTR) in specific neural cell types, and assayed prodrug-induced cell ablation kinetics using confocal time series imaging and plate reader-based quantification of fluorescent reporters expressed in targeted cell types. The results show that cell ablation can be achieved in mutNTR expressing transgenic lines with markedly shortened prodrug exposure times and/or at lower prodrug concentrations. The mutNTR variant characterized here can circumvent problematic nonspecific/toxic effects arising from low prodrug conversion efficiency, thus increasing the effectiveness and versatility of this selective cell ablation methodology.

Preparation, characterization and in vitro evaluation of a new nucleotide analogue prodrug cyclodextrin inclusion complexes.

PubMed

Diab, Roudayna; Jordheim, Lars P; Degobert, Ghania; Peyrottes, Suzanne; Périgaud, Christian; Dumontet, Charles; Fessi, Hatem

2009-01-01

Bis(tbutyl-S-acyl-2-thioethyl)-cytidine monophosophate is a new cytotoxic mononucleotide prodrug which have been developed to reverse the cellular resistance to nucleoside analogues. Unfortunately, its in vivo utilisation was hampered by its poor water solubility, raising the need of a molecular vector capable to mask its physicochemical characteristics although without affecting its cytotoxic activity. Hydroxypropyl-beta-cyclodextrin was used to prepare the prodrug inclusion complexes, allowing it to be solubilized in water and hence to be used for in vitro and in vivo experiments. A molar ratio of the cyclodextrin: prodrug of 3 was sufficient to obtain complete solubilization of the prodrug. The inclusion complex was characterized by differential scanning calorimetry, which revealed the disappearance of the melting peak of the prodrug suggesting the formation of inclusion complex. Proton Nuclear Magnetic Resonance spectroscopy provided a definitive proof of the inclusion complex formation, which was evidenced by the large chemical shift displacements observed for protons located in the interior of the hydrophobic cyclodextrin cavity. The complex retained its cytotoxic activity as shown by in vitro cell survival assays on murine leukemia cells. These results provided a basis for potential therapeutic applications of co-formulation of this new nucleotide analogue with hydroxypropyl-beta-CD in cancer therapy.

In Vitro and Clinical Evaluations of the Drug-Drug Interaction Potential of a Metabotropic Glutamate 2/3 Receptor Agonist Prodrug with Intestinal Peptide Transporter 1

PubMed Central

Long, Amanda J.; Annes, William F.; Witcher, Jennifer W.; Knadler, Mary Pat; Ayan-Oshodi, Mosun A.; Mitchell, Malcolm I.; Leese, Phillip; Hillgren, Kathleen M.

2017-01-01

Despite peptide transporter 1 (PEPT1) being responsible for the bioavailability for a variety of drugs, there has been little study of its potential involvement in drug-drug interactions. Pomaglumetad methionil, a metabotropic glutamate 2/3 receptor agonist prodrug, utilizes PEPT1 to enhance absorption and bioavailability. In vitro studies were conducted to guide the decision to conduct a clinical drug interaction study and to inform the clinical study design. In vitro investigations determined the prodrug (LY2140023 monohydrate) is a substrate of PEPT1 with Km value of approximately 30 µM, whereas the active moiety (LY404039) is not a PEPT1 substrate. In addition, among the eight known PEPT1 substrates evaluated in vitro, valacyclovir was the most potent inhibitor (IC50 = 0.46 mM) of PEPT1-mediated uptake of the prodrug. Therefore, a clinical drug interaction study was conducted to evaluate the potential interaction between the prodrug and valacyclovir in healthy subjects. No effect of coadministration was observed on the pharmacokinetics of the prodrug, valacyclovir, or either of their active moieties. Although in vitro studies showed potential for the prodrug and valacyclovir interaction via PEPT1, an in vivo study showed no interaction between these two drugs. PEPT1 does not appear to easily saturate because of its high capacity and expression in the intestine. Thus, a clinical interaction at PEPT1 is unlikely even with a compound with high affinity for the transporter. PMID:27895114

Prodrugs of herpes simplex thymidine kinase inhibitors.

PubMed

Yanachkova, Milka; Xu, Wei-Chu; Dvoskin, Sofya; Dix, Edward J; Yanachkov, Ivan B; Focher, Federico; Savi, Lida; Sanchez, M Dulfary; Foster, Timothy P; Wright, George E

2015-04-01

Because guanine-based herpes simplex virus thymidine kinase inhibitors are not orally available, we synthesized various 6-deoxy prodrugs of these compounds and evaluated them with regard to solubility in water, oral bioavailability, and efficacy to prevent herpes simplex virus-1 reactivation from latency in a mouse model. Organic synthesis was used to prepare compounds, High Performance Liquid Chromatography (HPLC) to analyze hydrolytic conversion, Mass Spectrometry (MS) to measure oral bioavailability, and mouse latent infection and induced reactivation to evaluate the efficacy of a specific prodrug. Aqueous solubilities of prodrugs were improved, oxidation of prodrugs by animal cytosols occurred in vitro, and oral absorption of the optimal prodrug sacrovir™ (6-deoxy-mCF3PG) in the presence of the aqueous adjuvant Soluplus® and conversion to active compound N(2)-[3-(trifluoromethyl)pheny])guanine (mCF3PG) were accomplished in mice. Treatment of herpes simplex virus-1 latent mice with sacrovir™ in 1% Soluplus in drinking water significantly suppressed herpes simplex virus-1 reactivation and viral genomic replication. Ad libitum oral delivery of sacrovir™ was effective in suppressing herpes simplex virus-1 reactivation in ocularly infected latent mice as measured by the numbers of mice shedding infectious virus at the ocular surface, numbers of trigeminal ganglia positive for infectious virus, number of corneas that had detectable infectious virus, and herpes simplex virus-1 genome copy numbers in trigeminal ganglia following reactivation. These results demonstrate the statistically significant effect of the prodrug on suppressing herpes simplex virus-1 reactivation in vivo. © The Author(s) 2015.

Genetically engineered theranostic mesenchymal stem cells for the evaluation of the anticancer efficacy of enzyme/prodrug systems.

PubMed

Nouri, Faranak Salman; Wang, Xing; Hatefi, Arash

2015-02-28

Over the past decade, various enzyme/prodrug systems such as thymidine kinase/ganciclovir (TK/GCV), yeast cytosine deaminase/5-fluorocytosine (yCD/5-FC) and nitroreductase/CB1954 (NTR/CB1954) have been used for stem cell mediated suicide gene therapy of cancer. Yet, no study has been conducted to compare and demonstrate the advantages and disadvantages of using one system over another. Knowing that each enzyme/prodrug system has its own strengths and weaknesses, we utilized mesenchymal stem cells (MSCs) as a medium to perform for the first time a comparative study that illustrated the impact of subtle differences among these systems on the therapeutic outcome. For therapeutic purposes, we first genetically modified MSCs to stably express a panel of four suicide genes including TK (TK007 and TK(SR39) mutants), yeast cytosine deaminase:uracil phosphoribosyltransferase (yCD:UPRT) and nitroreductase (NTR). Then, we evaluated the anticancer efficacies of the genetically engineered MSCs in vitro and in vivo by using SKOV3 cell line which is sensitive to all four enzyme/prodrug systems. In addition, all MSCs were engineered to stably express luciferase gene making them suitable for quantitative imaging and dose-response relationship studies in animals. Considering the limitations imposed by the prodrugs' bystander effects, our findings show that yCD:UPRT/5-FC is the most effective enzyme/prodrug system among the ones tested. Our findings also demonstrate that theranostic MSCs are a reliable medium for the side-by-side evaluation and screening of the enzyme/prodrug systems at the preclinical level. The results of this study could help scientists who utilize cell-based, non-viral or viral vectors for suicide gene therapy of cancer make more informed decisions when choosing enzyme/prodrug systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Gastric-sparing nitric oxide-releasable 'true' prodrugs of aspirin and naproxen.

PubMed

Gund, Machhindra; Gaikwad, Parikshit; Borhade, Namdev; Burhan, Aslam; Desai, Dattatraya C; Sharma, Ankur; Dhiman, Mini; Patil, Mohan; Sheikh, Javed; Thakre, Gajanan; Tipparam, Santhosh G; Sharma, Somesh; Nemmani, Kumar V S; Satyam, Apparao

2014-12-15

Nitric oxide-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) are gaining attention as potentially gastric-sparing NSAIDs. Herein, we report a novel class of '1-(nitrooxy)ethyl ester' group-containing NSAIDS as efficient NO releasing 'true' prodrugs of aspirin and naproxen. While an aspirin prodrug exhibited comparable oral bioavailability and antiplatelet activity (i.e., TXB2 inhibition) to those of aspirin, a naproxen prodrug exhibited better bioavailability than naproxen. These promising NO-NSAIDs protected experimental rats from gastric damage. We therefore believe that these promising NO-NSAIDs could represent a new class of potentially 'Safe NSAIDs' for the treatment of arthritic pain, inflammation and cardiovascular disorders in the case of NO-aspirin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Click polymerization for the synthesis of reduction-responsive polymeric prodrug

NASA Astrophysics Data System (ADS)

Zhang, Xiaojin; Wang, Hongquan; Dai, Yu

2018-05-01

Click polymerization is a powerful polymerization technique for the construction of new macromolecules with well-defined structures and multifaceted functionalities. Here, we synthesize reduction-responsive polymeric prodrug PEG- b-(PSS- g-MTX)- b-PEG containing disulfide bonds and pendant methotrexate (MTX) via two-step click polymerization followed by conjugating MTX to pendant hydroxyl. MTX content in polymeric prodrug is 13.5%. Polymeric prodrug is able to form polymeric micelles by self-assembly in aqueous solution. Polymeric micelles are spherical nanoparticles with tens of nanometers in size. Of note, polymeric micelles are reduction-responsive due to disulfide bonds in the backbone of PEG- b-(PSS- g-MTX)- b-PEG and could release pendant drugs in the presence of the reducing agents such as dl-dithiothreitol (DTT).

Transporter targeted gatifloxacin prodrugs: synthesis, permeability, and topical ocular delivery.

PubMed

Vooturi, Sunil K; Kadam, Rajendra S; Kompella, Uday B

2012-11-05

In this work, we aim to design and synthesize prodrugs of gatifloxacin targeting organic cation transporter (OCT), monocarboxylate transporter (MCT), and ATB (0, +) transporters and to identify a prodrug with enhanced delivery to the back of the eye. Dimethylamino-propyl, carboxy-propyl, and amino-propyl(2-methyl) derivatives of gatifloxacin (GFX), DMAP-GFX, CP-GFX, and APM-GFX, were designed and synthesized to target OCT, MCT, and ATB (0, +) transporters, respectively. An LC-MS method was developed to analyze drug and prodrug levels in various studies. Solubility and log D (pH 7.4) were measured for prodrugs and the parent drug. The permeability of the prodrugs was determined in the cornea, conjunctiva, and sclera-choroid-retinal pigment epitheluim (SCRPE) and compared with gatifloxacin using an Ussing chamber assembly. Permeability mechanisms were elucidated by determining the transport in the presence of transporter specific inhibitors. 1-Methyl-4-phenylpyridinium iodide (MPP+), nicotinic acid sodium salt, and α-methyl-DL-tryptophan were used to inhibit OCT, MCT, and ATB (0, +) transporters, respectively. A prodrug selected based on in vitro studies was administered as an eye drop to pigmented rabbits, and the delivery to various eye tissues including vitreous humor was compared with gatifloxacin dosing. DMAP-GFX exhibited 12.8-fold greater solubility than GFX. All prodrugs were more lipophilic, with the measured log D (pH 7.4) values ranging from 0.05 to 1.04, when compared to GFX (log D: -1.15). DMAP-GFX showed 1.4-, 1.8-, and 1.9-fold improvement in permeability across the cornea, conjunctiva, and SCRPE when compared to GFX. Moreover, it exhibited reduced permeability in the presence of MPP+ (competitive inhibitor of OCT), indicating OCT-mediated transport. CP-GFX showed 1.2-, 2.3-, and 2.5-fold improvement in permeability across the cornea, conjunctiva, and SCRPE, respectively. In the presence of nicotinic acid (competitive inhibitor of MCT), the permeability of CP-GFX was reduced across the conjunctiva. However, the cornea and SCRPE permeability of CP-GFX was not affected by nicotinic acid. APM-GFX did not show any improvement in permeability when compared to GFX across the cornea, conjunctiva, and SCRPE. Based on solubility and permeability, DMAP-GFX was selected for in vivo studies. DMAP-GFX showed 3.6- and 1.95-fold higher levels in vitreous humor and CRPE compared to that of GFX at 1 h after topical dosing. In vivo conversion of DMAP-GFX prodrug to GFX was quantified in tissues isolated at 1 h after dosing. The parent drug-to-prodrug ratio was 8, 70, 24, 21, 29, 13, 55, and 60% in the cornea, conjunctiva, iris-ciliary body, aqueous humor, sclera, CRPE, retina, and vitreous humor, respectively. In conclusion, DMAP-GFX prodrug enhanced solubility, log D, as well as OCT mediated delivery of gatifloxacin to the back of the eye.

Activation of a camptothecin prodrug by specific carboxylesterases as predicted by quantitative structure-activity relationship and molecular docking studies.

PubMed

Yoon, Kyoung Jin P; Krull, Erik J; Morton, Christopher L; Bornmann, William G; Lee, Richard E; Potter, Philip M; Danks, Mary K

2003-11-01

7-Ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin (irinotecan, CPT-11) is a camptothecin prodrug that is metabolized by carboxylesterases (CE) to the active metabolite 7-ethyl-10-hydroxycamptothecin (SN-38), a topoisomerase I inhibitor. CPT-11 has shown encouraging antitumor activity against a broad spectrum of tumor types in early clinical trials, but hematopoietic and gastrointestinal toxicity limit its administration. To increase the therapeutic index of CPT-11 and to develop other prodrug analogues for enzyme/prodrug gene therapy applications, our laboratories propose to develop camptothecin prodrugs that will be activated by specific CEs. Specific analogues might then be predicted to be activated, for example, predominantly by human liver CE(hCE1), by human intestinal CE (hiCE), or in gene therapy approaches using a rabbit liver CE (rCE). This study describes a molecular modeling approach to relate the structure of rCE-activated camptothecin prodrugs with their biological activation. Comparative molecular field analysis, comparative molecular similarity index analysis, and docking studies were used to predict the biological activity of a 4-benzylpiperazine derivative of CPT-11 [7-ethyl-10-[4-(1-benzyl)-1-piperazino]carbonyloxycamptothecin (BP-CPT)] in U373MG glioma cell lines transfected with plasmids encoding rCE or hiCE. BP-CPT has been reported to be activated more efficiently than CPT-11 by a rat serum esterase activity; however, three-dimensional quantitative structure-activity relationship studies predicted that rCE would activate BP-CPT less efficiently than CPT-11. This was confirmed by both growth inhibition experiments and kinetic studies. The method is being used to design camptothecin prodrugs predicted to be activated by specific CEs.

Pharmacokinetics in Vitro and in Vivo of Two Novel Prodrugs of Oleanolic Acid in Rats and Its Hepatoprotective Effects against Liver Injury Induced by CCl4.

PubMed

Yu, Zongjiang; Sun, Weizhi; Peng, Weibing; Yu, Rilei; Li, Guoqiang; Jiang, Tao

2016-05-02

Oleanolic acid (OA) is a well-known pentacyclic triterpenoid compound, which has been used as a dietary supplement and is supplied as an over-the-counter drug for the treatment of human liver diseases. These are reasons for the low bioavailability of OA which have restricted its wider application. In this study, two OA prodrugs (1,3-cyclic propanyl phosphate esters of OA) were designed and synthesized. The hepatoprotective effects of these prodrugs were evaluated against carbon tetrachloride (CCl4) induced liver injury in mice; the levels of alanine aminotransferase (ALT), lactic dehydrogenase (LDH), and aspartate aminotransferase (AST) were significantly increased, and the level of the hepatic malondialdehyde (MDA) was increased. The metabolism, in vitro, of the prodrugs was studied by incubation in rat liver microsome; the plasma pharmacokinetics and the biodistribution in vivo after intravenous (iv) injection to six rats were investigated, respectively. The prodrugs diminished gradually with time; most of the parent drugs were released within 30 min in vitro, and the presumed mechanism of the in vitro metabolism was confirmed. The plasma-concentration data in vivo was analyzed by a compartmental method: both the prodrugs and the corresponding released parent drugs existed at up to 48 h in rats. The t1/2 improved after intravenous administration in rats compared with direct injection of the parent drugs. All analyte concentrations were highest in the liver, and most of the prodrugs were excreted in feces (>47.11%). Therefore, 1,3-cyclic propanyl phosphate esters of OA can serve as a promising lead candidate for drugs.

Genetically Engineered Theranostic Mesenchymal Stem Cells for the Evaluation of the Anticancer Efficacy of Enzyme/Prodrug Systems

PubMed Central

Nouri, Faranak Salman; Wang, Xing; Hatefi, Arash

2015-01-01

Over the past decade, various enzyme/prodrug systems such as thymidine kinase/ganciclovir (TK/GCV), yeast cytosine deaminase/5-fluorocytosine (yCD/5-FC) and nitroreductase/CB1954 (NTR/CB1954) have been used for stem cell mediated suicide gene therapy of cancer. Yet, no study has been conducted to compare and demonstrate the advantages and disadvantages of using one system over another. Knowing that each enzyme/prodrug system has its own strengths and weaknesses, we utilized mesenchymal stem cells (MSCs) as a medium to perform for the first time a comparative study that illustrated the impact of subtle differences among these systems on the therapeutic outcome. For therapeutic purposes, we first genetically modified MSCs to stably express a panel of four suicide genes including TK (TK007 and TKSR39 mutants), yeast cytosine deaminase: uracil phosphoribosyltransferase (yCD:UPRT) and nitroreductase (NTR). Then, we evaluated the anticancer efficacies of the genetically engineered MSCs in vitro and in vivo by using SKOV3 cell line which is sensitive to all four enzyme/prodrug systems. In addition, all MSCs were engineered to stably express luciferase gene making them suitable for quantitative imaging and dose-response relationship studies in animals. Considering the limitations imposed by the prodrugs’ bystander effects, our findings show that yCD:UPRT/5-FC is the most effective enzyme/prodrug system among the ones tested. Our findings also demonstrate that theranostic MSCs are a reliable medium for the side-by-side evaluation and screening of the enzyme/prodrug systems at the preclinical level. The results of this study could help scientists who utilize cell-based, non-viral or viral vectors for suicide gene therapy of cancer make more informed decisions when choosing enzyme/prodrug systems. PMID:25575867

Syntheses of prodrug-type phosphotriester oligonucleotides responsive to intracellular reducing environment for improvement of cell membrane permeability and nuclease resistance.

PubMed

Hayashi, Junsuke; Samezawa, Yusuke; Ochi, Yosuke; Wada, Shun-Ichi; Urata, Hidehito

2017-07-15

We synthesized prodrug-type phosphotriester (PTE) oligonucleotides containing the six-membered cyclic disulfide moiety by using phosphoramidite chemistry. Prodrug-type oligonucleotides named "Reducing-Environment-Dependent Uncatalyzed Chemical Transforming (REDUCT) PTE oligonucleotides" were converted into natural oligonucleotides under cytosol-mimetic reductive condition. Furthermore, the REDUCT PTE oligonucleotides were robust to nuclease digestion and exhibited good cell membrane permeability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of alternative prodrugs for use with E. coli nitroreductase in 'suicide gene' approaches to cancer therapy.

PubMed

Bailey, S M; Knox, R J; Hobbs, S M; Jenkins, T C; Mauger, A B; Melton, R G; Burke, P J; Connors, T A; Hart, I R

1996-12-01

The most commonly employed 'suicide' gene/prodrug system used in cancer gene therapy is the herpes simplex virus thymidine kinase (HSVtk)/ganciclovir system. We have examined the efficacy of an alternative approach utilising the E. coli nitroreductase B enzyme with CB1954 and a variety of other prodrugs. V79 cells transfected with a nitroreductase expression vector were up to 770-fold more sensitive to CB1954 than control non-expressing cells. In general other prodrugs which were found by HPLC to act as substrates for purified E. coli nitroreductase also exhibited increased cytotoxicity against the nitroreductase-expressing cells, although this correlation was not absolute. In particular nitrofurazone (97-fold) and additional aromatic nitro-compounds (nine- to 50-fold) showed a large differential whereas the quinones and the antimetabolite, B-FU, were less effective (< three-fold). The results support the possibility of using nitroreductase and CB1954 for 'suicide gene' therapy and in addition suggest that alternative prodrugs, such as nitrofurazone, warrant further investigation in this novel approach.

Amino Acid Derivatives as Palmitoylethanolamide Prodrugs: Synthesis, In Vitro Metabolism and In Vivo Plasma Profile in Rats

PubMed Central

Vacondio, Federica; Bassi, Michele; Silva, Claudia; Castelli, Riccardo; Carmi, Caterina; Scalvini, Laura; Lodola, Alessio; Vivo, Valentina; Flammini, Lisa; Barocelli, Elisabetta; Mor, Marco; Rivara, Silvia

2015-01-01

Palmitoylethanolamide (PEA) has antinflammatory and antinociceptive properties widely exploited in veterinary and human medicine, despite its poor pharmacokinetics. Looking for prodrugs that could progressively release PEA to maintain effective plasma concentrations, we prepared carbonates, esters and carbamates at the hydroxyl group of PEA. Chemical stability (pH 7.4) and stability in rat plasma and liver homogenate were evaluated by in vitro assays. Carbonates and carbamates resulted too labile and too resistant in plasma, respectively. Ester derivatives, prepared by conjugating PEA with various amino acids, allowed to modulate the kinetics of PEA release in plasma and stability in liver homogenate. L-Val-PEA, with suitable PEA release in plasma, and D-Val-PEA, with high resistance to hepatic degradation, were orally administered to rats and plasma levels of prodrugs and PEA were measured at different time points. Both prodrugs showed significant release of PEA, but provided lower plasma concentrations than those obtained with equimolar doses of PEA. Amino-acid esters of PEA are a promising class to develop prodrugs, even if they need further chemical optimization. PMID:26053855

Smart activatable and traceable dual-prodrug for image-guided combination photodynamic and chemo-therapy.

PubMed

Hu, Fang; Yuan, Youyong; Mao, Duo; Wu, Wenbo; Liu, Bin

2017-11-01

Activatable photosensitizers (PSs) and chemo-prodrugs are highly desirable for anti-cancer therapy to reduce systemic toxicity. However, it is difficult to integrate both together into a molecular probe for combination therapy due to the complexity of introducing PS, singlet oxygen quencher, chemo-drug, chemo-drug inhibitor and active linker at the same time. To realize activatable PS and chemo-prodrug combination therapy, we develop a smart therapeutic platform in which the chemo-prodrug serves as the singlet oxygen quencher for the PS. Specifically, the photosensitizing activity and fluorescence of the PS (TPEPY-SH) are blocked by the chemo-prodrug (Mitomycin C, MMC) in the probe. Meanwhile, the cytotoxicity of MMC is also inhibited by the electron-withdrawing acyl at the nitrogen position next to the linker. Upon glutathione activation, TPEPY-S-MMC can simultaneously release active PS and MMC for combination therapy. The restored fluorescence of TPEPY-SH is also used to report the activation for both PS and MMC as well as to guide the photodynamic therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alkoxycarbonate Ester Prodrugs of Preclinical Drug Candidate ELQ-300 for Prophylaxis and Treatment of Malaria.

PubMed

Frueh, Lisa; Li, Yuexin; Mather, Michael W; Li, Qigui; Pou, Sovitj; Nilsen, Aaron; Winter, Rolf W; Forquer, Isaac P; Pershing, April M; Xie, Lisa H; Smilkstein, Martin J; Caridha, Diana; Koop, Dennis R; Campbell, Robert F; Sciotti, Richard J; Kreishman-Deitrick, Mara; Kelly, Jane X; Vesely, Brian; Vaidya, Akhil B; Riscoe, Michael K

2017-10-13

ELQ-300 is a preclinical antimalarial drug candidate that is active against liver, blood, and transmission stages of Plasmodium falciparum. While ELQ-300 is highly effective when administered in a low multidose regimen, poor aqueous solubility and high crystallinity have hindered its clinical development. To overcome its challenging physiochemical properties, a number of bioreversible alkoxycarbonate ester prodrugs of ELQ-300 were synthesized. These bioreversible prodrugs are converted to ELQ-300 by host and parasite esterase action in the liver and bloodstream of the host. One such alkoxycarbonate prodrug, ELQ-331, is curative against Plasmodium yoelii with a single low dose of 3 mg/kg in a murine model of patent malaria infection. ELQ-331 is at least as fully protective as ELQ-300 in a murine malaria prophylaxis model when delivered 24 h before sporozoite inoculation at an oral dose of 1 mg/kg. Here, we show that ELQ-331 is a promising prodrug of ELQ-300 with improved physiochemical and metabolic properties and excellent potential for clinical formulation.

Clinical Advances of Hypoxia-Activated Prodrugs in Combination With Radiation Therapy.

PubMed

Mistry, Ishna N; Thomas, Matthew; Calder, Ewen D D; Conway, Stuart J; Hammond, Ester M

2017-08-01

With the increasing incidence of cancer worldwide, the need for specific, effective therapies is ever more urgent. One example of targeted cancer therapeutics is hypoxia-activated prodrugs (HAPs), also known as bioreductive prodrugs. These prodrugs are inactive in cells with normal oxygen levels but in hypoxic cells (with low oxygen levels) undergo chemical reduction to the active compound. Hypoxia is a common feature of solid tumors and is associated with a more aggressive phenotype and resistance to all modes of therapy. Therefore, the combination of radiation therapy and bioreductive drugs presents an attractive opportunity for synergistic effects, because the HAP targets the radiation-resistant hypoxic cells. Hypoxia-activated prodrugs have typically been precursors of DNA-damaging agents, but a new generation of molecularly targeted HAPs is emerging. By targeting proteins associated with tumorigenesis and survival, these compounds may result in greater selectivity over healthy tissue. We review the clinical progress of HAPs as adjuncts to radiation therapy and conclude that the use of HAPs alongside radiation is vastly underexplored at the clinical level. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Synthesis of n-squalenoyl cytarabine and evaluation of its affinity with phospholipid bilayers and monolayers.

PubMed

Sarpietro, Maria Grazia; Ottimo, Sara; Giuffrida, Maria Chiara; Rocco, Flavio; Ceruti, Maurizio; Castelli, Francesco

2011-03-15

Cytarabine (1-β-D-arabinofuranosylcytosine, Ara-C), a pyrimidine nucleoside analogue, is an attractive therapeutic agent for the treatment of both acute and chronic myeloblastic leukemias. 1,1',2-tris-nor-Squalene acid (squaleneCOOH) has been conjugated to cytarabine with the formation of the squalenoyl-cytarabine prodrug, in order to improve the drug lipophilicity and, consequently, the affinity towards the environment of biological membranes, as well as of lipophilic carriers. The interaction of cytarabine and its prodrug with dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles and monolayers has been studied by the differential scanning calorimetry and the Langmuir-Blodgett techniques. The interaction has been evaluated considering the effect of the compounds on the DMPC MLV and monolayers behaviour. The aim was to have information on the interaction of the drug and the prodrug with the biological membranes and on the possibility to use liposomes as carriers for the prodrug. The results showed an improved affinity of the prodrug with MLV and monolayers with respect to the free drug. Copyright © 2011 Elsevier B.V. All rights reserved.

An acetate prodrug of a pyridinol-based vitamin E analogue.

PubMed

Khdour, Omar M; Lu, Jun; Hecht, Sidney M

2011-11-01

To investigate of an approach to stabilize a novel pyridinol based α-tocopherol analogue (1) as a prodrug by acetylation of its phenol moiety. Biochemical indicators of oxidative stress in mitochondria were utilized to gain insight into the cytoprotective mechanism(s) of compound 1 acetate. Oxygen free radical scavenging activity was measured using DCF probe in a cultured cell model system that had been placed under oxidative stress. Lipid peroxidation was examined both in a cell-free system and in oxidatively stressed cultured cells. The bioenergetic parameters of mitochondria were evaluated by measuring mitochondrial membrane potential (Δψ(m)) and the MPT. The present results suggest strongly that the antioxidant efficacy of compound 1 can be improved by using it as a prodrug. The tested prodrug has shown to be activated as a function of time, presumably due to susceptibility to enzymatic hydrolysis, and exhibits an antioxidant effect in time-dependent manner, providing a compound that is more effective than α-tocopherol acetate with regard to all protective properties studied. An effective approach to stabilize compound 1 was realized by using its acetate as a prodrug.

Evaluation of diclofenac prodrugs for enhancing transdermal delivery.

PubMed

Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

2014-03-01

Abstract Objective: The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD) and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates and bioconversion rates. In vitro fluxes across human epidermal membrane (HEM) in the Franz diffusion cell were determined on DA-, MD-, ED-, GD- and PD-saturated aqueous solutions. The formation of GD and ED led to the prodrugs with higher aqueous solubilities and lower partition coefficients than those of the parent drug. Prodrugs with improved aqueous solubility showed better fluxes across HEM in aqueous solution than that of the parent drug, with GD showing the highest aqueous solubility and also the highest flux. There is a linear relationship between the aqueous solubility and flux for DA, ED and PD, but GD and MD deviated from the linear line. Diclofenac prodrugs with improved hydrophilicity than the parent drug could be utilized for enhancing transdermal diclofenac delivery.

Development of novel small molecules for imaging and drug release

NASA Astrophysics Data System (ADS)

Cao, Yanting

Small organic molecules, including small molecule based fluorescent probes, small molecule based drugs or prodrugs, and smart multifunctional fluorescent drug delivery systems play important roles in biological research, drug discovery, and clinical practices. Despite the significant progress made in these fields, the development of novel and diverse small molecules is needed to meet various demands for research and clinical applications. My Ph.D study focuses on the development of novel functional molecules for recognition, imaging and drug release. In the first part, a turn-on fluorescent probe is developed for the detection of intracellular adenosine-5'-triphosphate (ATP) levels based on multiplexing recognitions. Considering the unique and complicated structure of ATP molecules, a fluorescent probe has been implemented with improved sensitivity and selectivity due to two synergistic binding recognitions by incorporating of 2, 2'-dipicolylamine (Dpa)-Zn(II) for targeting of phospho anions and phenylboronic acid group for cis-diol moiety. The novel probe is able to detect intracellular ATP levels in SH-SY5Y cells. Meanwhile, the advantages of multiplexing recognition design concept have been demonstrated using two control molecules. In the second part, a prodrug system is developed to deliver multiple drugs within one small molecule entity. The prodrug is designed by using 1-(2-nitrophenyl)ethyl (NPE) as phototrigger, and biphenol biquaternary ammonium as the prodrug. With controlled photo activation, both DNA cross-linking agents mechlorethamine and o-quinone methide are delivered and released at the preferred site, leading to efficient DNA cross-links formation and cell death. The prodrug shows negligible cytotoxicity towards normal skin cells (Hekn cells) with and without UV activation, but displays potent activity towards cancer cells (HeLa cells) upon UV activation. The multiple drug release system may hold a great potential for practical application. In the last part, a new photo-initiated fluorescent anticancer prodrug for DNA alkylating agent mechlorethamine releasing and monitoring has been developed. The theranostic prodrug consists a photolabile NPE group, an inactive form of mechlorethamine and a nonfluorescent coumarin in one small molecule. It is demonstrated that the prodrug shows negligible cytotoxicity towards normal skin cells (Hekn cells) with and without UV activation, while the original parent drug mechlorethamine can be photocontrol-released and induces effective DNA cross-linking activity. Importantly, the drug release progress can be conveniently monitored by the 'off-on' fluorescence enhancement in cells. Moreover, the selective prodrug is not only cell permeable but also nuclear permeable. Therefore, the prodrug serves as a promising drug delivery system for spatiotemporal control release and monitoring of an anticancer drug to obtain the optimal treatment efficacy.

Synthesis of mutual azo prodrugs of anti-inflammatory agents and peptides facilitated by α-aminoisobutyric acid.

PubMed

Kennedy, David A; Vembu, Nagarajan; Fronczek, Frank R; Devocelle, Marc

2011-12-02

Reported is the synthesis of azo mutual prodrugs of the nonsteroidal anti-inflammatory agents (NSAIDs) 4-aminophenylacetic acid (4-APAA) or 5-aminosalicylic acid (5-ASA) with peptides, including an antibiotic peptide temporin analogue modified at the amino terminal by an α-aminoisobutyric acid (Aib) residue. These prodrugs are designed for colonic delivery of two agents to treat infection and inflammation by the bacterial pathogen Clostridium difficile . © 2011 American Chemical Society

[Radiation Anticarcinogenesis by Thiazolidine Pro-drug

NASA Technical Reports Server (NTRS)

Warters, Raymond L.; Roberts, Jeanette C.; Fain, Heidi

1999-01-01

The original goal of this work was to determine the capacity of selected aminothiols to modulate radiation induced cytotoxicity, mutagenesis and carcinogenesis in a human mammary epithelial cell line. The conclusions from this work are that WR-1065 is the "gold standard" for protection against radiation induced cytotoxicity, mutagenesis and carcinogenesis. While a potent radiation protector, WR-1065 is cytotoxic in vitro and in vivo. Our rationale for a study of the thiazolidine pro-drugs was that these compounds are neither toxic in vitro or in vivo. The results obtained during this funding period indicate that the thiazolidine pro-drugs are as potent as WR-1065 as protectors against radiation induced mutation induction, and thus presumably against radiation induced carcinogenesis. Our results indicate that the thiazolidine prodrugs are excellent candidates to test as non-toxic anticarcinogens for protecting astronauts from cancer induction during space travel.

Troxacitabine prodrugs for pancreatic cancer.

PubMed

Adema, A D; Radi, M; Daft, J; Narayanasamy, J; Hoebe, E K; Alexander, L E; Chu, C K; Peters, G J

2007-01-01

Troxacitabine is a cytotoxic deoxycytidine analogue with an unnatural L-configuration, which is activated by deoxycytidine kinase (dCK). The configuration is responsible for differences in the uptake and metabolism of troxacitabine compared to other deoxynucleoside analogues. The main drawback in the use of most nucleoside anticancer agents originates from their hydrophilic nature, which property requires a high and frequent dosage for an intravenous administration. To overcome this problem several troxacitabine prodrugs modified in the aminogroup with a linear aliphatic chain with a higher lipophilicity were developed. To determine whether these prodrugs have an advantage over Troxacitabine pancreatic cancer cell lines were exposed to Troxacitabine and the lipophilic prodrugs. The addition of linear aliphatic chains to troxacitabine increased sensitivity of pancreatic cancer cell lines to the drug > 100-fold, possibly due to a better uptake and retention of the drug.

Stepwise-activable multifunctional peptide-guided prodrug micelles for cancerous cells intracellular drug release

NASA Astrophysics Data System (ADS)

Zhang, Jing; Li, Mengfei; Yuan, Zhefan; Wu, Dan; Chen, Jia-da; Feng, Jie

2016-10-01

A novel type of stepwise-activable multifunctional peptide-guided prodrug micelles (MPPM) was fabricated for cancerous cells intracellular drug release. Deca-lysine sequence (K10), a type of cell-penetrating peptide, was synthesized and terminated with azido-glycine. Then a new kind of molecule, alkyne modified doxorubicin (DOX) connecting through disulfide bond (DOX-SS-alkyne), was synthesized. After coupling via Cu-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry reaction, reduction-sensitive peptide-guided prodrug was obtained. Due to the amphiphilic property of the prodrug, it can assemble to form micelles. To prevent the nanocarriers from unspecific cellular uptake, the prodrug micelles were subsequently modified with 2,3-dimethyl maleic anhydride to obtain MPPM with a negatively charged outer shell. In vitro studies showed that MPPM could be shielded from cells under psychological environment. However, when arriving at mild acidic tumor site, the cell-penetrating capacity of MPPM would be activated by charge reversal of the micelles via hydrolysis of acid-labile β-carboxylic amides and regeneration of K10, which enabled efficient internalization of MPPM by tumor cells as well as following glutathione- and protease-induced drug release inside the cancerous cells. Furthermore, since the guide peptide sequences can be accurately designed and synthesized, it can be easily changed for various functions, such as targeting peptide, apoptotic peptide, even aptamers, only need to be terminated with azido-glycine. This method can be used as a template for reduction-sensitive peptide-guided prodrug for cancer therapy.

Nonlinear intestinal absorption kinetics of cefuroxime axetil in rats.

PubMed Central

Ruiz-Balaguer, N; Nacher, A; Casabo, V G; Merino, M

1997-01-01

Cefuroxime is commercially available for parenteral administration as a sodium salt and for oral administration as cefuroxime axetil, the 1-(acetoxy)ethyl ester of the drug. Cefuroxime axetil is a prodrug of cefuroxime and has little, if any, antibacterial activity until hydrolyzed in vivo to cefuroxime. In this study, the absorption of cefuroxime axetil in the small intestines of anesthetized rats was investigated in situ, by perfusion at four concentrations (11.8, 5, 118 and 200 microM). Oral absorption of cefuroxime axetil can apparently be described as a specialized transport mechanism which obeys Michaelis-Menten kinetics. Parameters characterizing absorption of prodrug in free solution were obtained: maximum rate of absorption (Vmax) = 289.08 +/- 46.26 microM h-1, and Km = 162.77 +/- 31.17 microM. Cefuroxime axetil transport was significantly reduced in the presence of the enzymatic inhibitor sodium azide. On the other hand, the prodrug was metabolized in the gut wall through contact with membrane-bound enzymes in the brush border membrane before absorption occurred. This process reduces the prodrug fraction directly available for absorption. From a bioavailability point of view, therefore, the effects mentioned above can explain the variable and poor bioavailability following oral administration of cefuroxime axetil. Thus, future strategies in oral cefuroxime axetil absorption should focus on increasing the stability of the prodrug in the intestine by modifying the prodrug structure and/or targeting the compound to the absorption site. PMID:9021205

Amphipathic dextran-doxorubicin prodrug micelles for solid tumor therapy.

PubMed

Jin, Rong; Guo, Xuelian; Dong, Lingli; Xie, Enyuan; Cao, Aoneng

2017-10-01

A group of micelles self-assembled from deoxycholic acid-doxorubicin-conjugated dextran (denoted as Dex-DCA-DOX) prodrugs were designed and prepared for pH-triggered drug release and cancer chemotherapy. These prodrugs could be successfully produced by chemically coupling hydrophobic deoxycholic acid (DCA) to dextran hydrazine (denoted as Dex-NHNH 2 ) and hydrazone linker formation between doxorubicin (DOX) and Dex-NHNH 2 . These Dex-DCA-DOX prodrugs self-assembled to form micelles under physiological conditions with varied particle sizes depending on molecular weight of dextran, degree of substitution (DS) of DCA and DOX. After optimization, Dex10k-DCA9-DOX5.5 conjugate comprising dextran of 10kDa, DCA of DS 9 and DOX loading content of 5.5wt%, formed the micelles with the smallest size (110nm). These prodrug micelles could slowly liberate DOX under physiological conditions but efficiently released the drug at an acidified endosomal pH by the hydrolysis of acid-labile hydrazone linker. In vitro cytotoxicity experiment indicated that Dex10k-DCA9-DOX5.5 micelles exerted marked antitumor activity against MCF-7 and SKOV-3 cancer cells. Besides, intravenous administration of the micelles afforded growth inhibition of SKOV-3 tumor bearing in nude mice at a dosage of 2.5mg per kg with anti-cancer efficacy comparable to free DOX-chemotherapy but low systemic toxicity. This study highlights the feasibility of bio-safe and efficient dextran-based prodrug micelles designed for cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of octreotide-conjugated polymeric prodrug of bufalin for targeted delivery to somatostatin receptor 2 overexpressing breast cancer in vitro and in vivo

PubMed Central

Liu, Tao; Jia, Tingting; Yuan, Xia; Liu, Cheng; Sun, Jian; Ni, Zhenhua; Xu, Jian; Wang, Xuhui; Yuan, Yi

2016-01-01

Background Development of polymeric prodrugs of small molecular anticancer drugs has become one of the most promising strategies to overcome the intrinsic shortcomings of small molecular anticancer drugs and improve their anticancer performance. Materials and methods In the current work, we fabricated a novel octreotide (Oct)-modified esterase-sensitive tumor-targeting polymeric prodrug of bufalin (BUF) and explored its anticancer performance against somatostatin receptor 2 overexpressing breast cancer. Results The obtained tumor-targeting polymeric prodrug of BUF, P(oligo[ethylene glycol] monomethyl ether methacrylate [OEGMA]-co-BUF-co-Oct), showed a nanosize dimension and controlled drug release features in the presence of esterase. It was demonstrated by in vitro experiment that P(OEGMA-co-BUF-co-Oct) showed enhanced cytotoxicity, cellular uptake, and apoptosis in comparison with those of free BUF. In vivo experiment further revealed the improved accumulation of drugs in tumor tissues and enhanced anticancer performance of P(OEGMA-co-BUF-co-Oct). Conclusion Taken together, this study indicated that polymeric prodrug of BUF holds promising potential toward the treatment of somatostatin receptor 2 overexpressing breast cancer. PMID:27284243

Antimycobacterial activity of pyrazinoate prodrugs in replicating and non-replicating Mycobacterium tuberculosis.

PubMed

Segretti, Natanael Dante; Simões, Cristina Kortstee; Corrêa, Michelle Fidelis; Felli, Veni Maria Andres; Miyata, Marcelo; Cho, Sang Hyun; Franzblau, Scott Gary; Fernandes, João Paulo Dos Santos

2016-07-01

Tuberculosis (TB) is an important infectious disease caused by Mycobacterium tuberculosis (Mtb) and responsible for thousands of deaths every year. Although there are antimycobacterial drugs available in therapeutics, just few new chemical entities have reached clinical trials, and in fact, since introduction of rifampin only two important drugs had reached the market. Pyrazinoic acid (POA), the active agent of pyrazinamide, has been explored through prodrug approach to achieve novel molecules with anti-Mtb activity, however, there is no activity evaluation of these molecules against non-replicating Mtb until the present. Additionally, pharmacokinetic must be preliminary evaluated to avoid future problems during clinical trials. In this paper, we have presented six POA esters as prodrugs in order to evaluate their anti-Mtb activity in replicating and non-replicating Mtb, and these showed activity highly influenced by medium composition (especially by albumin). Lipophilicity seems to play the main role in the activity, possibly due to controlling membrane passage. Novel duplicated prodrugs of POA were also described, presenting interesting activity. Cytotoxicity of these prodrugs set was also evaluated, and these showed no important cytotoxic profile. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced Cellular Uptake and Pharmacokinetic Characteristics of Doxorubicin-Valine Amide Prodrug.

PubMed

Park, Yohan; Park, Ju-Hwan; Park, Suryeon; Lee, Song Yi; Cho, Kwan Hyung; Kim, Dae-Duk; Shim, Won-Sik; Yoon, In-Soo; Cho, Hyun-Jong; Maeng, Han-Joo

2016-09-22

In this study, we synthesized the valine (Val)-conjugated amide prodrug of doxorubicin (DOX) by the formation of amide bonds between DOX and Val. The synthesis of the DOX-Val prodrug was identified by a proton nuclear magnetic resonance (¹H-NMR) assay. In the MCF-7 cells (human breast adenocarcinoma cell; amino acid transporter-positive cell), the cellular accumulation efficiency of DOX-Val was higher than that of DOX according to the flow cytometry analysis data. Using confocal laser scanning microscopy (CLSM) imaging, it was confirmed that DOX-Val as well as DOX was mainly distributed in the nucleus of cancer cells. DOX-Val was intravenously administered to rats at a dose of 4 mg/kg, and the plasma concentrations of DOX-Val (prodrug) and DOX (formed metabolite) were quantitatively determined. Based on the systemic exposure (represented as area under the curve (AUC) values) of DOX-Val (prodrug) and DOX (formed metabolite), approximately half of DOX-Val seemed to be metabolized into DOX. However, it is expected that the remaining DOX-Val may exert improved cellular uptake efficiency in cancer cells after its delivery to the cancer region.

Effective gene silencing activity of prodrug-type 2'-O-methyldithiomethyl siRNA compared with non-prodrug-type 2'-O-methyl siRNA.

PubMed

Hayashi, Junsuke; Nishigaki, Misa; Ochi, Yosuke; Wada, Shun-Ichi; Wada, Fumito; Nakagawa, Osamu; Obika, Satoshi; Harada-Shiba, Mariko; Urata, Hidehito

2018-07-01

Small interfering RNAs (siRNAs) are an active agent to induce gene silencing and they have been studied for becoming a biological and therapeutic tool. Various 2'-O-modified RNAs have been extensively studied to improve the nuclease resistance. However, the 2'-O-modified siRNA activities were often decreased by modification, since the bulky 2'-O-modifications inhibit to form a RNA-induced silencing complex (RISC). We developed novel prodrug-type 2'-O-methyldithiomethyl (MDTM) siRNA, which is converted into natural siRNA in an intracellular reducing environment. Prodrug-type 2'-O-MDTM siRNAs modified at the 5'-end side including 5'-end nucleotide and the seed region of the antisense strand exhibited much stronger gene silencing effect than non-prodrug-type 2'-O-methyl (2'-O-Me) siRNAs. Furthermore, the resistances for nuclease digestion of siRNAs were actually enhanced by 2'-O-MDTM modifications. Our results indicate that 2'-O-MDTM modifications improve the stability of siRNA in serum and they are able to be introduced at any positions of siRNA. Copyright © 2018 Elsevier Ltd. All rights reserved.

[In vitro metabolism of fenbendazole prodrug].

PubMed

Wen, Ai-Dan; Duan, Li-Ping; Liu, Cong-Shan; Tao, Yi; Xue, Jian; Wu, Ning-Bo; Jiang, Bin; Zhang, Hao-Bing

2013-02-01

Synthesized fenbendazole prodrug N-methoxycarbonyl-N'-(2-nitro-4-phenylthiophenyl) thiourea (MPT) was analyzed in vitro in artificial gastric juice, intestinal juice and mouse liver homogenate model by using HPLC method, and metabolic curve was then generated. MPT was tested against Echinococcus granulosus protoscolices in vitro. The result showed that MPT could be metabolized in the three biological media, and to the active compound fenbendazole in liver homogenate, with a metabolic rate of 7.92%. Besides, the prodrug showed a weak activity against E. granulosus protoscolices with a mortality of 45.9%.

Ethylene glycol-linked amino acid diester prodrugs of oleanolic acid for PepT1-mediated transport: synthesis, intestinal permeability and pharmacokinetics.

PubMed

Cao, Feng; Jia, Jinghao; Yin, Zhi; Gao, Yahan; Sha, Lei; Lai, Yisheng; Ping, Qineng; Zhang, Yihua

2012-08-06

The purposes of this study were to expand the structure of parent drugs selected for peptide transporter 1 (PepT1)-targeted ester prodrug design and to improve oral bioavailability of oleanolic acid (OA), a Biopharmaceutics Classification System (BCS) class IV drug. Through an ethoxy linker the carboxylic acid group of OA was conjugated with the carboxylic acid group of different amino acid promoieties to form six diester prodrugs. The effective permeability (P(eff)) of prodrugs was screened by in situ rat single-pass intestinal perfusion (SPIP) model in two buffers with different pH (6.0 and 7.4) as PepT1 employs a proton-gradient as the driving force. Compared to OA, 2.5-fold, 2.3-fold, 2.2-fold, 2.1-fold, and 1.9-fold enhancement of P(eff) in buffer with pH 6.0 was observed for L-Phe ester (5c), L-Val ester (5a), L-Lys ester (5e), D-Phe ester (5d), and D-Val ester (5b), respectively. Furthermore, P(eff) of 5a, 5c, 5d and 5e in pH 6.0 was significantly higher than that in pH 7.4 (p < 0.01), respectively. These results showed that the H(+) concentration of perfusion solution had great effect on the transport of the prodrugs across intestinal membrane. For the further evaluation of affinity to PepT1, inhibition studies were performed by coperfusing 0.1 mM prodrug with 50 mM glycyl-sarcosine (Gly-Sar, a typical substrate of PepT1). It turned out that the P(eff) of 5a, 5b, 5c and L-Tyr ester (6f) significantly reduced in the presence of Gly-Sar (1.7-fold, 2.2-fold, 1.9-fold, and 1.4-fold, respectively). We supposed that it may be attributed to PepT1 mediated transport of these prodrugs. 5a and 6f were selected as the optimal target prodrugs for oral absorption in vivo. Following intragastric administration of 300 mg/kg (calculated as OA) 5a, 6f and OA in three groups of rats, compared with group OA, Cmax for the group of 5a and 6f was enhanced by 1.56-fold and 1.54-fold, respectively. Fapp of group 5a and 6f was 2.21- and 2.04-fold increased, respectively, indicating that 5a and 6f had better oral absorption than OA. The combined results also suggest that diester prodrugs which conjugated two carboxylic acid groups of proper amino acid promoieties and parent drug through a linker can be used for PepT1-targeted prodrug design. With this strategy, oral bioavailability of OA in rats could be improved significantly.

Lymphatic Transport and Lymphocyte Targeting of a Triglyceride Mimetic Prodrug Is Enhanced in a Large Animal Model: Studies in Greyhound Dogs.

PubMed

Han, Sifei; Hu, Luojuan; Gracia; Quach, Tim; Simpson, Jamie S; Edwards, Glenn A; Trevaskis, Natalie L; Porter, Christopher J H

2016-10-03

In previous studies, a triglyceride (TG) mimetic prodrug of the model immunomodulator mycophenolic acid (MPA) was shown to significantly enhance lymphatic transport of MPA-related species in the rat. The rat gastrointestinal tract, however, is somewhat different from that in higher order species such as dogs and humans and may underestimate lymphatic transport. Here the effectiveness of the prodrug strategy has been examined in conscious greyhound dogs, the GI physiology of which is more representative of that in humans. The bioavailability and lymphatic transport of free MPA and total MPA related materials were examined following oral administration of the parent drug (MPA) and the prodrug (2-MPA-TG) to both thoracic lymph duct cannulated and intact (noncannulated) greyhound dogs. The enrichment of free MPA in lymph nodes and lymph-derived lymphocytes was also determined to examine the efficiency of drug targeting to potential sites of action within the lymph. Via biochemical integration into a series of site-specific metabolic processes, the prodrug markedly increased (288-fold) lymphatic transport of total MPA related material (present as re-esterified 2-MPA-TG) when compared to the parent MPA and the extent of lymphatic transport was significantly greater in the dog (36.4% of the dose recovered in lymph) when compared to the previous data in the rat (13.4% of the dose). Conversion from 2-MPA-TG derivatives to parent MPA occurred in vivo, resulting in a marked increase in MPA concentrations in lymph nodes (5-6-fold) and lymph lymphocytes (21-fold), when compared to animals administered the parent drug. In conclusion, the data demonstrate that the TG prodrug of MPA facilitates efficient delivery of MPA to the lymphatic system in dogs and suggest that the TG prodrug strategy may more effectively facilitate targeted delivery in large animals than in rats.

Investigation of mitigating effect of colon-specific prodrugs of boswellic acid on 2,4,6-trinitrobenzene sulfonic acid-induced colitis in Wistar rats: Design, kinetics and biological evaluation

PubMed Central

Sarkate, Ajinkya; Dhaneshwar, Suneela S

2017-01-01

AIM To develop a colon-targeting bioreversible delivery system for β-boswellic acid (BBA) and explore utility of its prodrugs in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. METHODS Synthesis of 4 co-drugs of BBA with essential amino acids was achieved by CDI coupling, followed by their spectral characterization. In vitro kinetics were studied by HPLC in aqueous buffers, homogenates of gastrointestinal tract and fecal matter. In vivo kinetic studies were performed in Wistar rat plasma, urine and feces. The prodrugs were screened in TNBS-induced colitis modeled Wistar rats. Statistical significance was assumed at P < 0.05, P < 0.01, P < 0.001 when compared with disease controls using one-way and two-way ANOVAs. RESULTS Prodrugs were stable in 0.05 mol/L HCl buffer (pH 1.2) and stomach homogenates. Negligible hydrolysis was observed in phosphate buffer and intestinal homogenates. Substantial release (55%-72% and 68%-86%) of BBA was achieved in rat fecal matter and homogenates of colon. In vivo studies of BBA with L-tryptophan (BT) authenticated colon-specific release of BBA. But, surprisingly substantial concentration of BBA was seen to reach the systemic circulation due to probable absorption through colonic mucosa. Site-specifically enhanced bioavailability of BBA could be achieved in colon, which resulted in demonstration of significant mitigating effect on TNBS-induced colitis in rats without inducing any adverse effects on stomach, liver and pancreas. Prodrug of BT was found to be 1.7% (P < 0.001) superior than sulfasalazine in reducing the inflammation to colon among all prodrugs tested. CONCLUSION The outcome of this study strongly suggests that these prodrugs might have dual applicability to inflammatory bowel disease and chronotherapy of rheumatoid arthritis. PMID:28275295

PARP Inhibitor and NO-Donor Dual Prodrugs as Anticancer Agents | NCI Technology Transfer Center | TTC

Cancer.gov

The National Cancer Institute’s Chemical Biology Laboratory seeks partners interested in collaborative research to co-develop PARP inhibitor and NO-donor hybrid prodrugs for the treatment of cancer.

Modular adeno-associated virus (rAAV) vectors used for cellular virus-directed enzyme prodrug therapy

PubMed Central

Hagen, Sven; Baumann, Tobias; Wagner, Hanna J.; Morath, Volker; Kaufmann, Beate; Fischer, Adrian; Bergmann, Stefan; Schindler, Patrick; Arndt, Katja M.; Müller, Kristian M.

2014-01-01

The pre-clinical and clinical development of viral vehicles for gene transfer increased in recent years, and a recombinant adeno-associated virus (rAAV) drug took center stage upon approval in the European Union. However, lack of standardization, inefficient purification methods and complicated retargeting limit general usability. We address these obstacles by fusing rAAV-2 capsids with two modular targeting molecules (DARPin or Affibody) specific for a cancer cell-surface marker (EGFR) while simultaneously including an affinity tag (His-tag) in a surface-exposed loop. Equipping these particles with genes coding for prodrug converting enzymes (thymidine kinase or cytosine deaminase) we demonstrate tumor marker specific transduction and prodrug-dependent apoptosis of cancer cells. Coding terminal and loop modifications in one gene enabled specific and scalable purification. Our genetic parts for viral production adhere to a standardized cloning strategy facilitating rapid prototyping of virus directed enzyme prodrug therapy (VDEPT). PMID:24457557

The application of prodrug-based nano-drug delivery strategy in cancer combination therapy.

PubMed

Ge, Yanxiu; Ma, Yakun; Li, Lingbing

2016-10-01

Single drug therapy that leads to the multidrug resistance of cancer cells and severe side-effect is a thing of the past. Combination therapies that affect multiple signaling pathways have been the focus of recent active research. Due to the successful development of prodrug-based nano-drug delivery systems (P-N-DDSs), their use has been extended to combination therapy as drug delivery platforms. In this review, we focus specifically on the P-N-DDSs in the field of combination therapy including the combinations of prodrugs with different chemotherapeutic agents, other therapeutic agents, nucleic acid or the combination of different types of therapy (e.g. chemotherapy and phototherapy). The relevant examples of prodrug-based nanoparticulate drug delivery strategy in combination cancer therapy from the recent literature are discussed to demonstrate the feasibilities of relevant technology. Copyright © 2016 Elsevier B.V. All rights reserved.

pH-sensitive pHluorins as a molecular sensor for in situ monitoring of enzyme-catalyzed prodrug activation.

PubMed

Liu, Hui; Cao, Xiaodan; Wang, Ping; Ma, Xingyuan

2017-07-01

This work examines the feasibility of using a pH-sensitive fluorescent protein as a molecular reporter for enzyme-catalyzed prodrug activation reaction. Specifically, a ratiometric pHluorins was examined for detection of the activity of horseradish peroxidase (HRP) for the activation of indole-3-acetic acid. The pHluorins and HRP were conjugated chemically, forming a biocatalyst with a self-reporting function. Results showed that the characteristic fluorescence intensity ratio of the conjugate shifted from 1.47 to 1.40 corresponding to the progress of the prodrug activation reaction. The effectiveness of applying the conjugate for inhibition of the growth of Bcap-37 cells was also demonstrated simultaneously with reaction monitoring. The results reveal a very promising approach to realizing in situ monitoring of enzyme activities based on pH shifting for enzyme-based prodrug therapy applications. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

Development of Platinum(iv) Complexes as Anticancer Prodrugs: the Story so Far

NASA Astrophysics Data System (ADS)

Wong, Daniel Yuan Qiang; Ang, Wee Han

2012-06-01

The serendipitous discovery of the antitumor properties of cisplatin by Barnett Rosenberg some forty years ago brought about a paradigm shift in the field of medicinal chemistry and challenged conventional thinking regarding the role of potentially toxic heavy metals in drugs. Platinum(II)-based anticancer drugs have since become some of the most effective and widely-used drugs in a clinician's arsenal and have saved countless lives. However, they are limited by high toxicity, severe side-effects and the incidence of drug resistance. In recent years, attention has shifted to stable platinum(IV) complexes as anticancer prodrugs. By exploiting the unique chemical and structural attributes of their scaffolds, these platinum(IV) prodrugs offer new strategies of targeting and killing cancer cells. This review summarizes the development of anticancer platinum(IV) prodrugs to date and some of the exciting strategies that utilise the platinum(IV) construct as targeted chemotherapeutic agents against cancer.

Amphiphilic naproxen prodrugs: differential scanning calorimetry study on their interaction with phospholipid bilayers.

PubMed

Giuffrida, Maria Chiara; Pignatello, Rosario; Castelli, Francesco; Sarpietro, Maria Grazia

2017-09-01

Naproxen, a nonsteroid anti-inflammatory drug studied for Alzheimer's disease, was conjugated with lipoamino acids (LAA) directly or through a diethylamine (EDA) spacer to improve the drug lipophilicity and the interaction with phospholipid bilayers. The interaction of naproxen and its prodrugs with biomembrane models consisting of dimyristoylphosphatidylcholine multilamellar vesicles was studied by differential scanning calorimetry. The transfer of prodrugs from a lipophilic carrier to a biomembrane model was also studied. Naproxen conjugation to lipoamino acids improves its interaction with biomembrane models and affects the transfer from a lipophilic carrier to biomembrane model. LAA portion may localize between the phospholipid chains; the entity of the interaction depends not only on the presence of the spacer but also on the LAA chain length. Variation of LAA portion can modulate the naproxen prodrugs affinity towards the biological membrane as well as towards the lipophilic carrier. © 2017 Royal Pharmaceutical Society.

N,N'-dihydroxyamidines: a new prodrug principle to improve the oral bioavailability of amidines.

PubMed

Reeh, Christiane; Wundt, Judith; Clement, Bernd

2007-12-27

N, N'-dihydroxybenzamdine represents a model compound for a new prodrug principle to improve the oral bioavailability of drugs containing amidine functions. The activation of the prodrug could be demonstrated in vitro by porcine and human subcellular enzyme fractions, the mitochondrial benzamidoxime reducing system, and porcine hepatocytes. In vivo, the bioavailability of benzamidine after oral application of N, N'-dihydroxybenzamidine was about 91% and exceeded that of benzamidine after oral application of benzamidoxime, being about 74% (Liu, L.; Ling, Y.; Havel, C.; Bashnick, L.; Young, W.; Rai, R.; Vijaykumar, D.; Riggs, J. R.; Ton, T.; Shaghafi, M.; Graupe, D.; Mordenti, J.; Sukbuntherng, J. Species comparison of in vitro and in vivo conversion of five N-hydroxyamidine prodrugs of fVIIA inhibitors to their corresponding active amidines. Presented at the 13th North America ISSX Meeting, Maui, HI, 2005).

Examining the effects of mass media campaign exposure and interpersonal discussions on youth's drug use: the mediating role of visiting pro-drug websites.

PubMed

Kam, Jennifer A; Lee, Chul-Joo

2013-01-01

To extend past research on interpersonal communication and campaign effects, we hypothesized that anti-drug mass media campaign message exposure indirectly affects visiting anti- and pro-drug websites through targeted parent-child and friend-to-friend communication against drugs, as well as through having drug-related discussions during organized group activities. Second, we posited that engaging in anti-drug interpersonal communication indirectly affects adolescents' drug use through two intervening variables: visiting anti-drug websites and visiting pro-drug websites. Using self-reported longitudinal data from 2,749 youth, we found that as youth reported higher levels of anti-drug mass media campaign message exposure, they were more likely to talk to friends about the bad consequences of drugs, how to avoid drugs, and anti-drug ads. In turn, however, they were more likely to visit pro-drug websites, and subsequently, to smoke cigarettes.

Pharmacokinetics of Curcumin Diethyl Disuccinate, a Prodrug of Curcumin, in Wistar Rats.

PubMed

Bangphumi, Kunan; Kittiviriyakul, Chuleeporn; Towiwat, Pasarapa; Rojsitthisak, Pornchai; Khemawoot, Phisit

2016-12-01

Curcumin is the major bioactive component of turmeric, but has poor oral bioavailability that limits its clinical applications. To improve the in vitro solubility and alkaline stability, we developed a prodrug of curcumin by succinylation to obtain curcumin diethyl disuccinate, with the goal of improving the oral bioavailability of curcumin. The in vivo pharmacokinetic profile of curcumin diethyl disuccinate was compared with that of curcumin in male Wistar rats. Doses of curcumin 20 mg/kg intravenous or 40 mg/kg oral were used as standard regimens for comparison with the prodrug at equivalent doses in healthy adult rats. Blood, tissues, urine, and faeces were collected from time zero to 48 h after dosing to determine the prodrug level, curcumin level and a major metabolite by liquid chromatography-tandem spectrometry. The absolute oral bioavailability of curcumin diethyl disuccinate was not significantly improved compared with curcumin, with both compounds having oral bioavailability of curcumin less than 1 %. The major metabolic pathway of the prodrug was rapid hydrolysis to obtain curcumin, followed by glucuronidation. Interestingly, curcumin diethyl disuccinate gave superior tissue distribution with higher tissue to plasma ratio of curcumin and curcumin glucuronide in several organs after intravenous dosing at 1 and 4 h. The primary elimination route of curcumin glucuronide occurred via biliary and faecal excretion, with evidence of an entry into the enterohepatic circulation. Curcumin diethyl disuccinate did not significantly improve the oral bioavailability of curcumin due to first pass metabolism in the gastrointestinal tract. Further studies on reduction of first pass metabolism are required to optimise delivery of curcumin using a prodrug approach.

A polymeric prodrug of 5-fluorouracil-1-acetic acid using a multi-hydroxyl polyethylene glycol derivative as the drug carrier.

PubMed

Li, Man; Liang, Zhen; Sun, Xun; Gong, Tao; Zhang, Zhirong

2014-01-01

Macromolecular prodrugs obtained by covalently conjugating small molecular drugs with polymeric carriers were proven to accomplish controlled and sustained release of the therapeutic agents in vitro and in vivo. Polyethylene glycol (PEG) has been extensively used due to its low toxicity, low immunogenicity and high biocompatibility. However, for linear PEG macromolecules, the number of available hydroxyl groups for drug coupling does not change with the length of polymeric chain, which limits the application of PEG for drug conjugation purposes. To increase the drug loading and prolong the retention time of 5-fluorouracil (5-Fu), a macromolecular prodrug of 5-Fu, 5-fluorouracil-1 acid-PAE derivative (5-FA-PAE) was synthesized and tested for the antitumor activity in vivo. PEG with a molecular weight of 38 kDa was selected to synthesize the multi-hydroxyl polyethylene glycol derivative (PAE) through an addition reaction. 5-fluorouracil-1 acetic acid (5-FA), a 5-Fu derivative was coupled with PEG derivatives via ester bond to form a macromolecular prodrug, 5-FA-PAE. The in vitro drug release, pharmacokinetics, in vivo distribution and antitumor effect of the prodrug were investigated, respectively. The PEG-based prodrug obtained in this study possessed an exceedingly high 5-FA loading efficiency of 10.58%, much higher than the maximum drug loading efficiency of unmodified PEG with the same molecular weight, which was 0.98% theoretically. Furthermore, 5-FA-PAE exhibited suitable sustained release in tumors. This study provides a new approach for the development of the delivery to tumors of anticancer agents with PEG derivatives.

Impact of ester promoieties on transdermal delivery of ketorolac.

PubMed

Liu, Kuo-Sheng; Hsieh, Pei-Wen; Aljuffali, Ibrahim A; Lin, Yin-Ku; Chang, Shu-Hao; Wang, Jhi-Joung; Fang, Jia-You

2014-03-01

Different types of ketorolac ester prodrugs incorporating tert-butyl (KT), benzyl (KB), heptyl (KH), and diketorolac heptyl (DKH) promoieties were synthesized for the comparison of percutaneous penetration. The prodrugs were characterized according to their melting point, capacity factor, lipophilicity, solubility in 30% ethanol/buffer, enzymatic hydrolysis, in vitro skin permeation, hair follicle accumulation, and in vivo skin tolerance. Interactions between the prodrugs and esterases were predicted by molecular docking. Both equimolar suspensions and saturated solutions in 30% ethanol/pH 7.4 buffer were employed as the applied dose. All of the prodrugs exhibited a lower melting point than ketorolac. The lipophilicity increased in the following order: ketorolac < KT < KB < KH < DKH. The prodrugs were rapidly hydrolyzed to the parent drug in esterase medium, skin homogenate, and plasma, with KT and KB exhibiting higher degradation rates. KT exhibited the highest skin permeation, followed by KB. The flux of KT and KB exceeded that of ketorolac by 2.5-fold and twofold, respectively. KH and DKH did not improve ketorolac permeation but exhibited a sustained release behavior. KT and KH revealed selective absorption into follicles and a threefold greater follicular uptake compared with ketorolac. KB, KH, and DKH slightly but significantly increased transepidermal water loss (TEWL) after consecutive administration for 7 days, whereas ketorolac and KT exhibited no influence on TEWL. According to the experimental results, it can be concluded that an optimal balance between lipophilicity and aqueous solubility is important in the design of a successful prodrug. The acceptable skin tolerance for safe application is also an important consideration. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Clickable prodrugs bearing potent and hydrolytically cleavable nicotinamide phosphoribosyltransferase inhibitors.

PubMed

Sadrerafi, Keivan; Mason, Emilia O; Lee, Mark W

2018-01-01

Our previous study indicated that carborane containing small-molecule 1-(hydroxymethyl)-7-(4'-( trans -3″-(3'″-pyridyl)acrylamido)butyl)-1,7-dicarbadodecaborane (hm-MC4-PPEA), was a potent inhibitor of nicotinamide phosphoribosyltransferase (Nampt). Nampt has been shown to be upregulated in most cancers and is a promising target for the treatment of many different types of cancers, including breast cancers. To increase the selectivity of hm-MC4-PPEA toward cancer cells, three prodrugs were synthesized with different hydrolyzable linkers: ester, carbonate, and carbamate. Using click chemistry a fluorophore was attached to these prodrugs to act as a model for our conjugation strategy and to serve as an aid for prodrug stability studies. The stabilities of these drug conjugates were tested in phosphate-buffered saline (PBS) at normothermia (37°C) using three different pH levels, 5.5, 7.5, and 9.5, as well as in horse serum at physiological pH. The stability of each was monitored using reversed-phase HPLC equipped with both diode array and fluorescence detection. The inhibitory activity of hm-MC4-PPEA was also measured using a commercially available colorimetric assay. The biological activities of the drug conjugates as well as those of the free drug (hm-MC4-PPEA), were evaluated using the MTT assay against the human breast cancer cell lines T47D and MCF7, as well as the noncancerous, transformed, Nampt-dependent human breast epithelium cell line 184A1. hm-MC4-PPEA showed to be a potent inhibitor of recombinant Nampt activity, exhibiting an IC50 concentration of 6.8 nM. The prodrugs showed great stability towards hydrolytic degradation under neutral, mildly acidic and mildly basic conditions. The carbamate prodrug also showed to be stable in rat serum. However, the carbonate and the ester prodrug release at various rates in serum presumably owing to the presence of several different classes of esterase. The biological activities of the drug conjugates correlate with the stability of their cleavable linkers observed in serum. The targeted and selective delivery of potent Nampt inhibitors to cancer cells is a potentially new route for the treatment of many cancers. These prodrugs linked to small cancer-associated peptides may be optimum for their use as targetable Nampt inhibitors.

Ocular drug metabolism of the bioactivating antioxidant N-acetylcarnosine for vision in ophthalmic prodrug and codrug design and delivery.

PubMed

Babizhayev, Mark A

2008-10-01

The basic idea in this study relates to the interesting research problem to employ with the knowledgeable pharmacy staff N-acetylcarnosine (NAC) in the developed suitable compounded prodrug ophthalmic preparations, which are currently used for the treatment of cataract and have antioxidant effect, in order to provide the molecular support to one of the most popular beliefs of the growing market for the treatment of senile cataract in patients and animals with efficacious NAC drug formulations worldwide patented by the author. This work presents the progress in ocular NAC prodrug and codrug design and delivery in light of revealed ocular metabolic activities. There is a considerable interest in the ophthalmic codrug design including NAC prodrug based on the strategies to improve ophthalmic drug delivery of the active peptide principal L-carnosine through the sustained intraocular metabolic activation of a dipeptide while making it resistant to enzymatic hydrolysis. Novel approaches to ocular NAC drug delivery, developed by Innovative Vision Products, Inc. (IVP), aim at enhancing the drug bioavailability by ensuring a prolonged retention of the medication in the eye, and/or by facilitating transcorneal penetration. IVP team studied the effects of lubricant eye drops designed as 1% NAC prodrug of L-carnosine containing a mucoadhesive cellulose-based and corneal absorption promoters in a drug delivery system. The predicted responses of the corneal and conjunctival penetrations to the synergistic promoters are useful in controlling the extent and pathway of the ocular and systemic absorptions of instilled NAC prodrug in designed ophthalmic formulations thereof. Utility of peptidase enzyme inhibitors in the codrug formulation to modulate the transport and metabolism of NAC prodrug appears to be a promising strategy for enhancing dipeptide drug transport across the cornea. The developed and officially CE mark registered by IVP NAC prodrug and codrug lubricating eye drop systems (including principal regulatory registered eye drops design and lubricating eye drops marketed under numerous brand labels), increase the intraocular uptake of the active principle L-carnosine from its ophthalmic carrier NAC in the aqueous humor and the permeability of a drug into the eye, and so enhance the ocular bioavailability, bioactivating universal antioxidant, and anti-cataract efficacy (in human and in canine eyes) of the developed NAC eye drops.

Platinum(iv) prodrug conjugated Pd@Au nanoplates for chemotherapy and photothermal therapy

NASA Astrophysics Data System (ADS)

Shi, Saige; Chen, Xiaolan; Wei, Jingping; Huang, Yizhuan; Weng, Jian; Zheng, Nanfeng

2016-03-01

Owing to the excellent near infrared (NIR) light absorption and efficient passive targeting toward tumor tissue, two-dimensional (2D) core-shell PEGylated Pd@Au nanoplates have great potential in both photothermal therapy and drug delivery systems. In this work, we successfully conjugate Pd@Au nanoplates with a platinum(iv) prodrug c,c,t-[Pt(NH3)2Cl2(O2CCH2CH2CO2H)2] to obtain a nanocomposite (Pd@Au-PEG-Pt) for combined photothermal-chemotherapy. The prepared Pd@Au-PEG-Pt nanocomposite showed excellent stability in physiological solutions and efficient Pt(iv) prodrug loading. Once injected into biological tissue, the Pt(iv) prodrug was easily reduced by physiological reductants (e.g. ascorbic acid or glutathione) into its cytotoxic and hydrophilic Pt(ii) form and released from the original nanocomposite, and the NIR laser irradiation could accelerate the release of Pt(ii) species. More importantly, Pd@Au-PEG-Pt has high tumor accumulation (29%ID per g), which makes excellent therapeutic efficiency at relatively low power density possible. The in vivo results suggested that, compared with single therapy the combined thermo-chemotherapy treatment with Pd@Au-PEG-Pt resulted in complete destruction of the tumor tissue without recurrence, while chemotherapy using Pd@Au-PEG-Pt without irradiation or photothermal treatment using Pd@Au-PEG alone did not. Our work highlights the prospects of a feasible drug delivery strategy of the Pt prodrug by using 2D Pd@Au nanoplates as drug delivery carriers for multimode cancer treatment.Owing to the excellent near infrared (NIR) light absorption and efficient passive targeting toward tumor tissue, two-dimensional (2D) core-shell PEGylated Pd@Au nanoplates have great potential in both photothermal therapy and drug delivery systems. In this work, we successfully conjugate Pd@Au nanoplates with a platinum(iv) prodrug c,c,t-[Pt(NH3)2Cl2(O2CCH2CH2CO2H)2] to obtain a nanocomposite (Pd@Au-PEG-Pt) for combined photothermal-chemotherapy. The prepared Pd@Au-PEG-Pt nanocomposite showed excellent stability in physiological solutions and efficient Pt(iv) prodrug loading. Once injected into biological tissue, the Pt(iv) prodrug was easily reduced by physiological reductants (e.g. ascorbic acid or glutathione) into its cytotoxic and hydrophilic Pt(ii) form and released from the original nanocomposite, and the NIR laser irradiation could accelerate the release of Pt(ii) species. More importantly, Pd@Au-PEG-Pt has high tumor accumulation (29%ID per g), which makes excellent therapeutic efficiency at relatively low power density possible. The in vivo results suggested that, compared with single therapy the combined thermo-chemotherapy treatment with Pd@Au-PEG-Pt resulted in complete destruction of the tumor tissue without recurrence, while chemotherapy using Pd@Au-PEG-Pt without irradiation or photothermal treatment using Pd@Au-PEG alone did not. Our work highlights the prospects of a feasible drug delivery strategy of the Pt prodrug by using 2D Pd@Au nanoplates as drug delivery carriers for multimode cancer treatment. Electronic supplementary information (ESI) available: Synthesis process of Pt(iv) prodrug, mass data and FT-IR spectra of the intermediate product and Pt(iv) prodrug, TEM images of Pd@Au and Au NPs, thermal gravimetric analysis of nanoparticles, dispersion stability of Pd@Au-PEG-Pt NSs in different solutions, chemical reduction of Pt(ii) in a water bath, viability of different cell lines incubated with different concentrations of materials, uptake of different drugs by HeLa cells, size distribution of nanoparticles, tissue distribution by measuring the Pt amounts and zeta potential information of prodrug function nanomaterials. See DOI: 10.1039/c5nr09120a

Solid dispersions of the penta-ethyl ester prodrug of diethylenetriaminepentaacetic acid (DTPA): Formulation design and optimization studies

PubMed Central

Yang, Yu-Tsai; Di Pasqua, Anthony J.; Zhang, Yong; Sueda, Katsuhiko; Jay, Michael

2015-01-01

The penta-ethyl ester prodrug of diethylenetriaminepentaacetic acid (DTPA), which exists as an oily liquid, was incorporated into a solid dispersion for oral administration by the solvent evaporation method using blends of polyvinylpyrrolidone (PVP), Eudragit® RL PO and α-tocopherol. D-optimal mixture design was used to optimize the formulation. Formulations that had a high concentration of both Eudragit® RL PO and α-tocopherol exhibited low water absorption and enhanced stability of the DTPA prodrug. Physicochemical properties of the optimal formulation were evaluated using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). In vitro release of the prodrug was evaluated using the USP Type II apparatus dissolution method. DSC studies indicated that the matrix had an amorphous structure, while FTIR spectrometry showed that DTPA penta-ethyl ester and excipients did not react with each other during formation of the solid dispersion.. Dissolution testing showed that the optimized solid dispersion exhibited a prolonged release profile, which could potentially result in a sustained delivery of DTPA penta-ethyl to enhance bioavailability. In conclusion, DTPA penta-ethyl ester was successfully incorporated into a solid matrix with high drug loading and improved stability compared to prodrug alone. PMID:24047113

Prodrug and nanomedicine approaches for the delivery of the camptothecin analogue SN38.

PubMed

Bala, Vaskor; Rao, Shasha; Boyd, Ben J; Prestidge, Clive A

2013-11-28

SN38 (7-ethyl-10-hydroxy camptothecin) is a prominent and efficacious anticancer agent. It is poorly soluble in both water and pharmaceutically approved solvents; therefore, the direct formulation of SN38 in solution form is limited. Currently, the water soluble prodrug of SN38, irinotecan (CPT-11), is formulated as a low pH solution and is approved for chemotherapy. However, CPT-11, along with most other water-soluble prodrugs shows unpredictable inter-patient conversion to SN38 in vivo, instability in the physiological environment and variable dose-related toxicities. More recently, macromolecular prodrugs (i.e. EZN-2208, IMMU-130) and nanomedicine formulations (i.e. nanoemulsions, polymeric micelles, lipid nanocapsule/nanoparticle, and liposomes) of SN38 have been investigated for improved delivery to cancer cells and tissues. Specifically, these carriers can take advantage of the EPR effect to direct drug preferentially to tumour tissues, thereby substantially improving efficacy and minimising side effects. Furthermore, oral delivery has been shown to be possible in preclinical results using nanomedicine formulations (i.e. dendrimers, lipid nanocapsules, polymeric micelles). This review summarizes the recent advances for the delivery of SN38 with a focus on macromolecular prodrugs and nanomedicines. © 2013 Elsevier B.V. All rights reserved.

Orally administered DTPA penta-ethyl ester for the decorporation of inhaled 241Am

PubMed Central

Sueda, Katsuhiko; Sadgrove, Matthew P.; Huckle, James E.; Leed, Marina G. D.; Weber, Waylon M.; Doyle-Eisele, Melanie; Guilmette, Raymond A.; Jay, Michael

2014-01-01

Diethylenetriaminepentaacetic acid (DTPA) is an effective decorporation agent to facilitate the elimination of radionuclides from the body, but its permeability-limited oral bioavailability limits its utility in mass-casualty emergencies. To overcome this limitation, a prodrug strategy using the penta-ethyl ester form of DTPA is under investigation. Pharmacokinetic and biodistribution studies were conducted in rats by orally administering [14C]DTPA penta-ethyl ester, and this prodrug and its hydrolysis products were analyzed as a single entity. Compared to a previous reporting of intravenously administered DTPA, the oral administration of this prodrug resulted in a sustained plasma concentration profile with higher plasma exposure and lower clearance. An assessment of the urine composition revealed that the bioactivation was extensive but incomplete, with no detectable levels of the penta- or tetra-ester forms. Tissue distribution at 12 h was limited, with approximately 73% of the administered dose being associated with the gastrointestinal tract. In the efficacy study, rats were exposed to aerosols of 241Am nitrate before receiving a single oral treatment of the prodrug. The urinary excretion of 241Am was found to be 19% higher than with the control. Consistent with prior reports of DTPA, the prodrug was most effective when the treatment delays were minimized. PMID:24619514

Rational design of a dual-mode optical and chemical prodrug.

PubMed

McCoy, Colin P; Rooney, Clare; Jones, David S; Gorman, Sean P; Nieuwenhuyzen, Mark

2007-01-01

The purpose of this study is to demonstrate the rational design and behaviour of the first dual-mode optical and chemical prodrug, exemplified by an acetyl salicylic acid-based system. A cyclic 1,4-benzodioxinone prodrug was synthesised by reaction of 3,5-dimethoxybenzoin and acetyl salicoyl chloride with pyridine. After purification by column chromatography and recrystallization, characterization was achieved using infrared and NMR spectroscopies, mass spectrometry, elemental analysis and single crystal X-ray diffraction. Light-triggered drug liberation was characterised via UV-visible spectroscopy following low-power 365 nm irradiation for controlled times. Chemical drug liberation was characterised via UV-visible spectroscopy in pH 5.5 solution. The synthetic method yielded pure prodrug, with full supporting characterisation. Light-triggered drug liberation proceeded at a rate of 8.30x10(-2) s-1, while chemical, hydrolytic liberation proceeded independently at 1.89x10(-3) s-1. The photochemical and hydrolytic reactions were both quantitative. This study demonstrates the first rational dual-mode optical and chemical prodrug, using acetyl salicylic acid as a model, acting as a paradigm for future dual-mode systems. Photochemical drug liberation proceeds 44 times faster than chemical liberation, suggesting potential use in drug-eluting medical devices where an additional burst of drug is required at the onset of infection.

Hyaluronic acid-coated, prodrug-based nanostructured lipid carriers for enhanced pancreatic cancer therapy.

PubMed

Lu, Zhihe; Su, Jingrong; Li, Zhengrong; Zhan, Yuzhu; Ye, Decai

2017-01-01

Gemcitabine (GEM) and Baicalein (BCL) are reported to have anti-tumor effects including pancreatic cancer. Hyaluronic acid (HA) can bind to over-expressed receptors in various kinds of cancer cells. The aim of this study is to develop prodrugs containing HA, BCL and GEM, and construct nanomedicine incorporate GEM and BCL in the core and HA on the surface. This system could target the cancer cells and co-deliver the drugs. GEM-stearic acid lipid prodrug (GEM-SA) and hyaluronic acid-amino acid-baicalein prodrug (HA-AA-BCL) were synthesized. Then, GEM and BCL prodrug-based targeted nanostructured lipid carriers (HA-GEM-BCL NLCs) were prepared by the nanoprecipitation technique. The in vitro cytotoxicity studies of the NLCs were evaluated on AsPC1 pancreatic cancer cell line. In vivo anti-tumor effects were observed on the murine-bearing pancreatic cancer model. HA-GEM-BCL NLCs were effective in entering pancreatic cancer cells over-expressing HA receptors, and showed cytotoxicity of tumor cells in vitro. In vivo study revealed significant tumor growth inhibition ability of HA-GEM-BCL NLCs in murine pancreatic cancer model. It could be concluded that HA-GEM-BCL NLCs could be featured as promising co-delivery, tumor-targeted nanomedicine for the treatment of cancers.

Metformin and Its Sulfenamide Prodrugs Inhibit Human Cholinesterase Activity.

PubMed

Markowicz-Piasecka, Magdalena; Sikora, Joanna; Mateusiak, Łukasz; Mikiciuk-Olasik, Elżbieta; Huttunen, Kristiina M

2017-01-01

The results of epidemiological and pathophysiological studies suggest that type 2 diabetes mellitus (T2DM) may predispose to Alzheimer's disease (AD). The two conditions present similar glucose levels, insulin resistance, and biochemical etiologies such as inflammation and oxidative stress. The diabetic state also contributes to increased acetylcholinesterase (AChE) activity, which is one of the factors leading to neurodegeneration in AD. The aim of this study was to assess in vitro the effects of metformin, phenformin, and metformin sulfenamide prodrugs on the activity of human AChE and butyrylcholinesterase (BuChE) and establish the type of inhibition. Metformin inhibited 50% of the AChE activity at micromolar concentrations (2.35  μ mol/mL, mixed type of inhibition) and seemed to be selective towards AChE since it presented low anti-BuChE activity. The tested metformin prodrugs inhibited cholinesterases (ChE) at nanomolar range and thus were more active than metformin or phenformin. The cyclohexyl sulfenamide prodrug demonstrated the highest activity towards both AChE (IC 50  = 890 nmol/mL, noncompetitive inhibition) and BuChE (IC 50  = 28 nmol/mL, mixed type inhibition), while the octyl sulfenamide prodrug did not present anti-AChE activity, but exhibited mixed inhibition towards BuChE (IC 50  = 184 nmol/mL). Therefore, these two bulkier prodrugs were concluded to be the most selective compounds for BuChE over AChE. In conclusion, it was demonstrated that biguanides present a novel class of inhibitors for AChE and BuChE and encourages further studies of these compounds for developing both selective and nonselective inhibitors of ChEs in the future.

A Polymeric Prodrug of 5-Fluorouracil-1-Acetic Acid Using a Multi-Hydroxyl Polyethylene Glycol Derivative as the Drug Carrier

PubMed Central

Sun, Xun; Gong, Tao; Zhang, Zhirong

2014-01-01

Purpose Macromolecular prodrugs obtained by covalently conjugating small molecular drugs with polymeric carriers were proven to accomplish controlled and sustained release of the therapeutic agents in vitro and in vivo. Polyethylene glycol (PEG) has been extensively used due to its low toxicity, low immunogenicity and high biocompatibility. However, for linear PEG macromolecules, the number of available hydroxyl groups for drug coupling does not change with the length of polymeric chain, which limits the application of PEG for drug conjugation purposes. To increase the drug loading and prolong the retention time of 5-fluorouracil (5-Fu), a macromolecular prodrug of 5-Fu, 5-fluorouracil-1 acid-PAE derivative (5-FA-PAE) was synthesized and tested for the antitumor activity in vivo. Methods PEG with a molecular weight of 38 kDa was selected to synthesize the multi-hydroxyl polyethylene glycol derivative (PAE) through an addition reaction. 5-fluorouracil-1 acetic acid (5-FA), a 5-Fu derivative was coupled with PEG derivatives via ester bond to form a macromolecular prodrug, 5-FA-PAE. The in vitro drug release, pharmacokinetics, in vivo distribution and antitumor effect of the prodrug were investigated, respectively. Results The PEG-based prodrug obtained in this study possessed an exceedingly high 5-FA loading efficiency of 10.58%, much higher than the maximum drug loading efficiency of unmodified PEG with the same molecular weight, which was 0.98% theoretically. Furthermore, 5-FA-PAE exhibited suitable sustained release in tumors. Conclusion This study provides a new approach for the development of the delivery to tumors of anticancer agents with PEG derivatives. PMID:25389968

Interaction of dipeptide prodrugs of saquinavir with multidrug resistance protein-2 (MRP-2): evasion of MRP-2 mediated efflux.

PubMed

Jain, Ritesh; Agarwal, Sheetal; Mandava, Nanda Kishore; Sheng, Ye; Mitra, Ashim K

2008-10-01

Saquinavir (SQV), the first protease inhibitor approved by FDA to treat HIV-1 infection. This drug is a well-known substrate for multidrug resistance protein-2 (MRP-2). The objective of this study was to investigate whether derivatization of SQV to dipeptide prodrugs, valine-valine-saquinavir (Val-Val-SQV) and glycine-valine-saquinavir (Gly-Val-SQV), targeting peptide transporter can circumvent MRP-2 mediated efflux. Uptake and transport studies were carried out across MDCKII-MRP2 cell monolayers to investigate the interaction of SQV and its prodrugs with MRP-2. In situ single pass intestinal perfusion experiments in rat jejunum were performed to calculate intestinal absorption rate constants and permeabilities of SQV, Val-Val-SQV and Gly-Val-SQV. Uptake studies demonstrated that the prodrugs have significantly lower interaction with MRP-2 relative to SQV. Transepithelial transport of Val-Val-SQV and Gly-Val-SQV across MDCKII-MRP2 cells exhibited an enhanced absorptive flux and reduced secretory flux as compared to SQV. Intestinal perfusion studies revealed that synthesized prodrugs have higher intestinal permeabilities relative to SQV. Enhanced absorption of Val-Val-SQV and Gly-Val-SQV relative to SQV can be attributed to their translocation by the peptide transporter in the jejunum. In the presence of MK-571, a MRP family inhibitor, there was a significant increase in the permeabilities of SQV and Gly-Val-SQV indicating that these compounds are probably substrates for MRP-2. However, there was no change in the permeability of Val-Val-SQV with MK-571 indicating lack of any interaction of Val-Val-SQV with MRP-2. In conclusion, peptide transporter targeted prodrug modification of MRP-2 substrates may lead to shielding of these drug molecules from MRP-2 efflux pumps.

Comparative plasma disposition kinetics of albendazole and its new benzimidazol prodrug in dog.

PubMed

Khalil, Z; El Karbane, M; Faouzi, M E A; Ansar, M; Azougagh, M; El Harti, J; Taoufik, J

2016-01-01

The comparative pharmacokinetic behavior of albendazole (ABZ) and its new benzimidazol prodrug [1-tert-butyloxycarbonyl-5-propylthio-1-H-benzimidazol-2ylcarbamate of methyl] (ABZBoc), following their oral administration (10mg/kg) to healthy dogs was explored. Blood samples were obtained serially over a 24h period after treatment, then the plasma was analyzed by high-performance liquid chromatography (HPLC) to search the albendazole metabolites (ABZSO and ABZSO2). However, the albendazole parent drug was not detectable at any time after both treatments (ABZ and ABZBoc). By albendazole metabolites (ABZSO and ABZSO2) were the analytes recovered in the plasma after oral administration of ABZ and ABZBoc. Furthermore, some amounts of ABZBoc were also available in the plasma samples treated with this new produg. The plasma profile of each analyte followed a similar pattern after both treatments, the active metabolite (ABZSO) was the major analyte recovered in plasma (between 1 and 24h post-treatment). The pharmacokinetic parameters of both groups were calculated (Cmax, Tmax, t1/2, AUC0-›∞), and analyzed using the Student's t-test, P<0.05. Thus,the pharmacokinetic analysis indicated four statistically significant changes in the pharmacokinetic parameters defined above of the albendazole metabolites (ABZSO, ABZSO2) between the group treated with albendazole (group A) and that treated with ABZBoc prodrug (group B). Hence, the levels of the various pharmacokinetics parameters were low in the group treated with prodrug, as well they did not reach equivalent concentrations to that of albendazole. These differences between albendazole and its new prodrug may be explained by the fact that ABZBoc prodrug was not effectively reduced in the intestine of dogs. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

Design, synthesis and in vitro kinetic study of tranexamic acid prodrugs for the treatment of bleeding conditions

NASA Astrophysics Data System (ADS)

Karaman, Rafik; Ghareeb, Hiba; Dajani, Khuloud Kamal; Scrano, Laura; Hallak, Hussein; Abu-Lafi, Saleh; Mecca, Gennaro; Bufo, Sabino A.

2013-07-01

Based on density functional theory (DFT) calculations for the acid-catalyzed hydrolysis of several maleamic acid amide derivatives four tranexamic acid prodrugs were designed. The DFT results on the acid catalyzed hydrolysis revealed that the reaction rate-limiting step is determined on the nature of the amine leaving group. When the amine leaving group was a primary amine or tranexamic acid moiety, the tetrahedral intermediate collapse was the rate-limiting step, whereas in the cases by which the amine leaving group was aciclovir or cefuroxime the rate-limiting step was the tetrahedral intermediate formation. The linear correlation between the calculated DFT and experimental rates for N-methylmaleamic acids 1- 7 provided a credible basis for designing tranexamic acid prodrugs that have the potential to release the parent drug in a sustained release fashion. For example, based on the calculated B3LYP/6-31G(d,p) rates the predicted t1/2 (a time needed for 50 % of the prodrug to be converted into drug) values for tranexamic acid prodrugs ProD 1- ProD 4 at pH 2 were 556 h [50.5 h as calculated by B3LYP/311+G(d,p)] and 6.2 h as calculated by GGA: MPW1K), 253 h, 70 s and 1.7 h, respectively. Kinetic study on the interconversion of the newly synthesized tranexamic acid prodrug ProD 1 revealed that the t1/2 for its conversion to the parent drug was largely affected by the pH of the medium. The experimental t1/2 values in 1 N HCl, buffer pH 2 and buffer pH 5 were 54 min, 23.9 and 270 h, respectively.

Improved synthesis of N-benzylaminoferrocene-based prodrugs and evaluation of their toxicity and antileukemic activity.

PubMed

Daum, Steffen; Chekhun, Vasiliy F; Todor, Igor N; Lukianova, Natalia Yu; Shvets, Yulia V; Sellner, Leopold; Putzker, Kerstin; Lewis, Joe; Zenz, Thorsten; de Graaf, Inge A M; Groothuis, Geny M M; Casini, Angela; Zozulia, Oleksii; Hampel, Frank; Mokhir, Andriy

2015-02-26

We report on an improved method of synthesis of N-benzylaminoferrocene-based prodrugs and demonstrate its applicability by preparing nine new aminoferrocenes. Their effect on the viability of selected cancer cells having different p53 status was studied. The obtained data are in agreement with the hypothesis that the toxicity of aminoferrocenes is not dependent upon p53 status. Subsequently the toxicity of a selected prodrug (4) was investigated ex vivo using rat precision cut liver slices and in vivo on hybrid male mice BDF1. In both experiments no toxicity was observed: ex vivo, up to 10 μM; in vivo, up to 6 mg/kg. Finally, prodrug 4 was shown to extend the survival of BDF1 mice carrying L1210 leukemia from 13.7 ± 0.6 days to 17.5 ± 0.7 days when injected daily 6 times at a dose of 26 μg/kg starting from the second day after injection of L1210 cells.

Mono- and di-bromo platinum(IV) prodrugs via oxidative bromination: synthesis, characterization, and cytotoxicity.

PubMed

Xu, Zoufeng; Wang, Zhigang; Yiu, Shek-Man; Zhu, Guangyu

2015-12-14

Platinum(IV)-based anticancer prodrugs have attracted much attention due to their relative inertness under physiological conditions, being activated inside cells, and their capacity for functionalization with a variety of small-molecule or macromolecule moieties. Novel asymmetric platinum(IV) compounds synthesized through expedient and unique methods are desired. Here we utilize N-bromosuccinimide (NBS) and carry out oxidative bromination on platinum(II) drugs, namely cisplatin, carboplatin, and oxaliplatin, to obtain asymmetric and mono-bromo platinum(IV) prodrugs. Different solvents are used to obtain various compounds, and the compounds are further functionalized. Di-bromo compounds are also obtained through NBS-directed oxidative bromination in ethanol. The crystal structures of representative compounds are discussed, and the reduction potentials of some compounds are examined. A cytotoxicity test shows that the mono- and di-bromo platinum(IV) compounds are active against human ovarian cancer cells. Our study enriches the family of asymmetric platinum(IV) prodrugs and provides with a convenient strategy to obtain brominated platinum(IV) complexes.

Gender Differences in the Effect of Linguistic Acculturation on Substance Use Among Mexican-Origin Youth in the Southwest United States

PubMed Central

Marsiglia, Flavio F.; Kulis, Stephen; Hussaini, Syed Khaleel; Nieri, Tanya A.; Becerra, David

2010-01-01

This study tested for gender differences in the impact of linguistic acculturation on pro-drug norms, substance use intentions, and actual substance use among youth of Mexican heritage in a large metropolitan area in the Southwest United States. The authors analyzed baseline survey data provided by 2,487 middle school students of Mexican heritage who were part of a larger, multiethnic randomized efficacy trial of a drug abuse prevention program. Using multi-group structural equation modeling, the authors found that linguistic acculturation was positively and directly related to adherence to pro-drug norms, substance use intentions, and recent alcohol use, controlling for age, poor grades, and socioeconomic status. In addition, linguistic acculturation had an indirect effect on substance use intentions and recent alcohol use through pro-drug norms. The direct effect of linguistic acculturation on pro-drug norms was stronger for girls than for boys, as was its indirect effect on substance use intentions. PMID:20390972

Enzyme Prodrug Therapy Engineered into Electrospun Fibers with Embedded Liposomes for Controlled, Localized Synthesis of Therapeutics.

PubMed

Chandrawati, Rona; Olesen, Morten T J; Marini, Thatiane C C; Bisra, Gurpal; Guex, Anne Géraldine; de Oliveira, Marcelo G; Zelikin, Alexander N; Stevens, Molly M

2017-09-01

Enzyme prodrug therapy (EPT) enables localized conversion of inert prodrugs to active drugs by enzymes. Performance of EPT necessitates that the enzyme remains active throughout the time frame of the envisioned therapeutic application. β-glucuronidase is an enzyme with historically validated performance in EPT, however it retains its activity in biomaterials for an insufficiently long period of time, typically not exceeding 7 d. Herein, the encapsulation of β-glucuronidase in liposomal subcompartments within poly(vinyl alcohol) electrospun fibers is reported, leading to the assembly of biocatalytically active materials with activity of the enzyme sustained over at least seven weeks. It is further shown that liposomes provide the highly beneficial stabilization of the enzyme when incubated in cell culture media. The assembled biocatalytic materials successfully produce antiproliferative drugs (SN-38) using externally administered prodrugs (SN-38-glucuronide) and effectively suppress cell proliferation, with envisioned utility in the design of cardiovascular grafts. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of two self-assembled macromolecular prodrug micelles with different conjugate positions of SN38 for enhancing antitumor activity

PubMed Central

Liu, Yi; Piao, Hongyu; Gao, Ying; Xu, Caihong; Tian, Ye; Wang, Lihong; Liu, Jinwen; Tang, Bo; Zou, Meijuan; Cheng, Gang

2015-01-01

7-Ethyl-10-hydroxycamptothecin (SN38), an active metabolite of irinotecan (CPT-11), is a remarkably potent antitumor agent. The clinical application of SN38 has been extremely restricted by its insolubility in water. In this study, we successfully synthesized two macromolecular prodrugs of SN38 with different conjugate positions (chitosan-(C10-OH)SN38 and chitosan-(C20-OH)SN38) to improve the water solubility and antitumor activity of SN38. These prodrugs can self-assemble into micelles in aqueous medium. The particle size, morphology, zeta potential, and in vitro drug release of SN38 and its derivatives, as well as their cytotoxicity, pharmacokinetics, and in vivo antitumor activity in a xenograft BALB/c mouse model were studied. In vitro, chitosan-(C10-OH)SN38 (CS-(10s)SN38) and chitosan-(C20-OH) SN38 (CS-(20s)SN38) were 13.3- and 25.9-fold more potent than CPT-11 in the murine colon adenocarcinoma cell line CT26, respectively. The area under the curve (AUC)0–24 of SN38 after intravenously administering CS-(10s)SN38 and CS-(20s)SN38 to Sprague Dawley rats was greatly improved when compared with CPT-11 (both P<0.01). A larger AUC0–24 of CS-(20s)SN38 was observed when compared to CS-(10s)SN38 (P<0.05). Both of the novel self-assembled chitosan-SN38 prodrugs demonstrated superior anticancer activity to CPT-11 in the CT26 xenograft BALB/c mouse model. We have also investigated the differences between these macromolecular prodrug micelles with regards to enhancing the antitumor activity of SN38. CS-(20s)SN38 exhibited better in vivo antitumor activity than CS-(10s)SN38 at a dose of 2.5 mg/kg (P<0.05). In conclusion, both macromolecular prodrug micelles improved the in vivo conversion rate and antitumor activity of SN38, but the prodrug in which C20-OH was conjugated to macromolecular materials could be a more promising platform for SN38 delivery. PMID:25848251

Catechin prodrugs and analogs: a new array of chemical entities with improved pharmacological and pharmacokinetic properties.

PubMed

Bansal, Sumit; Vyas, Sandeep; Bhattacharya, Shoumyo; Sharma, Manu

2013-10-11

Extensive research on tea catechins, mainly (-)-epigallocatechin gallate, has shown numerous health promoting effects. However, various clinical studies demonstrated several issues associated with tea catechins which account for their poor systemic bioavailability. In order to improve pharmacological activity and bioavailability of natural tea catechins, two major strategies have been adopted to date which include synthesizing catechin analogs/prodrugs and the development of novel drug delivery systems. In this review, we provide a detailed account of novel synthetic analogs/prodrugs as well as novel drug delivery approaches used for natural tea catechins to make them therapeutically potent drug-like molecules.

Intestinal absorption and activation of decitabine amino acid ester prodrugs mediated by peptide transporter PEPT1 and enterocyte enzymes.

PubMed

Tao, Wenhui; Zhao, Dongyang; Sun, Mengchi; Wang, Ziyu; Lin, Bin; Bao, Yu; Li, Yingying; He, Zhonggui; Sun, Yinghua; Sun, Jin

2018-04-25

Decitabine (DAC), a potent DNA methyltransferase (DNMT) inhibitor, has a limited oral bioavailability. Its 5'-amino acid ester prodrugs could improve its oral delivery but the specific absorption mechanism is not yet fully understood. The aim of this present study was to investigate the in vivo absorption and activation mechanism of these prodrugs using in situ intestinal perfusion and pharmacokinetics studies in rats. Although PEPT1 transporter is pH dependent, there appeared to be no proton cotransport in the perfusion experiment with a preferable transport at pH 7.4 rather than pH 6.5. This suggested that the transport was mostly dependent on the dissociated state of the prodrugs and the proton gradient might play only a limited role. In pH 7.4 HEPES buffer, an increase in P eff was observed for L-val-DAC, D-val-DAC, L-phe-DAC and L-trp-DAC (2.89-fold, 1.2-fold, 2.73-fold, and 1.90-fold, respectively), compared with the parent drug. When co-perfusing the prodrug with Glysar, a known substrate of PEPT1, the permeabilities of the prodrugs were significantly inhibited compared with the control. To further investigate the absorption of the prodrugs, L-val-DAC was selected and found to be concentration-dependent and saturable, suggesting a carrier-mediated process (intrinsic K m : 7.80 ± 2.61 mM) along with passive transport. Determination of drug in intestinal homogenate after perfusion further confirmed that the metabolic activation mainly involved an intestinal first-pass effect. In a pharmacokinetic evaluation, the oral bioavailability of L-val-DAC, L-phe-DAC and L-trp-DAC were nearly 1.74-fold, 1.69-fold and 1.49-fold greater than that of DAC. The differences in membrane permeability and oral bioavailability might be due to the different stability in the intestinal lumen and the distinct PEPT1 affinity which is mainly caused by the stereochemistry, hydrophobicity and steric hindrance of the side chains. In summary, the detailed investigation of the absorption mechanism by in vivo intestinal perfusion and pharmacokinetic studies showed that the prodrugs of DAC exhibited excellent permeability and oral bioavailability, which might be attributed to a hybrid (partly PEPT1-mediated and partly passive) transport mode and a rapid activation process in enterocytes. Copyright © 2018 Elsevier B.V. All rights reserved.

Prodrugs of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs), More Than Meets the Eye: A Critical Review

PubMed Central

Qandil, Amjad M.

2012-01-01

The design and the synthesis of prodrugs for nonsteroidal anti-inflammatory drugs (NSAIDs) have been given much attention by medicinal chemists, especially in the last decade. As a therapeutic group, NSAIDs are among the most widely used prescribed and over the counter (OTC) medications. The rich literature about potential NSAID prodrugs clearly shows a shift from alkyl, aryalkyl or aryl esters with the sole role of masking the carboxylic acid group, to more elaborate conjugates that contain carefully chosen groups to serve specific purposes, such as enhancement of water solubility and dissolution, nitric oxide release, hydrogen sulfide release, antioxidant activity, anticholinergic and acetylcholinesterase inhibitory (AChEI) activity and site-specific targeting and delivery. This review will focus on NSAID prodrugs that have been designed or were, later, found to possess intrinsic pharmacological activity as an intact chemical entity. Such intrinsic activity might augment the anti-inflammatory activity of the NSAID, reduce its side effects or transform the potential therapeutic use from classical anti-inflammatory action to something else. Reports discussed in this review will be those of NO-NSAIDs, anticholinergic and AChEI-NSAIDs, Phospho-NSAIDs and some miscellaneous agents. In most cases, this review will cover literature dealing with these NSAID prodrugs from the year 2006 and later. Older literature will be used when necessary, e.g., to explain the chemical and biological mechanisms of action. PMID:23247285

Comparative pharmacokinetics of two prodrugs of zidovudine in rabbits: enhanced levels of zidovudine in brain tissue.

PubMed

Lupia, R H; Ferencz, N; Lertora, J J; Aggarwal, S K; George, W J; Agrawal, K C

1993-04-01

The pharmacokinetics of two prodrugs of zidovudine (AZT), 1,4-dihydro-1-methyl-3-[(pyridylcarbonyl)oxy] ester and isoleucinyl ester (DPAZT and IAZT, respectively), were investigated in a rabbit model to determine their potential utility as drugs against human immunodeficiency virus. Drugs were administered by intravenous infusion over 5 min at doses equal to 10 mg of AZT per kg of body weight. The levels of the prodrugs and of released AZT in plasma, cerebrospinal fluid (CSF), and brain were determined by high-performance liquid chromatography analysis. DPAZT disappeared rapidly from plasma, whereas IAZT maintained a sustained level in plasma for up to 4 h. The levels in plasma of AZT released from DPAZT were consistently lower than the levels of AZT released from IAZT or AZT itself. At 75 min after infusion of AZT, DPAZT, and IAZT, the CSF plasma AZT ratios were 0.23, 0.30, and 0.25, while the brain/CSF AZT ratios were 0.32, 0.63, and 0.64, respectively. These results indicate that the administration of each of the prodrugs produced a higher concentration of AZT in the brain than did the direct administration of AZT. Both prodrugs therefore may be superior to AZT itself with respect to achieving anti-human immunodeficiency virus concentrations within the central nervous system.

Comparative pharmacokinetics of two prodrugs of zidovudine in rabbits: enhanced levels of zidovudine in brain tissue.

PubMed Central

Lupia, R H; Ferencz, N; Lertora, J J; Aggarwal, S K; George, W J; Agrawal, K C

1993-01-01

The pharmacokinetics of two prodrugs of zidovudine (AZT), 1,4-dihydro-1-methyl-3-[(pyridylcarbonyl)oxy] ester and isoleucinyl ester (DPAZT and IAZT, respectively), were investigated in a rabbit model to determine their potential utility as drugs against human immunodeficiency virus. Drugs were administered by intravenous infusion over 5 min at doses equal to 10 mg of AZT per kg of body weight. The levels of the prodrugs and of released AZT in plasma, cerebrospinal fluid (CSF), and brain were determined by high-performance liquid chromatography analysis. DPAZT disappeared rapidly from plasma, whereas IAZT maintained a sustained level in plasma for up to 4 h. The levels in plasma of AZT released from DPAZT were consistently lower than the levels of AZT released from IAZT or AZT itself. At 75 min after infusion of AZT, DPAZT, and IAZT, the CSF plasma AZT ratios were 0.23, 0.30, and 0.25, while the brain/CSF AZT ratios were 0.32, 0.63, and 0.64, respectively. These results indicate that the administration of each of the prodrugs produced a higher concentration of AZT in the brain than did the direct administration of AZT. Both prodrugs therefore may be superior to AZT itself with respect to achieving anti-human immunodeficiency virus concentrations within the central nervous system. PMID:8494380

Computational modeling and in-vitro/in-silico correlation of phospholipid-based prodrugs for targeted drug delivery in inflammatory bowel disease

NASA Astrophysics Data System (ADS)

Dahan, Arik; Markovic, Milica; Keinan, Shahar; Kurnikov, Igor; Aponick, Aaron; Zimmermann, Ellen M.; Ben-Shabat, Shimon

2017-11-01

Targeting drugs to the inflamed intestinal tissue(s) represents a major advancement in the treatment of inflammatory bowel disease (IBD). In this work we present a powerful in-silico modeling approach to guide the molecular design of novel prodrugs targeting the enzyme PLA2, which is overexpressed in the inflamed tissues of IBD patients. The prodrug consists of the drug moiety bound to the sn-2 position of phospholipid (PL) through a carbonic linker, aiming to allow PLA2 to release the free drug. The linker length dictates the affinity of the PL-drug conjugate to PLA2, and the optimal linker will enable maximal PLA2-mediated activation. Thermodynamic integration and Weighted Histogram Analysis Method (WHAM)/Umbrella Sampling method were used to compute the changes in PLA2 transition state binding free energy of the prodrug molecule (ΔΔGtr) associated with decreasing/increasing linker length. The simulations revealed that 6-carbons linker is the optimal one, whereas shorter or longer linkers resulted in decreased PLA2-mediated activation. These in-silico results were shown to be in excellent correlation with experimental in-vitro data. Overall, this modern computational approach enables optimization of the molecular design of novel prodrugs, which may allow targeting the free drug specifically to the diseased intestinal tissue of IBD patients.

Simvastatin Prodrug Micelles Target Fracture and Improve Healing

PubMed Central

Dusad, Anand; Yuan, Hongjiang; Ren, Ke; Li, Fei; Fehringer, Edward V.; Purdue, P. Edward; Goldring, Steven R.; Daluiski, Aaron; Wang, Dong

2014-01-01

Simvastatin (SIM), a widely used anti-lipidaemic drug, has been identified as a bone anabolic agent. Its poor water solubility and the lack of distribution to the skeleton, however, have limited its application in the treatment of bone metabolic diseases. In this study, an amphiphilic macromolecular prodrug of SIM was designed and synthesized to overcome these limitations. The polyethylene glycol (PEG)-based prodrug can spontaneously self-assemble to form micelles. The use of SIM trimer as the prodrug’s hydrophobic segment allows easy encapsulation of additional free SIM. The in vitro studies showed that SIM/SIM-mPEG micelles were internalized by MC3T3 cells via lysosomal trafficking and consistently induced expression of both BMP2 and DKK1 mRNA, suggesting that the prodrug micelle retains the biological functions of SIM. After systemic administration, optical imaging suggests that the micelles would passively target to bone fracture sites associated with hematoma and inflammation. Furthermore, flow cytometry study revealed that SIM/SIM-mPEG micelles had preferred cellular uptake by inflammatory and resident cells within the fracture callus tissue. The treatment study using a mouse osteotomy model validated the micelles’ therapeutic efficacy in promoting bone fracture healing as demonstrated by micro-CT and histological analyses. Collectively, these data suggest that the macromolecular prodrug-based micelle formulation of SIM may have great potential for clinical management of impaired fracture healing. PMID:25542644

Synthesis and in vitro evaluation of potential sustained release prodrugs via targeting ASBT.

PubMed

Zheng, Xiaowan; Polli, James E

2010-08-30

The objective was to synthesize prodrugs of niacin and ketoprofen that target the human apical sodium-dependent bile acid transporter (ASBT) and potentially allow for prolonged drug release. Each drug was conjugated to the naturally occurring bile acid chenodeoxycholic acid (CDCA) using lysine as a linker. Their inhibitory binding and transport properties were evaluated in stably transfected ASBT-MDCK monolayers, and the kinetic parameters K(i), K(t), normJ(max), and P(p) were characterized. Enzymatic stability of the conjugates was evaluated in Caco-2 and liver homogenate. Both conjugates were potent inhibitors of ASBT. For the niacin prodrug, substrate kinetic parameter K(t) was 8.22microM and normJ(max) was 0.0917. In 4h, 69.4% and 26.9% of niacin was released from 1microM and 5microM of the conjugate in Caco-2 homogenate, respectively. For the ketoprofen prodrug, K(t) was 50.8microM and normJ(max) was 1.58. In 4h, 5.94% and 3.73% of ketoprofen was released from 1microM and 5microM of the conjugate in Caco-2 homogenate, and 24.5% and 12.2% of ketoprofen was released in liver homogenate, respectively. In vitro results showed that these bile acid conjugates are potential prolonged release prodrugs with binding affinity for ASBT. Copyright 2010 Elsevier B.V. All rights reserved.

Prodrug and covalent linker strategies for the solubilization of dual-action antioxidants/iron chelators.

PubMed

Bebbington, David; Dawson, Claire E; Gaur, Suneel; Spencer, John

2002-11-18

Water soluble prodrugs of hybrid free radical scavenger/iron chelating molecules, based on 3,5-disubstituted-4-hydroxyphenyl derivatives and 3-hydroxy-2-methyl-4(1H)-pyridinone (deferiprone), have been prepared. Related hybrid molecules containing a covalent poly(ethylene)glycol or an amine linker were also synthesized.

"Project ALERT's" Effects on Adolescents' Prodrug Beliefs: A Replication and Extension Study

ERIC Educational Resources Information Center

Clark, Heddy Kovach; Ringwalt, Chris L.; Hanley, Sean; Shamblen, Stephen R.

2010-01-01

This article represents a replication and extension of previous studies of the effects of "Project ALERT", a school-based substance use prevention program, on the prodrug beliefs of adolescents. Specifically, the authors' research examined "Project ALERT's" effects on adolescents' intentions to use substances in the future, beliefs about substance…

Synthesis and biological evaluation of novel 10-substituted-7-ethyl-10-hydroxycamptothecin (SN-38) prodrugs.

PubMed

Zhou, Mo; Liu, Meixia; He, Xinhua; Yu, Hong; Wu, Di; Yao, Yishan; Fan, Shiyong; Zhang, Ping; Shi, Weiguo; Zhong, Bohua

2014-11-27

In an attempt to improve the antitumor activity and reduce the side effects of irinotecan (2), novel prodrugs of SN-38 (3) were prepared by conjugating amino acids or dipeptides to the 10-hydroxyl group of SN-38 via a carbamate linkage. The synthesized compounds completely generated SN-38 in pH 7.4 buffer or in human plasma, while remaining stable under acidic conditions. All prodrug compounds demonstrated much greater in vitro antitumor activities against HeLa cells and SGC-7901 cells than irinotecan. The most active compounds, 5h, 7c, 7d, and 7f, exhibited IC50 values that were 1000 times lower against HeLa cells and 30 times lower against SGC-7901 cells than those of irinotecan, and the inhibitory activities of these prodrugs against acetylcholinesterase (AchE) were significantly reduced, with IC50 values more than 6.8 times greater than that of irinotecan. In addition, compound 5e exhibited the same level of tumor growth inhibitory activity as irinotecan (CPT-11) in a human colon xenograft model in vivo.

Synthesis, kinetic studies and pharmacological evaluation of mutual azo prodrug of 5-aminosalicylic acid with D-phenylalanine for colon specific drug delivery in inflammatory bowel disease.

PubMed

Dhaneshwar, Suneela S; Gairola, Neha; Kandpal, Mini; Bhatt, Lokesh; Vadnerkar, Gaurav; Kadam, S S

2007-04-01

Mutual azo prodrug of 5-aminosalicylic acid with d-phenylalanine was synthesized by coupling D-phenylalanine with salicylic acid, for targeted drug delivery to the inflamed gut tissue in inflammatory bowel disease. The structure of synthesized prodrug was confirmed by elemental analysis, IR and NMR spectroscopy. In vitro kinetic studies in HCl buffer (pH 1.2) showed negligible release of 5-aminosalicylic acid, whereas in phosphate buffer (pH 7.4) only 15% release was observed over a period of 7h. In rat fecal matter the release of 5-aminosalicylic acid was almost complete (85%), with a half-life of 160.1 min, following first order kinetics. The azo conjugate was evaluated for its ulcerogenic potential by Rainsford's cold stress method. Therapeutic efficacy of the carrier system and the mitigating effect of the azo conjugate were evaluated in trinitrobenzenesulfonic acid-induced experimental colitis model. The synthesized prodrug was found to be equally effective in mitigating the colitis in rats as that of sulfasalazine without the ulcerogenicity of 5-aminosalicylic acid.

Photo-triggered fluorescent theranostic prodrugs as DNA alkylating agents for mechlorethamine release and spatiotemporal monitoring.

PubMed

Cao, Yanting; Pan, Rong; Xuan, Weimin; Wei, Yongyi; Liu, Kejian; Zhou, Jiahong; Wang, Wei

2015-06-28

We describe a new theranostic strategy for selective delivery and spatiotemporal monitoring of mechlorethamine, a DNA alkylating agent. A photo-responsive prodrug is designed and composed of a photolabile o-nitrophenylethyl group, a DNA alkylating mechlorethamine drug and a coumarin fluorophore. Masking of the "N" in mechlorethamine in a positively charged state in the prodrug renders it inactive, non-toxic, selective and non-fluorescent. Indeed, the stable prodrug shows negligible cytotoxicity towards normal cells with and without UV activation and is completely non-fluorescent. However, upon photo-irradiation, the active mechlorethamine is released and induces efficient DNA cross-links, accompanied by a strong fluorescence enhancement (152 fold). Furthermore, DNA cross-linking activity from the release can be transformed into anticancer activity observed in in vitro studies of tumor cells. Importantly, the drug release progress and the movement can be conveniently monitored by fluorescence spectroscopy. The mechanistic study proves that the DNA cross-linking activity is mainly due to the release of DNA alkylating mechlorethamine. Altogether, the studies show the power of the theranostic strategy for efficient therapy in cancer treatment.

Camptothecin prodrug nanomicelle based on a boronate ester-linked diblock copolymer as the carrier of doxorubicin with enhanced cellular uptake.

PubMed

Gao, Ya; Xiao, Yi; Liu, Shiyuan; Yu, Jiahui

2018-02-01

A novel pH-sensitive polymeric prodrug of camptothecin (CPT) by polymerizing γ-camptothecin-glutamate N-carboxyanhydride (Glu (CPT)-NCA) on boronate ester-linked poly (ethyleneglycol) (PEG) directly via the amine-initiated ring open polymerization (ROP) has been developed. The resulting amphiphilic prodrug (mPEG-BC-PGluCPT) could self-assemble into nanoparticles and encapsulate doxorubicin (Dox) simultaneously in aqueous solution for dual-drug delivery. The formation of polymeric prodrug micelles (mPEG-BC@PGluCPT) was confirmed by the measurements of critical aggregation concentration (CAC), particle size, and morphology observations. The mPEG-BC@PGluCPT micelles were colloidally stable in solutions for two weeks. Polymeric prodrug micelles mPEG-BC@PGluCPT and Dox-loaded micelles mPEG-BC@PGluCPT⋅Dox showed sustained drug release profiles over 48 h. As expected, drug release was accelerated by the decreasement of pH value from 7.4 to 6.0, which demonstrated pH-dependent manner of drug release. Additionally, it was found that cellular uptake of mPEG-BC@PGluCPT⋅Dox micelles on HepG2 cells was higher than that on HL-7702 cells, especially in culture medium at pH 6.0. The enhanced cellular uptake of mPEG-BC@PGluCPT⋅Dox micelles under acidic condition on HepG2 cells resulted in the higher cytotoxicity of mPEG-BC@PGluCPT⋅Dox micelles at acidic pH than that at pH 7.4.

Construction of dual-functional polymer nanomaterials with near-infrared fluorescence imaging and polymer prodrug by RAFT-mediated aqueous dispersion polymerization.

PubMed

Tian, Chun; Niu, Jinyun; Wei, Xuerui; Xu, Yujie; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

2018-05-31

The performance of functional polymer nanomaterials is a vigorously discussed topic in polymer science. We devoted ourselves to investigating polymer nanomaterials based on near-infrared (NIR) fluorescence imaging and polymer prodrug in this study. Aza-boron dipyrromethene (BODIPY) is an important organic dye, having characteristics such as environmental resistance, light resistance, high molar extinction coefficient, and fluorescence quantum yield. We incorporated it into our target monomer, which can be polymerized without changing its parent structure in a polar solvent and copolymerized with water-soluble monomer to improve the solubility of the dye in an aqueous solution. At the same time, the hydrophobic drug camptothecin (CPT) was designed as a prodrug monomer, and the polymeric nanoparticles (NPs) with NIR fluorescence imaging and prodrug were synthesized in situ in reversible addition-fragmentation chain transfer (RAFT)-mediated aqueous dispersion polymerization. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed the final uniform size of the dual-functional polymeric NPs morphology. The dual-functional polymeric NPs had a strong absorption and emission signal in the NIR region (>650 nm) based on the fluorescence tests. In consideration of the long-term biological toxicity, confocal laser scanning microscopy (CLSM) results indicated that the dual-functional NPs with controlled drug content exhibited effective capability of killing HeLa cells. In addition, in vivo imaging of the dual-functional NPs was observed in real time, and the fluorescent signals clearly demonstrated the dynamic process of prodrug transfer.

Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery.

PubMed

Pan, Dipanjan; Pham, Christine T N; Weilbaecher, Katherine N; Tomasson, Michael H; Wickline, Samuel A; Lanza, Gregory M

2016-01-01

Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a 'magic bullet' to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a 'Grail Quest' by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made 'made the turn' toward meaningful translational success. © 2015 The Authors. WIREs Nanomedicine and Nanobiotechnology published by Wiley Periodicals, Inc.

Expression of β-glucuronidase on the surface of bacteria enhances activation of glucuronide prodrugs.

PubMed

Cheng, C-M; Chen, F M; Lu, Y-L; Tzou, S-C; Wang, J-Y; Kao, C-H; Liao, K-W; Cheng, T-C; Chuang, C-H; Chen, B-M; Roffler, S; Cheng, T-L

2013-05-01

Extracellular activation of hydrophilic glucuronide prodrugs by β-glucuronidase (βG) was examined to increase the therapeutic efficacy of bacteria-directed enzyme prodrug therapy (BDEPT). βG was expressed on the surface of Escherichia coli by fusion to either the bacterial autotransporter protein Adhesin (membrane βG (mβG)/AIDA) or the lipoprotein (lpp) outermembrane protein A (mβG/lpp). Both mβG/AIDA and mβG/lpp were expressed on the bacterial surface, but only mβG/AIDA displayed enzymatic activity. The rate of substrate hydrolysis by mβG/AIDA-BL21cells was 2.6-fold greater than by pβG-BL21 cells, which express periplasmic βG. Human colon cancer HCT116 cells that were incubated with mβG/AIDA-BL21 bacteria were sensitive to a glucuronide prodrug (p-hydroxy aniline mustard β-D-glucuronide, HAMG) with an half maximal inhibitory concentration (IC50) value of 226.53±45.4 μM, similar to the IC50 value of the active drug (p-hydroxy aniline mustard, pHAM; 70.6±6.75 μM), indicating that mβG/AIDA on BL21 bacteria could rapidly and efficiently convert HAMG to an active anticancer agent. These results suggest that surface display of functional βG on bacteria can enhance the hydrolysis of glucuronide prodrugs and may increase the effectiveness of BDEPT.

Developing a novel dual PI3K–mTOR inhibitor from the prodrug of a metabolite

PubMed Central

Zhou, Yan; Zhang, Genyan; Wang, Feng; Wang, Jin; Ding, Yanwei; Li, Xinyu; Shi, Chongtie; Li, Jiakui; Shih, Chengkon; You, Song

2017-01-01

This study presents a process of developing a novel PI3K–mTOR inhibitor through the prodrug of a metabolite. The lead compound (compound 1) was identified with similar efficacy as that of NVP-BEZ235 in a tumor xenograft model, but the exposure of compound 1 was much lower than that of NVP-BEZ235. After reanalysis of the blood sample, a major metabolite (compound 2) was identified. Compound 2 exerted similar in vitro activity as compound 1, which indicated that compound 2 was an active metabolite and that the in vivo efficacy in the animal model came from compound 2 instead of compound 1. However, compound 1 was metabolized into compound 2 predominantly in the liver microsomes of mouse, but not in the liver microsomes of rat, dog, or human. In order to translate the efficacy in the animal model into clinical development or predict the pharmacokinetic/pharmacodynamic parameters in the clinical study using a preclinical model, we developed the metabolite (compound 2) instead of compound 1. Due to the low bioavailability of compound 2, its prodrug (compound 3) was designed and synthesized to improve the solubility. The prodrug was quickly converted to compound 2 through both intravenous and oral administrations. Because the prodrug (compound 3) did not improve the oral exposure of compound 2, developing compound 3 as an intravenous drug was considered by our team, and the latest results will be reported in the future. PMID:29118584

Co-delivery of doxorubicin and curcumin by pH-sensitive prodrug nanoparticle for combination therapy of cancer

NASA Astrophysics Data System (ADS)

Zhang, Yumin; Yang, Cuihong; Wang, Weiwei; Liu, Jinjian; Liu, Qiang; Huang, Fan; Chu, Liping; Gao, Honglin; Li, Chen; Kong, Deling; Liu, Qian; Liu, Jianfeng

2016-02-01

Ample attention has focused on cancer drug delivery via prodrug nanoparticles due to their high drug loading property and comparatively lower side effects. In this study, we designed a PEG-DOX-Cur prodrug nanoparticle for simultaneous delivery of doxorubicin (DOX) and curcumin (Cur) as a combination therapy to treat cancer. DOX was conjugated to PEG by Schiff’s base reaction. The obtained prodrug conjugate could self-assemble in water at pH 7.4 into nanoparticles (PEG-DOX NPs) and encapsulate Cur into the core through hydrophobic interaction (PEG-DOX-Cur NPs). When the PEG-DOX-Cur NPs are internalized by tumor cells, the Schiff’s base linker between PEG and DOX would break in the acidic environment that is often observed in tumors, causing disassembling of the PEG-DOX-Cur NPs and releasing both DOX and Cur into the nuclei and cytoplasma of the tumor cells, respectively. Compared with free DOX, free Cur, free DOX-Cur combination, or PEG-DOX NPs, PEG-DOX-Cur NPs exhibited higher anti-tumor activity in vitro. In addition, the PEG-DOX-Cur NPs also showed prolonged blood circulation time, elevated local drug accumulation and increased tumor penetration. Enhanced anti-tumor activity was also observed from the PEG-DOX-Cur-treated animals, demonstrating better tumor inhibitory property of the NPs. Thus, the PEG-DOX-Cur prodrug nanoparticle system provides a simple yet efficient approach of drug delivery for chemotherapy.

Design and in vitro evaluation of self-assembled indometacin prodrug nanoparticles for sustained/controlled release and reduced normal cell toxicity

NASA Astrophysics Data System (ADS)

Lin, Jinyan; Pan, Zhou; Song, Liang; Zhang, Yanmei; Li, Yang; Hou, Zhenqing; Lin, Changjian

2017-12-01

Despite the great efficacy of indomethacin (IND) as an anti-inflammatory agent, its clinical translation has been obstructed by the water insolubility, severe side effects, and exceedingly low bioavailability. Indomethacin prodrug-based nanoparticles (NPs) combining the strengths of both nanotechnology and prodrugs that might overcome this crucial problem are presented. Here, using the carbodiimide-mediated couple reaction, IND was conjugated to clinically approved poly(ethylene glycol) (PEG) polymer via peptide linkage that was cleavaged in the presence of cathepsin B, which was significantly induced after inflammatory. The synthesized IND-PEG-IND conjugate was characterized by UV-vis, FTIR, 1H NMR, XRD, and MALDI-TOF-MS analyses. For its intrinsic amphiphilic property, the IND prodrug self-assembled into NPs in aqueous solution and served two roles-as an anti-inflammatory prodrug and a drug carrier. The constructed IND-PEG-IND NPs had naoscaled particle size of approximately 80 nm, negative surface, spherical shape, good water-dispersity, and high and fixed drug-loading content of 20.1 wt%. In addition, IND-PEG-IND NPs demonstrated sustained and cathepsin B-controlled drug release behavior. More importantly, IND-PEG-IND NPs significantly reduced the acute totoxicity agaist normal osteoblast cells and displayed the more potent anti-inflammatory effect against macrophage cells compared to the free IND. Taken together, the nanoprodrug might exhibit increased potency for nanomedicine-prospective therapeutic use in clinical treatement of implant inflammatory diseases.

Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery

PubMed Central

Pan, Dipanjan; Pham, Christine TN; Weilbaecher, Katherine N; Tomasson, Michael H; Wickline, Samuel A; Lanza, Gregory M

2016-01-01

Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a ‘magic bullet’ to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a ‘Grail Quest’ by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made ‘made the turn’ toward meaningful translational success. PMID:26296541

Conjugation of metronidazole with dextran: a potential pharmaceutical strategy to control colonic distribution of the anti-amebic drug susceptible to metabolism by colonic microbes

PubMed Central

Kim, Wooseong; Yang, Yejin; Kim, Dohoon; Jeong, Seongkeun; Yoo, Jin-Wook; Yoon, Jeong-Hyun; Jung, Yunjin

2017-01-01

Metronidazole (MTDZ), the drug of choice for the treatment of protozoal infections such as luminal amebiasis, is highly susceptible to colonic metabolism, which may hinder its conversion from a colon-specific prodrug to an effective anti-amebic agent targeting the entire large intestine. Thus, in an attempt to control the colonic distribution of the drug, a polymeric colon-specific prodrug, MTDZ conjugated to dextran via a succinate linker (Dex-SA-MTDZ), was designed. Upon treatment with dextranase for 8 h, the degree of Dex-SA-MTDZ depolymerization (%) with a degree of substitution (mg of MTDZ bound in 100 mg of Dex-SA-MTDZ) of 7, 17, and 30 was 72, 38, and 8, respectively, while that of dextran was 85. Depolymerization of Dex-SA-MTDZ was found to be necessary for the release of MTDZ, because dextranase pretreatment ensures that de-esterification occurs between MTDZ and the dextran backbone. In parallel, Dex-SA-MTDZ with a degree of substitution of 17 was found not to release MTDZ upon incubation with the contents of the small intestine and stomach of rats, but it released MTDZ when incubated with rat cecal contents (including microbial dextranases). Moreover, Dex-SA-MTDZ exhibited prolonged release of MTDZ, which contrasts with drug release by small molecular colon-specific prodrugs, MTDZ sulfate and N-nicotinoyl-2-{2-(2-methyl-5-nitroimidazol-1-yl)ethyloxy}-d,l-glycine. These prodrugs were eliminated very rapidly, and no MTDZ was detected in the cecal contents. Consistent with these in vitro results, we found that oral gavage of Dex-SA-MTDZ delivered MTDZ (as MTDZ conjugated to [depolymerized] dextran) to the distal colon. However, upon oral gavage of the small molecular prodrugs, no prodrugs were detected in the distal colon. Collectively, these data suggest that dextran conjugation is a potential pharmaceutical strategy to control the colonic distribution of drugs susceptible to colonic microbial metabolism. PMID:28243064

Conjugation of metronidazole with dextran: a potential pharmaceutical strategy to control colonic distribution of the anti-amebic drug susceptible to metabolism by colonic microbes.

PubMed

Kim, Wooseong; Yang, Yejin; Kim, Dohoon; Jeong, Seongkeun; Yoo, Jin-Wook; Yoon, Jeong-Hyun; Jung, Yunjin

2017-01-01

Metronidazole (MTDZ), the drug of choice for the treatment of protozoal infections such as luminal amebiasis, is highly susceptible to colonic metabolism, which may hinder its conversion from a colon-specific prodrug to an effective anti-amebic agent targeting the entire large intestine. Thus, in an attempt to control the colonic distribution of the drug, a polymeric colon-specific prodrug, MTDZ conjugated to dextran via a succinate linker (Dex-SA-MTDZ), was designed. Upon treatment with dextranase for 8 h, the degree of Dex-SA-MTDZ depolymerization (%) with a degree of substitution (mg of MTDZ bound in 100 mg of Dex-SA-MTDZ) of 7, 17, and 30 was 72, 38, and 8, respectively, while that of dextran was 85. Depolymerization of Dex-SA-MTDZ was found to be necessary for the release of MTDZ, because dextranase pretreatment ensures that de-esterification occurs between MTDZ and the dextran backbone. In parallel, Dex-SA-MTDZ with a degree of substitution of 17 was found not to release MTDZ upon incubation with the contents of the small intestine and stomach of rats, but it released MTDZ when incubated with rat cecal contents (including microbial dextranases). Moreover, Dex-SA-MTDZ exhibited prolonged release of MTDZ, which contrasts with drug release by small molecular colon-specific prodrugs, MTDZ sulfate and N -nicotinoyl-2-{2-(2-methyl-5-nitroimidazol-1-yl)ethyloxy}-d,l-glycine. These prodrugs were eliminated very rapidly, and no MTDZ was detected in the cecal contents. Consistent with these in vitro results, we found that oral gavage of Dex-SA-MTDZ delivered MTDZ (as MTDZ conjugated to [depolymerized] dextran) to the distal colon. However, upon oral gavage of the small molecular prodrugs, no prodrugs were detected in the distal colon. Collectively, these data suggest that dextran conjugation is a potential pharmaceutical strategy to control the colonic distribution of drugs susceptible to colonic microbial metabolism.

The In-Situ One-Step Synthesis of a PDC Macromolecular Pro-Drug and the Fabrication of a Novel Core-Shell Micell.

PubMed

Yu, Cui-Yun; Yang, Sa; Li, Zhi-Ping; Huang, Can; Ning, Qian; Huang, Wen; Yang, Wen-Tong; He, Dongxiu; Sun, Lichun

2016-01-01

The development of slow release nano-sized carriers for efficient antineoplastic drug delivery with a biocompatible and biodegradable pectin-based macromolecular pro-drug for tumor therapy has been reported in this study. Pectin-doxorubicin conjugates (PDC), a macromolecular pro-drug, were prepared via an amide condensation reaction, and a novel amphiphilic core-shell micell based on a PDC macromolecular pro-drug (PDC-M) was self-assembled in situ, with pectin as the hydrophilic shell and doxorubicin (DOX) as the hydrophobic core. Then the chemical structure of the PDC macromolecular pro-drug was identified by both Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy ((1)H-NMR), and proved that doxorubicin combined well with the pectin and formed macromolecular pro-drug. The PDC-M were observed to have an unregularly spherical shape and were uniform in size by scanning electron microscopy (SEM). The average particle size of PDC-M, further measured by a Zetasizer nanoparticle analyzer (Nano ZS, Malvern Instruments), was about 140 nm. The encapsulation efficiency and drug loading were 57.82% ± 3.7% (n = 3) and 23.852% ±2.3% (n = 3), respectively. The in vitro drug release behaviors of the resulting PDC-M were studied in a simulated tumor environment (pH 5.0), blood (pH 7.4) and a lysosome media (pH 6.8), and showed a prolonged slow release profile. Assays for antiproliferative effects and flow cytometry of the resulting PDC-M in HepG2 cell lines demonstrated greater properties of delayed and slow release as compared to free DOX. A cell viability study against endothelial cells further revealed that the resulting PDC-M possesses excellent cell compatibilities and low cytotoxicities in comparison with that of the free DOX. Hemolysis activity was investigated in rabbits, and the results also demonstrated that the PDC-M has greater compatibility in comparison with free DOX. This shows that the resulting PDC-M can ameliorate the hydrophobicity of free DOX. This work proposes a novel strategy for in-situ one-step synthesis of macromolecular pro-drugs and fabrication of a core-shell micelle, demonstrating great potential for cancer chemotherapy.

Novel double prodrugs of the iron chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED): Synthesis, characterization, and investigation of activation by chemical hydrolysis and oxidation.

PubMed

Thiele, Nikki A; Abboud, Khalil A; Sloan, Kenneth B

2016-08-08

The development of iron chelators suitable for the chronic treatment of diseases where iron accumulation and subsequent oxidative stress are implicated in disease pathogenesis is an active area of research. The clinical use of the strong chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) and its alkyl ester prodrugs has been hindered by poor oral bioavailability and lack of conversion to the parent chelator, respectively. Here, we present novel double prodrugs of HBED that have the carboxylate and phenolate donors of HBED masked with carboxylate esters and boronic acids/esters, respectively. These double prodrugs were successfully synthesized as free bases (7a-f) or as dimesylate salts (8a-c,e), and were characterized by (1)H, (13)C, and (11)B NMR; MP; MS; and elemental analysis. The crystal structure of 8a was solved. Three of the double prodrugs (8a-c) were selected for further investigation into their abilities to convert to HBED by stepwise hydrolysis and H2O2 oxidation. The serial hydrolysis of the pinacol and methyl esters of N,N'-bis(2-boronic acid pinacol ester benzyl)ethylenediamine-N,N'-diacetic acid methyl ester dimesylate (8a) was verified by LC-MS. The macro half-lives for the hydrolyses of 8a-c, measured by UV, ranged from 3.8 to 26.3 h at 37 °C in pH 7.5 phosphate buffer containing 50% MeOH. 9, the product of hydrolysis of 8a-c and the intermediate in the conversion pathway, showed little-to-no affinity for iron or copper in UV competition experiments. 9 underwent a serial oxidative deboronation by H2O2 in N-methylmorpholine buffer to generate HBED (k = 10.3 M(-1) min(-1)). The requirement of this second step, oxidation, before conversion to the active chelator is complete may confer site specificity when only localized iron chelation is needed. Overall, these results provide proof of principle for the activation of the double prodrugs by chemical hydrolysis and H2O2 oxidation, and merit further investigation into the protective capabilities of the prodrugs against H2O2-induced cell death. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Melanoma-targeted delivery system (part 1): design, synthesis and evaluation of releasable disulfide drug by glutathione.

PubMed

El Aissi, Radhia; Chezal, Jean-Michel; Tarrit, Sébastien; Chavignon, Olivier; Moreau, Emmanuel

2015-08-28

Here we describe the design and synthesis of a prodrug developed for pigmented melanoma therapy, consisting of a Melanin-Targeting Probe (MTP) conjugated to 5-iodo-2'-deoxyuridine (IUdR) with a reduction-sensitive pre-determined breaking point. Compared with the non-cleavable conjugate (17b), prodrug (17a) bearing a self-immolative disulfide linker achieved complete release of IUdR within 20 min in the presence of reducing agents such as DTT or glutathione. Analytical results also showed that prodrug (17a) was more sensitive than parent non-cleavable conjugate (17b) for a concentration range of glutathione similar to that found in the intracellular compartment of tumours. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A Versatile Bioorthogonal Copper-free Click Chemistry Platform to Functionalize Cisplatin Prodrugs

PubMed Central

Pathak, Rakesh K.; McNitt, Christopher D.; Popik, Vladimir V.; Dhar, Shanta

2015-01-01

The ability to rationally design and construct a platform technology to develop new platinum(IV) [Pt(IV)] prodrugs with functionalities for installation of targeting moieties, delivery systems, fluorescent reporters from a single precursor with the ability to release biologically active cisplatin using well-defined chemistry is critical for discovering new platinum-based therapeutics. With limited numbers of possibilities by considering the sensitivity of Pt(IV) centers to reduction, thiols, etc, we used a strain promoted azide alkyne cycloaddition (SPAAC) approach to provide a novel platform where new functionalities can easily be installed on cisplatin prodrugs from a single Pt(IV) precursor. The ability of this platform to be incorporated in nano-delivery vehicle and conjugation to fluorescent reporters were also investigated. PMID:24756923

Copper-free click-chemistry platform to functionalize cisplatin prodrugs.

PubMed

Pathak, Rakesh K; McNitt, Christopher D; Popik, Vladimir V; Dhar, Shanta

2014-06-02

The ability to rationally design and construct a platform technology to develop new platinum(IV) [Pt(IV)] prodrugs with functionalities for installation of targeting moieties, delivery systems, fluorescent reporters from a single precursor with the ability to release biologically active cisplatin by using well-defined chemistry is critical for discovering new platinum-based therapeutics. With limited numbers of possibilities considering the sensitivity of Pt(IV) centers, we used a strain-promoted azide-alkyne cycloaddition approach to provide a platform, in which new functionalities can easily be installed on cisplatin prodrugs from a single Pt(IV) precursor. The ability of this platform to be incorporated in nanodelivery vehicle and conjugation to fluorescent reporters were also investigated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prodrugs of phosphonates and phosphates: crossing the membrane barrier

PubMed Central

Wiemer, Andrew J.; Wiemer, David F.

2016-01-01

A substantial portion of metabolism involves transformation of phosphate esters, including pathways leading to nucleotides and oligonucleotides, carbohydrates, isoprenoids and steroids, and phosphorylated proteins. Because the natural substrates bear one or more negative charges, drugs that target these enzymes generally must be charged as well but small charged molecules can have difficulty traversing the cell membrane other than by endocytosis. The resulting dichotomy has stimulated abundant effort to develop effective prodrugs, compounds that carry little or no charge to enable them to transit biological membranes but then able to release the parent drug once inside the target cell. This chapter will present recent studies on advances in prodrug forms, along with representative examples of their application to marketed and developmental drugs. PMID:25391982

Transdermal delivery and cutaneous targeting of antivirals using a penetration enhancer and lysolipid prodrugs.

PubMed

Diblíková, Denisa; Kopečná, Monika; Školová, Barbora; Krečmerová, Marcela; Roh, Jaroslav; Hrabálek, Alexandr; Vávrová, Kateřina

2014-04-01

In this work, we investigate prodrug and enhancer approaches for transdermal and topical delivery of antiviral drugs belonging to the 2,6-diaminopurine acyclic nucleoside phosphonate (ANP) group. Our question was whether we can differentiate between transdermal and topical delivery, i.e., to control the delivery of a given drug towards either systemic absorption or retention in the skin. The in vitro transdermal delivery and skin concentrations of seven antivirals, including (R)- and (S)-9-[2-(phosphonomethoxy)propyl]-2,6-diaminopurine (PMPDAP), (S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]-2,6-diaminopurine ((S)-HPMPDAP), its 8-aza analog, and their cyclic and hexadecyloxypropyl (HDP) prodrugs, was investigated with and without the penetration enhancer dodecyl-6-(dimethylamino)hexanoate (DDAK) using human skin. The ability of ANPs to cross the human skin barrier was very low (0.5-1.4 nmol/cm(2)/h), and the majority of the compounds were found in the stratum corneum, the uppermost skin layer. The combination of antivirals and the penetration enhancer DDAK proved to be a viable approach for transdermal delivery, especially in case of (R)-PMPDAP, an anti-HIV effective drug (30.2 ± 2.3 nmol/cm(2)/h). On the other hand, lysophospholipid-like HDP prodrugs, e.g., HDP-(S)-HPMPDAP, reached high concentrations in viable epidermis without significant systemic absorption. By using penetration enhancers or lysolipid prodrugs, it is possible to effectively target systemic diseases by the transdermal route or to target cutaneous pathologies by topical delivery.

New antibiotics for healthcare-associated pneumonia.

PubMed

Neuner, Elizabeth A; Ritchie, David J; Micek, Scott T

2009-02-01

Current antibiotics available for the treatment of healthcare-associated pneumonia (HCAP) may result in clinical failure due to resistance development, side effect intolerance, or poor pharmacokinetic-pharmacodynamic profiles. New agents active against common HCAP pathogens are needed. The mechanism of action, spectrum of activity, pharmacokinetics, adverse effects, and clinical efficacy of seven new agents in clinical development or recently approved with either methicillin-resistant Staphylococcus aureus (MRSA) or pseudomonal activity are reviewed. They include doripenem, a new antipseudomonal carbapenem; ceftobiprole and ceftaroline, two anti-MRSA cephalosporins; iclaprim, a selective dihydrofolate reductase antagonist; and three glycopeptides, dalbavancin, telavancin, and oritavancin.

Current and novel antibiotics against resistant Gram-positive bacteria.

PubMed

Perez, Federico; Salata, Robert A; Bonomo, Robert A

2008-01-01

The challenge posed by resistance among Gram-positive bacteria, epitomized by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and vancomycin-intermediate and -resistant S. aureus (VISA and VRSA) is being met by a new generation of antimicrobials. This review focuses on the new β-lactams with activity against MRSA (ceftobiprole and ceftaroline) and on the new glycopeptides (oritavancin, dalbavancin, and telavancin). It will also consider the role of vancomycin in an era of existing alternatives such as linezolid, daptomycin and tigecycline. Finally, compounds in early development are described, such as iclaprim, friulimicin, and retapamulin, among others.

Physiological Feedback Control 2011-2012 Annual Report

DTIC Science & Technology

2013-01-07

Invention Title: UM 3709 – Dendrimeric Prodrug as a Controlled Release Formulation in Pain Management – Patent Title: Dendrimer Conjugates Patent... Dendrimeric Prodrug as a Controlled Release Formulation in Pain Management – Patent Title: Dendrimer Conjugates Patent/Application Numbers: 61/101,461; 12...class of dendrimer -oxime drug conjugates, and evaluated the mechanism by which these conjugates hydrolyze paraoxon. (a) Papers published in peer

Tyrosine-Based 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine and -adenine ((S)-HPMPC and (S)-HPMPA) Prodrugs: Synthesis, Stability, Antiviral Activity and in Vivo Transport Studies

PubMed Central

Zakharova, Valeria M.; Serpi, Michaela; Krylov, Ivan S.; Peterson, Larryn W.; Breitenbach, Julie M.; Borysko, Katherine Z.; Drach, John C.; Collins, Mindy; Hilfinger, John M.; Kashemirov, Boris A.; McKenna, Charles E.

2011-01-01

Eight novel single amino acid (6–11) and dipeptide (12, 13) tyrosine P-O esters of cyclic cidofovir ((S)-cHPMPCa, 4) and its cyclic adenine analog ((S)-cHPMPA, 3) were synthesized and evaluated as prodrugs. In vitro IC50 values for the prodrugs vs vaccinia, cowpox, human cytomegalo- and herpes simplex type 1 viruses were similar to those for the parent drugs ((S)-HPMPC, 2, (S)-HPMPA, 1; IC50 0.3 – 30 µM); there were no cytoxicity with KB or HFF cells at ≤ 100 µM. The prodrugs exhibited a wide range of half-lives in rat intestinal homogenate at pH 6.5 (<30 – 1732 min) with differences of 3–10× between phostonate diastereomers. The tyrosine-alkylamide derivatives of 3 and 4 were the most stable. (L)-Tyr-NHiBu cHPMPA (11) was converted in rat or mouse plasma solely to two active metabolites and had significantly enhanced oral bioavailability vs parent drug 1 in a mouse model (39 % vs <5 %). PMID:21812420

Theranostic Imaging of Cancer Gene Therapy.

PubMed

Sekar, Thillai V; Paulmurugan, Ramasamy

2016-01-01

Gene-directed enzyme prodrug therapy (GDEPT) is a promising therapeutic approach for treating cancers of various phenotypes. This strategy is independent of various other chemotherapeutic drugs used for treating cancers where the drugs are mainly designed to target endogenous cellular mechanisms, which are different in various cancer subtypes. In GDEPT an external enzyme, which is different from the cellular proteins, is expressed to convert the injected prodrug in to a toxic metabolite, that normally kill cancer cells express this protein. Theranostic imaging is an approach used to directly monitor the expression of these gene therapy enzymes while evaluating therapeutic effect. We recently developed a dual-GDEPT system where we combined mutant human herpes simplex thymidine kinase (HSV1sr39TK) and E. coli nitroreductase (NTR) enzyme, to improve therapeutic efficiency of cancer gene therapy by simultaneously injecting two prodrugs at a lower dose. In this approach we use two different prodrugs such as ganciclovir (GCV) and CB1954 to target two different cellular mechanisms to kill cancer cells. The developed dual GDEPT system was highly efficacious than that of either of the system used independently. In this chapter, we describe the complete protocol involved for in vitro and in vivo imaging of therapeutic cancer gene therapy evaluation.

Synthesis and evaluation of macromolecule-bound derivatives of a peptidyl-1-beta-D-arabinofuranosylcytosine prodrug.

PubMed

Balajthy, Zoltan

2008-04-01

Macromolecule-bound Val-Leu-Lys-ara-C (1) prodrugs were synthesized with spacers (-HN-(CH(2))(x)-CO-; x =1,3,5) between the dextran carrier (T-70) and 1, in order to achieve a sustained-release drug delivery system dextran-NH-(CH(2))(x:1,3,5)-CO-Val-Leu-Lys-ara-C (5, 6 and 7). The conjugation increased the stability of 1 in aqueous buffer solutions by three times (t((1/2)) 53.0 h, pH 7.4). The length of spacer also regulated the rate of hydrolysis of the prodrugs in serum. The shortest spacer (-HN-(CH(2))-CO-, (2)) in 5 provided the best protection of 1 against the hydrolyzing ability of proteinase- alpha(2)-macroglobulin complexes, increasing its half-life approximately 30-fold. The conjugation procedure resulted in a growth arrest ability for macromolecular-bound prodrugs 5, 6 and 7 against L1210 with IC(50) of 0.01 microM in vitro, which is significantly lower than that of other ara-C-macromolecule conjugates. 5 and 6 arrested cell growth in a broader range of concentration, between 1 x 10(-5)-1.0 microM, than ara-C could.

Physiologically Based Absorption Modeling to Design Extended-Release Clinical Products for an Ester Prodrug.

PubMed

Ding, Xuan; Day, Jeffrey S; Sperry, David C

2016-11-01

Absorption modeling has demonstrated its great value in modern drug product development due to its utility in understanding and predicting in vivo performance. In this case, we integrated physiologically based modeling in the development processes to effectively design extended-release (ER) clinical products for an ester prodrug LY545694. By simulating the trial results of immediate-release products, we delineated complex pharmacokinetics due to prodrug conversion and established an absorption model to describe the clinical observations. This model suggested the prodrug has optimal biopharmaceutical properties to warrant developing an ER product. Subsequently, we incorporated release profiles of prototype ER tablets into the absorption model to simulate the in vivo performance of these products observed in an exploratory trial. The models suggested that the absorption of these ER tablets was lower than the IR products because the extended release from the formulations prevented the drug from taking advantage of the optimal absorption window. Using these models, we formed a strategy to optimize the ER product to minimize the impact of the absorption window limitation. Accurate prediction of the performance of these optimized products by modeling was confirmed in a third clinical trial.

In vivo multimodality imaging and cancer therapy by near-infrared light-triggered trans-platinum pro-drug-conjugated upconverison nanoparticles.

PubMed

Dai, Yunlu; Xiao, Haihua; Liu, Jianhua; Yuan, Qinghai; Ma, Ping'an; Yang, Dongmei; Li, Chunxia; Cheng, Ziyong; Hou, Zhiyao; Yang, Piaoping; Lin, Jun

2013-12-18

Controlling anticancer drug activity and release on demand is very significant in cancer therapy. The photoactivated platinum(IV) pro-drug is stable in the dark and can be activated by UV light. In this study, we develop a multifunctional drug delivery system combining upconversion luminescence/magnetic resonance/computer tomography trimodality imaging and NIR-activated platinum pro-drug delivery. We use the core-shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate the trans-platinum(IV) pro-drug, trans,trans,trans-[Pt(N3)2(NH3)(py)(O2CCH2CH2COOH)2]. Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum(IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug-conjugated nanoparticles under near-infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multimodality bioimaging contrast agents and transducers by converting NIR light into UV for control of drug activity in practical cancer therapy.

Direct chemical grafted curcumin on halloysite nanotubes as dual-responsive prodrug for pharmacological applications.

PubMed

Massaro, M; Amorati, R; Cavallaro, G; Guernelli, S; Lazzara, G; Milioto, S; Noto, R; Poma, P; Riela, S

2016-04-01

Covalently functionalized halloysite nanotubes (HNTs) were successfully employed as dual-responsive nanocarriers for curcumin (Cur). Particularly, we synthesized HNT-Cur prodrug with a controlled curcumin release on dependence of both intracellular glutathione (GSH) and pH conditions. In order to obtain HNT-Cur produgs, halloysite was firstly functionalized with cysteamine through disulphide linkage. Afterwards, curcumin molecules were chemically conjugated to the amino end groups of halloysite via Schiff's base formation. The successful functionalization of halloysite was proved by thermogravimetric analysis, FT-IR spectroscopy, dynamic light scattering and scanning electron microscopy. Experimental data confirmed the presence of curcumin on HNT external surface. Moreover, we investigated the kinetics of curcumin release by UV-vis spectroscopy, which highlighted that HNT-Cur prodrug possesses dual stimuli-responsive ability upon exposure to GSH-rich or acidic environment. In vitro antiproliferative and antioxidant properties of HNT-Cur prodrug were studied with the aim to explore their potential applications in pharmaceutics. This work puts forward an efficient strategy to prepare halloysite based nanocarriers with controlled drug delivery capacity through direct chemical grafting with stimuli-responsive linkage. Copyright © 2016 Elsevier B.V. All rights reserved.

PSMA-Specific Theranostic Nanoplex for Combination of TRAIL Gene and 5-FC Prodrug Therapy of Prostate Cancer

PubMed Central

Chen, Zhihang; Penet, Marie-France; Krishnamachary, Balaji; Banerjee, Sangeeta R.; Pomper, Martin G.; Bhujwalla, Zaver M.

2015-01-01

Metastatic prostate cancer causes significant morbidity and mortality and there is a critical unmet need for effective treatments. We have developed a theranostic nanoplex platform for combined imaging and therapy of prostate cancer. Our prostate-specific membrane antigen (PSMA) targeted nanoplex is designed to deliver plasmid DNA encoding tumor necrosis factor related apoptosis-inducing ligand (TRAIL), together with bacterial cytosine deaminase (bCD) as a prodrug enzyme. Nanoplex specificity was tested using two variants of human PC3 prostate cancer cells in culture and in tumor xenografts, one with high PSMA expression and the other with negligible expression levels. The expression of EGFP-TRAIL was demonstrated by fluorescence optical imaging and real-time PCR. Noninvasive 19F MR spectroscopy detected the conversion of the nontoxic prodrug 5-fluorocytosine (5-FC) to cytotoxic 5-fluorouracil (5-FU) by bCD. The combination strategy of TRAIL gene and 5-FC/bCD therapy showed significant inhibition of the growth of prostate cancer cells and tumors. These data demonstrate that the PSMA-specific theranostic nanoplex can deliver gene therapy and prodrug enzyme therapy concurrently for precision medicine in metastatic prostate cancer. PMID:26706476

Propylene glycol-linked amino acid/dipeptide diester prodrugs of oleanolic acid for PepT1-mediated transport: synthesis, intestinal permeability, and pharmacokinetics.

PubMed

Cao, Feng; Gao, Yahan; Wang, Meng; Fang, Lei; Ping, Qineng

2013-04-01

In our previous studies, ethylene glycol-linked amino acid diester prodrugs of oleanolic acid (OA), a Biopharmaceutics Classification System (BCS) class IV drug, designed to target peptide transporter 1 (PepT1) have been synthesized and evaluated. Unlike ethylene glycol, propylene glycol is of very low toxicity in vivo. In this study, propylene glycol was used as a linker to further compare the effect of the type of linker on the stability, permeability, affinity, and bioavailability of the prodrugs of OA. Seven diester prodrugs with amino acid/dipeptide promoieties containing L-Val ester (7a), L-Phe ester (7b), L-Ile ester (7c), D-Val-L-Val ester (9a), L-Val-L-Val ester (9b), L-Ala-L-Val ester (9c), and L-Ala-L-Ile ester (9d) were designed and successfully synthesized. In situ rat single-pass intestinal perfusion (SPIP) model was performed to screen the effective permeability (P(eff)) of the prodrugs. P(eff) of 7a, 7b, 7c, 9a, 9b, 9c, and 9d (6.7-fold, 2.4-fold, 1.24-fold, 1.22-fold, 4.15-fold, 2.2-fold, and 1.4-fold, respectively) in 2-(N-morpholino)ethanesulfonic acid buffer (MES) with pH 6.0 showed significant increase compared to that of OA (p < 0.01). In hydroxyethyl piperazine ethanesulfonic acid buffer (HEPES) of pH 7.4, except for 7c, 9a, and 9d, P(eff) of the other prodrugs containing 7a (5.2-fold), 7b (2.0-fold), 9b (3.1-fold), and 9c (1.7-fold) exhibited significantly higher values than that of OA (p < 0.01). In inhibition studies with glycyl-sarcosine (Gly-Sar, a typical substrate of PepT1), P(eff) of 7a (5.2-fold), 7b (2.0-fold), 9b (3.1-fold), and 9c (2.3-fold) had significantly reduced values (p < 0.01). Compared to the apparent permeability coefficient (P(app)) of OA with Caco-2 cell monolayer, significant enhancement of the P(app) of 7a (5.27-fold), 9b (3.31-fold), 9a (2.26-fold), 7b (2.10-fold), 7c (2.03-fold), 9c (1.87-fold), and 9d (1.39-fold) was also observed (p < 0.01). Inhibition studies with Gly-Sar (1 mM) showed that P(app) of 7a, 9b, and 9c significantly reduced by 1.3-fold, 1.6-fold, and 1.4-fold (p < 0.01), respectively. These results may be attributed to PepT1-mediated transport and their differential affinity toward PepT1. According to the permeability and affinity, 7a and 9b were selected in the pharmacokinetic studies in rats. Compared with group OA, C(max) for group 7a and 9b was enhanced to 3.04-fold (p < 0.01) and 2.62-fold (p < 0.01), respectively. AUC(0→24) was improved to 3.55-fold (p < 0.01) and 3.39-fold (p < 0.01), respectively. Compared to the ethylene glycol-linked amino acid diester prodrugs of OA in our previous work, results from this study revealed that part of the propylene glycol-linked amino acid/dipeptide diester prodrugs showed better stability, permeability, affinity, and bioavailability. In conclusion, propylene glycol-linked amino acid/dipeptide diester prodrugs of OA may be suitable for PepT1-targeted prodrugs of OA to improve the oral bioavailability of OA.

Tanovea® for the treatment of lymphoma in dogs.

PubMed

De Clercq, Erik

2018-05-17

Tanovea® (first named GS-9219, then VDC-1101, generic name: rabacfosadine) is a pro-prodrug or "double" prodrug of PMEG [9-(2-phosphonylmethoxyethyl)guanine], which has been conditionally approved by the US FDA (Food and Drug Administration) for the treatment of lymphoma in dogs. Tanovea has been demonstrated to be effective against non-Hodgkin's lymphoma (NHL) in dogs, as well as canine cutaneous T-cell lymphoma, spontaneous canine multiple myeloma, naïve canine multicentric lymphoma and relapsed canine B-cell lymphoma. As a double prodrug of PMEG, GS-9219 is first converted intracellularly by hydrolysis to cPr-PMEDAP, then deaminated to PMEG, which is then phosphorylated twice to its active metabolite PMEGpp, acting at the level of the cellular DNA polymerases. Copyright © 2018 Elsevier Inc. All rights reserved.

A 2'-deoxy-2'-fluoro-2'-C-methyl uridine cyclopentyl carbocyclic analog and its phosphoramidate prodrug as inhibitors of HCV NS5B polymerase.

PubMed

Liu, Jian; Du, Jinfa; Wang, Peiyuan; Nagarathnam, Dhanapalan; Espiritu, Christine L; Bao, Haiying; Murakami, Eisuke; Furman, Phillip A; Sofia, Michael J

2012-04-01

The 2 '-deoxy-2 '-fluoro-2 '-C-methyluridine nucleotide prodrug, PSI-7851 and its single diastereomer PSI-7977 have displayed potent antiviral activity against hepatitis C virus in clinical trials, and PSI-7977 is currently in Phase III studies. As part of our SAR study of the 2 '-deoxy-2 '-fluoro-2 '- C-methyl class of nucleosides, we prepared the cyclopentyl carbocyclic uridine analog 11 and its phosphoramidate prodrug 15. Both 11 and 15 were shown not to inhibit HCV replication. This lack of activity might be attributed to the inability of the monophosphate to be converted to the corresponding diphosphate or triphosphate or the inactivity of triphosphate of 11 as an inhibitor of the polymerase.

Novel derivatives of 6-mercaptopurine: synthesis, characterization and antiproliferative activities of S-allylthio-mercaptopurines.

PubMed

Miron, T; Arditti, F; Konstantinovski, L; Rabinkov, A; Mirelman, D; Berrebi, A; Wilchek, M

2009-02-01

Biologically active S-allylthio derivatives of 6-mercaptopurine (6-MP) and 6-mercaptopurine riboside (6-MPR) were synthesized. The products, S-allylthio-6-mercaptopurine (SA-6MP) and S-allylthio-6-mercaptopurine riboside (SA-6MPR) were characterized. The antiproliferative activity of the new prodrugs was tested on human leukemia and monolayer cell lines, and compared to that of their parent reactants. The new prodrugs acted by a concentration-dependent mechanism. They inhibited cell proliferation and induced-apoptosis more efficiently than the parent molecules. Leukemia cell lines were more sensitive to the new prodrugs than monolayer cell lines. Higher hydrophobicity of the derivatives improves their penetration into cells, where upon reaction with glutathione, S-allylthioglutathione (GSSA) is formed, and 6-MP or 6-MPR is released for further processing.

Alkylation of 6-mercaptopurine (6-MP) with N-alkyl-N-alkoxycarbonylaminomethyl chlorides: S6-(N-alkyl-N-alkoxycarbonyl)aminomethyl-6-MP prodrug structure effect on the dermal delivery of 6-MP.

PubMed

Siver, K G; Sloan, K B

1990-01-01

The S6-(N-alkyl-N-alkoxycarbonyl)aminomethyl-6-MP (6-CARB-6-MP) prodrugs 5-20 were synthesized from the reaction of 6-MP with N-alkyl-N-alkyoxycarbonylaminomethyl chlorides (4) in dimethyl sulfoxide in overall yields of 5-62%, depending on the N-alkyl and the alkoxy groups involved. The derivatives were fully characterized by spectral and microanalyses. The assignment of the substitution pattern as S6-alkyl was based on comparisons of the UV, 1H NMR and 13C NMR spectra with model compounds. A S6, 9-bis-alkyl derivative was obtained from the reaction of 2 equivalents of 4 with 6-MP but the product was unstable and decomposed on standing to a 9-alkyl derivative. The 6-CARB-6-MP prodrugs reverted to 6-MP in water by an SN1-type mechanism involving unimolecular charge separation in the transition state of the rate determining step. There was no effect of dermal enzymes on the rate of hydrolysis. The solubilities in isopropyl myristate (IPM) for all of the 6-CARB-6-MP prodrugs were significantly greater than the solubility of 6-MP in IPM but only one prodrug (5) was apparently even as soluble as 6-MP in water. Selected 6-CARB-6-MP prodrugs were examined in diffusion cell experiments. Only the N-methyl-N-methoxycarbonyl derivative 5 gave a steady-state rate of delivery of 6-MP from IPM that was significantly greater than the steady-state rate of delivery of 6-MP from 6-MP in IPM. All the other derivatives gave steady-state rates of delivery of 6-MP from IPM that were either not significantly different, or were significantly lower than the rate obtained from 6-MP in IPM. In all cases, the effect of the 6-CARB-6-MP:IPM suspensions on the permeability of the skin, as determined by the second application flux of theophylline:propylene glycol, was of the same magnitude as the effect of IPM alone.

Electrospun poly-l-lactide scaffold for the controlled and targeted delivery of a synthetically obtained Diclofenac prodrug to treat actinic keratosis.

PubMed

Piccirillo, Germano; Bochicchio, Brigida; Pepe, Antonietta; Schenke-Layland, Katja; Hinderer, Svenja

2017-04-01

Actinic Keratosis' (AKs) are small skin lesions that are related to a prolonged sun-damage, which can develop into invasive squamous cell carcinoma (SCC) when left untreated. Effective, specific and well tolerable therapies to cure AKs are still of great interest. Diclofenac (DCF) is the current gold standard for the local treatment of AKs in terms of costs, effectiveness, side effects and tolerability. In this work, an electrospun polylactic acid (PLA) scaffold loaded with a synthetic DCF prodrug was developed and characterized. Specifically, the prodrug was successfully synthetized by binding DCF to a glycine residue via solid phase peptide synthesis (SPPS) and then incorporated in an electrospun PLA scaffold. The drug encapsulation was verified using multiphoton microscopy (MPM) and its scaffold release was spectrophotometrically monitored and confirmed with MPM. The scaffold was further characterized with scanning electron microscopy (SEM), tensile testing and contact angle measurements. Its biocompatibility was verified by performing a cell proliferation assay and compared to PLA scaffolds containing the same amount of DCF sodium salt (DCFONa). Finally, the effect of the electrospun scaffolds on human dermal fibroblasts (HDFs) morphology and metabolism was investigated by combining MPM with fluorescence lifetime imaging microscopy (FLIM). The obtained results suggest that the obtained scaffold could be suitable for the controlled and targeted delivery of the synthesized prodrug for the treatment of AKs. Electrospun scaffolds are of growing interest as materials for a controlled drug delivery. In this work, an electrospun polylactic acid scaffold containing a synthetically obtained Diclofenac prodrug is proposed as a novel substrate for the topical treatment of actinic keratosis. A controlled drug delivery targeted to the area of interest could enhance the efficacy of the therapy and favor the healing process. The prodrug was synthesized via solid phase, employing a clean and versatile approach to obtain Diclofenac derivatives. Here, we used multiphoton microscopy to image drug encapsulation within the fibrous scaffold and fluorescence lifetime imaging microscopy to investigate Diclofenac effects and potential mechanisms of action. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

PET imaging of β-glucuronidase activity by an activity-based 124I-trapping probe for the personalized glucuronide prodrug targeted therapy.

PubMed

Su, Yu-Cheng; Cheng, Ta-Chun; Leu, Yu-Ling; Roffler, Steve R; Wang, Jaw-Yuan; Chuang, Chih-Hung; Kao, Chien-Han; Chen, Kai-Chuan; Wang, Hsin-Ell; Cheng, Tian-Lu

2014-12-01

Beta-glucuronidase (βG) is a potential biomarker for cancer diagnosis and prodrug therapy. The ability to image βG activity in patients would assist in personalized glucuronide prodrug cancer therapy. However, whole-body imaging of βG activity for medical usage is not yet available. Here, we developed a radioactive βG activity-based trapping probe for positron emission tomography (PET). We generated a (124)I-tyramine-conjugated difluoromethylphenol beta-glucuronide probe (TrapG) to form (124)I-TrapG that could be selectively activated by βG for subsequent attachment of (124)I-tyramine to nucleophilic moieties near βG-expressing sites. We estimated the specificity of a fluorescent FITC-TrapG, the cytotoxicity of tyramine-TrapG, and the serum half-life of (124)I-TrapG. βG targeting of (124)I-TrapG in vivo was examined by micro-PET. The biodistribution of (131)I-TrapG was investigated in different organs. Finally, we imaged the endogenous βG activity and assessed its correlation with therapeutic efficacy of 9-aminocamptothecin glucuronide (9ACG) prodrug in native tumors. FITC-TrapG showed specific trapping at βG-expressing CT26 (CT26/mβG) cells but not in CT26 cells. The native TrapG probe possessed low cytotoxicity. (124)I-TrapG preferentially accumulated in CT26/mβG but not CT26 cells. Meanwhile, micro-PET and whole-body autoradiography results demonstrated that (124)I-TrapG signals in CT26/mβG tumors were 141.4-fold greater than in CT26 tumors. Importantly, Colo205 xenografts in nude mice that express elevated endogenous βG can be monitored by using infrared glucuronide trapping probes (NIR-TrapG) and suppressed by 9ACG prodrug treatment. (124)I-TrapG exhibited low cytotoxicity allowing long-term monitoring of βG activity in vivo to aid in the optimization of prodrug targeted therapy. ©2014 American Association for Cancer Research.

A glutathione-responsive sulfur dioxide polymer prodrug as a nanocarrier for combating drug-resistance in cancer chemotherapy.

PubMed

Shen, Wei; Liu, Wanguo; Yang, Huailin; Zhang, Peng; Xiao, Chunsheng; Chen, Xuesi

2018-02-03

Multidrug resistance (MDR) in cancer remains a significant challenge for curing cancer by chemotherapy. In this work, a kind of glutathione (GSH)-responsive polymer prodrug of SO 2 was designed and synthesized, which presented synergistic effect with doxorubicin (DOX) for combating MCF-7 ADR human breast cancer cell. Firstly, a small molecular prodrug of SO 2 , N-(3-azidopropyl)-2,4-dinitrobenzenesulfonamide (AP-DNs), was chemically conjugated onto the side chain of methoxy poly (ethylene glycol)-block-poly (γ-propargyl-l-glutamate) (mPEG-PPLG) block copolymer to generate an amphiphilic polymer prodrug of SO 2 , mPEG-PLG (DNs). The obtained mPEG-PLG (DNs) prodrug could self-assemble into micelles in aqueous media and release SO 2 rapidly in response to thiol compounds. Then, DOX was loaded into mPEG-PLG (DNs) nanoparticles with ultrahigh drug-loading efficiency (97.3%). In vitro drug release tests indicated that the DOX-loaded nanoparticles could simultaneously release SO 2 and DOX by GSH triggering. Moreover, the effective cellular uptake of the DOX-loaded nanoparticles and subsequent intracellular release of SO 2 and DOX were verified by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) analyses. The released SO 2 could promote the reactive oxygen species (ROS) level in tumor cells, which thereby resulted in oxidative damages of cancer cells, together with restoration of MCF-7 ADR cells sensitivity to DOX. As a result, the released DOX and SO 2 showed synergistic therapeutic effect against MCF-7 ADR cells. In vivo antitumor evaluation further indicated that, compared with free DOX, the DOX-loaded nanoparticles exhibited better antitumor effect in a MCF-7 ADR-xenografted nude mice model while had lower system toxicity. Overall, we demonstrated, for the first time, that a SO 2 polymer prodrug, acting as a stimuli-responsive nanocarrier to codeliver DOX, can efficiently inhibit the proliferation of MDR tumor cells, which may offer a new weapon for combating MDR in cancer therapy. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evaluation of Telavancin Alone and Combined with Ceftaroline or Rifampin against Methicillin-Resistant Staphylococcus aureus (MRSA) in an in vitro Biofilm Model.

PubMed

Jahanbakhsh, Seyedehameneh; Singh, Nivedita B; Yim, Juwon; Rose, Warren E; Rybak, Michael J

2018-05-21

Biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) infections are challenging due to increasing antibiotic resistance. Synergistic activity of lipopeptides and lipoglycopeptides with β-lactams has been demonstrated for MRSA, but little is known about biofilm-embedded organisms. Our objective was to evaluate two telavancin (TLV) dosage regimens (7.5 mg/kg and 10 mg/kg q 24h)alone and in combination with ceftaroline (CPT) (600 mg q 8 h) or rifampin (RIF) (450 mg q 12h) against two biofilm-producing MRSA (494 and N315). Pharmacokinetic/pharmacodynamic CDC biofilm reactor models with polyurethane coupons were used to evaluate the efficacy of the antibiotic combinations over 72h. Overall, there were no significant differences observed between the two TLV dosing regimens either alone or in combination with RIF or CPT against these strains. Both TLV dosing regimens or CPT alone demonstrated killing but did not reach bactericidal reduction at 72h. However, both TLV regimens in combination with RIF demonstrated enhanced activity against both strains with a rapid decrease in CFU/ml at 4h that was bactericidal and maintained over the 72h experiment (-Δ 3.75 log10CFU/ml from baseline; P <0.0001). Of interest, no enhanced activity was observed for TLV combined with CPT. No development of resistance was observed in any of the combination models. However, resistance to RIF developed as early as 24h with MIC values exceeding 32 mg/L. Our results show that TLV plus RIF displayed therapeutic improvement against biofilm-producing MRSA. These results suggest that the TLV 7.5 and 10mg/kg q24h are equally effective in eradicating biofilm-associated MRSA in vitro . Copyright © 2018 American Society for Microbiology.

Lipid prodrug nanocarriers in cancer therapy.

PubMed

Mura, Simona; Bui, Duc Trung; Couvreur, Patrick; Nicolas, Julien

2015-06-28

Application of nanotechnology in the medical field (i.e., nanomedicine) plays an important role in the development of novel drug delivery methods. Nanoscale drug delivery systems can indeed be customized with specific functionalities in order to improve the efficacy of the treatments. However, despite the progresses of the last decades, nanomedicines still face important obstacles related to: (i) the physico-chemical properties of the drug moieties which may reduce the total amount of loaded drug; (ii) the rapid and uncontrolled release (i.e., burst release) of the encapsulated drug after administration and (iii) the instability of the drug in biological media where a fast transformation into inactive metabolites can occur. As an alternative strategy to alleviate these drawbacks, the prodrug approach has found wide application. The covalent modification of a drug molecule into an inactive precursor from which the drug will be freed after administration offers several benefits such as: (i) a sustained drug release (mediated by chemical or enzymatic hydrolysis of the linkage between the drug-moiety and its promoiety); (ii) an increase of the drug chemical stability and solubility and, (iii) a reduced toxicity before the metabolization occurs. Lipids have been widely used as building blocks for the design of various prodrugs. Interestingly enough, these lipid-derivatized drugs can be delivered through a nanoparticulate form due to their ability to self-assemble and/or to be incorporated into lipid/polymer matrices. Among the several prodrugs developed so far, this review will focus on the main achievements in the field of lipid-based prodrug nanocarriers designed to improve the efficacy of anticancer drugs. Gemcitabine (Pubchem CID: 60750); 5-fluorouracil (Pubchem CID: 3385); Doxorubicin (Pubchem CID: 31703); Docetaxel (Pubchem CID: 148124); Methotrexate (Pubchem CID: 126941); Paclitaxel (Pubchem CID: 36314). Copyright © 2015 Elsevier B.V. All rights reserved.

In Vitro Virology Profile of Tenofovir Alafenamide, a Novel Oral Prodrug of Tenofovir with Improved Antiviral Activity Compared to That of Tenofovir Disoproxil Fumarate

PubMed Central

Stepan, George; Tian, Yang; Miller, Michael D.

2015-01-01

Tenofovir alafenamide (TAF) is an investigational oral prodrug of the HIV-1 nucleotide reverse transcriptase inhibitor tenofovir (TFV). Tenofovir disoproxil fumarate (TDF) is another TFV prodrug, widely used for the treatment of HIV-1 infection. TAF is converted mostly intracellularly to TFV and, in comparison to TDF, achieves higher tenofovir diphosphate (TFV-DP) levels in peripheral blood mononuclear cells. As a result, TAF has demonstrated potent anti-HIV-1 activity at lower doses than TDF in monotherapy studies. Here, the in vitro virology profile of TAF was evaluated and compared to that of TDF. TAF displayed potent antiviral activity against all HIV-1 groups/subtypes, as well as HIV-2. TAF exhibited minimal changes in the drug concentration needed to inhibit 50% of viral spread (EC50) upon removal of the prodrug, similar to TDF, demonstrating intracellular antiviral persistence. While TAF and TDF exhibited comparable potencies in the absence of serum pretreatment, TAF maintained activity in the presence of human serum, whereas TDF activity was significantly reduced. This result demonstrates TAF's improved plasma stability over TDF, which is driven by the different metabolic pathways of the two prodrugs and is key to TAF's improved in vivo antiviral activity. The activity of TAF is specific for HIV, as TAF lacked activity against a large panel of human viruses, with the exception of herpes simplex virus 2, where weak TAF antiviral activity was observed, as previously observed with TFV. Finally, in vitro combination studies with antiretroviral drugs from different classes showed additive to synergistic interactions with TAF, consistent with ongoing clinical studies with TAF in fixed-dose combinations with multiple other antiretroviral drugs for the treatment of HIV. PMID:26149992

Pharmacokinetic and pharmacodynamic assessment of bioavailability for two prodrugs of methylprednisolone

PubMed Central

Daley-Yates, P. T.; Gregory, A. J.; Brooks, C. D.

1997-01-01

Aims The aim of this study was to establish whether pharmacokinetic differences between two pro-drugs of methylprednisolone (MP) are likely to be of clinical significance. Methods This study was a single-blind, randomized, crossover design comparing the bioequivalence of MP released from the pro-drugs Promedrol (MP suleptanate) and Solu-Medrol (MP succinate) after a single 250 mg (MP equivalent) intramuscular injection to 20 healthy male volunteers. Bioequivalence was assessed by conventional pharmacokinetic analysis, by measuring pharmacodynamic responses plus a novel approach using pharmacokinetic/pharmacodynamic modeling. The main measure of pharmacodynamic response was whole blood histamine (WBH), a measure of basophil numbers. Results The MP Cmax was less for MP suleptanate due to a longer absorption half-life of the prodrug from the intramuscular injection site. The bioavailability of MP was equivalent when based on AUC with a MP suleptanate median 108% of the MP succinate value (90% CI: 102–114%). For Cmax the MP suleptanate median was 81% of the MP succinate value (90% CI: 75–88%). The tmax for MP from MP suleptanate was delayed relative to MP succinate. The median difference was 200% (90% non-parametric CI: 141–283%). The area under the WBH effect-time curve (AUEC) and the maximum response (Emax ) were found to be equivalent (90% CI: 98–113% and 93–109% respectively). The maximum changes in other white blood cell counts, blood glucose concentration and the parameters of the pharmacodynamic sigmoid Emax model (EC50, Emax and γ) were also not significantly different between prodrugs. Conclusions MP suleptanate is an acceptable pharmaceutical alternative to MP succinate. The use of both pharmacokinetic and pharmacodynamic response data together gives greater confidence in the conclusions compared with those based only on conventional pharmacokinetic bioequivalence analysis. PMID:9205819

Nanostructured self-assembly materials from neat and aqueous solutions of C18 lipid pro-drug analogues of Capecitabine—a chemotherapy agent. Focus on nanoparticulate cubosomes™ of the oleyl analogue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Xiaojuan; Moghaddam, Minoo J.; Sagnella, Sharon M.

2014-09-24

A series of prodrug analogues based on the established chemotherapy agent, 5-fluorouracil, have been prepared and characterized. C18 alkyl and alkenyl chains with increasing degree of unsaturation were attached to the N 4 position of the 5-fluorocytosine (5-FC) base via a carbamate bond. Physicochemical characterization of the prodrug analogues was carried out using a combination of differential scanning calorimetry, cross-polarized optical microscopy, X-ray diffraction and small-angle X-ray scattering. The presence of a monounsaturated oleyl chain was found to promote lyotropic liquid crystalline phase formation in excess water with a fluid lamellar phase observed at room temperature and one or moremore » bicontinuous cubic phases at 37 °C. The bulk phase was successfully dispersed into liposomes or cubosomes at room and physiological temperature respectively. In vitro toxicity of the nanoparticulate 5-FCOle dispersions was evaluated against several normal and cancer cell types over a 48 h period and exhibited an IC 50 of -100 μM against all cell types. The in vivo efficacy of 5-FCOle cubosomes was assessed against the highly aggressive mouse 4T1 breast cancer model and compared to Capecitabine (a water-soluble commercially available 5-FU prodrug) delivered at the same dosages. After 21 days of treatment, the 0.5 mmol 5-FCOle treatment group exhibited a significantly smaller average tumour volume than all other treatment groups including Capecitabine at similar dosage. These results exemplify the potential of self-assembled amphiphile prodrugs for delivery of bioactives in vivo.« less

Pharmacokinetics of penciclovir after oral administration of its prodrug famciclovir to horses.

PubMed

Tsujimura, Koji; Yamada, Masayuki; Nagata, Shun-ichi; Yamanaka, Takashi; Nemoto, Manabu; Kondo, Takashi; Kurosawa, Masahiko; Matsumura, Tomio

2010-03-01

We investigated the pharmacokinetics of penciclovir after oral administration of its prodrug famciclovir to horses. Following an oral dose of famciclovir at 20 mg/kg, maximum plasma concentrations of penciclovir occurred between 0.75 and 1.5 hr (mean 0.94 + or - 0.38 hr) after dosing and were in the range 2.22 to 3.56 microg/ml (mean 2.87 + or - 0.61 microg/ml). The concentrations of penciclovir declined in a biphasic manner after the peak concentration was attained. The mean half-life of the rapid elimination phase was 1.73 + or - 0.34 hr whereas that of the slow elimination phase was 34.34 + or - 13.93 hr. These pharmacokinetic profiles observed were similar to those of another antiherpesvirus drug, acyclovir, previously reported in horses following oral dosing of its prodrug valacyclovir.

Photolabile ruthenium complexes to cage and release a highly cytotoxic anticancer agent.

PubMed

Wei, Jianhua; Renfrew, Anna K

2018-02-01

CHS-828 (N-(6-(4-chlorophenoxy)hexyl)-N'-cyano-N″-4-pyridyl guanidine) is an anticancer agent with low bioavailability and high systemic toxicity. Here we present an approach to improve the therapeutic profile of the drug using photolabile ruthenium complexes to generate light-activated prodrugs of CHS-828. Both prodrug complexes are stable in the dark but release CHS-828 when irradiated with visible light. The complexes are water-soluble and accumulate in tumour cells in very high concentrations, predominantly in the mitochondria. Both prodrug complexes are significantly less cyototoxic than free CHS-828 in the dark but their toxicity increases up to 10-fold in combination with visible light. The cellular responses to light treatment are consistent with release of the cytotoxic CHS-828 ligand. Copyright © 2017 Elsevier Inc. All rights reserved.

Persuader sex differences and peer pressure effects on attitudes toward drug abuse.

PubMed

Stone, C I; Shute, R E

1977-01-01

This experiment was performed to assess the effects of the experimental confederates' sex and contrived group peer pressure on the drug attitudes of male college students. Subjects were exposed to all-male or all-female groups of experimental confederates (ersuaders) who expressed either extremely pro-drug or anti-drug sentiments in a guided group discussion. A drug attitude survey encompassing four drug categories was administered immediately following the discussion. Significant differences were found between subjects in the anti-drug and pro-drug groups. The sex effect data indicated that the male subjects reported more liberal drug attitudes following exposure to female persuaders in both the anti-and pro-drug treatment conditions for the more socially acceptable drugs such as marijuana, hashish, and stimulants. Implications of these findings for possible prevention and intervention strategies and for further research are discussed.

Synthesis and properties of a new water-soluble prodrug of the adenosine A 2A receptor antagonist MSX-2.

PubMed

Vollmann, Karl; Qurishi, Ramatullah; Hockemeyer, Jörg; Müller, Christa E

2008-02-12

The compound L-valine-3-{8-[(E)-2-[3-methoxyphenyl)ethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4) was synthesized as an amino acid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to be stable in artificial gastric acid, but readily cleaved by pig liver esterase.

Quantitative insight into the design of compounds recognized by the L-type amino acid transporter 1 (LAT1).

PubMed

Ylikangas, Henna; Malmioja, Kalle; Peura, Lauri; Gynther, Mikko; Nwachukwu, Emmanuel O; Leppänen, Jukka; Laine, Krista; Rautio, Jarkko; Lahtela-Kakkonen, Maija; Huttunen, Kristiina M; Poso, Antti

2014-12-01

L-Type amino acid transporter 1 (LAT1) is a transmembrane protein expressed abundantly at the blood-brain barrier (BBB), where it ensures the transport of hydrophobic acids from the blood to the brain. Due to its unique substrate specificity and high expression at the BBB, LAT1 is an intriguing target for carrier-mediated transport of drugs into the brain. In this study, a comparative molecular field analysis (CoMFA) model with considerable statistical quality (Q(2) =0.53, R(2) =0.75, Q(2) SE=0.77, R(2) SE=0.57) and good external predictivity (CCC=0.91) was generated. The model was used to guide the synthesis of eight new prodrugs whose affinity for LAT1 was tested by using an in situ rat brain perfusion technique. This resulted in the creation of a novel LAT1 prodrug with L-tryptophan as the promoiety; it also provided a better understanding of the molecular features of LAT1-targeted high-affinity prodrugs, as well as their promoiety and parent drug. The results obtained will be beneficial in the rational design of novel LAT1-binding prodrugs and other compounds that bind to LAT1. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Abrogation of Microsatellite-instable Tumors Using a Highly Selective Suicide Gene/Prodrug Combination

PubMed Central

Ferrás, Cristina; Oude Vrielink, Joachim AF; Verspuy, Johan WA; te Riele, Hein; Tsaalbi-Shtylik, Anastasia; de Wind, Niels

2009-01-01

A substantial fraction of sporadic and inherited colorectal and endometrial cancers in humans is deficient in DNA mismatch repair (MMR). These cancers are characterized by length alterations in ubiquitous simple sequence repeats, a phenotype called microsatellite instability. Here we have exploited this phenotype by developing a novel approach for the highly selective gene therapy of MMR-deficient tumors. To achieve this selectivity, we mutated the VP22FCU1 suicide gene by inserting an out-of-frame microsatellite within its coding region. We show that in a significant fraction of microsatellite-instable (MSI) cells carrying the mutated suicide gene, full-length protein becomes expressed within a few cell doublings, presumably resulting from a reverting frameshift within the inserted microsatellite. Treatment of these cells with the innocuous prodrug 5-fluorocytosine (5-FC) induces strong cytotoxicity and we demonstrate that this owes to multiple bystander effects conferred by the suicide gene/prodrug combination. In a mouse model, MMR-deficient tumors that contained the out-of-frame VP22FCU1 gene displayed strong remission after treatment with 5-FC, without any obvious adverse systemic effects to the mouse. By virtue of its high selectivity and potency, this conditional enzyme/prodrug combination may hold promise for the treatment or prevention of MMR-deficient cancer in humans. PMID:19471249

Hydrazone linked doxorubicin-PLA prodrug nanoparticles with high drug loading

NASA Astrophysics Data System (ADS)

Gatti, Simone; Agostini, Azzurra; Capasso Palmiero, Umberto; Colombo, Claudio; Peviani, Marco; Biffi, Alessandra; Moscatelli, Davide

2018-07-01

An optimal drug delivery system should be characterized by biocompatibility, biodegradability, high drug loading and favorable drug release profile. To achieve this goal a hydrazone linked doxorubicin-poly(lactic acid) prodrug (PLA-DOX) was synthesized by the functionalization of a short polymer chain produced by ring opening polymerization. The hydrophobic prodrug generated in this way was nanoprecipitated using a block copolymer to form polymeric nanoparticles (NPs) with a quantitative loading efficiency and a high and tunable drug loading. The effects of the concentration of the PLA-DOX prodrug and surfactant were studied by dynamic light scattering showing a range of NP size between 50 and 90 nm and monodispersed size distributions with polydispersity indexes lower then 0.27 up to a maximum DOX concentration of 27% w/w. The release profile of DOX from these NPs, tested at different pH conditions, showed a higher release rate in acidic conditions, consistent with the nature of the hydrazone bond which was used to conjugate the drug to the polymer. In vitro cytotoxicity studies performed on BV2 microglia-like cell line highlighted a specific cytotoxic effect of these NPs suggesting the maintenance of the drug efficacy and a modified release profile upon encapsulation of DOX in the NPs.

Effects of histone deacetylase inhibitory prodrugs on epigenetic changes and DNA damage response in tumor and heart of glioblastoma xenograft.

PubMed

Tarasenko, Nataly; Nudelman, Abraham; Rozic, Gabriela; Cutts, Suzanne M; Rephaeli, Ada

2017-08-01

The histone deacetylase (HDAC) inhibitory prodrugs of butyric (AN7) and valproic (AN446) acids, which release the active acids upon metabolic degradation, were studied examining their differential effects on the viability, HDAC inhibitory activity and the DNA damage response (DDR), in glioblastoma cell and normal human astrocytes (NHAs). In xenografts of glioblastoma, AN7 or AN446 given or the combination of each of them with Dox augmented the anticancer activity of Dox and protected the heart from its toxicity. In order to determine the processes underlying these opposing effects, the changes induced by these treatments on the epigenetic landscape, the DDR, and fibrosis were compared in tumors and hearts of glioblastoma xenografts. The potency of AN7 and AN446 as HDAC inhibitors was correlated with their effects on the viability of the cancer and non-cancer cells. The prodrugs affected the epigenetic landscape and the DDR in a tissue-specific and context-dependent manner. Findings suggest that the selectivity of the prodrugs could be attributed to their different effects on histone modification patterns in normal vs. transformed tissues. Further studies are warranted to substantiate the potential of AN446 as a new anticancer drug for glioblastoma patients.

Amino acid and peptide prodrugs of diphenylpropanones positive allosteric modulators of α7 nicotinic receptors with analgesic activity.

PubMed

Balsera, Beatriz; Mulet, José; Sala, Salvador; Sala, Francisco; de la Torre-Martínez, Roberto; González-Rodríguez, Sara; Plata, Adrián; Naesens, Lieve; Fernández-Carvajal, Asia; Ferrer-Montiel, Antonio; Criado, Manuel; Pérez de Vega, María Jesús; González-Muñiz, Rosario

2018-01-01

α7 Nicotinic acetylcholine receptors (nAChRs) are ion channels implicated in a number of CNS pathological processes, including pain and psychiatric, cognitive and inflammatory diseases. Comparing with orthosteric agonism, positive allosteric modulation of these channels constitutes an interesting approach to achieve selectivity versus other nicotinic receptors. We have recently described new chalcones and 1,3-diphenylpropanones as positive allosteric modulators (PAMs) of α7 nAChRs, which proved to have good analgesic activities but poor pharmacokinetic properties. Here we report the preparation of amino acid and peptide derivatives as prodrugs of these modulators with the aim of improving their in vivo biological activity. While the valine derivative showed very short half life in aqueous solutions to be considered a prodrug, Val-Val and Val-Pro-Val are suitable precursors of the parent 1,3-diphenylpropanones, via chemical and enzymatic transformation, respectively. Compounds 19 (Val-Val) and 21 (Val-Pro-Val), prodrugs of the 2',5',4-trihydroxy-1,3-diphenylpropan-1-one 3, showed significant antinociceptive activity in in vivo assays. The best compound, 21, displayed a better profile in the analgesia test than its parent compound 3, exhibiting about the same potency but long-lasting effects. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Synthesis of pro-prodrugs L-lysine based for 5-aminosalicylic acid and 6-mercaptopurine colon specific release.

PubMed

Trombino, Sonia; Cassano, Roberta; Cilea, Alessia; Ferrarelli, Teresa; Muzzalupo, Rita; Picci, Nevio

2011-11-28

The aim of this work is to design, prepare and characterize L-lysine based prodrugs capable of targeting 6-mercaptopurine to the colon, an anti-tumor and immunosuppressant drug, and 5-aminosalicylic acid (5-ASA), drug of choice for inflammatory bowel disease (IBD). More specifically, Nɛ-feruloyl-S-(6-purinyl)-L-lysine and Nɛ-acryloyl-S-(6-purinyl)-L-lysine were synthesized and then characterized by FT-IR, (1)H-NMR and GC/MS spectroscopies. The ability of feruloyl derivative in inhibiting lipid peroxidation in rat liver microsomal membranes, induced in vitro by tert-butyl hydroperoxide as source of free radicals, was evaluated. Moreover, Nɛ-acryloyl-S-(6-purinyl)-L-lysine, polymerizable prodrug, was used to microspheres realization for 5-ASA release. These lasts, obtained by emulsion inverse technique, were characterized by light scattering and scanning electron microscopy (SEM) analysis. The microspheres equilibrium swelling degree was evaluated and showed good swelling behaviour in simulating colonic fluids. Results confirm the possibility that the application range of L-lysine prodrug can be extended to the treatment of intestinal diseases whose conventional therapy envisages medications with serious side effects that, thanks to this new strategy, can be minimized in an optimal way. Copyright © 2011 Elsevier B.V. All rights reserved.

New prodrugs of metformin do not influence the overall haemostasis potential and integrity of the erythrocyte membrane.

PubMed

Markowicz-Piasecka, Magdalena; Sikora, Joanna; Mateusiak, Łukasz; Mikiciuk-Olasik, Elżbieta; Huttunen, Kristiina M

2017-09-15

Although metformin, an oral anti-diabetic drug, has been found to have multidirectional effects over the past decade, it is characterised by unfavourable pharmacokinetic properties. This study discusses the effects of metformin, phenformin and three prodrugs of metformin on the haemostasis and integrity of Red Blood Cells (RBCs). The influence of examined biguanide derivatives on haemostasis was evaluated spectrophotometrically by clot formation and lysis test (CL-test) at 405nm. The extrinsic and intrinsic coagulation pathway were examined by measuring the PT (Prothrombin Time) and aPTT (Activated Partial Tromboplastin Time). Haemolysis assay, microscopy and flow cytometry studies were used to assess the effect of the tested compounds on RBCs. Although none of the tested biguanide derivatives significantly influenced the overall potential of clot formation and fibrinolysis (CL AUC constants), statistically significant changes were seen in the values of the kinetic parameters of fibrinolysis. Furthermore, only prodrug 2, with an 8-carbon alkyl chain, unfavourably affected RBCs by interaction with the erythrocyte membrane leading to significant haemolysis. Our results provide a further insight into the effects of metformin and its prodrugs on haemostasis and RBCs and underscore the necessity for further research. Copyright © 2017 Elsevier B.V. All rights reserved.

The antiproliferative cytostatic effects of a self-activating viridin prodrug

PubMed Central

Smith, Adam; Blois, Joseph; Yuan, Hushan; Aikawa, Elena; Ellson, Christian; Figueiredo, Jose-Luiz; Weissleder, Ralph; Kohler, Rainer; Yaffe, Michael B.; Cantley, Lewis C.; Josephson, Lee

2009-01-01

Although viridins like wortmannin (Wm) have long been examined as anticancer agents, their ability to self-activate has only recently been recognized. Here, we describe the cytostatic effects of a self-activating viridin (SAV), which is an inactive, polymeric prodrug. SAV self-activates to generate a bioactive, fluorescent viridin NBD-Wm with a half-time of 9.2 hours. With cultured A549 cells, 10 µmol/L SAV caused growth arrest without inducing apoptosis or cell death, a cytostatic action markedly different from other chemotherapeutic agents (vinblastine, camptothecin, and paclitaxel). In vivo, a SAV dosing of 1 mg/kg once in 48 hours (i.p.) resulted in growth arrest of an A549 tumor xenograft, with growth resuming when dosing ceased. With a peak serum concentration of SAV of 2.36 µmol/L (at 2 hours post i.p. injection), the concentration of bioactive NBD-Wm was 41 nmol/L based on the partial inhibition of neutrophil respiratory burst. Therefore, SAV was present as an inactive prodrug in serum (peak = 2.36 µmol/L), which generated low concentrations of active viridin (41 nmol/L). SAV is a prodrug, the slowrelease and cytostatic activities of which suggest that it might be useful as a component of metronomic-based chemotherapeutic strategies. PMID:19509266

The Moderating Role of Parental Monitoring on the Influence of Peer Pro-Drug Norms on Alcohol and Cigarette Use among Adolescents in Mexico

ERIC Educational Resources Information Center

Becerra, David; Castillo, Jason T.; Ayón, Cecilia; Blanchard, Kelly N.

2014-01-01

This study utilized data drawn from a study of 980 adolescents living in Tijuana, Mexico, in February 2009 to examine whether parental monitoring had a moderating impact on the influence of peer pro-drug norms on lifetime and past-30-day alcohol and cigarette use among a group of adolescents living along the United States-Mexico border. The…

Strategy for Imidazotetrazine Prodrugs with Anticancer Activity Independent of MGMT and MMR

PubMed Central

2012-01-01

The imidazotetrazine ring is an acid-stable precursor and prodrug of highly reactive alkyl diazonium ions. We have shown that this reactivity can be managed productively in an aqueous system for the generation of aziridinium ions with 96% efficiency. The new compounds are potent DNA alkylators and have antitumor activity independent of the O6-methylguanine-DNA methyltransferase and DNA mismatch repair constraints that limit the use of Temozolomide. PMID:24900418

Far-Red Light Activatable, Multifunctional Prodrug for Fluorescence Optical Imaging and Combinational Treatment

PubMed Central

2015-01-01

We recently developed “photo-unclick chemistry”, a novel chemical tool involving the cleavage of aminoacrylate by singlet oxygen, and demonstrated its application to visible light-activatable prodrugs. In this study, we prepared an advanced multifunctional prodrug, Pc-(L-CA4)2, composed of the fluorescent photosensitizer phthalocyanine (Pc), an SO-labile aminoacrylate linker (L), and a cytotoxic drug combretastatin A-4 (CA4). Pc-(L-CA4)2 had reduced dark toxicity compared with CA4. However, once illuminated, it showed improved toxicity similar to CA4 and displayed bystander effects in vitro. We monitored the time-dependent distribution of Pc-(L-CA4)2 using optical imaging with live mice. We also effectively ablated tumors by the illumination with far-red light to the mice, presumably through the combined effects of photodynamic therapy (PDT) and released chemotherapy drug, without any sign of acute systemic toxicity. PMID:24694092

S-allyl derivatives of 6-mercaptopurine are highly potent drugs against human B-CLL through synergism between 6-mercaptopurine and allicin.

PubMed

Miron, Talia; Wilchek, Meir; Shvidel, Lev; Berrebi, Alain; Arditti, Fabian D

2012-12-01

S-allylthio-6-mercaptopurine and its ribose derivative were tested for anti-leukemic activity, using a human- mouse B-CLL model. The novel prodrugs contain two components, a purine analog, which interferes with DNA synthesis, and an S-allylthio, readily engaging in thiol-disulfide exchange reactions. The latter component targets the redox homeostasis which is more sensitive in leukemic cells, than in normal B-cells. Upon administration, the prodrug permeates cells, instantly reacts with free thiol, forming S-allyl mixed disulfides and releasing purine. Several cycles of thiol-disulfide exchange reactions occur, thus extending the duration of the prodrug effects. The concerted action of 2 components, as compared with purine alone, boosted in vitro apoptotis in B-CLL cells from 10% to 38%, and decreased in vivo engraftment of B-CLL from 30% to 0.7%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inhibition of epithelial ovarian cancer by Minnelide, a water-soluble pro-drug.

PubMed

Rivard, Colleen; Geller, Melissa; Schnettler, Erica; Saluja, Manju; Vogel, Rachel Isaksson; Saluja, Ashok; Ramakrishnan, Sundaram

2014-11-01

Minnelide is a water-soluble pro-drug of triptolide, a natural product. The goal of this study was to evaluate the effectiveness of Minnelide on ovarian cancer growth in vitro and in vivo. The effect of Minnelide on ovarian cancer cell proliferation was determined by real time electrical impedance measurements. Multiple mouse models with C200 and A2780 epithelial ovarian cancer cell lines were used to assess the efficacy of Minnelide in inhibiting ovarian cancer growth. Minnelide decreased cell viability of both platinum sensitive and resistant epithelial ovarian cancer cells in vitro. Minnelide with carboplatin showed additive effects in vitro. Minnelide monotherapy increased the survival of mice bearing established ovarian tumors. Minnelide, in combination with carboplatin and paclitaxel, improved overall survival of mice. Minnelide is a promising pro-drug for the treatment of ovarian cancer, especially when combined with standard chemotherapy. Copyright © 2014 Elsevier Inc. All rights reserved.

The synthesis of amphipathic prodrugs of 1,2-diol drugs with saccharide conjugates by high regioselective enzymatic protocol.

PubMed

Quan, Jing; Chen, Zhichun; Han, Chengyou; Lin, Xianfu

2007-02-15

A facile, high regioselective enzymatic synthesis approach for the preparation of amphipathic prodrugs with saccharides of mephenesin and chlorphenesin was developed. Firstly, transesterification of two drugs with divinyl dicarboxylates with different carbon chain length was performed under the catalysis of Candida antarctica lipase acrylic resin and Lipozyme in anhydrous acetone at 50 degrees C, respectively. A series of lipophilic derivatives with vinyl groups of mephenesin and chlorphenesin were prepared. The influences of different organic solvents, enzyme sources, reaction time, and the acylation reagents on the synthesis of vinyl esters were investigated. And then, protease-catalyzed high regioselective acylation of D-glucose and D-mannose with vinyl esters of mephenesin and chlorphenesin gave drug-saccharide derivatives in good yields. The studies of lipophilicity and hydrolysis in vitro of prodrugs verified that drug-saccharide derivatives had amphipathic properties, and both lipophilic and amphipathic drug derivatives had obvious controlled release characteristics.

Prodrug Strategies for Paclitaxel.

PubMed

Meng, Ziyuan; Lv, Quanxia; Lu, Jun; Yao, Houzong; Lv, Xiaoqing; Jiang, Feng; Lu, Aiping; Zhang, Ge

2016-05-23

Paclitaxel is an anti-tumor agent with remarkable anti-tumor activity and wide clinical uses. However, it is also faced with various challenges especially for its poor water solubility and low selectivity for the target. To overcome these disadvantages of paclitaxel, approaches using small molecule modifications and macromolecule modifications have been developed by many research groups from all over the world. In this review, we discuss the different strategies especially prodrug strategies that are currently used to make paclitaxel more effective.

Breast Cancer-Targeted Nuclear Drug Delivery Overcoming Drug Resistance for Breast Cancer Chemotherapy

DTIC Science & Technology

2010-09-01

compared with the reported results that the cur- cumin concentrations in tumor tissues were usu- ally very low when curcumin was administrated. The...prodrug and as a drug carrier. This cur- cumin prodrug has a fixed composition with a curcumin-loading content of 25.3 wt% and can release curcumin...200 or 400, Aldrich, 99%) was dried over calcium hydride. Cur- cumin (high purity, Axxora LLC) was further purified by repeated recrystallization in

In vitro evaluation of dendrimer prodrugs for oral drug delivery.

PubMed

Najlah, Mohammad; Freeman, Sally; Attwood, David; D'Emanuele, Antony

2007-05-04

Dendrimer-based prodrugs were used to enhance the transepithelial permeability of naproxen, a low solubility model drug. The stability of the dendrimer-naproxen link was assessed. Naproxen was conjugated to G0 polyamidoamine (PAMAM) dendrimers either by an amide bond or an ester bond. The stability of G0 prodrugs was evaluated in 80% human plasma and 50% rat liver homogenate. The cytotoxicity of conjugates towards Caco-2 cells was determined and the transport of the conjugates across Caco-2 monolayers (37 degrees C) was reported. In addition, one lauroyl chain (L) was attached to the surface group of G0 PAMAM dendrimer of the diethylene glycol ester conjugate (G0-deg-NAP) to enhance permeability. The lactic ester conjugate, G0-lact-NAP, hydrolyzed slowly in 80% human plasma and in 50% rat liver homogenate (t(1/2)=180 min). G0-deg-NAP was hydrolyzed more rapidly in 80% human plasma (t(1/2)=51 min) and was rapidly cleaved in 50% liver homogenate (t(1/2)=4.7 min). The conjugates were non-toxic when exposed to Caco-2 cells for 3h. Permeability studies showed a significant enhancement in the transport of naproxen when conjugated to dendrimers; L-G0-deg-NAP yielding the highest permeability. Dendrimer-based prodrugs with appropriate linkers have potential as carriers for the oral delivery of low solubility drugs such as naproxen.

Discovery of 1-((2R,4aR,6R,7R,7aR)-2-Isopropoxy-2-oxidodihydro-4H,6H-spiro[furo[3,2-d][1,3,2]dioxaphosphinine-7,2'-oxetan]-6-yl)pyrimidine-2,4(1H,3H)-dione (JNJ-54257099), a 3'-5'-Cyclic Phosphate Ester Prodrug of 2'-Deoxy-2'-Spirooxetane Uridine Triphosphate Useful for HCV Inhibition.

PubMed

Jonckers, Tim H M; Tahri, Abdellah; Vijgen, Leen; Berke, Jan Martin; Lachau-Durand, Sophie; Stoops, Bart; Snoeys, Jan; Leclercq, Laurent; Tambuyzer, Lotke; Lin, Tse-I; Simmen, Kenny; Raboisson, Pierre

2016-06-23

JNJ-54257099 (9) is a novel cyclic phosphate ester derivative that belongs to the class of 2'-deoxy-2'-spirooxetane uridine nucleotide prodrugs which are known as inhibitors of the HCV NS5B RNA-dependent RNA polymerase (RdRp). In the Huh-7 HCV genotype (GT) 1b replicon-containing cell line 9 is devoid of any anti-HCV activity, an observation attributable to inefficient prodrug metabolism which was found to be CYP3A4-dependent. In contrast, in vitro incubation of 9 in primary human hepatocytes as well as pharmacokinetic evaluation thereof in different preclinical species reveals the formation of substantial levels of 2'-deoxy-2'-spirooxetane uridine triphosphate (8), a potent inhibitor of the HCV NS5B polymerase. Overall, it was found that 9 displays a superior profile compared to its phosphoramidate prodrug analogues (e.g., 4) described previously. Of particular interest is the in vivo dose dependent reduction of HCV RNA observed in HCV infected (GT1a and GT3a) human hepatocyte chimeric mice after 7 days of oral administration of 9.

Construction and cellular uptake behavior of redox-sensitive docetaxel prodrug-loaded liposomes.

PubMed

Ren, Guolian; Jiang, Mengjuan; Guo, Weiling; Sun, Bingjun; Lian, He; Wang, Yongjun; He, Zhonggui

2018-01-01

A redox-responsive docetaxel (DTX) prodrug consisting of a disulfide linkage between DTX and vitamin E (DTX-SS-VE) was synthesized in our laboratory and was successfully formulated into liposomes. The aim of this study was to optimize the formulation and investigate the cellular uptake of DTX prodrug-loaded liposomes (DPLs). The content of DTX-SS-VE was determined by ultrahigh-performance liquid chromatography (UPLC). The formulation and process were optimized using entrapment efficiency (EE), drug-loading (DL), particle size and polydispersity index (PDI) as the evaluation indices. The optimal formulation was as follows: drug/lipid ratio of 1:12, cholesterol/lipid ratio of 1:10, hydration temperature of 40 °C, sonication power and time of 400 W and 5 min. The EE, DL and particle size of the optimized DPLs were 97.60 ± 0.03%, 7.09 ± 0.22% and 93.06 ± 0.72 nm, respectively. DPLs had good dilution stability under the physiological conditions over 24 h. In addition, DPLs were found to enter tumor cells via different pathways and released DTX from the prodrug to induce apoptosis. Taken together, the optimized formulation and process were found to be a simple, stable and applicable method for the preparation of DPLs that could successfully escape from lysosomes.

Making the leap from daily oral dosing to long-acting injectables: lessons from the antipsychotics.

PubMed

Remenar, Julius F

2014-06-02

There are now long-acting versions of six antipsychotic drugs on the U.S. market, and with them, five unique combinations of molecular form and delivery strategy long-acting-injectable-antipsychotics (LAIAs) show evidence of reduced relapses of schizophrenia, but their introduction has been slow, taking at least nine years after the approval of each oral drug. Oily solutions of lipophilic prodrugs were the first to enter the LAIA market, but they relied on esterification of a hydroxyl handle that was lost with the emergence of the atypical antipsychotics. A review of the literature and patents shows that companies tested many different approaches before reaching the currently marketed versions, including aqueous suspensions of poorly soluble salts, polymeric microspheres, and new approaches to making prodrugs. Yet, very little has been published to support faster development of safe long-acting injectables (LAIs). This review introduces some of the critical considerations in creating an LAI; then it analyzes the existing products and discusses areas where further research is needed. The available literature suggests that lipophilic prodrugs may be inherently safer than poorly soluble salts as LAIs. Other areas needing additional study include (1) the range of physical properties acceptable for LAIs and the effect of prodrug tail length in achieving them, and (2) the role of physiological responses at the injection site in the release of drug from a depot.

Novel epigallocatechin gallate analogs as potential anticancer agents: a patent review (2009 – present)

PubMed Central

Landis-Piwowar, Kristin; Chen, Di; Foldes, Robert; Chan, Tak-Hang; Dou, Qing Ping

2013-01-01

Introduction Over the past three years numerous patents and patent applications have been published relating to scientific advances in the use of the green tea polyphenol epigallocatechin gallate (EGCG) (the most abundant, and bioactive compound in green tea) and its analogs as anticancer agents. EGCG affects multiple molecular targets involved in cancer cell proliferation and survival; however, polyphenolic catechins, such as EGCG, generally exhibit poor oral bioavailability. Since the anticancer activity of polyphenols largely depends on their susceptibility to biotransformation reactions, numerous EGCG derivatives, analogs and prodrugs have been designed to improve the stability, bioavailability and anticancer potency of the native compound. Areas covered This review focuses on the applications of EGCG and its analogs, derivatives and prodrugs in the prevention and treatment of human cancers. A comprehensive description of patents related to EGCG and its derivatives, analogs and prodrugs and their uses as anticancer agents is included. Expert opinion EGCG targets multiple essential survival proteins and pathways in human cancer cells. Because it is unstable physiologically, numerous alterations to the EGCG molecule have been patented, either to improve the integrity of the native compound or to generate a more stable yet similarly efficacious molecule. EGCG and its derivatives, analogs and prodrugs could be developed into future drugs for chemoprevention, chemosensitization, radiosensitization and/or cancer interception. PMID:23230990

Influence of Plasticizers on the Stability and Release of a Prodrug of Δ9-Tetrahydrocannabinol Incorporated in Poly (Ethylene Oxide) Matrices

PubMed Central

Thumma, Sridhar; ElSohly, Mahmoud A.; Zhang, Shuang-Qing; Gul, Waseem; Repka, Michael A.

2008-01-01

The objective of the present research was to stabilize a heat-labile novel prodrug of Δ9-tetrahydrocannabinol (THC), THC-hemiglutarate (THC-HG), in polyethylene oxide (PEO) [PolyOx® WSR N-80 (PEO N-80), MW 200,000 Daltons] polymeric matrix systems produced by hot-melt fabrication for systemic delivery of THC through the oral transmucosal route. For this purpose, the effects of processing conditions (processing temperature and heating duration), plasticizer type and concentration and storage conditions on the stability of the prodrug were investigated. The selected plasticizers studied included vitamin E succinate (VES), acetyltributyl citrate (ATBC), triethyl citrate (TEC), triacetin and polyethylene glycol 8000 (PEG 8000). Furthermore, the influence of plasticizer concentration on drug release was also studied. The stability of THC-HG in PEO matrices was influenced by all of the aforementioned variables. Films processed at 110 °C for 7 min were found to be favorable for hot-melt processing with a post- processing drug content of 95%, while significant degradation of THC-HG (~42%) was observed in those processed at 200 °C for 15 min. The degradation of the prodrug during hot-melt fabrication and also upon storage was considerably reduced in the presence of the plasticizers investigated, VES being the most effective. Modulation of the microenvironmental pH to an acidic range via incorporation of citric acid in PEO-plasticizer matrices significantly improved the stability of the prodrug, with almost 90% of the theoretical drug remaining as opposed to only 15% remaining in PEO-only matrices when stored at 40 °C for up to 3 months. The release of drug from PEO matrices was influenced both by the plasticizer type and concentration. A faster release resulted from water-soluble plasticizers, PEG 8000 and triacetin, and with increasing concentration. However, a slower release was observed with an increase in concentration of water-insoluble plasticizers, VES and ATBC. PMID:18602993

Lamellar crystalline self-assembly behaviour and solid lipid nanoparticles of a palmityl prodrug analogue of Capecitabine—A chemotherapy agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Xiaojuan; Moghaddam, Minoo J.; Sagnella, Sharon M.

2014-09-24

An amphiphile prodrug, 5'-deoxy-5-fluoro-N 4-(palmityloxycarbonyl) cytidine or 5'-deoxy-5-fluoro-N 4-(hexadecanaloxycarbonyl) cytidine (5-FCPal), consisting of the same head group as the commercially available chemotherapeutic agent Capecitabine, linked to a palmityl hydrocarbon chain via a carbamate bond is reported. Thermal analysis of this prodrug indicates that it melts at ~115 °C followed quickly by degradation beginning at ~120 °C. The neat solid 5-FCPal amphiphile acquires a lamellar crystalline arrangement with a d-spacing of 28.6 ± 0.3 Å, indicating interdigitation of the hydrocarbon chains. Under aqueous conditions, solid 5-FCPal is non-swelling and no lyotropic liquid crystalline phase formation is observed. In order to assessmore » the in vitro toxicity and in vivo efficacy in colloidal form, solid lipid nanoparticles (SLNs) with an average size of ~700 nm were produced via high pressure homogenization. The in vitro toxicity of the 5-FCPal SLNs against several different cancer and normal cell types was assessed over a 48 h period, and IC 50 values were comparable to those observed for Capecitabine. The in vivo efficacy of the 5-FCPal SLNs was then assessed against the highly aggressive mouse 4T1 breast cancer model. To do so, the prodrug SLNs were administered orally at 3 different dosages (0.1, 0.25, 0.5 mmol/mouse/day) and compared to Capecitabine delivered at the same dosages. After 21 days of receiving the treatments, the 0.5 mmol dose of 5-FCPal exhibited the smallest average tumour volume. Since 5-FCPal is activated in a similar manner to Capecitabine via a 3 step enzymatic pathway with the final step occurring preferentially at the tumour site, formulation of the prodrug into SLNs combines the advantage of selective, localized activation with the sustained release properties of nanostructured amphiphile self-assembly and multiple payload materials thereby potentially creating a more effective anticancer agent.« less

Extracellular palladium-catalysed dealkylation of 5-fluoro-1-propargyl-uracil as a bioorthogonally activated prodrug approach

PubMed Central

Weiss, Jason T.; Dawson, John C.; Macleod, Kenneth G.; Rybski, Witold; Fraser, Craig; Torres-Sánchez, Carmen; Patton, E. Elizabeth; Bradley, Mark; Carragher, Neil O.; Unciti-Broceta, Asier

2014-01-01

A bioorthogonal organometallic reaction is a biocompatible transformation undergone by a synthetic material exclusively through the mediation of a non-biotic metal source; a selective process used to label biomolecules and activate probes in biological environs. Here we report the in vitro bioorthogonal generation of 5-fluorouracil from a biologically inert precursor by heterogeneous Pd0 catalysis. Although independently harmless, combined treatment of 5-fluoro-1-propargyl-uracil and Pd0-functionalized resins exhibits comparable antiproliferative properties to the unmodified drug in colorectal and pancreatic cancer cells. Live-cell imaging and immunoassay studies demonstrate that the cytotoxic activity of the prodrug/Pd0-resin combination is due to the in situ generation of 5-fluorouracil. Pd0-resins can be carefully implanted in the yolk sac of zebrafish embryos and display excellent biocompatibility and local catalytic activity. The in vitro efficacy shown by this masking/activation strategy underlines its potential to develop a bioorthogonally activated prodrug approach and supports further in vivo investigations. PMID:24522696

Structure-activity relationship of uridine-based nucleoside phosphoramidate prodrugs for inhibition of dengue virus RNA-dependent RNA polymerase.

PubMed

Wang, Gang; Lim, Siew Pheng; Chen, Yen-Liang; Hunziker, Jürg; Rao, Ranga; Gu, Feng; Seh, Cheah Chen; Ghafar, Nahdiyah Abdul; Xu, Haoying; Chan, Katherine; Lin, Xiaodong; Saunders, Oliver L; Fenaux, Martijn; Zhong, Weidong; Shi, Pei-Yong; Yokokawa, Fumiaki

2018-05-03

To identify a potent and selective nucleoside inhibitor of dengue virus RNA-dependent RNA polymerase, a series of 2'- and/or 4'-ribose sugar modified uridine nucleoside phosphoramidate prodrugs and their corresponding triphosphates were synthesized and evaluated. Replacement of 2'-OH with 2'-F led to be a poor substrate for both dengue virus and human mitochondrial RNA polymerases. Instead of 2'-fluorination, the introduction of fluorine at the ribose 4'-position was found not to affect the inhibition of the dengue virus polymerase with a reduction in uptake by mitochondrial RNA polymerase. 2'-C-ethynyl-4'-F-uridine phosphoramidate prodrug displayed potent anti-dengue virus activity in the primary human peripheral blood mononuclear cell-based assay with no significant cytotoxicity in human hepatocellular liver carcinoma cell lines and no mitochondrial toxicity in the cell-based assay using human prostate cancer cell lines. Copyright © 2018 Elsevier Ltd. All rights reserved.

A prodrug approach to enhance azelaic acid percutaneous availability.

PubMed

Al-Marabeh, Sara; Khalil, Enam; Khanfar, Mohammad; Al-Bakri, Amal G; Alzweiri, Muhammed

2017-06-01

Azelaic acid is a dicarboxylic acid compound used in treatment of acne vulgaris. However, high concentration (ca 20%) is needed to guarantee the drug availability in the skin. The latter increases the incidence of side effects such as local irritation. The prodrug strategy to enhance azelaic acid diffusion through skin was not reported before. Thus, a lipophilic prodrug of azelaic acid (diethyl azelate [DEA]) was synthesized and investigated to improve percutaneous availability of azelaic acid, with a subsequent full physical, chemical, and biological characterization. Expectedly, DEA exhibited a significant increase in diffusion compared to azelaic acid through silicone membrane. In contrast, the diffusion results through human stratum corneum (SC) displayed weaker permeation for DEA with expected retention in the SC. Therefore, a desorption study of DEA from SC was conducted to examine the reservoir behavior in SC. Results showed an evidence of sustained release behavior of DEA from SC. Consequently, enhancement of keratolytic effect is expected due to azelaic acid produced from enzymatic conversion of DEA released from SC.

Optically active antifungal azoles. XII. Synthesis and antifungal activity of the water-soluble prodrugs of 1-[(1R,2R)-2-(2,4-difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone.

PubMed

Ichikawa, T; Kitazaki, T; Matsushita, Y; Yamada, M; Hayashi, R; Yamaguchi, M; Kiyota, Y; Okonogi, K; Itoh, K

2001-09-01

1-[(1R,2R)-2-(2,4-Difluorophenyl)-2-hydroxy-1-methyl-3-(1H-1,2,4-triazol-1-yl)propyl]-3-[4-(1H-1-tetrazolyl)phenyl]-2-imidazolidinone (1: TAK-456) was selected as a candidate for clinical trials, but since its water-solubility was insufficient for an injectable formulation, the quaternary triazolium salts 2 were designed as water-soluble prodrugs. Among the prodrugs prepared, 4-acetoxymethyl-1-[(2R,3R)-2-(2,4-difluorophenyl)-2-hydroxy-3-[2-oxo-3-[4-(1H-1-terazolyl)phenyl]-1-imidazolidinyl]butyl]-1H-1,2,4-triazolium chloride (2a: TAK-457) was selected as an injectable candidate for clinical trials based on the results of evaluations on solubility, stability, hemolytic effect and in vivo antifungal activities.

Redox activation of metal-based prodrugs as a strategy for drug delivery

PubMed Central

Graf, Nora

2012-01-01

This review provides an overview of metal-based anticancer drugs and drug candidates. In particular, we focus on metal complexes that can be activated in the reducing environment of cancer cells, thus serving as prodrugs. There are many reports of Pt and Ru complexes as redox-activatable drug candidates, but other d-block elements with variable oxidation states have a similar potential to serve as prodrugs in this manner. In this context are compounds based on Fe, Co, or Cu chemistry, which are also covered. A trend in the field of medicinal inorganic chemistry has been toward molecularly targeted, metal-based drugs obtained by functionalizing complexes with biologically active ligands. Another recent activity is the use of nanomaterials for drug delivery, exploiting passive targeting of tumors with nanosized constructs made from Au, Fe, carbon, or organic polymers. Although complexes of all of the above mentioned metals will be described, this review focuses primarily on Pt compounds, including constructs containing nanomaterials. PMID:22289471

The nitric oxide prodrug JS-K and its structural analogues as cancer therapeutic agents.

PubMed

Maciag, Anna E; Saavedra, Joseph E; Chakrapani, Harinath

2009-09-01

Nitric oxide (NO) prodrugs of the diazeniumdiolate class are routinely used as reliable sources of nitric oxide in chemical and biological laboratory settings. O(2)-(2,4-dinitrophenyl) diazeniumdiolates, which are derivatized forms of ionic diazeniumdiolates, have been found to show potent anti-proliferative activity in a variety of cancer cells, presumably through the effects of NO. One important member of this class of diazeniumdiolates, O(2)-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K), has shown promise as a novel cancer therapeutic agent in a number of animal models. This review describes the developments in chemical and biochemical characterization and structure-activity relationship of JS-K and its analogues. In addition, some molecular mechanistic insights into the observed anti-proliferative activity of JS-K are discussed. Finally, a structural motif is presented for O(2)-(aryl) diazeniumdiolate nitric oxide prodrugs that show potency comparable with that of JS-K.

Successful Treatment of Intracranial Glioblastoma Xenografts With a Monoamine Oxidase B-Activated Pro-Drug.

PubMed

Sharpe, Martyn A; Livingston, Andrew D; Gist, Taylor L; Ghosh, Pardip; Han, Junyan; Baskin, David S

2015-09-01

The last major advance in the treatment of glioblastoma multiforme (GBM) was the introduction of temozolomide in 1999. Treatment with temozolomide following surgical debulking extends survival rate compared to radiotherapy and debulking alone. However, virtually all glioblastoma patients experience disease progression within 7 to 10 months. Although many salvage treatments, including bevacizumab, rechallenge with temozolomide, and other alkylating agents, have been evaluated, none of these clearly improves survival. Monoamine oxidase B (MAOB) is highly expressed in glioblastoma cell mitochondria, and mitochondrial function is intimately tied to treatment-resistant glioblastoma progression. These glioblastoma properties provide a strong rationale for pursuing a MAOB-selective pro-drug treatment approach that, upon drug activation, targets glioblastoma mitochondria, especially mitochondrial DNA. MP-MUS is the lead compound in a family of pro-drugs designed to treat GBM that is converted into the mature, mitochondria-targeting drug, P(+)-MUS, by MAOB. We show that MP-MUS can successfully kill primary gliomas in vitro and in vivo mouse xenograft models.

Successful Treatment of Intracranial Glioblastoma Xenografts With a Monoamine Oxidase B-Activated Pro-Drug

PubMed Central

Sharpe, Martyn A.; Livingston, Andrew D.; Gist, Taylor L.; Ghosh, Pardip; Han, Junyan; Baskin, David S.

2015-01-01

The last major advance in the treatment of glioblastoma multiforme (GBM) was the introduction of temozolomide in 1999. Treatment with temozolomide following surgical debulking extends survival rate compared to radiotherapy and debulking alone. However, virtually all glioblastoma patients experience disease progression within 7 to 10 months. Although many salvage treatments, including bevacizumab, rechallenge with temozolomide, and other alkylating agents, have been evaluated, none of these clearly improves survival. Monoamine oxidase B (MAOB) is highly expressed in glioblastoma cell mitochondria, and mitochondrial function is intimately tied to treatment-resistant glioblastoma progression. These glioblastoma properties provide a strong rationale for pursuing a MAOB-selective pro-drug treatment approach that, upon drug activation, targets glioblastoma mitochondria, especially mitochondrial DNA. MP-MUS is the lead compound in a family of pro-drugs designed to treat GBM that is converted into the mature, mitochondria-targeting drug, P+-MUS, by MAOB. We show that MP-MUS can successfully kill primary gliomas in vitro and in vivo mouse xenograft models. PMID:26501110

New Approaches to Antibiotic Use and Review of Recently Approved Antimicrobial Agents.

PubMed

Hahn, Andrew W; Jain, Rupali; Spach, David H

2016-07-01

Antimicrobial drug-resistance continues to force adaptation in our clinical practice. We explore new evidence regarding adjunctive antibiotic therapy for skin and soft tissue abscesses as well as duration of therapy for intra-abdominal abscesses. As new evidence refines optimal practice, it is essential to support clinicians in adopting practice patterns concordant with evidence-based guidelines. We review a simple approach that can 'nudge' clinicians towards concordant practices. Finally, the use of novel antimicrobials will play an increasingly important role in contemporary therapy. We review five new antimicrobials recently FDA-approved for use in drug-resistant infections: dalbavancin, oritavancin, ceftaroline, ceftolozane-tazobactam, and ceftazidime-avibactam. Copyright © 2016 Elsevier Inc. All rights reserved.

A prodrug approach to the use of coumarins as potential therapeutics for superficial mycoses.

PubMed

Mercer, Derry K; Robertson, Jennifer; Wright, Kristine; Miller, Lorna; Smith, Shane; Stewart, Colin S; O Neil, Deborah A

2013-01-01

Superficial mycoses are fungal infections of the outer layers of the skin, hair and nails that affect 20-25% of the world's population, with increasing incidence. Treatment of superficial mycoses, predominantly caused by dermatophytes, is by topical and/or oral regimens. New therapeutic options with improved efficacy and/or safety profiles are desirable. There is renewed interest in natural product-based antimicrobials as alternatives to conventional treatments, including the treatment of superficial mycoses. We investigated the potential of coumarins as dermatophyte-specific antifungal agents and describe for the first time their potential utility as topical antifungals for superficial mycoses using a prodrug approach. Here we demonstrate that an inactive coumarin glycone, esculin, is hydrolysed to the antifungal coumarin aglycone, esculetin by dermatophytes. Esculin is hydrolysed to esculetin β-glucosidases. We demonstrate that β-glucosidases are produced by dermatophytes as well as members of the dermal microbiota, and that this activity is sufficient to hydrolyse esculin to esculetin with concomitant antifungal activity. A β-glucosidase inhibitor (conduritol B epoxide), inhibited antifungal activity by preventing esculin hydrolysis. Esculin demonstrates good aqueous solubility (<6 g/l) and could be readily formulated and delivered topically as an inactive prodrug in a water-based gel or cream. This work demonstrates proof-of-principle for a therapeutic application of glycosylated coumarins as inactive prodrugs that could be converted to an active antifungal in situ. It is anticipated that this approach will be applicable to other coumarin glycones.

A Prodrug Approach to the Use of Coumarins as Potential Therapeutics for Superficial Mycoses

PubMed Central

Mercer, Derry K.; Robertson, Jennifer; Wright, Kristine; Miller, Lorna; Smith, Shane; Stewart, Colin S.; O′Neil, Deborah A.

2013-01-01

Superficial mycoses are fungal infections of the outer layers of the skin, hair and nails that affect 20–25% of the world's population, with increasing incidence. Treatment of superficial mycoses, predominantly caused by dermatophytes, is by topical and/or oral regimens. New therapeutic options with improved efficacy and/or safety profiles are desirable. There is renewed interest in natural product-based antimicrobials as alternatives to conventional treatments, including the treatment of superficial mycoses. We investigated the potential of coumarins as dermatophyte-specific antifungal agents and describe for the first time their potential utility as topical antifungals for superficial mycoses using a prodrug approach. Here we demonstrate that an inactive coumarin glycone, esculin, is hydrolysed to the antifungal coumarin aglycone, esculetin by dermatophytes. Esculin is hydrolysed to esculetin β-glucosidases. We demonstrate that β-glucosidases are produced by dermatophytes as well as members of the dermal microbiota, and that this activity is sufficient to hydrolyse esculin to esculetin with concomitant antifungal activity. A β-glucosidase inhibitor (conduritol B epoxide), inhibited antifungal activity by preventing esculin hydrolysis. Esculin demonstrates good aqueous solubility (<6 g/l) and could be readily formulated and delivered topically as an inactive prodrug in a water-based gel or cream. This work demonstrates proof-of-principle for a therapeutic application of glycosylated coumarins as inactive prodrugs that could be converted to an active antifungal in situ. It is anticipated that this approach will be applicable to other coumarin glycones. PMID:24260474

Annexin-directed β-glucuronidase for the targeted treatment of solid tumors.

PubMed

Guillen, Katrin P; Ruben, Eliza A; Virani, Needa; Harrison, Roger G

2017-02-01

Enzyme prodrug therapy has the potential to remedy the lack of selectivity associated with the systemic administration of chemotherapy. However, most current systems are immunogenic and constrained to a monotherapeutic approach. We developed a new class of fusion proteins centered about the human enzyme β-glucuronidase (βG), capable of converting several innocuous prodrugs into chemotherapeutics. We targeted βG to phosphatidylserine on tumor cells, tumor vasculature and metastases via annexin A1/A5. Phosphatidylserine shows promise as a universal marker for solid tumors and allows for tumor type-independent targeting. To create fusion proteins, human annexin A1/A5 was genetically fused to the activity-enhancing 16a3 mutant of human βG, expressed in chemically defined, fed-batch suspension culture, and chromatographically purified. All fusion constructs achieved >95% purity with yields up to 740 μg/l. Fusion proteins displayed cancer selective cell-surface binding with cell line-dependent binding stability. One fusion protein in combination with the prodrug SN-38 glucuronide was as effective as the drug SN-38 on Panc-1 pancreatic cancer cells and HAAE-1 endothelial cells, and demonstrated efficacy against MCF-7 breast cancer cells. βG fusion proteins effectively enable localized combination therapy that can be tailored to each patient via prodrug selection, with promising clinical potential based on their near fully human design. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Multifactorial resistance to aminopeptidase inhibitor prodrug CHR2863 in myeloid leukemia cells: down-regulation of carboxylesterase 1, drug sequestration in lipid droplets and pro-survival activation ERK/Akt/mTOR

PubMed Central

Verbrugge, Sue Ellen; Al, Marjon; Assaraf, Yehuda G.; Kammerer, Sarah; Chandrupatla, Durga M.S.H.; Honeywell, Richard; Musters, Rene P.J.; Giovannetti, Elisa; O'Toole, Tom; Scheffer, George L.; Krige, David; de Gruijl, Tanja D.; Niessen, Hans W.M.; Lems, Willem F.; Kramer, Pieternella A.; Scheper, Rik J.; Cloos, Jacqueline; Ossenkoppele, Gert J.; Peters, Godefridus J.; Jansen, Gerrit

2016-01-01

Aminopeptidase inhibitors are receiving attention as combination chemotherapeutic agents for the treatment of refractory acute myeloid leukemia. However, the factors determining therapeutic efficacy remain elusive. Here we identified the molecular basis of acquired resistance to CHR2863, an orally available hydrophobic aminopeptidase inhibitor prodrug with an esterase-sensitive motif, in myeloid leukemia cells. CHR2863 enters cells by diffusion and is retained therein upon esterase activity-mediated conversion to its hydrophilic active metabolite drug CHR6768, thereby exerting amino acid depletion. Carboxylesterases (CES) serve as candidate prodrug activating enzymes given CES1 expression in acute myeloid leukemia specimens. We established two novel myeloid leukemia sublines U937/CHR2863(200) and U937/CHR2863(5uM), with low (14-fold) and high level (270-fold) CHR2863 resistance. The latter drug resistant cells displayed: (i) complete loss of CES1-mediated drug activation associated with down-regulation of CES1 mRNA and protein, (ii) marked retention/sequestration of the prodrug, (iii) a substantial increase in intracellular lipid droplets, and (iv) a dominant activation of the pro-survival Akt/mTOR pathway. Remarkably, the latter feature coincided with a gain of sensitivity to the mTOR inhibitor rapamycin. These finding delineate the molecular basis of CHR2863 resistance and offer a novel modality to overcome this drug resistance in myeloid leukemia cells. PMID:26496029

Gelatin-encapsulated iron oxide nanoparticles for platinum (IV) prodrug delivery, enzyme-stimulated release and MRI.

PubMed

Cheng, Ziyong; Dai, Yunlu; Kang, Xiaojiao; Li, Chunxia; Huang, Shanshan; Lian, Hongzhou; Hou, Zhiyao; Ma, Pingan; Lin, Jun

2014-08-01

A facile method for transferring hydrophobic iron oxide nanoparticles (IONPs) from chloroform to aqueous solution via encapsulation of FITC-modified gelatin based on the hydrophobic-hydrophobic interaction is described in this report. Due to the existence of large amount of active groups such as amine groups in gelatin, the fluorescent labeling molecules of fluorescein isothiocyanate (FITC) and platinum (IV) prodrug functionalized with carboxylic groups can be conveniently conjugated on the IONPs. The nanoparticles carrying Pt(IV) prodrug exhibit good anticancer activities when the Pt(IV) complexes are reduced to Pt(II) in the intracellular environment, while the pure Pt(IV) prodrug only presents lower cytotoxicity on cancer cells. Meanwhile, fluorescence of FITC on the surface of nanoparticles was completely quenched due to the possible Förster Resonance Energy Transfer (FRET) mechanism and showed a fluorescence recovery after gelatin release and detachment from IONPs. Therefore FITC as a fluorescence probe can be used for identification, tracking and monitoring the drug release. In addition, adding pancreatic enzyme can effectively promote the gelatin release from IONPs owing to the degradation of gelatin. Noticeable darkening in magnetic resonance image (MRI) was observed at the tumor site after in situ injection of nanoparticles, indicating the IONPs-enhanced T2-weighted imaging. Our results suggest that the gelatin encapsulated Fe3O4 nanoparticles have potential applications in multi-functional drug delivery system for disease therapy, MR imaging and fluorescence sensor. Copyright © 2014 Elsevier Ltd. All rights reserved.

Carrier-Mediated Prodrug Uptake to Improve the Oral Bioavailability of Polar Drugs: An Application to an Oseltamivir Analogue

PubMed Central

Incecayir, Tuba; Sun, Jing; Tsume, Yasuhiro; Xu, Hao; Gose, Tomoka; Nakanishi, Takeo; Tamai, Ikumi; Hilfinger, John; Lipka, Elke; Amidon, Gordon L.

2016-01-01

The goal of this study was to improve the intestinal mucosal cell membrane permeability of the poorly absorbed guanidino analogue of a neuraminidase inhibitor, oseltamivir carboxylate (GOC) using a carrier mediated strategy. Valyl amino acid prodrug of GOC with isopropyl-methylenedioxy linker (GOC-ISP-Val) was evaluated as the potential substrate for intestinal oligopeptide transporter, hPEPT1 in Xenopus laevis oocytes heterologously expressing hPEPT1 and an intestinal mouse perfusion system. The diastereomers of GOC-ISP-Val were assessed for chemical and metabolic stability. Permeability of GOC-ISP-Val was determined in Caco-2 cells and mice. Diastereomer 2 was about two times more stable than diastereomer 1 in simulated intestinal fluid and rapidly hydrolyzed to the parent drug in cell homogenates. The prodrug had a nine times enhanced apparent permeability (Papp) in Caco-2 cells compared to the parent drug. Both diastereomer exhibited high effective permeability (Peff ) in mice, 6.32±3.12 and 5.20±2.81 x10−5 cm/s for diastereomer 1 and 2, respectively. GOC-ISP-Val was found to be a substrate of hPEPT1. Overall, this study indicates that the prodrug, GOC-ISP-Val seems to be a promising oral anti-influenza agent that has sufficient stability at physiologically relevant pHs prior to absorption, significantly improved permeability via hPEPT1 and potentially rapid activation in the intestinal cells. PMID:26869437

A prodrug-doped cellular Trojan Horse for the potential treatment of prostate cancer.

PubMed

Levy, Oren; Brennen, W Nathaniel; Han, Edward; Rosen, David Marc; Musabeyezu, Juliet; Safaee, Helia; Ranganath, Sudhir; Ngai, Jessica; Heinelt, Martina; Milton, Yuka; Wang, Hao; Bhagchandani, Sachin H; Joshi, Nitin; Bhowmick, Neil; Denmeade, Samuel R; Isaacs, John T; Karp, Jeffrey M

2016-06-01

Despite considerable advances in prostate cancer research, there is a major need for a systemic delivery platform that efficiently targets anti-cancer drugs to sites of disseminated prostate cancer while minimizing host toxicity. In this proof-of-principle study, human mesenchymal stem cells (MSCs) were loaded with poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) that encapsulate the macromolecule G114, a thapsigargin-based prostate specific antigen (PSA)-activated prodrug. G114-particles (∼950 nm in size) were internalized by MSCs, followed by the release of G114 as an intact prodrug from loaded cells. Moreover, G114 released from G114 MP-loaded MSCs selectively induced death of the PSA-secreting PCa cell line, LNCaP. Finally, G114 MP-loaded MSCs inhibited tumor growth when used in proof-of-concept co-inoculation studies with CWR22 PCa xenografts, suggesting that cell-based delivery of G114 did not compromise the potency of this pro-drug in-vitro or in-vivo. This study demonstrates a potentially promising approach to assemble a cell-based drug delivery platform, which inhibits cancer growth in-vivo without the need of genetic engineering. We envision that upon achieving efficient homing of systemically infused MSCs to cancer sites, this MSC-based platform may be developed into an effective, systemic 'Trojan Horse' therapy for targeted delivery of therapeutic agents to sites of metastatic PCa. Copyright © 2016 Elsevier Ltd. All rights reserved.

Amphiphilic curcumin conjugate-forming nanoparticles as anticancer prodrug and drug carriers: in vitro and in vivo effects.

PubMed

Tang, Huadong; Murphy, Caitlin J; Zhang, Bo; Shen, Youqing; Sui, Meihua; Van Kirk, Edward Alva; Feng, Xiaowen; Murdoch, William J

2010-08-01

Curcumin has been shown to have high cytotoxicity towards various cancer cell lines, but its water insolubility and instability make its bioavailability exceedingly low and, thus, it is generally inactive in in vivo anticancer tests. Here, we report an intracellular-labile amphiphilic surfactant-like curcumin prodrug--curcumin conjugated with two short oligo(ethylene glycol) (Curc-OEG) chains via beta-thioester bonds that are labile in the presence of intracellular glutathione and esterase. Curc-OEG formed stable nanoparticles in aqueous conditions and served two roles--as an anticancer prodrug and a drug carrier. As an anticancer prodrug, the formed nanoparticles had a high and fixed curcumin-loading content of 25.3 wt%, and released active curcumin in the intracellular environment. Curc-OEG had high inhibition ability to several cancer cell lines due to apoptosis. Intravenously injected Curc-OEG significantly reduced the tumor weights and tumor numbers in the athymic mice xenografted with intraperitoneal SKOV-3 tumors and subcutaneous (mammary fat pad) MDA-MB-468 tumors. Preliminary systemic toxicity studies found that Curc-OEG did not cause acute and subchronic toxicities to mouse visceral organs at high doses. As drug carriers, Curc-OEG nanoparticles could carry other anticancer drugs, such as doxorubicin and camptothecin, and ship them into drug-resistant cells, greatly enhancing the cytotoxicity of the loaded drug. Thus, Curc-OEG is a promising prototype that merits further study for cancer therapy.

Inhibition by Avibactam and Clavulanate of the β-Lactamases KPC-2 and CTX-M-15 Harboring the Substitution N132G in the Conserved SDN Motif.

PubMed

Ourghanlian, Clément; Soroka, Daria; Arthur, Michel

2017-03-01

The substitution N 132 G in the SDN motif of class A β-lactamases from rapidly growing mycobacteria was previously shown to impair their inhibition by avibactam but to improve the stability of acyl-enzymes formed with clavulanate. The same substitution was introduced in KPC-2 and CTX-M-15 to assess its impact on β-lactamases from Enterobacteriaceae and evaluate whether it may lead to resistance to the ceftazidime-avibactam combination. Kinetic parameters for the inhibition of the β-lactamases by avibactam and clavulanate were determined by spectrophotometry using nitrocefin as the substrate. The substitution N 132 G impaired (>1,000-fold) the efficacy of carbamylation of KPC-2 and CTX-M-15 by avibactam. The substitution improved the inhibition of KPC-2 by clavulanate due to reduced deacylation, whereas the presence or absence of N 132 G resulted in the inhibition of CTX-M-15 by clavulanate. The hydrolysis of amoxicillin and nitrocefin by KPC-2 and CTX-M-15 was moderately affected by the substitution N 132 G, but that of ceftazidime, ceftaroline, and aztreonam was drastically reduced. Isogenic strains producing KPC-2 and CTX-M-15 were constructed to assess the impact of the substitution N 132 G on the antibacterial activities of β-lactam-inhibitor combinations. For amoxicillin, the substitution resulted in resistance and susceptibility for avibactam and clavulanate, respectively. For ceftazidime, ceftaroline, and aztreonam, the negative impact of the substitution on β-lactamase activity prevented resistance to the β-lactam-avibactam combinations. In conclusion, the N 132 G substitution has profound effects on the substrate and inhibition profiles of class A β-lactamases, which are largely conserved in distantly related enzymes. Fortunately, the substitution does not lead to resistance to the ceftazidime-avibactam combination. Copyright © 2017 American Society for Microbiology.

Susceptibility patterns of Staphylococcus aureus biofilms in diabetic foot infections.

PubMed

Mottola, Carla; Matias, Carina S; Mendes, João J; Melo-Cristino, José; Tavares, Luís; Cavaco-Silva, Patrícia; Oliveira, Manuela

2016-06-23

Foot infections are a major cause of morbidity in people with diabetes and the most common cause of diabetes-related hospitalization and lower extremity amputation. Staphylococcus aureus is by far the most frequent species isolated from these infections. In particular, methicillin-resistant S. aureus (MRSA) has emerged as a major clinical and epidemiological problem in hospitals. MRSA strains have the ability to be resistant to most β-lactam antibiotics, but also to a wide range of other antimicrobials, making infections difficult to manage and very costly to treat. To date, there are two fifth-generation cephalosporins generally efficacious against MRSA, ceftaroline and ceftobripole, sharing a similar spectrum. Biofilm formation is one of the most important virulence traits of S. aureus. Biofilm growth plays an important role during infection by providing defence against several antagonistic mechanisms. In this study, we analysed the antimicrobial susceptibility patterns of biofilm-producing S. aureus strains isolated from diabetic foot infections. The antibiotic minimum inhibitory concentration (MIC) was determined for ten antimicrobial compounds, along with the minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC), followed by PCR identification of genetic determinants of biofilm production and antimicrobial resistance. Results demonstrate that very high concentrations of the most used antibiotics in treating diabetic foot infections (DFI) are required to inhibit S. aureus biofilms in vitro, which may explain why monotherapy with these agents frequently fails to eradicate biofilm infections. In fact, biofilms were resistant to antibiotics at concentrations 10-1000 times greater than the ones required to kill free-living or planktonic cells. The only antibiotics able to inhibit biofilm eradication on 50 % of isolates were ceftaroline and gentamicin. The results suggest that the antibiotic susceptibility patterns cannot be applied to biofilm established infections. Selection of antimicrobial therapy is a critical step in DFI and should aim at overcoming biofilm disease in order to optimize the outcomes of this complex pathology.

Facile synthesis of corticosteroids prodrugs from isolated hydrocortisone acetate and their quantum chemical calculations

NASA Astrophysics Data System (ADS)

Sethi, Arun; Singh, Ranvijay Pratap; Prakash, Rohit; Amandeep

2017-02-01

In the present research paper corticosteroids prodrugs of hydrocortisone acetate (1) have been synthesized, which was isolated from the flowers of Allamanda Violacea. The hydrocortisone acetate (1) was hydrolyzed to hydrocortisone (2) which was subsequently converted to prednisolone (3). Both the hydrocortisone (1) and prednisolone (2) underwent Steglich esterification with naproxen and Ibuprofen yielding compounds 11, 17 dihydroxy-21-(2-(6-methoxynaphthalene-2yl) propionoxy)-pregn-4-ene-3, 20-dione (4), 11, 17-dihydroxy-21-(2-(4-isobutylphenyl) propionoxy)-pregn-4-ene-3, 20-dione (5), 21-(2-(6-methoxynaphthalene-2-yl) propionoxy) 11,17-di-hydroxy-3,20-diketo-pregn-1,4-diene (6) and 11,17-di-hydroxy-3,20-diketo-pregn-1,4-diene-21-yl-2-(4-isobutylphenyl) propanoate (7). The synthesized compounds have been characterized with the help of spectroscopic techniques like 1H, 13C NMR, FT-IR spectroscopy and mass spectrometry. Density functional theory (DFT) with B3LYP functional and 6-31G (d, p) basis set has been used for the Quantum chemical calculations. The electronic properties such as frontier orbitals and band gap energies were calculated by TD-DFT approach. Intramolecular interactions have been identified by AIM (Atoms in Molecule) approach and vibrational wavenumbers have been calculated using DFT method. The reactivity and reactive site within the synthesized prodrugs have been examined with the help of reactivity descriptors. Dipole moment, polarizability and first static hyperpolarizability have been calculated to get a better insight of the properties of synthesized prodrugs. The molecular electrostatic potential (MEP) surface analysis has also been carried out.

Development of macromolecular prodrug for rheumatoid arthritis☆

PubMed Central

Yuan, Fang; Quan, Ling-dong; Cui, Liao; Goldring, Steven R.; Wang, Dong

2012-01-01

Rheumatoid arthritis (RA) is a chronic autoimmune disease that is considered to be one of the major public health problems worldwide. The development of therapies that target tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and co-stimulatory pathways that regulate the immune system have revolutionized the care of patients with RA. Despite these advances, many patients continue to experience symptomatic and functional impairment. To address this issue, more recent therapies that have been developed are designed to target intracellular signaling pathways involved in immunoregulation. Though this approach has been encouraging, there have been major challenges with respect to off-target organ side effects and systemic toxicities related to the widespread distribution of these signaling pathways in multiple cell types and tissues. These limitations have led to an increasing interest in the development of strategies for the macromolecularization of anti-rheumatic drugs, which could target them to the inflamed joints. This approach enhances the efficacy of the therapeutic agent with respect to synovial inflammation, while markedly reducing non-target organ adverse side effects. In this manuscript, we provide a comprehensive overview of the rational design and optimization of macromolecular prodrugs for treatment of RA. The superior and the sustained efficacy of the prodrug may be partially attributed to their Extravasation through Leaky Vasculature and subsequent Inflammatory cell-mediated Sequestration (ELVIS) in the arthritic joints. This biologic process provides a plausible mechanism, by which macromolecular prodrugs preferentially target arthritic joints and illustrates the potential benefits of applying this therapeutic strategy to the treatment of other inflammatory diseases. PMID:22433784

Targeted theranostic platinum(IV) prodrug with a built-in aggregation-induced emission light-up apoptosis sensor for noninvasive early evaluation of its therapeutic responses in situ.

PubMed

Yuan, Youyong; Kwok, Ryan T K; Tang, Ben Zhong; Liu, Bin

2014-02-12

Targeted drug delivery to tumor cells with minimized side effects and real-time in situ monitoring of drug efficacy is highly desirable for personalized medicine. In this work, we report the synthesis and biological evaluation of a chemotherapeutic Pt(IV) prodrug whose two axial positions are functionalized with a cyclic arginine-glycine-aspartic acid (cRGD) tripeptide for targeting integrin αvβ3 overexpressed cancer cells and an apoptosis sensor which is composed of tetraphenylsilole (TPS) fluorophore with aggregation-induced emission (AIE) characteristics and a caspase-3 enzyme specific Asp-Glu-Val-Asp (DEVD) peptide. The targeted Pt(IV) prodrug can selectively bind to αvβ3 integrin overexpressed cancer cells to facilitate cellular uptake. In addition, the Pt(IV) prodrug can be reduced to active Pt(II) drug in cells and release the apoptosis sensor TPS-DEVD simultaneously. The reduced Pt(II) drug can induce the cell apoptosis and activate caspase-3 enzyme to cleave the DEVD peptide sequence. Due to free rotation of the phenylene rings, TPS-DEVD is nonemissive in aqueous media. The specific cleavage of DEVD by caspase-3 generates the hydrophobic TPS residue, which tends to aggregate, resulting in restriction of intramolecular rotations of the phenyl rings and ultimately leading to fluorescence enhancement. Such noninvasive and real-time imaging of drug-induced apoptosis in situ can be used as an indicator for early evaluation of the therapeutic responses of a specific anticancer drug.

Development and characterization of PLGA nanoparticles as delivery systems of a prodrug of zidovudine obtained by its conjugation with ursodeoxycholic acid.

PubMed

Dalpiaz, Alessandro; Contado, Catia; Mari, Lara; Perrone, Daniela; Pavan, Barbara; Paganetto, Guglielmo; Hanuskovà, Miriam; Vighi, Eleonora; Leo, Eliana

2014-05-01

Zidovudine (AZT) is employed against AIDS and hepatitis; its use is limited by active efflux transporters (AETs) that induce multidrug resistance for intracellular therapies and hamper AZT to reach the brain. Ursodeoxycholic acid (UDCA) conjugation with AZT (prodrug UDCA-AZT) allows to elude the AET systems. To investigate the effect of the Pluronic F68 coating on the loading, release and stability of poly(D,L lactide-co-glicolide) nanoparticles (NPs) embedded with UDCA-AZT. The mean diameter of the NP prepared by nanoprecipitation or emulsion/solvent evaporation methods was determined using both photon correlation spectroscopy and sedimentation field-flow fractionation; particle morphology was detected by scanning electron microscope. The stability of the free and encapsulated UDCA-AZT was evaluated in rat liver homogenates by high-performance liquid chromatography analysis. The mean diameter of the NPs was found to be ∼ 600 nm with a relatively high polydispersity. The NPs obtained by emulsion/solvent evaporation were not able to control the prodrug release, differently from NPs obtained by nanoprecipitation. The presence of the Pluronic coating did not substantially modify the kinetics of the drug release, or the extent of the burst effect that were instead only influenced by the preparation parameters. UDCA-AZT incorporated in the NPs was more stable in the rat liver homogenates than the free prodrug and no influence of the Pluronic coating was observed. Considering the different potential applications of nanoparticles coated and uncoated with Pluronic (brain and macrophage targeting, respectively), both of these nanoparticle systems could be useful in the therapies against HIV.

A fully human anti-Ep-CAM scFv-beta-glucuronidase fusion protein for selective chemotherapy with a glucuronide prodrug.

PubMed

de Graaf, M; Boven, E; Oosterhoff, D; van der Meulen-Muileman, I H; Huls, G A; Gerritsen, W R; Haisma, H J; Pinedo, H M

2002-03-04

Monoclonal antibodies against tumour-associated antigens could be useful to deliver enzymes selectively to the site of a tumour for activation of a non-toxic prodrug. A completely human fusion protein may be advantageous for repeated administration, as host immune responses may be avoided. We have constructed a fusion protein consisting of a human single chain Fv antibody, C28, against the epithelial cell adhesion molecule and the human enzyme beta-glucuronidase. The sequences encoding C28 and human enzyme beta-glucuronidase were joined by a sequence encoding a flexible linker, and were preceded by the IgGkappa signal sequence for secretion of the fusion protein. A CHO cell line was engineered to secrete C28-beta-glucuronidase fusion protein. Antibody specificity and enzyme activity were retained in the secreted fusion protein that had an apparent molecular mass of 100 kDa under denaturing conditions. The fusion protein was able to convert a non-toxic prodrug of doxorubicin, N-[4-doxorubicin-N-carbonyl(oxymethyl)phenyl]-O-beta-glucuronyl carbamate to doxorubicin, resulting in cytotoxicity. A bystander effect was demonstrated, as doxorubicin was detected in all cells after N-[4-doxorubicin-N-carbonyl(oxymethyl)phenyl]-O-beta-glucuronyl carbamate administration when only 10% of the cells expressed the fusion protein. This is the first fully human and functional fusion protein consisting of an scFv against epithelial cell adhesion molecule and human enzyme beta-glucuronidase for future use in tumour-specific activation of a non-toxic glucuronide prodrug. Copyright 2002 Cancer Research UK

ELQ-300 prodrugs for enhanced delivery and single-dose cure of malaria.

PubMed

Miley, Galen P; Pou, Sovitj; Winter, Rolf; Nilsen, Aaron; Li, Yuexin; Kelly, Jane X; Stickles, Allison M; Mather, Michael W; Forquer, Isaac P; Pershing, April M; White, Karen; Shackleford, David; Saunders, Jessica; Chen, Gong; Ting, Li-Min; Kim, Kami; Zakharov, Lev N; Donini, Cristina; Burrows, Jeremy N; Vaidya, Akhil B; Charman, Susan A; Riscoe, Michael K

2015-09-01

ELQ-300 is a preclinical candidate that targets the liver and blood stages of Plasmodium falciparum, as well as the forms that are crucial to transmission of disease: gametocytes, zygotes, and ookinetes. A significant obstacle to the clinical development of ELQ-300 is related to its physicochemical properties. Its relatively poor aqueous solubility and high crystallinity limit absorption to the degree that only low blood concentrations can be achieved following oral dosing. While these low blood concentrations are sufficient for therapy, the levels are too low to establish an acceptable safety margin required by regulatory agencies for clinical development. One way to address the challenging physicochemical properties of ELQ-300 is through the development of prodrugs. Here, we profile ELQ-337, a bioreversible O-linked carbonate ester prodrug of the parent molecule. At the molar equivalent dose of 3 mg/kg of body weight, the delivery of ELQ-300 from ELQ-337 is enhanced by 3- to 4-fold, reaching a maximum concentration of drug in serum (C max) of 5.9 μM by 6 h after oral administration, and unlike ELQ-300 at any dose, ELQ-337 provides single-dose cures of patent malaria infections in mice at low-single-digit milligram per kilogram doses. Our findings show that the prodrug strategy represents a viable approach to overcome the physicochemical limitations of ELQ-300 to deliver the active drug to the bloodstream at concentrations sufficient for safety and toxicology studies, as well as achieving single-dose cures. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Integrating a novel SN38 prodrug into the PEGylated liposomal system as a robust platform for efficient cancer therapy in solid tumors.

PubMed

Fang, Tao; Dong, Yuehan; Zhang, Xiaomin; Xie, Ke; Lin, Li; Wang, Hangxiang

2016-10-15

Liposomal nanoassemblies have been used extensively as carriers for the delivery of both lipophilic and hydrophilic drugs. They represent a mature, versatile technology with considerable potential for improving the pharmacokinetics of drugs. However, the formulation of many chemotherapeutics into liposome systems has posed a significant challenge due to their incompatible physicochemical properties, as was the case with camptothecin-based chemotherapeutics. Here, we present a rational paradigm of potent chemotherapeutics that were reconstructed and subsequently integrated into liposomal nanoassemblies. Using SN38 (7-ethyl-10-hydroxy camptothecin) as a model drug, a lipophilic prodrug 1 (designated as LA-SN38) was constructed by tethering the linoleic acid (LA) moiety via esterification, which was further facilitated to form liposomal nanoparticles (LipoNP) through supramolecular nanoassembly. The resulting 1-loaded LipoNP exhibited sustained drug release kinetics and decreased cellular uptake by macrophage cells. Uptake by tumor cells was enhanced relative to our previous supramolecular nanoparticles (SNP 1), which were derived from the self-assembling prodrug 1. Notably, LipoNP outperformed SNP 1 in terms of pharmacokinetics and in vivo therapeutic efficacy in both human BEL-7402 hepatocellular carcinoma (HCC) and HCT-116 colorectal cancer-derived xenograft mouse models. These results were likely due to the improved systemic circulation and preferential accumulation of nanodrugs in tumors. Hence, our results suggest that the combination of liposomal delivery platforms with rational prodrug engineering may emerge as a promising approach for the effective and safe delivery of anticancer chemotherapeutics. Copyright © 2016 Elsevier B.V. All rights reserved.

Stabilization of the Nitric Oxide (NO) Prodrugs and Anti-Cancer Leads, PABA/NO and Double JS-K through Incorporation into PEG-Protected Nanoparticles

PubMed Central

Kumar, Varun; Hong, Sam Y.; Maciag, Anna E.; Saavedra, Joseph E.; Adamson, Douglas H.; Prud'homme, Robert K.; Keefer, Larry K.; Chakrapani, Harinath

2009-01-01

Here we report the stabilization of the nitric oxide (NO) prodrugs and anti-cancer lead compounds, PABA/NO (O2-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and “Double JS-K” (1,5-bis{[1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato]-2,4-dinitrobenzene), through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit. PMID:20000791

Stabilization of the nitric oxide (NO) prodrugs and anticancer leads, PABA/NO and Double JS-K, through incorporation into PEG-protected nanoparticles.

PubMed

Kumar, Varun; Hong, Sam Y; Maciag, Anna E; Saavedra, Joseph E; Adamson, Douglas H; Prud'homme, Robert K; Keefer, Larry K; Chakrapani, Harinath

2010-02-01

We report the stabilization of the nitric oxide (NO) prodrugs and anticancer lead compounds, PABA/NO (O(2)-{2,4-dinitro-5-[4-(N-methylamino)benzoyloxy]phenyl} 1-(N,N-dimethylamino)diazen-1-ium-1,2-diolate) and "Double JS-K" 1,5-bis-{1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diol-2-ato}-2,4-dinitrobenzene, through their incorporation into polymer-protected nanoparticles. The prodrugs were formulated in block copolymer-stabilized nanoparticles with sizes from 220 to 450 nm by a novel rapid precipitation process. The block copolymers, with polyethylene glycol (PEG) soluble blocks, provide a steric barrier against NO prodrug activation by glutathione. Too rapid activation and NO release has been a major barrier to effective administration of this class of compounds. The nanoparticle stabilized PABA/NO are protected from attack by glutathione as evidenced by a significant increase in time taken for 50% decomposition from 15 min (unformulated) to 5 h (formulated); in the case of Double JS-K, the 50% decomposition time was extended from 4.5 min (unformulated) to 40 min (formulated). The more hydrophobic PABA/NO produced more stable nanoparticles and correspondingly more extended release times in comparison with Double JS-K. The hydrophobic blocks of the polymer were either polystyrene or polylactide. Both blocks produced nanoparticles of approximately the same size and release kinetics. This combination of PEG-protected nanoparticles with sizes appropriate for cancer targeting by enhanced permeation and retention (EPR) and delayed release of NO may afford enhanced therapeutic benefit.

Carrier-Mediated Prodrug Uptake to Improve the Oral Bioavailability of Polar Drugs: An Application to an Oseltamivir Analogue.

PubMed

Incecayir, Tuba; Sun, Jing; Tsume, Yasuhiro; Xu, Hao; Gose, Tomoka; Nakanishi, Takeo; Tamai, Ikumi; Hilfinger, John; Lipka, Elke; Amidon, Gordon L

2016-02-01

The goal of this study was to improve the intestinal mucosal cell membrane permeability of the poorly absorbed guanidino analogue of a neuraminidase inhibitor, oseltamivir carboxylate (GOC) using a carrier-mediated strategy. Valyl amino acid prodrug of GOC with isopropyl-methylene-dioxy linker (GOC-ISP-Val) was evaluated as the potential substrate for intestinal oligopeptide transporter, hPEPT1 in Xenopus laevis oocytes heterologously expressing hPEPT1, and an intestinal mouse perfusion system. The diastereomers of GOC-ISP-Val were assessed for chemical and metabolic stability. Permeability of GOC-ISP-Val was determined in Caco-2 cells and mice. Diastereomer 2 was about 2 times more stable than diastereomer 1 in simulated intestinal fluid and rapidly hydrolyzed to the parent drug in cell homogenates. The prodrug had a 9 times-enhanced apparent permeability (P(app)) in Caco-2 cells compared with the parent drug. Both diastereomer exhibited high effective permeability (P(eff)) in mice, 6.32 ± 3.12 and 5.20 ± 2.81 × 10(-5) cm/s for diastereomer 1 and 2, respectively. GOC-ISP-Val was found to be a substrate of hPEPT1. Overall, this study indicates that the prodrug, GOC-ISP-Val, seems to be a promising oral anti-influenza agent that has sufficient stability at physiologically relevant pHs before absorption, significantly improved permeability via hPEPT1 and potentially rapid activation in the intestinal cells. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

[Cellular uptake of TPS-L-carnitine synthesised as transporter-based renal targeting prodrug].

PubMed

Li, Li; Zhu, Di; Sun, Xun

2012-11-01

To synthesize transporter-based renal targeting prodrug TPS-L-Carnitine and to determine its cellular uptake in vitro. Triptolide (TP) was conjugated with L-carnitine using succinate as the linker to form TPS-L-Carnitine, which could be specifically recognized by OCTN2, a cationic transporter with high affinity to L-Carnitine and is highly expressed on the apical membrane of renal proximal tubule cells. Cellular uptake assays of the prodrug and its parent drug were performed on HK-2 cells, a human proximal tubule cell line, in different temperature, concentration and in the presence of competitive inhibitors. TPS-L-Carnitine was taken up into HK-2 cells in a saturable and temperature- and concentration-dependent manner. The uptake process could be inhibited by the competitive inhibitors. The uptake of TPS-L-Carnitine was significantly higher than that of TP at 37 degrees C in the same drug concentration. TPS-L-Carnitine was taken through endocytosis mediated by transporter. TPS-L-Carnitine provides a good renal targeting property and lays the foundation for further studies in vivo.

Hybrid molecule from O2-(2,4-dinitrophenyl)diazeniumdiolate and oleanolic acid: a glutathione S-transferase π-activated nitric oxide prodrug with selective anti-human hepatocellular carcinoma activity and improved stability.

PubMed

Fu, Junjie; Liu, Ling; Huang, Zhangjian; Lai, Yisheng; Ji, Hui; Peng, Sixun; Tian, Jide; Zhang, Yihua

2013-06-13

A series of hybrids from O(2)-(2,4-dinitrophenyl)diazeniumdiolate and oleanolic acid (OA) were designed, synthesized, and biologically evaluated as novel nitric oxide (NO)-releasing prodrugs that could be activated by glutathione S-transferase π (GSTπ) overexpressed in a number of cancer cells. It was discovered that the most active compound, 21, released high levels of NO selectively in HCC cells but not in the normal cells and exhibited potent antiproliferative activity in vitro as well as remarkable tumor-retarding effects in vivo. Compared with the reported GSTπ-activated prodrugs JS-K and PABA/NO, 21 exhibited remarkably improved stability in the absence of GSTπ. Importantly, the decomposition of 21 occurred in the presence of GSTπ and was much more effective than in glutathione S-transferase α. Additionally, 21 induced apoptosis in HepG2 cells by arresting the cell cycle at the G2/M phase, activating both the mitochondrion-mediated pathway and the MAPK pathway and enhancing the intracellular production of ROS.

Cytochrome P450 Bioconjugate as a Nanovehicle for Improved Chemotherapy Treatment.

PubMed

Quester, Katrin; Juarez-Moreno, Karla; Secundino, Isamel; Roseinstein, Yvonne; Alejo, Karla P; Huerta-Saquero, Alejandro; Vazquez-Duhalt, Rafael

2017-05-01

Cancer is still a growing public health problem, especially breast cancer that is one of the most important cancers in women. Chemotherapy, even though a successful treatment, is accompanied by severe side effects. Moreover, most of the drugs used for chemotherapy are administered as prodrugs and need to be transformed to the active form by cytochromes P450 (CYPs). In addition, increasing numbers of cancer tissues show lower CYP activity than the surrounding healthy tissues in which prodrugs are preferentially activated causing cytotoxicity. Here, the design of a functionalized cytochrome P450 bioconjugate is reported as nanovehicle for the enzyme direct delivery to the tumor tissue in order to improve the local drug activation. MCF-7 breast cancer cells are treated with CYP-polyethylene glycol bioconjugate functionalized folic acid, where it activates the prodrug tamoxifen and significantly reduces the dose of tamoxifen needed to kill the tumor cells. The CYP bioconjugate covered with polyethylene glycol shows no immunogenic activity. The advantages of increasing the site-specific CYP activity in tumor tissues are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macrophage mediated PCI enhanced gene-directed enzyme prodrug therapy

NASA Astrophysics Data System (ADS)

Christie, Catherine E.; Zamora, Genesis; Kwon, Young J.; Berg, Kristian; Madsen, Steen J.; Hirschberg, Henry

2015-03-01

Photochemical internalization (PCI) is a photodynamic therapy-based approach for improving the delivery of macromolecules and genes into the cell cytosol. Prodrug activating gene therapy (suicide gene therapy) employing the transduction of the E. coli cytosine deaminase (CD) gene into tumor cells, is a promising method. Expression of this gene within the target cell produces an enzyme that converts the nontoxic prodrug, 5-FC, to the toxic metabolite, 5-fluorouracil (5-FU). 5-FC may be particularly suitable for brain tumors, because it can readily cross the bloodbrain barrier (BBB). In addition the bystander effect, where activated drug is exported from the transfected cancer cells into the tumor microenvironment, plays an important role by inhibiting growth of adjacent tumor cells. Tumor-associated macrophages (TAMs) are frequently found in and around glioblastomas. Monocytes or macrophages (Ma) loaded with drugs, nanoparticles or photosensitizers could therefore be used to target tumors by local synthesis of chemo attractive factors. The basic concept is to combine PCI, to enhance the ex vivo transfection of a suicide gene into Ma, employing specially designed core/shell NP as gene carrier.

Non-immune cells equipped with T cell receptor-like signaling for cancer cell ablation

PubMed Central

Kojima, Ryosuke; Scheller, Leo; Fussenegger, Martin

2017-01-01

The ability to engineer custom cell-contact-sensing output devices into human non-immune cells would be useful for extending the applicability of cell-based cancer therapies and avoiding risks associated with engineered immune cells. Here, we have developed a new class of synthetic T-cell receptor-like signal-transduction device that functions efficiently in human non-immune cells and triggers release of output molecules specifically upon sensing contact with a target cell. This device employs an interleukin signaling cascade, whose OFF/ON switching is controlled by biophysical segregation of a transmembrane signal-inhibitory protein from the sensor cell/target cell interface. We further showed that designer non-immune cells equipped with this device driving expression of a membrane-penetrator/prodrug-activating enzyme construct could specifically kill target cells in the presence of the prodrug, indicating its potential usefulness for target-cell-specific, cell-based enzyme-prodrug cancer therapy. Our study also contributes to advancement of synthetic biology by extending available design principles to transmit extracellular information to cells. PMID:29131143

Nifurpirinol: A more potent and reliable substrate compared to metronidazole for nitroreductase-mediated cell ablations.

PubMed

Bergemann, David; Massoz, Laura; Bourdouxhe, Jordane; Carril Pardo, Claudio A; Voz, Marianne L; Peers, Bernard; Manfroid, Isabelle

2018-04-17

The zebrafish is a popular animal model with well-known regenerative capabilities. To study regeneration in this fish, the nitroreductase/metronidazole-mediated system is widely used for targeted ablation of various cell types. Nevertheless, we highlight here some variability in ablation efficiencies with the metronidazole prodrug that led us to search for a more efficient and reliable compound. Herein, we present nifurpirinol, another nitroaromatic antibiotic, as a more potent prodrug compared to metronidazole to trigger cell-ablation in nitroreductase expressing transgenic models. We show that nifurpirinol induces robust and reliable ablations at concentrations 2,000 fold lower than metronidazole and three times below its own toxic concentration. We confirmed the efficiency of nifurpirinol in triggering massive ablation of three different cell types: the pancreatic beta cells, osteoblasts, and dopaminergic neurons. Our results identify nifurpirinol as a very potent prodrug for the nitroreductase-mediated ablation system and suggest that its use could be extended to many other cell types, especially if difficult to ablate, or when combined pharmacological treatments are desired. © 2018 by the Wound Healing Society.

Labile conjugation of a hydrophilic drug to PLA oligomers to modify a drug delivery system: cephradin in a PLAGA matrix.

PubMed

Ustariz-Peyret, C; Coudane, J; Vert, M; Kaltsatos, V; Boisramené, B

2000-01-01

The physical entrapment of a hydrophilic drug within degradable microspheres is generally difficult because of poor entrapment yield and/or fast release, depending on the microsphere fabrication method. In order to counter the effects of drug hydrophilicity, it is proposed to covalently attach the drug to lactic acid oligomers, with the aim of achieving temporary hydrophobization and slower release controlled by the separation of the drug from the degradable link within the polymer matrix. This strategy was tested on microspheres of the antibiotic cephradin. As the prodrug form, the entrapment of the drug was almost quantitative. The prodrug did degrade in an aqueous medium, modelling body fluids, but cleavage did not occur at the drug-oligomer junction and drug molecules bearing two lactyl residual units were released. When the prodrug is entrapped within a PLAGA matrix, no release was observed within the experimental time period. However, data suggest that conjugation via a bond more sensitive to hydrolysis than the main chain PLA ester bonds should make the system work as desired.

ALA-Butyrate prodrugs for Photo-Dynamic Therapy

NASA Astrophysics Data System (ADS)

Berkovitch, G.; Nudelman, A.; Ehenberg, B.; Rephaeli, A.; Malik, Z.

2010-05-01

The use of 5-aminolevulinic acid (ALA) administration has led to many applications of photodynamic therapy (PDT) in cancer. However, the hydrophilic nature of ALA limits its ability to penetrate the cells and tissues, and therefore the need for ALA derivatives became an urgent research target. In this study we investigated the activity of novel multifunctional acyloxyalkyl ester prodrugs of ALA that upon metabolic hydrolysis release active components such as, formaldehyde, and the histone deacetylase inhibitory moiety, butyric acid. Evaluation of these prodrugs under photo-irradiation conditions showed that butyryloxyethyl 5-amino-4-oxopentanoate (ALA-BAC) generated the most efficient photodynamic destruction compared to ALA. ALA-BAC stimulated a rapid biosynthesis of protoporphyrin IX (PpIX) in human glioblastoma U-251 cells which resulted in generation of intracellular ROS, reduction of mitochondrial activity, leading to apoptotic and necrotic death of the cells. The apoptotic cell death induced by ALA / ALA-BAC followed by PDT equally activate intrinsic and extrinsic apoptotic signals and both pathways may occur simultaneously. The main advantage of ALA-BAC over ALA stems from its ability to induce photo-damage at a significantly lower dose than ALA.

Aspartic acid based nucleoside phosphoramidate prodrugs as potent inhibitors of hepatitis C virus replication.

PubMed

Maiti, Munmun; Maiti, Mohitosh; Rozenski, Jef; De Jonghe, Steven; Herdewijn, Piet

2015-05-14

In view of a persistent threat to mankind, the development of nucleotide-based prodrugs against hepatitis C virus (HCV) is considered as a constant effort in many medicinal chemistry groups. In an attempt to identify novel nucleoside phosphoramidate analogues for improving the anti-HCV activity, we have explored, for the first time, aspartic acid (Asp) and iminodiacetic acid (IDA) esters as amidate counterparts by considering three 2'-C-methyl containing nucleosides, 2'-C-Me-cytidine, 2'-C-Me-uridine and 2'-C-Me-2'-fluoro-uridine. Synthesis of these analogues required protection for the vicinal diol functionality of the sugar moiety and the amino group of the cytidine nucleoside to regioselectively perform phosphorylation reaction at the 5'-hydroxyl group. Anti-HCV data demonstrate that the Asp-based phosphoramidates are ∼550 fold more potent than the parent nucleosides. The inhibitory activity of the Asp-ProTides was higher than the Ala-ProTides, suggesting that Asp would be a potential amino acid candidate to be considered for developing novel antiviral prodrugs.

Structure of ThiM from Vitamin B1 biosynthetic pathway of Staphylococcus aureus - Insights into a novel pro-drug approach addressing MRSA infections

NASA Astrophysics Data System (ADS)

Drebes, Julia; Künz, Madeleine; Windshügel, Björn; Kikhney, Alexey G.; Müller, Ingrid B.; Eberle, Raphael J.; Oberthür, Dominik; Cang, Huaixing; Svergun, Dmitri I.; Perbandt, Markus; Betzel, Christian; Wrenger, Carsten

2016-03-01

Infections caused by the methicillin-resistant Staphylococcus aureus (MRSA) are today known to be a substantial threat for global health. Emerging multi-drug resistant bacteria have created a substantial need to identify and discover new drug targets and to develop novel strategies to treat bacterial infections. A promising and so far untapped antibiotic target is the biosynthesis of vitamin B1 (thiamin). Thiamin in its activated form, thiamin pyrophosphate, is an essential co-factor for all organisms. Therefore, thiamin analogous compounds, when introduced into the vitamin B1 biosynthetic pathway and further converted into non-functional co-factors by the bacterium can function as pro-drugs which thus block various co-factor dependent pathways. We characterized one of the key enzymes within the S. aureus vitamin B1 biosynthetic pathway, 5-(hydroxyethyl)-4-methylthiazole kinase (SaThiM; EC 2.7.1.50), a potential target for pro-drug compounds and analyzed the native structure of SaThiM and complexes with the natural substrate 5-(hydroxyethyl)-4-methylthiazole (THZ) and two selected substrate analogues.

Metabolism of captopril carboxyl ester derivatives for percutaneous absorption.

PubMed

Gullick, Darren R; Ingram, Matthew J; Pugh, W John; Cox, Paul A; Gard, Paul; Smart, John D; Moss, Gary P

2009-02-01

To determine the metabolism of captopril n-carboxyl derivatives and how this may impact on their use as transdermal prodrugs. The pharmacological activity of the ester derivatives was also characterised in order to compare the angiotensin converting enzyme inhibitory potency of the derivatives compared with the parent drug, captopril. The metabolism rates of the ester derivatives were determined in vitro (using porcine liver esterase and porcine ear skin) and in silico (using molecular modelling to investigate the potential to predict metabolism). Relatively slow pseudo first-order metabolism of the prodrugs was observed, with the ethyl ester displaying the highest rate of metabolism. A strong relationship was established between in-vitro methods, while in-silico methods support the use of in-vitro methods and highlight the potential of in-silico techniques to predict metabolism. All the prodrugs behaved as angiotensin converting enzyme inhibitors, with the methyl ester displaying optimum inhibition. In-vitro porcine liver esterase metabolism rates inform in-vitro skin rates well, and in-silico interaction energies relate well to both. Thus, in-silico methods may be developed that include interaction energies to predict metabolism rates.

Gene expression profiling for nitric oxide prodrug JS-K to kill HL-60 myeloid leukemia cells.

PubMed

Liu, Jie; Malavya, Swati; Wang, Xueqian; Saavedra, Joseph E; Keefer, Larry K; Tokar, Erik; Qu, Wei; Waalkes, Michael P; Shami, Paul J

2009-07-01

The nitric oxide (NO) prodrug JS-K is shown to have anticancer activity. To profile the molecular events associated with the anticancer effects of JS-K, HL-60 leukemia cells were treated with JS-K and subjected to microarray and real-time RT-PCR analysis. JS-K induced concentration- and time-dependent gene expression changes in HL-60 cells corresponding to the cytolethality effects. The apoptotic genes (caspases, Bax, and TNF-alpha) were induced, and differentiation-related genes (CD14, ITGAM, and VIM) were increased. For acute phase protein genes, some were increased (TP53, JUN) while others were suppressed (c-myc, cyclin E). The expression of anti-angiogenesis genes THBS1 and CD36 and genes involved in tumor cell migration such as tissue inhibitors of metalloproteinases, were also increased by JS-K. Confocal analysis confirmed key gene changes at the protein levels. Thus, multiple molecular events are associated with JS-K effects in killing HL-60, which could be molecular targets for this novel anticancer NO prodrug.

Effect of alginate microencapsulation on the catalytic efficiency and in vitro enzyme-prodrug therapeutic efficacy of cytosine deaminase and of recombinant E. coli expressing cytosine deaminase.

PubMed

Funaro, Michael G; Nemani, Krishnamurthy V; Chen, Zhihang; Bhujwalla, Zaver M; Griswold, Karl E; Gimi, Barjor

2016-02-01

Cytosine deaminase (CD) catalyses the enzymatic conversion of the non-toxic prodrug 5-fluorocytosine (5-FC) to the potent chemotherapeutic form, 5-fluorouracil (5-FU). Intratumoral delivery of CD localises chemotherapy dose while reducing systemic toxicity. Encapsulation in biocompatible microcapsules immunoisolates CD and protects it from degradation. We report on the effect of alginate encapsulation on the catalytic and functional activity of isolated CD and recombinant E. coli engineered to express CD (E. coli(CD)). Alginate microcapsules containing either CD or Escherichia coli(CD) were prepared using ionotropic gelation. Conversion of 5-FC to 5-FU was quantitated in unencapsulated and encapsulated CD/E. coli(CD) using spectrophotometry, with a slower rate of conversion observed following encapsulation. Both encapsulated CD/5-FC and E. coli(CD)/5-FC resulted in cell kill and reduced proliferation of 9 L rat glioma cells, which was comparable to direct 5-FU treatment. Our results show that encapsulation preserves the therapeutic potential of CD and E. coli(CD) is equally effective for enzyme-prodrug therapy.

Design, Synthesis, and Pharmacokinetics of a Bone-Targeting Dual-Action Prodrug for the Treatment of Osteoporosis.

PubMed

Xie, Haibo; Chen, Gang; Young, Robert N

2017-08-24

A dual-action bone-targeting prodrug has been designed, synthesized, and evaluated for in vitro and in vivo metabolic stability, in vivo tissue distribution, and rates of release of the active constituents after binding to bones through the use of differentially double-labeled derivatives. The conjugate (general structure 7) embodies the merger of a very potent and proven anabolic selective agonist of the prostaglandin EP4 receptor, compound 5, and alendronic acid, a potent inhibitor of bone resorption, optimally linked through a differentially hydrolyzable linker unit, N-4-carboxymethylphenyl-methyloxycarbonyl-leucinyl-argininyl-para-aminophenylmethylalcohol (Leu-Arg-PABA). Optimized conjugate 16 was designed so that esterase activity will liberate 5 and cathepsin K cleavage of the Leu-Arg-PABA element will liberate alendronic acid. Studies with doubly radiolabeled 16 provide a proof-of-concept for the use of a cathepsin K cleavable peptide-linked conjugate for targeting of bisphosphonate prodrugs to bone and slow release liberation of the active constituents in vivo. Such conjugates are potential therapies for the treatment of bone disorders such as osteoporosis.

The Recombinant Bacteriophage Endolysin HY-133 Exhibits In Vitro Activity against Different African Clonal Lineages of the Staphylococcus aureus Complex, Including Staphylococcus schweitzeri.

PubMed

Idelevich, Evgeny A; Schaumburg, Frieder; Knaack, Dennis; Scherzinger, Anna S; Mutter, Wolfgang; Peters, Georg; Peschel, Andreas; Becker, Karsten

2016-04-01

HY-133 is a recombinant bacteriophage endolysin with bactericidal activity againstStaphylococcus aureus Here, HY-133 showedin vitroactivity against major African methicillin-susceptible and methicillin-resistantS. aureuslineages and ceftaroline/ceftobiprole- and borderline oxacillin-resistant isolates. HY-133 was also active againstStaphylococcus schweitzeri, a recently described species of theS. aureuscomplex. The activity of HY-133 on the tested isolates (MIC50, 0.25 μg/ml; MIC90, 0.5 μg/ml; range, 0.125 to 0.5 μg/ml) was independent of the species and strain background or antibiotic resistance. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Diamidines as antitrypanosomal, antileishmanial and antimalarial agents.

PubMed

Werbovetz, Karl

2006-02-01

Diamidine-containing compounds have a long history of use in the treatment of African trypanosomiasis and leishmaniasis. The discovery that diamidine prodrugs possess in vivo antimicrobial activity when administered orally has led to a renewed interest in this class of compounds for the treatment of parasitic infections. In this review, the selectivity of diamidines against trypanosomes, Leishmania and Plasmodium is rationalized through mechanism-of-action studies. An overview of the antiprotozoal activities of newer diamidines and diamidine prodrugs is also presented, along with a summary of the progress made toward the clinical development of new diamidines for use against these parasitic diseases.

Topical nanoparticulate formulation of drugs for ocular keratitis

NASA Astrophysics Data System (ADS)

Yang, Xiaoyan

The primary objective of this project is to develop drug-loaded polymeric nanoparticles suspended in a biocompatible gel for topical delivery of therapeutic agents commonly employed in the treatment of ocular viral/bacterial keratitis. PART 1: Poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles (NP) of dipeptide monoester prodrugs of ganciclovir (GCV) including L-Val-L-Val-GCV (LLGCV), L-Val-D-Val-GCV (LDGCV), D-Val-L-Val-GCV (DLGCV) were formulated and dispersed in thermosensitive PLGA-PEG-PLGA polymer gel for the treatment of herpes simplex virus type 1 (HSV-1) induced viral corneal keratitis. NP containing prodrugs of GCV were prepared by a double-emulsion solvent evaporation technique using various PLGA polymers with different drug/polymer ratios. Cytotoxicity studies suggested that all NP formulations are non-toxic. In vitro release of prodrugs from NP showed a biphasic release pattern with an initial burst phase followed by a sustained phase. Such burst effect was completely eliminated when NP were suspended in thermosensitive gels with near zero-order release kinetics. Prodrugs-loaded PLGA NP dispersed in thermosensitive gels can thus serve as a promising drug delivery system for the treatment of anterior eye diseases. Maximum uptake (around 60%) was noted at 3 h for NP. Cellular uptake and intracellular accumulation of prodrugs are significantly different among three stereoisomeric dipeptide prodrugs. The microscopic images show that NP are avidly internalized by HCEC cells and distributed throughout the cytoplasm instead of being localized on the cell surface. Following cellular uptake, prodrugs released from NP gradually bioreversed into parent drug GCV. LLGCV showed the highest degradation rate, followed by LDGCV and DLGCV. LLGCV, LDGCV and DLGCV released from NP exhibited superior uptake and bioreversion in corneal cells. PART 2: PLGA NP of hydrocortisone butyrate (HB) suspended in thermosensitive PLGA-PEG-PLGA gel were developed for the treatment of bacterial corneal keratitis. Experimental designs were employed in order to investigate specific effects of independent variables during preparation of HB-loaded PLGA NP and corresponding responses in optimizing the formulation. NP containing HB were prepared by an oil-in-water (O/W) emulsion evaporation technique with different surfactants including polyvinyl alcohol (PVA), pluronic F-108 and chitosan. NP were characterized with respect to particle size, entrapment efficiency, polydispersity, drug loading, surface morphology, zeta potential and crystallinity. In vitro release of HB from NP showed a biphasic release pattern with an initial burst phase followed by a sustained phase. Such burst effect was completely eliminated when NP were suspended in thermosensitive gels and zero-order release kinetics was observed. Percentage of uptake in HCEC after 4 h was 59.09+/-6.21% for PVA-emulsified NP relative to 55.74+/-6.26% for pluronic-emulsified NP, and 62.54+/-3.30% for chitosan-emulsified NP, respectively. In HCEC cell line, chitosan-emulsified NP with chitosan showed highest cellular uptake efficiency over PVA- and pluronic-emulsified NP. However, NP with chitosan indicated significant cytotoxicity under 200 and 500 ?g/mL after 48 h, while NP with PVA and pluronic showed no significant cytotoxicity. PLGA NP dispersed in thermosensitive gels can be considered as a promising drug delivery system for the treatment of anterior eye diseases.

Intein-mediated site-specific synthesis of tumor-targeting protein delivery system: Turning PEG dilemma into prodrug-like feature

PubMed Central

Chen, Yingzhi; Zhang, Meng; Jin, Hongyue; Tang, Yisi; Wang, Huiyuan; Xu, Qin; Li, Yaping; Li, Feng; Huang, Yongzhuo

2017-01-01

Poor tumor-targeted and cytoplasmic delivery is a bottleneck for protein toxin-based cancer therapy. Ideally, a protein toxin drug should remain stealthy in circulation for prolonged half-life and reduced side toxicity, but turn activated at tumor. PEGylation is a solution to achieve the first goal, but creates a hurdle for the second because PEG rejects interaction between the drugs and tumor cells therein. Such PEG dilemma is an unsolved problem in protein delivery. Herein proposed is a concept of turning PEG dilemma into prodrug-like feature. A site-selectively PEGylated, gelatinase-triggered cell-penetrating trichosanthin protein delivery system is developed with three specific aims. The first is to develop an intein-based ligation method for achieving site-specific modification of protein toxins. The second is to develop a prodrug feature that renders protein toxins remaining stealthy in blood for reduced side toxicity and improved EPR effect. The third is to develop a gelatinase activatable cell-penetration strategy for enhanced tumor targeting and cytoplasmic delivery. Of note, site-specific modification is a big challenge in protein drug research, especially for such a complicated, multifunctional protein delivery system. We successfully develop a protocol for constructing a macromolecular prodrug system with intein-mediated ligation synthesis. With an on-column process of purification and intein-mediated cleavage, the site-specific PEGylation then can be readily achieved by conjugation with the activated C-terminus, thus constructing a PEG-capped, cell-penetrating trichosanthin system with a gelatinase-cleavable linker that enables tumor-specific activation of cytoplasmic delivery. It provides a promising method to address the PEG dilemma for enhanced protein drug delivery, and importantly, a facile protocol for site-specific modification of such a class of protein drugs for improving their druggability and industrial translation. PMID:27914267

Antitumor Synergism and Enhanced Survival with a Tumor Vasculature-Targeted Enzyme Prodrug System, Rapamycin, and Cyclophosphamide.

PubMed

Krais, John J; Virani, Needa; McKernan, Patrick H; Nguyen, Quang; Fung, Kar-Ming; Sikavitsas, Vassilios I; Kurkjian, Carla; Harrison, Roger G

2017-09-01

Mutant cystathionine gamma-lyase was targeted to phosphatidylserine exposed on tumor vasculature through fusion with Annexin A1 or Annexin A5. Cystathionine gamma-lyase E58N, R118L, and E338N mutations impart nonnative methionine gamma-lyase activity, resulting in tumor-localized generation of highly toxic methylselenol upon systemic administration of nontoxic selenomethionine. The described therapeutic system circumvents systemic toxicity issues using a novel drug delivery/generation approach and avoids the administration of nonnative proteins and/or DNA required with other enzyme prodrug systems. The enzyme fusion exhibits strong and stable in vitro binding with dissociation constants in the nanomolar range for both human and mouse breast cancer cells and in a cell model of tumor vascular endothelium. Daily administration of the therapy suppressed growth of highly aggressive triple-negative murine 4T1 mammary tumors in immunocompetent BALB/cJ mice and MDA-MB-231 tumors in SCID mice. Treatment did not result in the occurrence of negative side effects or the elicitation of neutralizing antibodies. On the basis of the vasculature-targeted nature of the therapy, combinations with rapamycin and cyclophosphamide were evaluated. Rapamycin, an mTOR inhibitor, reduces the prosurvival signaling of cells in a hypoxic environment potentially exacerbated by a vasculature-targeted therapy. IHC revealed, unsurprisingly, a significant hypoxic response (increase in hypoxia-inducible factor 1 α subunit, HIF1A) in the enzyme prodrug-treated tumors and a dramatic reduction of HIF1A upon rapamycin treatment. Cyclophosphamide, an immunomodulator at low doses, was combined with the enzyme prodrug therapy and rapamycin; this combination synergistically reduced tumor volumes, inhibited metastatic progression, and enhanced survival. Mol Cancer Ther; 16(9); 1855-65. ©2017 AACR . ©2017 American Association for Cancer Research.

Neural stem cell-mediated enzyme/prodrug therapy for glioma: preclinical studies.

PubMed

Aboody, Karen S; Najbauer, Joseph; Metz, Marianne Z; D'Apuzzo, Massimo; Gutova, Margarita; Annala, Alexander J; Synold, Timothy W; Couture, Larry A; Blanchard, Suzette; Moats, Rex A; Garcia, Elizabeth; Aramburo, Soraya; Valenzuela, Valerie V; Frank, Richard T; Barish, Michael E; Brown, Christine E; Kim, Seung U; Badie, Behnam; Portnow, Jana

2013-05-08

High-grade gliomas are extremely difficult to treat because they are invasive and therefore not curable by surgical resection; the toxicity of current chemo- and radiation therapies limits the doses that can be used. Neural stem cells (NSCs) have inherent tumor-tropic properties that enable their use as delivery vehicles to target enzyme/prodrug therapy selectively to tumors. We used a cytosine deaminase (CD)-expressing clonal human NSC line, HB1.F3.CD, to home to gliomas in mice and locally convert the prodrug 5-fluorocytosine to the active chemotherapeutic 5-fluorouracil. In vitro studies confirmed that the NSCs have normal karyotype, tumor tropism, and CD expression, and are genetically and functionally stable. In vivo biodistribution studies demonstrated NSC retention of tumor tropism, even in mice pretreated with radiation or dexamethasone to mimic clinically relevant adjuvant therapies. We evaluated safety and toxicity after intracerebral administration of the NSCs in non-tumor-bearing and orthotopic glioma-bearing immunocompetent and immunodeficient mice. We detected no difference in toxicity associated with conversion of 5-fluorocytosine to 5-fluorouracil, no NSCs outside the brain, and no histological evidence of pathology or tumorigenesis attributable to the NSCs. The average tumor volume in mice that received HB1.F3.CD NSCs and 5-fluorocytosine was about one-third that of the average volume in control mice. On the basis of these results, we conclude that combination therapy with HB1.F3.CD NSCs and 5-fluorocytosine is safe, nontoxic, and effective in mice. These data have led to approval of a first-in-human study of an allogeneic NSC-mediated enzyme/prodrug-targeted cancer therapy in patients with recurrent high-grade glioma.

Design of pH-sensitive methotrexate prodrug-targeted curcumin nanoparticles for efficient dual-drug delivery and combination cancer therapy.

PubMed

Xie, Jiajiang; Fan, Zhongxiong; Li, Yang; Zhang, Yinying; Yu, Fei; Su, Guanghao; Xie, Liya; Hou, Zhenqing

2018-01-01

We designed acid-labile methotrexate (MTX) targeting prodrug self-assembling nanoparticles loaded with curcumin (CUR) drug for simultaneous delivery of multi-chemotherapeutic drugs and combination cancer therapy. A dual-acting MTX, acting as both an anticancer drug and as a tumor-targeting ligand, was coupled to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[aldehyde(polyethylene glycol)-2000] via Schiff's base reaction. The synthesized prodrug conjugate (DSPE-PEG-Imine-MTX) could be self-assembled into micellar nanoparticles (MTX-Imine-M) in aqueous solution, which encapsulated CUR into their core by hydrophobic interactions (MTX-Imine-M-CUR). The prepared MTX-Imine-M-CUR nanoparticles were composed of an inner hydrophobic DSPE/CUR core and an outside hydrophilic bishydroxyl poly (ethyleneglycol) (PEG) shell with a self-targeting MTX prodrug corona. The imine linker between 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[aldehyde(polyethyleneglycol)-2000] and MTX, as a dynamic covalent bond, was strong enough to remain intact in physiological pH, even though it is rapidly cleaved in acidic pH. The MTX-Imine-M-CUR could codeliver MTX and CUR selectively and efficiently into the cancer cells via folate receptor-mediated endocytosis followed by the rapid intracellular release of CUR and the active form of MTX via the acidity of endosomes/lysosomes. Moreover, the MTX-Imine-M-CUR resulted in significantly higher in vitro and in vivo anticancer activity than pH-insensitive DSPE-PEGAmide-MTX assembling nanoparticles loaded with CUR (MTX-Amide-M-CUR), MTX unconjugated DSPE-PEG assembling micellar nanoparticles loaded with CUR (M-CUR), combination of both free drugs, and individual free drugs. The smart system provided a simple, yet feasible, drug delivery strategy for targeted combination chemotherapy.

A fully human anti-Ep-CAM scFv-beta-glucuronidase fusion protein for selective chemotherapy with a glucuronide prodrug

PubMed Central

de Graaf, M; Boven, E; Oosterhoff, D; van der Meulen-Muileman, I H; Huls, G A; Gerritsen, W R; Haisma, H J; Pinedo, H M

2002-01-01

Monoclonal antibodies against tumour-associated antigens could be useful to deliver enzymes selectively to the site of a tumour for activation of a non-toxic prodrug. A completely human fusion protein may be advantageous for repeated administration, as host immune responses may be avoided. We have constructed a fusion protein consisting of a human single chain Fv antibody, C28, against the epithelial cell adhesion molecule and the human enzyme β-glucuronidase. The sequences encoding C28 and human enzyme β-glucuronidase were joined by a sequence encoding a flexible linker, and were preceded by the IgGκ signal sequence for secretion of the fusion protein. A CHO cell line was engineered to secrete C28-β-glucuronidase fusion protein. Antibody specificity and enzyme activity were retained in the secreted fusion protein that had an apparent molecular mass of 100 kDa under denaturing conditions. The fusion protein was able to convert a non-toxic prodrug of doxorubicin, N-[4-doxorubicin-N-carbonyl(oxymethyl)phenyl]-O-β-glucuronyl carbamate to doxorubicin, resulting in cytotoxicity. A bystander effect was demonstrated, as doxorubicin was detected in all cells after N-[4-doxorubicin-N-carbonyl(oxymethyl)phenyl]-O-β-glucuronyl carbamate administration when only 10% of the cells expressed the fusion protein. This is the first fully human and functional fusion protein consisting of an scFv against epithelial cell adhesion molecule and human enzyme β-glucuronidase for future use in tumour-specific activation of a non-toxic glucuronide prodrug. British Journal of Cancer (2002) 86, 811–818. DOI: 10.1038/sj/bjc/6600143 www.bjcancer.com © 2002 Cancer Research UK PMID:11875747

Leveraging Hypoxia-Activated Prodrugs to Prevent Drug Resistance in Solid Tumors.

PubMed

Lindsay, Danika; Garvey, Colleen M; Mumenthaler, Shannon M; Foo, Jasmine

2016-08-01

Experimental studies have shown that one key factor in driving the emergence of drug resistance in solid tumors is tumor hypoxia, which leads to the formation of localized environmental niches where drug-resistant cell populations can evolve and survive. Hypoxia-activated prodrugs (HAPs) are compounds designed to penetrate to hypoxic regions of a tumor and release cytotoxic or cytostatic agents; several of these HAPs are currently in clinical trial. However, preliminary results have not shown a survival benefit in several of these trials. We hypothesize that the efficacy of treatments involving these prodrugs depends heavily on identifying the correct treatment schedule, and that mathematical modeling can be used to help design potential therapeutic strategies combining HAPs with standard therapies to achieve long-term tumor control or eradication. We develop this framework in the specific context of EGFR-driven non-small cell lung cancer, which is commonly treated with the tyrosine kinase inhibitor erlotinib. We develop a stochastic mathematical model, parametrized using clinical and experimental data, to explore a spectrum of treatment regimens combining a HAP, evofosfamide, with erlotinib. We design combination toxicity constraint models and optimize treatment strategies over the space of tolerated schedules to identify specific combination schedules that lead to optimal tumor control. We find that (i) combining these therapies delays resistance longer than any monotherapy schedule with either evofosfamide or erlotinib alone, (ii) sequentially alternating single doses of each drug leads to minimal tumor burden and maximal reduction in probability of developing resistance, and (iii) strategies minimizing the length of time after an evofosfamide dose and before erlotinib confer further benefits in reduction of tumor burden. These results provide insights into how hypoxia-activated prodrugs may be used to enhance therapeutic effectiveness in the clinic.

Evaluation of salicylic acid fatty ester prodrugs for UV protection.

PubMed

Im, Jong Seob; Balakrishnan, Prabagar; Oh, Dong Hoon; Kim, Jung Sun; Jeon, Eun-Mi; Kim, Dae-Duk; Yong, Chul Soon; Choi, Han-Gon

2011-07-01

The purpose of this study was to investigate the physicochemical properties and in vitro evaluation of fatty ester prodrugs of salicylic acid for ultraviolet (UV) protection. The physicochemical properties such as lipophilicity, chemical stability and enzymatic hydrolysis were investigated with the following fatty ester prodrugs of salicylic acid: octanoyl (C8SA), nonanoyl (C9SA), decanoyl (C10SA), lauroyl (C12SA), myristoyl (C14SA) and palmitoyl oxysalicylate (C16SA). Furthermore, their skin permeation and accumulation were evaluated using a combination of common permeation enhancing techniques such as the use of a lipophilic receptor solution, removal of stratum corneum and delipidization of skin. Their k' values were proportional to the degree of carbon-carbon saturation in the side chain. All these fatty esters were highly stable in 2-propanol, acetonitrile and glycerin, but unstable in methanol and ethanol. They were relatively unstable in liver and skin homogenates. In particular, C16SA was mostly hydrolyzed to its parent compound in hairless mouse liver and skin homogenates, suggesting that it might be converted to salicylic acid after its topical administration. In the skin permeation and accumulation study, C16SA showed the poorest permeation in all skins, suggesting that it could not be permeated in the skin. Furthermore, C14SA and C16SA were less accumulated in delipidized skin compared with normal skin or stripped skin, suggesting that these esters had relatively strong affinities for lipids compared with the other prodrugs in the skin. C16SA showed significantly higher dermal accumulation in all skins compared with its parent salicylic acid. Thus, the palmitoyl oxysalicylate (C16SA) might be a potential candidate for UV protection due to its absence of skin permeation, smaller uptake in the lipid phase and relatively lower skin accumulation.

Differential In Vitro and In Vivo Toxicities of Antimicrobial Peptide Prodrugs for Potential Use in Cystic Fibrosis

PubMed Central

Schütte, André; Reeves, Emer; Greene, Catherine; Humphreys, Hilary; Mall, Marcus; Fitzgerald-Hughes, Deirdre; Devocelle, Marc

2016-01-01

There has been considerable interest in the use of antimicrobial peptides (AMPs) as antimicrobial agents for the treatment of many conditions, including cystic fibrosis (CF). The challenging conditions of the CF patient lung require robust AMPs that are active in an environment of high proteolytic activity but that also have low cytotoxicity and immunogenicity. Previously, we developed prodrugs of AMPs that limited the cytotoxic effects of AMP treatment by rendering the antimicrobial activity dependent on the host enzyme neutrophil elastase (NE). However, cytotoxicity remained an issue. Here, we describe the further optimization of the AMP prodrug (pro-AMP) model for CF to produce pro-WMR, a peptide with greatly reduced cytotoxicity (50% inhibitory concentration against CFBE41o- cells, >300 μM) compared to that of the previous group of pro-AMPs. The bactericidal activity of pro-WMR was increased in NE-rich bronchoalveolar lavage (BAL) fluid from CF patients (range, 8.4% ± 6.9% alone to 91.5% ± 5.8% with BAL fluid; P = 0.0004), an activity differential greater than that of previous pro-AMPs. In a murine model of lung delivery, the pro-AMP modification reduced host toxicity, with pro-WMR being less toxic than the active peptide. Previously, host toxicity issues have hampered the clinical application of AMPs. However, the development of application-specific AMPs with modifications that minimize toxicity similar to those described here can significantly advance their potential use in patients. The combination of this prodrug strategy with a highly active AMP has the potential to produce new therapeutics for the challenging conditions of the CF patient lung. PMID:26902766

Synthesis, characterization and in vitro/in vivo evaluation of novel reduction-sensitive hybrid nano-echinus-like nanomedicine.

PubMed

Wang, Kaili; Guo, Chunjing; Zou, Shaohua; Yu, Yueming; Fan, Xinxin; Wang, Bingjie; Liu, Mengna; Fang, Lei; Chen, Daquan

2018-04-27

To remedy the problems resulting from the usage of anti-cancer drugs in cancer chemotherapy, such as deficient drug concentration in tumour cells, low water-solubility and non-specific distribution of antitumour drugs, a kind of reduction-sensitive polymer prodrug of curcumin (Cur) containing in the nano-echinus was synthesized and designed. The nano-echinus-like nanomedicine presented synergistic effect with glycyrrhetic acid (GA) and oligomeric hyaluronic (HA) for targeting and combating HepG2 human liver cancer cell. Firstly, a kind of small molecular prodrug of Cur, dithiodipropionic acid-Cur (-SS-Cur), was chemically conjugated onto the side chain of the conjugated glycyrrhetic acid- oligomeric hyaluronic (GA-HA) to generate an amphiphilic polymeric prodrug of Cur, GA-HA-SS-Cur. The obtained GA-HA-SS-Cur prodrug and subsidiary material mPEG-DSPE could self-assemble into a sea urchin-like micelles in aqueous media and release Cur rapidly in response to glutathion (GSH). Then, Cur was loaded into the nano-echinus with a particle size of (118.1 ± 0.2 nm) and drug-loading efficiency of (8.03 ± 2.1%). The structure of GA-HA-SS-Cur was characterized by 1 H-NMR in this report. The morphology of micelles was observed with a transmission electron microscope (TEM). Subsequently, the reduction-sensitivity of the nano-echinus was confirmed by the changes in in-vitro drug release after different concentrations of GSH treatment. Besides, the cellular uptake behaviour and MTT assays of the nano-echinus were investigated, suggesting that the nano-echinus was of desirable safety and could be taken into HepG2 cells in a time-dependent manner. Later, anti-tumour efficacy in vivo revealed the effective inhibition of tumour growth.

Selectivity and Efficiency of Late Transgene Expression by Transcriptionally Targeted Oncolytic Adenoviruses Are Dependent on the Transgene Insertion Strategy

PubMed Central

Quirin, Christina; Rohmer, Stanimira; Fernández-Ulibarri, Inés; Behr, Michael; Hesse, Andrea; Engelhardt, Sarah; Erbs, Philippe; Enk, Alexander H.

2011-01-01

Abstract Key challenges facing cancer therapy are the development of tumor-specific drugs and potent multimodal regimens. Oncolytic adenoviruses possess the potential to realize both aims by restricting virus replication to tumors and inserting therapeutic genes into the virus genome, respectively. A major effort in this regard is to express transgenes in a tumor-specific manner without affecting virus replication. Using both luciferase as a sensitive reporter and genetic prodrug activation, we show that promoter control of E1A facilitates highly selective expression of transgenes inserted into the late transcription unit. This, however, required multistep optimization of late transgene expression. Transgene insertion via internal ribosome entry site (IRES), splice acceptor (SA), or viral 2A sequences resulted in replication-dependent expression. Unexpectedly, analyses in appropriate substrates and with matching control viruses revealed that IRES and SA, but not 2A, facilitated indirect transgene targeting via tyrosinase promoter control of E1A. Transgene expression via SA was more selective (up to 1,500-fold) but less effective than via IRES. Notably, we also revealed transgene-dependent interference with splicing. Hence, the prodrug convertase FCU1 (a cytosine deaminase–uracil phosphoribosyltransferase fusion protein) was expressed only after optimizing the sequence surrounding the SA site and mutating a cryptic splice site within the transgene. The resulting tyrosinase promoter-regulated and FCU1-encoding adenovirus combined effective oncolysis with targeted prodrug activation therapy of melanoma. Thus, prodrug activation showed potent bystander killing and increased cytotoxicity of the virus up to 10-fold. We conclude that armed oncolytic viruses can be improved substantially by comparing and optimizing strategies for targeted transgene expression, thereby implementing selective and multimodal cancer therapies. PMID:20939692

Abrogation of Antibody-Induced Arthritis in Mice by a Self-Activating Viridin Prodrug and Association With Impaired Neutrophil and Endothelial Cell Function

PubMed Central

Stangenberg, Lars; Ellson, Chris; Cortez-Retamozo, Virna; Ortiz-Lopez, Adriana; Yuan, Hushan; Blois, Joseph; Smith, Ralph A.; Yaffe, Michael B.; Weissleder, Ralph; Benoist, Christophe; Mathis, Diane; Josephson, Lee; Mahmood, Umar

2009-01-01

Objective To test a novel self-activating viridin (SAV) prodrug that slowly releases wortmannin, a potent phosphoinositide 3-kinase inhibitor, in a model of antibody-mediated inflammatory arthritis. Methods The SAV prodrug was administered to K/BxN mice or to C57BL/6 (B6) mice that had been injected with K/BxN serum. Ankle thickness was measured, and histologic changes were scored after a 10-day disease course (serum-transfer arthritis). Protease activity was measured by a near-infrared imaging approach using a cleavable cathepsin–selective probe. Further near-infrared imaging techniques were used to analyze early changes in vascular permeability after serum injection, as well as neutrophil–endothelial cell interactions. Neutrophil functions were assessed using an oxidative burst assay as well as a degranulation assay. Results SAV prevented ankle swelling in mice with serum-transfer arthritis in a dose-dependent manner. It also markedly reduced the extent of other features of arthritis, such as protease activity and histology scores for inflammation and joint erosion. Moreover, SAV was an effective therapeutic agent. The underlying mechanisms for the antiinflammatory activity were manifold. Endothelial permeability after serum injection was reduced, as was firm neutrophil attachment to endothelial cells. Endothelial cell activation by tumor necrosis factor α was impeded by SAV, as measured by the expression of vascular cell adhesion molecule. Crucial neutrophil functions, such as generation of reactive oxygen species and degranulation of protease-laden vesicles, were decreased by SAV administration. Conclusion A novel SAV prodrug proved strongly antiinflammatory in a murine model of antibody-induced inflammatory arthritis. Its activity could be attributed, at least in part, to the inhibition of neutrophil and endothelial cell functions. PMID:19644878

Anti-inflammatory polymersomes of redox-responsive polyprodrug amphiphiles with inflammation-triggered indomethacin release characteristics.

PubMed

Tan, Jiajia; Deng, Zhengyu; Liu, Guhuan; Hu, Jinming; Liu, Shiyong

2018-03-21

Inflammation serves as a natural defense mechanism to protect living organisms from infectious diseases. Nonsteroidal anti-inflammatory drugs (NSAIDs) can help relieve inflammatory reactions and are clinically used to treat pain, fever, and inflammation, whereas long-term use of NSAIDs may lead to severe side effects including gastrointestinal damage and cardiovascular toxicity. Therefore, it is of increasing importance to configure new dosing strategies and alleviate the side effects of NSAIDs. Towards this goal, glutathione (GSH)-responsive disulfide bonds and hydrogen peroxide (H 2 O 2 )-reactive phenylboronic ester linkages were utilized as triggering moieties in this work to design redox-responsive prodrug monomers and polyprodrug amphiphiles based on indomethacin (IND) drug. Note that IND is a widely prescribed NSAID in the clinic. Starting from three types of redox-reactive IND prodrug monomers, redox-responsive polyprodrug amphiphiles were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerizations of prodrug monomers using poly(ethylene oxide) (PEO)-based macroRAFT agent. The resultant polyprodrug amphiphiles with high IND loading contents (>33 wt%) could self-assemble into polymersomes with PEO shielding coronas and redox-responsive bilayer membranes composed of IND prodrugs. Upon incubation with GSH or H 2 O 2 , controlled release of intact IND in the active form from polyprodrug polymersomes was actuated by GSH-mediated disulfide cleavage reaction and H 2 O 2 -mediated oxidation of phenylboronic ester moieties, respectively, followed by self-immolative degradation events. Furthermore, in vitro studies at the cellular level revealed that redox-responsive polymersomes could efficiently relieve inflammatory responses induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells. Copyright © 2018. Published by Elsevier Ltd.

Kinesin spindle protein (KSP) inhibitors. Part 3: synthesis and evaluation of phenolic 2,4-diaryl-2,5-dihydropyrroles with reduced hERG binding and employment of a phosphate prodrug strategy for aqueous solubility.

PubMed

Garbaccio, Robert M; Fraley, Mark E; Tasber, Edward S; Olson, Christy M; Hoffman, William F; Arrington, Kenneth L; Torrent, Maricel; Buser, Carolyn A; Walsh, Eileen S; Hamilton, Kelly; Schaber, Michael D; Fernandes, Christine; Lobell, Robert B; Tao, Weikang; South, Vicki J; Yan, Youwei; Kuo, Lawrence C; Prueksaritanont, Thomayant; Slaughter, Donald E; Shu, Cathy; Heimbrook, David C; Kohl, Nancy E; Huber, Hans E; Hartman, George D

2006-04-01

2,4-Diaryl-2,5-dihydropyrroles have been discovered to be novel, potent and water-soluble inhibitors of KSP, an emerging therapeutic target for the treatment of cancer. A potential concern for these basic KSP inhibitors (1 and 2) was hERG binding that can be minimized by incorporation of a potency-enhancing C2 phenol combined with neutral N1 side chains. Aqueous solubility was restored to these, and other, non-basic inhibitors, through a phosphate prodrug strategy.

Use of 2'-spirocyclic ethers in HCV nucleoside design.

PubMed

Du, Jinfa; Chun, Byoung-Kwon; Mosley, Ralph T; Bansal, Shalini; Bao, Haiying; Espiritu, Christine; Lam, Angela M; Murakami, Eisuke; Niu, Congrong; Micolochick Steuer, Holly M; Furman, Phillip A; Sofia, Michael J

2014-03-13

Conformationally restricted 2'-spironucleosides and their prodrugs were synthesized as potential anti-HCV agents. Although the replicon activity of the new agents containing pyrimidine bases was modest, the triphosphate of a 2'-oxetane cytidine analogue demonstrated potent intrinsic biochemical activity against the NS5B polymerase, with IC50 = 8.48 μM. Activity against NS5B bearing the S282T mutation was reduced. Phosphoramidate prodrugs of a 2'-oxetane 2-amino-6-O-methyl-purine nucleoside demonstrated potent anti-HCV activity in vitro, and the corresponding triphosphate retained similar potent activity against both wild-type and S282T HCV NS5B polymerase.

Antitubercular Nanocarrier Combination Therapy: Formulation Strategies and in Vitro Efficacy for Rifampicin and SQ641

PubMed Central

2015-01-01

Tuberculosis (TB) remains a major global health concern, and new therapies are needed to overcome the problems associated with dosing frequency, patient compliance, and drug resistance. To reduce side effects associated with systemic drug distribution and improve drug concentration at the target site, stable therapeutic nanocarriers (NCs) were prepared and evaluated for efficacy in vitro in Mycobacterium tuberculosis-infected macrophages. Rifampicin (RIF), a current, broad-spectrum antibiotic used in TB therapy, was conjugated by degradable ester bonds to form hydrophobic prodrugs. NCs encapsulating various ratios of nonconjugated RIF and the prodrugs showed the potential ability to rapidly deliver and knockdown intracellular M. tuberculosis by nonconjugated RIF and to obtain sustained release of RIF by hydrolysis of the RIF prodrug. NCs of the novel antibiotic SQ641 and a combination NC with cyclosporine A were formed by flash nanoprecipitation. Delivery of SQ641 in NC form resulted in significantly improved activity compared to that of the free drug against intracellular M. tuberculosis. A NC formulation with a three-compound combination of SQ641, cyclosporine A, and vitamin E inhibited intracellular replication of M. tuberculosis significantly better than SQ641 alone or isoniazid, a current first-line anti-TB drug. PMID:25811733

Immobilization of paracetamol and benzocaine pro-drug derivatives as long-range self-organized monolayers on graphite.

PubMed

Popoff, Alexandre; Fichou, Denis

2008-05-01

We show here by means of scanning tunneling microscopy (STM) at the liquid/solid interface that paracetamol and benzocaine molecules bearing a long aliphatic chain can be immobilized on highly oriented pyrolitic graphite (HOPG) as perfectly ordered two-dimensional domains extending over several hundreds of nanometers. In both cases, high-resolution STM images reveal that compounds 1 and 2 self-assemble into parallel lamellae having a head-to-head arrangement. The paracetamol heads of 1 are in a zigzag position with entangled n-dodecyloxy side chains while benzocaine heads of compound 2 are perfectly aligned as a double row and have their palmitic side chains on either sides of the head alignment. We attribute the very long-range ordering of these two pro-drug derivatives on HOPG to the combined effects of intermolecular H-bonding on one side and Van der Waals interactions between aliphatic side chains and graphite on the other side. The 2D immobilization of pro-drug derivatives via a non-destructive physisorption mechanism could prove to be useful for applications such as drug delivery if it can be realized on a biocompatible substrate.

Dextran-5-(4-ethoxycarbonylphenylazo)salicylic acid ester, a polymeric colon-specific prodrug releasing 5-aminosalicylic acid and benzocaine, ameliorates TNBS-induced rat colitis.

PubMed

Nam, Joon; Kim, Wooseong; Lee, Sunyoung; Jeong, Seongkeun; Yoo, Jin-Wook; Kim, Min-Soo; Jung, Yunjin

2016-01-01

Local anesthetics have beneficial effects on colitis. Dextran-5-(4-ethoxycarbonylphenylazo)salicylic acid ester (Dex-5-ESA), designed as a polymeric colon-specific prodrug liberating 5-ASA and benzocaine in the large intestine, was prepared and its therapeutic activity against colitis was evaluated using a TNBS-induced rat colitis model. Dex-5-ESA liberated 5-ASA and benzocaine in the cecal contents while (bio)chemically stable in the small intestinal contents and mucosa. Oral administration of Dex-5-ESA (equivalent to 10 mg 5-ASA/kg, twice a day) alleviated colonic injury and reduced MPO activity in the inflamed colon. In parallel, pro-inflammatory mediators, COX-2, iNOS and CINC-3, elevated by TNBS-induced colitis, were substantially diminished in the inflamed colon. Dex-5-ESA was much more effective for the treatment of colitis than 5-(4-ethoxycarbonylphenylazo)salicylic acid (5-ESA) that may not deliver benzocaine to the large intestine. Our data suggest that Dex-5-ESA is a polymeric colon-specific prodrug, liberating 5-ASA and benzocaine in the target site (large intestine), probably exerting anti-colitic effects by combined action of 5-ASA and benzocaine.

Behavior of platinum(iv) complexes in models of tumor hypoxia: cytotoxicity, compound distribution and accumulation.

PubMed

Schreiber-Brynzak, Ekaterina; Pichler, Verena; Heffeter, Petra; Hanson, Buck; Theiner, Sarah; Lichtscheidl-Schultz, Irene; Kornauth, Christoph; Bamonti, Luca; Dhery, Vineet; Groza, Diana; Berry, David; Berger, Walter; Galanski, Markus; Jakupec, Michael A; Keppler, Bernhard K

2016-04-01

Hypoxia in solid tumors remains a challenge for conventional cancer therapeutics. As a source for resistance, metastasis development and drug bioprocessing, it influences treatment results and disease outcome. Bioreductive platinum(iv) prodrugs might be advantageous over conventional metal-based therapeutics, as biotransformation in a reductive milieu, such as under hypoxia, is required for drug activation. This study deals with a two-step screening of experimental platinum(iv) prodrugs with different rates of reduction and lipophilicity with the aim of identifying the most appropriate compounds for further investigations. In the first step, the cytotoxicity of all compounds was compared in hypoxic multicellular spheroids and monolayer culture using a set of cancer cell lines with different sensitivities to platinum(ii) compounds. Secondly, two selected compounds were tested in hypoxic xenografts in SCID mouse models in comparison to satraplatin, and, additionally, (LA)-ICP-MS-based accumulation and distribution studies were performed for these compounds in hypoxic spheroids and xenografts. Our findings suggest that, while cellular uptake and cytotoxicity strongly correlate with lipophilicity, cytotoxicity under hypoxia compared to non-hypoxic conditions and antitumor activity of platinum(iv) prodrugs are dependent on their rate of reduction.

Potent and Selective Phosphopeptide Mimetic Prodrugs Targeted to the Src Homology 2 (SH2) Domain of Signal Transducer and Activator of Transcription 3

PubMed Central

Mandal, Pijus K.; Gao, Fengqin; Lu, Zhen; Ren, Zhiyong; Ramesh, Rajagopal; Birtwistle, J. Sanderson; Kaluarachchi, Kumaralal K.; Chen, Xiaomin; Bast, Robert C.; Liao, Warren S.; McMurray, John S.

2011-01-01

Signal transducer and activator of transcription 3 (Stat3), a target for anticancer drug design, is activated by recruitment to phosphotyrosine residues on growth factor and cytokine receptors via its SH2 domain. We report here structure-activity relationship studies on phosphopeptide mimics targeted to the SH2 domain of Stat3. Inclusion of a methyl group on the β-position of the pTyr mimic, 4-phosphocinfnamide, enhanced affinity 2–3 fold. Bis-pivaloyloxymethyl prodrugs containing β-methyl cinnamide, dipeptide scaffolds Haic and Nle-cis-3,4-methanoproline, and glutamine surrogates were highly potent, completely inhibiting phosphorylation of Stat3 Tyr705 at 0.5–1 µM in a variety of cancer cell lines. The inhibitors were selective for Stat3 over Stat1, Stat5, Src, and p85 of PI3K, indicating ability to discriminate individual SH2 domains in intact cells. At concentrations that completely inhibited Stat3 phosphorylation, the prodrugs were not cytotoxic to a panel of tumor cells, thereby showing clear distinction between cytotoxicity and effects downstream of activated Stat3. PMID:21486047

Targeting the hypoxic fraction of tumours using hypoxia-activated prodrugs.

PubMed

Phillips, Roger M

2016-03-01

The presence of a microenvironment within most tumours containing regions of low oxygen tension or hypoxia has profound biological and therapeutic implications. Tumour hypoxia is known to promote the development of an aggressive phenotype, resistance to both chemotherapy and radiotherapy and is strongly associated with poor clinical outcome. Paradoxically, it is recognised as a high-priority target and one of the therapeutic strategies designed to eradicate hypoxic cells in tumours is a group of compounds known collectively as hypoxia-activated prodrugs (HAPs) or bioreductive drugs. These drugs are inactive prodrugs that require enzymatic activation (typically by 1 or 2 electron oxidoreductases) to generate cytotoxic species with selectivity for hypoxic cells being determined by (1) the ability of oxygen to either reverse or inhibit the activation process and (2) the presence of elevated expression of oxidoreductases in tumours. The concepts underpinning HAP development were established over 40 years ago and have been refined over the years to produce a new generation of HAPs that are under preclinical and clinical development. The purpose of this article is to describe current progress in the development of HAPs focusing on the mechanisms of action, preclinical properties and clinical progress of leading examples.

N-(Pivaloyloxy)alkoxy-carbonyl Prodrugs of the Glutamine Antagonist 6-Diazo-5-oxo-l-norleucine (DON) as a Potential Treatment for HIV Associated Neurocognitive Disorders.

PubMed

Nedelcovych, Michael T; Tenora, Lukáš; Kim, Boe-Hyun; Kelschenbach, Jennifer; Chao, Wei; Hadas, Eran; Jančařík, Andrej; Prchalová, Eva; Zimmermann, Sarah C; Dash, Ranjeet P; Gadiano, Alexandra J; Garrett, Caroline; Furtmüller, Georg; Oh, Byoungchol; Brandacher, Gerald; Alt, Jesse; Majer, Pavel; Volsky, David J; Rais, Rana; Slusher, Barbara S

2017-08-24

Aberrant excitatory neurotransmission associated with overproduction of glutamate has been implicated in the development of HIV-associated neurocognitive disorders (HAND). The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON, 14) attenuates glutamate synthesis in HIV-infected microglia/macrophages, offering therapeutic potential for HAND. We show that 14 prevents manifestation of spatial memory deficits in chimeric EcoHIV-infected mice, a model of HAND. 14 is not clinically available, however, because its development was hampered by peripheral toxicities. We describe the synthesis of several substituted N-(pivaloyloxy)alkoxy-carbonyl prodrugs of 14 designed to circulate inert in plasma and be taken up and biotransformed to 14 in the brain. The lead prodrug, isopropyl 6-diazo-5-oxo-2-(((phenyl(pivaloyloxy)methoxy)carbonyl)amino)hexanoate (13d), was stable in swine and human plasma but liberated 14 in swine brain homogenate. When dosed systemically in swine, 13d provided a 15-fold enhanced CSF-to-plasma ratio and a 9-fold enhanced brain-to-plasma ratio relative to 14, opening a possible clinical path for the treatment of HAND.

Nonpolymeric nanoassemblies for ocular administration of acyclovir: pharmacokinetic evaluation in rabbits.

PubMed

Stella, Barbara; Arpicco, Silvia; Rocco, Flavio; Burgalassi, Susi; Nicosia, Nadia; Tampucci, Silvia; Chetoni, Patrizia; Cattel, Luigi

2012-01-01

The aim of this study was to increase bioavailability of the antiviral drug acyclovir (ACV) when administered by the ocular route. For this purpose, a new lipophilic derivative of acyclovir was synthesized, both possessing greater lipophilicity and providing the formation of a homogeneous water dispersion with higher amount of ACV than the aqueous solution of the parent drug. This was done by chemically linking acyclovir to the isoprenoid chain of squalene, obtaining 4'-trisnorsqualenoylacyclovir (SQACV), in which squalene is covalently coupled to the 4'-hydroxy group of acyclovir. This new prodrug was then formulated as nonpolymeric nanoassemblies through nanoprecipitation; the resulting particles were characterized in terms of mean diameter, zeta potential, and stability. The pharmacokinetic profile of the prodrug in the tear fluid and in the aqueous humor of rabbits was evaluated and compared to that of the parent drug. Data showed that SQACV nanoassemblies increased the amount of ACV in the aqueous humor of rabbits compared to free ACV solution. This new amphiphilic prodrug of acyclovir is a very promising tool to increase the ocular bioavailability of the parent drug. Copyright © 2011 Elsevier B.V. All rights reserved.

Multifunctional Surface-Enhanced Raman Spectroscopy-Detectable Silver Nanoparticles Combined Photodynamic Therapy and pH-Triggered Chemotherapy.

PubMed

Srinivasan, Supriya; Bhardwaj, Vinay; Nagasetti, Abhignyan; Fernandez-Fernandez, Alicia; McGoron, Anthony J

2016-12-01

This research paper reports the development of a multifunctional anti-cancer prodrug system based on silver nanoparticles. This prodrug system is composed of 70-nm sized nanoparticles and features photodynamic therapeutic properties and active, pH-triggered drug release. The silver nanoparticles are decorated with a folic acid (FA) targeting ligand via an amide bond, and also conjugated to the chemotherapeutic drug doxorubicin (DOX) via an acid-cleavable hydrazone bond. Both FA and DOX are attached to the silver nanoparticles through a polyethylene glycol (PEG) spacer. This prodrug system can preferentially enter cells that over-express folic acid receptors, with subsequent intracellular drug release triggered by reduced intracellular pH. Moreover, the silver nanoparticle carrier system exhibits photodynamic therapeutic (PDT) activity, so that the cell viability of cancer cells that overexpress folate receptors can be further reduced upon light irradiation. The dual effects of pH-triggered drug release and PDT increase the therapeutic efficacy of this system. The multifunctional nanoparticles can be probed intracellularly through Surface-Enhanced Raman Spectroscopy (SERS) and fluorescence spectroscopy. The current report explores the applicability of this multifunctional silver nanoparticle-based system for cancer theranostics.

Supramolecular curcumin-barium prodrugs for formulating with ceramic particles.

PubMed

Kamalasanan, Kaladhar; Anupriya; Deepa, M K; Sharma, Chandra P

2014-10-01

A simple and stable curcumin-ceramic combined formulation was developed with an aim to improve curcumin stability and release profile in the presence of reactive ceramic particles for potential dental and orthopedic applications. For that, curcumin was complexed with barium (Ba(2+)) to prepare curcumin-barium (BaCur) complex. Upon removal of the unbound curcumin and Ba(2+) by dialysis, a water-soluble BaCur complex was obtained. The complex was showing [M+1](+) peak at 10,000-20,000 with multiple fractionation peaks of MALDI-TOF-MS studies, showed that the complex was a supramolecular multimer. The (1)H NMR and FTIR studies revealed that, divalent Ba(2+) interacted predominantly through di-phenolic groups of curcumin to form an end-to-end complex resulted in supramolecular multimer. The overall crystallinity of the BaCur was lower than curcumin as per XRD analysis. The complexation of Ba(2+) to curcumin did not degrade curcumin as per HPLC studies. The fluorescence spectrum was blue shifted upon Ba(2+) complexation with curcumin. Monodisperse nanoparticles with size less than 200dnm was formed, out of the supramolecular complex upon dialysis, as per DLS, and upon loading into pluronic micelles the size was remaining in similar order of magnitude as per DLS and AFM studies. Stability of the curcumin was improved greater than 50% after complexation with Ba(2+) as per UV/Vis spectroscopy. Loading of the supramloecular nanoparticles into pluronic micelles had further improved the stability of curcumin to approx. 70% in water. These BaCur supramolecule nanoparticles can be considered as a new class of prodrugs with improved solubility and stability. Subsequently, ceramic nanoparticles with varying chemical composition were prepared for changing the material surface reactivity in terms of the increase in, degradability, surface pH and protein adsorption. Further, these ceramic particles were combined with curcumin prodrug formulations and optimized the curcumin release properties in the combined formulations. Our proof concept study shows that, the conversion of curcumin to a metal-organic supramolecular prodrug improved the solubility, stability and release profile of curcumin. The prodrug approach with the micellisation strategy appears to be more appropriate to deliver intact curcumin in the presence of ceramic particles of varying surface reactivity. Copyright © 2014 Elsevier B.V. All rights reserved.

Lipophilic nalmefene prodrugs to achieve a one-month sustained release.

PubMed

Gaekens, Tim; Guillaume, Michel; Borghys, Herman; De Zwart, Loeckie L; de Vries, Ronald; Embrechts, Roger C A; Vermeulen, An; Megens, Anton A H P; Leysen, Josée E; Herdewijn, Piet; Annaert, Pieter P; Atack, John R

2016-06-28

Nalmefene is an opioid antagonist which as a once-a-day tablet formulation has recently been approved for reducing ethanol intake in alcoholic subjects. In order to address the compliance issue in this patient population, a number of potential nalmefene prodrugs were synthesized with the aim of providing a formulation that could provide plasma drug concentrations in the region of 0.5-1.0ng/mL for a one-month period when dosed intramuscular to dogs or minipigs. In an initial series of studies, three different lipophilic nalmefene derivatives were evaluated: the palmitate (C16), the octadecyl glutarate diester (C18-C5) and the decyl carbamate (CB10). They were administered intramuscularly to dogs in a sesame oil solution at a dose of 1mg-eq. nalmefene/kg. The decyl carbamate was released relatively quickly from the oil depot and its carbamate bond was too stable to be used as a prodrug. The other two derivatives delivered a fairly constant level of 0.2-0.3ng nalmefene/mL plasma for one month and since there was no significant difference between these two, the less complex palmitate monoester was chosen to demonstrate that dog plasma nalmefene concentrations were dose-dependent at 1, 5 and 20mg-eq. nalmefene/kg. In a second set of experiments, the effect of the chain length of the fatty acid monoester promoieties was examined. The increasingly lipophilic octanoate (C8), decanoate (C10) and dodecanoate (C12) derivatives were evaluated in dogs and in minipigs, at a dose of 5mg-eq. nalmefene/kg and plasma nalmefene concentrations were measured over a four-week period. The pharmacokinetic profiles were very similar in both species with Cmax decreasing and Tmax increasing with increasing fatty acid chain length and the target plasma concentrations (0.5-1.0ng/mL over a month-long period) were achieved with the dodecanoate (C12) prodrug. These data therefore demonstrate that sustained plasma nalmefene concentrations can be achieved in both dog and minipig using nalmefene prodrugs and that the pharmacokinetic profile of nalmefene can be tuned by varying the length of the alkyl group. Copyright © 2016 Elsevier B.V. All rights reserved.

[New antibacterial agents on the market and in the pipeline].

PubMed

Kern, W V

2015-11-01

After some years of stagnation there have been several new successful developments in the field of antibacterial agents. Most of these new developments have been in conventional antibacterial classes. New drugs among the beta-lactam agents are methicillin-resistant Staphylococcus aureus (MRSA) active cephalosporins (ceftaroline and ceftobiprole) and new combinations of beta-lactam with beta-lactamase inhibitors (ceftolozane/tazobactam, ceftazidime/avibactam, imipenem/relebactam and meropenem/RPX7009). New developments can also be observed among oxazolidinones (tedizolid, radezolid, cadazolid and MRX-I), macrolides/ketolides (modithromycin and solithromycin), aminoglycosides (plazomicin), quinolones (nemonoxacin, delafloxacin and avarofloxacin), tetracyclines (omadacycline and eravacycline) as well as among glycopeptides and lipopeptides (oritavancin, telavancin, dalbavancin and surotomycin). New agents in a very early developmental phase are FabI inhibitors, endolysines, peptidomimetics, lipid A inhibitors, methionyl-tRNA synthetase inhibitors and teixobactin.

What is the best therapeutic approach to methicillin-resistant Staphylococcus aureus pneumonia?

PubMed

Peyrani, Paula; Ramirez, Julio

2015-04-01

The purpose of this review is to define what the best therapeutic approach is for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Although two meta-analyses reported conflicting findings, recent retrospective studies reported higher success rates in patients with MRSA pneumonia treated with linezolid when compared to vancomycin. Only registration trials are available for some anti-MRSA antibiotics, such as telavancin, ceftaroline, and ceftobiprole. Scarce information is available regarding the best therapeutic approach for MRSA community-acquired pneumonia. Linezolid seems to be a better choice than vancomycin for the treatment of MRSA ventilator-associated pneumonia. It is still unclear whether this affirmation holds for other forms of MRSA pneumonia. Further research is needed to define whether newer antibiotics are better alternatives than currently recommended agents.

Ceftobiprole Activity When Tested Against Contemporary Bacteria Causing Bloodstream Infections in the US (2016)

PubMed Central

Flamm, Robert K; Duncan, Leonard R; Shortridge, Dee; Smart, Jennifer I; Hamed, Kamal; Mendes, Rodrigo E; Sader, Helio S

2017-01-01

Abstract Background Ceftobiprole medocaril (prodrug of ceftobiprole) is an advanced cephalosporin, approved for adults in multiple European countries for the treatment of hospital-acquired pneumonia (excluding ventilator-associated pneumonia) or community-acquired pneumonia. It is not approved in the US; however, it has achieved qualified infectious disease product status and two phase 3 studies supported by BARDA are planned to begin in the US in 2017. Methods A total of 2,787 Gram-positive (GP) and -negative (GN) isolates from bloodstream infections (BSI) from 30 medical centers in the SENTRY Antimicrobial Surveillance Program were evaluated. Isolates were collected in the US during 2016. Susceptibility (S) testing was performed by reference broth microdilution method against ceftobiprole and comparators. Isolates included 693 Staphylococcus aureus (SA), 216 coagulase-negative staphylococci (CoNS), 244 enterococci, 63 Streptococcus pneumoniae (SPN), 74 viridans group streptococci (VGS), 138 β-haemolytic streptococci (BHS), 1,105 Enterobacteriaceae (ENT), 129 Pseudomonas aeruginosa (PSA), 41 Acinetobacter spp. (ASP), 30 Stenotrophomonas maltophila, 19 Haemophilus spp. and 35 miscellaneous bacteria. Results Methicillin-resistant S. aureus (MRSA) S rates were lower than for methicillin-susceptible S. aureus (MSSA) for most agents. For levofloxacin (LEV) and erythromycin (ERY), the S rates were LEV: MRSA, 23.2%; MSSA, 86.1%; ERY: MRSA, 9.0%; MSSA, 69.3%. All MSSA and 99.0% of MRSA were S to ceftobiprole, while all MSSA and 96.5% of MRSA were S to ceftaroline (CPT). For CoNS, 98.1% of ceftobiprole MIC values were ≤2mg/L. Ceftobiprole was active against Enterococcus faecalis (96.1% ≤2mg/L) and not against E. faecium (18.9% ≤2mg/L). Against ENT, ceftobiprole (85.0%S) was similar in activity to ceftazidime (CAZ, 87.2%S) and cefepime (FEP, 88.9%S). The MIC50/90 values for ceftobiprole, FEP, and CAZ against PSA were identical at 2/16 mg/L. Conclusion Ceftobiprole exhibited potent in vitro activity against GP and GN isolates from contemporary BSI in the US. These results support further clinical evaluation of ceftobiprole for the treatment of BSI. Disclosures R. K. Flamm, Basilea Pharmaceutica International Ltd.: Research Contractor, Research grant; L. R. Duncan, Basilea Pharmaceutica International Ltd.: Research Contractor, Research grant; D. Shortridge, Basilea Pharmaceutica International Ltd.: Research Contractor, Research grant; J. I. Smart, Basilea Pharmaceutica International Ltd.: Employee, Salary; K. Hamed, Basilea Pharmaceutica International Ltd.: Employee, Salary; R. E. Mendes, Basilea Pharmaceutica International Ltd.: Research Contractor, Research grant; H. S. Sader, Basilea Pharmaceutica International Ltd.: Research Contractor, Research grant

Carbamates as Potential Prodrugs and a New Warhead for HDAC Inhibition.

PubMed

King, Kristina; Hauser, Alexander-Thomas; Melesina, Jelena; Sippl, Wolfgang; Jung, Manfred

2018-02-02

We designed and synthesized carbamates of the clinically-approved HDAC (histone deacetylase) inhibitor vorinostat (suberoylanilide hydroxamic acid, SAHA) in order to validate our previously-proposed hypothesis that these carbamates might serve as prodrugs for hydroxamic acid containing HDAC inhibitors. Biochemical assays proved our new compounds to be potent inhibitors of histone deacetylases in vitro, and they also showed antiproliferative effects in leukemic cells. These results, as well as stability analysis led to the suggestion that the intact carbamates are inhibitors of histone deacetylases themselves, representing a new zinc-binding warhead in HDAC inhibitor design. This suggestion was further supported by the synthesis and evaluation of a carbamate derivative of the HDAC6-selective inhibitor bufexamac.

Neural stem cell-based dual suicide gene delivery for metastatic brain tumors.

PubMed

Wang, C; Natsume, A; Lee, H J; Motomura, K; Nishimira, Y; Ohno, M; Ito, M; Kinjo, S; Momota, H; Iwami, K; Ohka, F; Wakabayashi, T; Kim, S U

2012-11-01

In our previous works, we demonstrated that human neural stem cells (NSCs) transduced with the cytosine deaminase (CD) gene showed remarkable 'bystander killer effect' on glioma and medulloblastoma cells after administration of the prodrug 5-fluorocytosine (5-FC). In addition, herpes simplex virus thymidine kinase (TK) is a widely studied enzyme used for suicide gene strategies, for which the prodrug is ganciclovir (GCV). To apply this strategy to brain metastasis treatment, we established here a human NSC line (F3.CD-TK) expressing the dual suicide genes CD and TK. We examined whether F3.CD-TK cells intensified the antitumor effect on lung cancer brain metastases. In vitro studies showed that F3.CD-TK cells exerted a marked bystander effect on human lung cancer cells after treatment with 5-FC and GCV. In a novel experimental brain metastases model, intravenously administered F3 cells migrated near lung cancer metastatic lesions, which were induced by the injection of lung cancer cells via the intracarotid artery. More importantly, F3.CD-TK cells in the presence of prodrugs 5-FC and GCV decreased tumor size and considerably prolonged animal survival. The results of the present study indicate that the dual suicide gene-engineered, NSC-based treatment strategy might offer a new promising therapeutic modality for brain metastases.

Computational modeling and functional analysis of Herpes simplex virus type-1 thymidine kinase and Escherichia coli cytosine deaminase fusion protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jufeng; Wang, Zhanli; Wei, Fang

2007-08-17

Herpes simplex virus type-1 thymidine kinase (HSV-1TK) and Escherichia coli cytosine deaminase (CD) fusion protein was designed using InsightII software. The structural rationality of the fusion proteins incorporating a series of flexible linker peptide was analyzed, and a suitable linker peptide was chosen for further investigated. The recombinant plasmid containing the coding regions of HSV-1TK and CD cDNA connected by this linker peptide coding sequence was generated and subsequently transfected into the human embryonic kidney 293 cells (HEK293). The Western blotting indicated that the recombinant fusion protein existed as a dimer with a molecular weight of approximately 90 kDa. Themore » toxicity of the prodrug on the recombinant plasmid-transfected human lung cancer cell line NCIH460 was evaluated, which showed that TKglyCD-expressing cells conferred upon cells prodrug sensitivities equivalent to that observed for each enzyme independently. Most noteworthy, cytotoxicity could be enhanced by concurrently treating TKglyCD-expressing cells with prodrugs GCV and 5-FC. The results indicate that we have successfully constructed a HSV-1TKglyCD fusion gene which might have a potential application for cancer gene therapy.« less

Hydrogen peroxide-activatable antioxidant prodrug as a targeted therapeutic agent for ischemia-reperfusion injury.

PubMed

Lee, Dongwon; Park, Seunggyu; Bae, Soochan; Jeong, Dahee; Park, Minhyung; Kang, Changsun; Yoo, Wooyoung; Samad, Mohammed A; Ke, Qingen; Khang, Gilson; Kang, Peter M

2015-11-13

Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries.

Involvement of CYP4F2 in the Metabolism of a Novel Monophosphate Ester Prodrug of Gemcitabine and Its Interaction Potential In Vitro.

PubMed

Wang, Yedong; Li, Yuan; Lu, Jia; Qi, Huixin; Cheng, Isabel; Zhang, Hongjian

2018-05-16

Compound- 3 is an oral monophosphate prodrug of gemcitabine. Previous data showed that Compound- 3 was more potent than gemcitabine and it was orally active in a tumor xenograft model. In the present study, the metabolism of Compound- 3 was investigated in several well-known in vitro matrices. While relatively stable in human and rat plasma, Compound- 3 demonstrated noticeable metabolism in liver and intestinal microsomes in the presence of NADPH and human hepatocytes. Compound- 3 could also be hydrolyzed by alkaline phosphatase, leading to gemcitabine formation. Metabolite identification using accurate mass- and information-based scan techniques revealed that Compound- 3 was subjected to sequential metabolism, forming alcohol, aldehyde and carboxylic acid metabolites, respectively. Results from reaction phenotyping studies indicated that cytochrome P450 4F2 (CYP4F2) was a key CYP isozyme involved in Compound- 3 metabolism. Interaction assays suggested that CYP4F2 activity could be inhibited by Compound- 3 or an antiparasitic prodrug pafuramidine. Because CYP4F2 is a key CYP isozyme involved in the metabolism of eicosanoids and therapeutic drugs, clinical relevance of drug-drug interactions mediated via CYP4F2 inhibition warrants further investigation.

Hydrogen peroxide-activatable antioxidant prodrug as a targeted therapeutic agent for ischemia-reperfusion injury

PubMed Central

Lee, Dongwon; Park, Seunggyu; Bae, Soochan; Jeong, Dahee; Park, Minhyung; Kang, Changsun; Yoo, Wooyoung; Samad, Mohammed A.; Ke, Qingen; Khang, Gilson; Kang, Peter M.

2015-01-01

Overproduction of hydrogen peroxide (H2O2) causes oxidative stress and is the main culprit in the pathogenesis of ischemia/reperfusion (I/R) injury. Suppression of oxidative stress is therefore critical in the treatment of I/R injury. Here, we report H2O2-activatable antioxidant prodrug (BRAP) that is capable of specifically targeting the site of oxidative stress and exerting anti-inflammatory and anti-apoptotic activities. BRAP with a self-immolative boronic ester protecting group was designed to scavenge H2O2 and release HBA (p-hydroxybenzyl alcohol) with antioxidant and anti-inflammatory activities. BRAP exerted potent antioxidant and anti-inflammatory activity in lipopolysaccharide (LPS)- and H2O2-stimulated cells by suppressing the generation of ROS and pro-inflammatory cytokines. In mouse models of hepatic I/R and cardiac I/R, BRAP exerted potent antioxidant, anti-inflammatory and anti-apoptotic activities due to the synergistic effects of H2O2-scavenging boronic esters and therapeutic HBA. In addition, administration of high doses of BRAP daily for 7 days showed no renal or hepatic function abnormalities. Therefore BRAP has tremendous therapeutic potential as H2O2-activatable antioxidant prodrug for the treatment of I/R injuries. PMID:26563741

Re-engineering Cytochrome P450 2B11dH for Enhanced Metabolism of Several Substrates Including the Anti-cancer Prodrugs Cyclophosphamide and Ifosfamide

PubMed Central

Sun, Ling; Chen, Chong S.; Waxman, David J.; Liu, Hong; Halpert, James R.; Kumar, Santosh

2007-01-01

Based on recent directed evolution of P450 2B1, six P450 2B11 mutants at three positions were created in an N-terminal modified construct termed P450 2B11dH and characterized for enzyme catalysis using five substrates. Mutant I209A demonstrated a 3.2-fold enhanced kcat/Km for 7-ethoxy-4-trifluoromethylcourmarin O-deethylation, largely due to a dramatic decrease in Km (0.72 vs. 18 μM). I209A also demonstrated enhanced selectivity for testosterone 16β-hydroxylation over 16α-hydroxylation. In contrast, V183L showed a 4-fold increased kcat for 7-benzyloxyresorufin debenzylation and a 4.7-fold increased kcat/Km for testosterone 16α-hydroxylation. V183L also displayed a 1.7-fold higher kcat/Km than P450 2B11dH with the anti-cancer prodrugs cyclophosphamide and ifosfamide, resulting from a ~4-fold decrease in Km. Introduction of the V183L mutation into full-length P450 2B11 did not enhance the kcat/Km. Overall, the re-engineered P450 2B11dH enzymes exhibited enhanced catalytic efficiency with several substrates including the anti-cancer prodrugs. PMID:17254539

A Comparative Study of Molecular Structure, pKa, Lipophilicity, Solubility, Absorption and Polar Surface Area of Some Antiplatelet Drugs.

PubMed

Remko, Milan; Remková, Anna; Broer, Ria

2016-03-19

Theoretical chemistry methods have been used to study the molecular properties of antiplatelet agents (ticlopidine, clopidogrel, prasugrel, elinogrel, ticagrelor and cangrelor) and several thiol-containing active metabolites. The geometries and energies of most stable conformers of these drugs have been computed at the Becke3LYP/6-311++G(d,p) level of density functional theory. Computed dissociation constants show that the active metabolites of prodrugs (ticlopidine, clopidogrel and prasugrel) and drugs elinogrel and cangrelor are completely ionized at pH 7.4. Both ticagrelor and its active metabolite are present at pH = 7.4 in neutral undissociated form. The thienopyridine prodrugs ticlopidine, clopidogrel and prasugrel are lipophilic and insoluble in water. Their lipophilicity is very high (about 2.5-3.5 logP values). The polar surface area, with regard to the structurally-heterogeneous character of these antiplatelet drugs, is from very large interval of values of 3-255 Ų. Thienopyridine prodrugs, like ticlopidine, clopidogrel and prasugrel, with the lowest polar surface area (PSA) values, exhibit the largest absorption. A high value of polar surface area (PSA) of cangrelor (255 Ų) results in substantial worsening of the absorption in comparison with thienopyridine drugs.

A Comparative Study of Molecular Structure, pKa, Lipophilicity, Solubility, Absorption and Polar Surface Area of Some Antiplatelet Drugs

PubMed Central

Remko, Milan; Remková, Anna; Broer, Ria

2016-01-01

Theoretical chemistry methods have been used to study the molecular properties of antiplatelet agents (ticlopidine, clopidogrel, prasugrel, elinogrel, ticagrelor and cangrelor) and several thiol-containing active metabolites. The geometries and energies of most stable conformers of these drugs have been computed at the Becke3LYP/6-311++G(d,p) level of density functional theory. Computed dissociation constants show that the active metabolites of prodrugs (ticlopidine, clopidogrel and prasugrel) and drugs elinogrel and cangrelor are completely ionized at pH 7.4. Both ticagrelor and its active metabolite are present at pH = 7.4 in neutral undissociated form. The thienopyridine prodrugs ticlopidine, clopidogrel and prasugrel are lipophilic and insoluble in water. Their lipophilicity is very high (about 2.5–3.5 logP values). The polar surface area, with regard to the structurally-heterogeneous character of these antiplatelet drugs, is from very large interval of values of 3–255 Å2. Thienopyridine prodrugs, like ticlopidine, clopidogrel and prasugrel, with the lowest polar surface area (PSA) values, exhibit the largest absorption. A high value of polar surface area (PSA) of cangrelor (255 Å2) results in substantial worsening of the absorption in comparison with thienopyridine drugs. PMID:27007371

Nuclear receptor-mediated regulation of carboxylesterase expression and activity.

PubMed

Staudinger, Jeff L; Xu, Chenshu; Cui, Yue J; Klaassen, Curtis D

2010-03-01

Emerging evidence demonstrates that several nuclear receptor (NR) family members regulate drug-inducible expression and activity of several important carboxylesterase (CES) enzymes in mammalian liver and intestine. Numerous clinically prescribed anticancer prodrugs, carbamate and pyrethroid insecticides, environmental toxicants and procarcinogens are substrates for CES enzymes. Moreover, a key strategy used in rational drug design frequently utilizes an ester linkage methodology to selectively target a prodrug, or to improve the water solubility of a novel compound. This review summarizes the current state of knowledge regarding NR-mediated regulation of CES enzymes in mammals and highlights their importance in drug metabolism, drug-drug interactions and toxicology. New knowledge regarding the transcriptional regulation of CES enzymes by NR proteins pregnane x receptor (NR1I2) and constitutive androstane receptor (NR1I3) has recently come to light through the use of knockout and transgenic mouse models. Novel insights regarding the species-specific cross-regulation of glucocorticoid receptor (NR3C1) and PPAR-alpha (NR1C1) signaling and CES gene expression are discussed. Elucidation of the role of NR-mediated regulation of CES enzymes in liver and intestine will have a significant impact on rational drug design and the development of novel prodrugs, especially for patients on combination therapy.

Celecoxib coupled to dextran via a glutamic acid linker yields a polymeric prodrug suitable for colonic delivery.

PubMed

Lee, Yonghyun; Kim, Jungyun; Kim, Wooseong; Nam, Joon; Jeong, Seongkeun; Lee, Sunyoung; Yoo, Jin-Wook; Kim, Min-Soo; Jung, Yunjin

2015-01-01

Celecoxib, a selective cyclooxygenase-2 inhibitor, is potentially useful for the treatment of colonic diseases such as colorectal cancer and colitis. However, the cardiovascular toxicity of celecoxib limits its routine use in the clinic. Generally, colon-specific delivery of a drug both increases the therapeutic availability in the large intestine and decreases the systemic absorption of the drug, most likely resulting in enhanced therapeutic effects against colonic diseases such as colitis and reduced systemic side effects. To develop a colon-specific prodrug of celecoxib that could reduce its cardiovascular toxicity and improve its therapeutic activity, dextran-glutamic acid-celecoxib conjugate (glutam-1-yl celecoxib-dextran ester [G1CD]) was prepared and evaluated. While stable in pH 1.2 and 6.8 buffer solutions and small-intestinal contents, G1CD efficiently released celecoxib in cecal contents. Oral administration of G1CD to rats delivered a larger amount of celecoxib to the large intestine than free celecoxib. G1CD prevented the systemic absorption of celecoxib and did not decrease the serum level of 6-ketoprostaglandin F1α, an inverse indicator of cardiovascular toxicity of celecoxib. Collectively, G1CD may be a polymeric colon-specific celecoxib prodrug with therapeutic and toxicological advantages.

Effect of Simvastatin Prodrug on Experimental Periodontitis.

PubMed

Bradley, Aaron D; Zhang, Yijia; Jia, Zhenshan; Zhao, Gang; Wang, Xiaobei; Pranke, Laura; Schmid, Marian J; Wang, Dong; Reinhardt, Richard A

2016-05-01

Local application of statins has shown potential in preventing and regenerating bone loss associated with experimental periodontitis. This study evaluates the effect of a novel simvastatin (SIM) prodrug (capable of delivering high doses to periodontitis inflammatory lesion and cells) on experimental periodontitis bone loss and inflammation. Forty mature female Sprague Dawley rats were subjected to ligature-induced experimental periodontitis between maxillary first and second molars (M1-M2). Equal groups were treated with three weekly doses of: 1) prodrug carrier alone (mPEG); 2) 0.5 mg SIM dose equivalent in carrier (SIM/SIM-mPEG); 3) 1.0 mg SIM/SIM-mPEG; 4) 1.5 mg SIM/SIM-mPEG; or 5) ligature alone. Contralateral molars served as unmanipulated controls. Four weeks after initiation of periodontitis, animals were euthanized, the M1-M2 interproximal was evaluated with microcomputed tomography and histology, and data were analyzed with one-way analysis of variance. Ligature alone caused a mean bone loss of 1.01 ± 0.06 mm from the cemento-enamel junction, whereas all doses of SIM/SIM-mPEG reduced bone loss, especially 1.5 mg SIM/SIM-mPEG (0.68 ± 0.05 mm, P <0.001), which was not statistically different from contralateral control (0.47 ± 0.06 mm). A dose of 1.5 mg SIM/SIM-mPEG also reduced percentage of neutrophils compared with carrier alone (2.0% ± 1.0% versus 5.7% ± 1.1%; P <0.05), and increased amount of uninflamed connective tissue in the M1-M2 interproximal area (65.2% ± 3.3% versus 46.3% ± 3.3%; P <0.001). The mPEG carrier alone did not have bone-sparing or anti-inflammatory properties. Multiple local 1.5-mg doses of a macromolecular SIM prodrug decreases amount of experimental periodontitis bone loss and inflammation in rats.

Human glutathione transferases catalyzing the bioactivation of anticancer thiopurine prodrugs.

PubMed

Eklund, Birgitta I; Gunnarsdottir, Sjofn; Elfarra, Adnan A; Mannervik, Bengt

2007-06-01

cis-6-(2-Acetylvinylthio)purine (cAVTP) and trans-6-(2-acetylvinylthio)guanine (tAVTG) are thiopurine prodrugs provisionally inactivated by an alpha,beta-unsaturated substituent on the sulfur of the parental thiopurines 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG). The active thiopurines are liberated intracellularly by glutathione (GSH) in reactions catalyzed by glutathione transferases (GSTs) (EC 2.5.1.18). Catalytic activities of 13 human GSTs representing seven distinct classes of soluble GSTs have been determined. The bioactivation of cAVTP and tAVTG occurs via a transient addition of GSH to the activated double bond of the S-substituent of the prodrug, followed by elimination of the thiopurine. The first of these consecutive reactions is rate-limiting for thiopurine release, but GST-activation of this first addition is shifting the rate limitation to the subsequent elimination. Highly active GSTs reveal the transient intermediate, which is detectable by UV spectroscopy and HPLC analysis. LC/MS analysis of the reaction products demonstrates that the primary GSH conjugate, 4-glutathionylbuten-2-one, can react with a second GSH molecule to form the 4-(bis-glutathionyl)butan-2-one. GST M1-1 and GST A4-4 were the most efficient enzymes with tAVTG, and GST M1-1 and GST M2-2 had highest activity with cAVTP. The highly efficient GST M1-1 is polymorphic and is absent in approximately half of the human population. GST P1-1, which is overexpressed in many cancer cells, had no detectable activity with cAVTP and only minor activity with tAVTG. Other GST-activated prodrugs have targeted GST P1-1-expressing cancer cells. Tumors expressing high levels of GST M1-1 or GST A4-4 can be predicted to be particularly vulnerable to chemotherapy with cAVTP or tAVTG.

Validation and implementation of liquid chromatographic-mass spectrometric (LC-MS) methods for the quantification of tenofovir prodrugs.

PubMed

Hummert, Pamela; Parsons, Teresa L; Ensign, Laura M; Hoang, Thuy; Marzinke, Mark A

2018-04-15

The nucleotide reverse transcriptase inhibitor tenofovir (TFV) is widely administered in a disoproxil prodrug form (tenofovir disoproxil fumarate, TDF) for HIV management and prevention. Recently, novel prodrugs tenofovir alafenamide fumarate (TAF) and hexadecyloxypropyl tenofovir (CMX157) have been pursued for HIV treatment while minimizing adverse effects associated with systemic TFV exposure. Dynamic and sensitive bioanalytical tools are required to characterize the pharmacokinetics of these prodrugs in systemic circulation. Two parallel methods have been developed, one to combinatorially quantify TAF and TFV, and a second method for CMX157 quantification, in plasma. K 2 EDTA plasma was spiked with TAF and TFV, or CMX157. Following the addition of isotopically labeled internal standards and sample extraction via solid phase extraction (TAF and TFV) or protein precipitation (CMX157), samples were subjected to liquid chromatographic-tandem mass spectrometric (LC-MS/MS) analysis. For TAF and TFV, separation occurred using a Zorbax Eclipse Plus C18 Narrow Bore RR, 2.1 × 50 mm, 3.5 μm column and analytes were detected on an API5000 mass analyzer; CMX157 was separated using a Kinetex C8, 2.1 × 50 mm, 2.6 μm column and quantified using an API4500 mass spectrometer. Methods were validated according to FDA Bioanalytical Method Validation guidelines. Analytical methods: were optimized for the multiplexed monitoring of TAF and TFV, and CMX157 in plasma. The lower limits of quantification (LLOQs) for TAF, TFV, and CMX157 were 0.03, 1.0, and 0.25 ng/mL, respectively. Calibration curves were generated via weighted linear regression of standards. Intra- and inter-assay precision and accuracy studies demonstrated %CVs ≤ 14.4% and %DEVs ≤ ± 7.95%, respectively. Stability and matrix effects studies were also performed. All results were acceptable and in accordance with the recommended guidelines for bioanalytical methods. Assays were also applied to quantify in vivo concentrations of prodrugs and TFV in a preclinical study post-rectal administration. Sensitive, specific, and dynamic LC-MS/MS assays have been developed and validated for the multiplexed quantification TAF and TFV, as well as an independent assay for CMX157 quantification, in plasma. The described methods meet sufficient throughput criteria to support large research trials. Copyright © 2018 Elsevier B.V. All rights reserved.

Managing Severe Community-Acquired Pneumonia Due to Community Methicillin-Resistant Staphylococcus aureus (MRSA).

PubMed

Kwong, Jason C; Chua, Kyra; Charles, Patrick G P

2012-06-01

Community-associated methicillin-resistant Staphylococcus aureus (MRSA) is a rare, but significant cause of community-acquired pneumonia (CAP). A number of virulence determinants have been implicated in the development of severe community MRSA pneumonia, characterized by multilobar cavitating necrosis in patients without usual risk-factors for pneumonia. Optimal management is uncertain, and is extrapolated from anecdotal experiences with small case series, randomized studies of hospital-acquired pneumonia, and laboratory investigations using in vitro experiments and animal models of MRSA pneumonia. Adequate clinical suspicion, early diagnosis and administration of appropriate antibiotics are necessary for best patient outcomes, although some patients will still do badly even with early anti-MRSA therapy. Vancomycin or linezolid have been recommended as first-line therapy, possibly in combination with other antibiotics. Newer antibiotics such as ceftaroline are still being evaluated.

Development and characterization of a long-acting nanoformulated abacavir prodrug.

PubMed

Singh, Dhirender; McMillan, JoEllyn; Hilaire, James; Gautam, Nagsen; Palandri, Diana; Alnouti, Yazen; Gendelman, Howard E; Edagwa, Benson

2016-08-01

A myristoylated abacavir (ABC) prodrug was synthesized to extend drug half-life and bioavailability. Myristoylated ABC (MABC) was made by esterifying myristic acid to the drug's 5-hydroxy-cyclopentene group. Chemical composition, antiretroviral activity, cell uptake and retention and cellular trafficking of free MABC and poloxamer nanoformulations of MABC were assessed by proton nuclear magnetic resonance and tested in human monocyte-derived macrophages. Pharmacokinetics of ABC and nanoformulated MABC were evaluated after intramuscular injection into mice. MABC antiretroviral activity in monocyte-derived macrophages was comparable to native drug. Encasement of MABC into poloxamer nanoparticles extended drug bioavailability for 2 weeks. MABC synthesis and encasement in polymeric nanoformulations improved intracellular drug accumulation and demonstrate translational potential as part of a long-acting antiretroviral regimen.

Discovery of 2-Pyridinone Aminals: A Prodrug Strategy to Advance a Second Generation of HIV-1 Integrase Strand Transfer Inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raheem, Izzat T.; Walji, Abbas M.; Klein, Daniel

The search for new molecular constructs that resemble the critical two-metal binding pharmacophore required for HIV integrase strand transfer inhibition represents a vibrant area of research within drug discovery. Here we present the discovery of a new class of HIV integrase strand transfer inhibitors based on the 2-pyridinone core of MK-0536. These efforts led to the identification of two lead compounds with excellent antiviral activity and preclinical pharmacokinetic profiles to support a once-daily human dose prediction. Dose escalating PK studies in dog revealed significant issues with limited oral absorption and required an innovative prodrug strategy to enhance the high-dose plasmamore » exposures of the parent molecules.« less

Evidence against the participation of a pharmacokinetic interaction in the protective effect of single-dose curcumin against gastrointestinal damage induced by indomethacin in rats.

PubMed

Zazueta-Beltrán, Liliana; Medina-Aymerich, Lorena; Estela Díaz-Triste, Nadia; Chávez-Piña, Aracely Evangelina; Castañeda-Hernández, Gilberto; Cruz-Antonio, Leticia

2017-03-01

To determine the role of a pharmacokinetic interaction in the protective effect of curcumin against the gastric damage induced by indomethacin administration as such or as its prodrug acemetacin. Wistar rats orally received single dose of indomethacin (30 mg/kg) with and without curcumin (30 mg/kg); gastric injury was evaluated by determining the total damaged area. Additional groups of rats received an oral single dose of indomethacin (30 mg/kg) or its prodrug acemetacin (34.86 mg/kg) in the presence or absence of curcumin (30 mg/kg). Indomethacin and acemetacin concentrations in plasma from blood draws were determined by high-performance liquid chromatography.Plasma concentration-against-time curves were constructed, and bioavailability parameters, maximal concentration (C max ) and area under the curve to the last sampling time (AUC 0-t ) were estimated. Concomitant administration of indomethacin and curcumin resulted in a significantly reduced gastric damage compared to indomethacin alone. However, co-administration of curcumin did not produce any significant alteration in the bioavailability parameters of indomethacin and acemetacin after administration of either the active compound or the prodrug. Curcumin exhibits a protective effect against indomethacin-induced gastric damage, but does not produce a reduction of the bioavailability of this nonsteroidal anti-inflammatory drug, indomethacin. Data thus suggest that a pharmacokinetic mechanism of action is not involved in curcumin gastroprotection.

Kinetic and Mechanistic Study of the pH-Dependent Activation (Epoxidation) of Prodrug Treosulfan Including the Reaction Inhibition in a Borate Buffer.

PubMed

Romański, Michał; Ratajczak, Whitney; Główka, Franciszek

2017-07-01

A prodrug treosulfan (T) undergoes a pH-dependent activation to epoxide derivatives. The process seems to involve an intramolecular Williamson reaction (IWR) but clear kinetic evidence is lacking. Moreover, a cis-diol system present in the T structure is expected to promote complexation with boric acid. As a result, the prodrug epoxidation would be inhibited; however, this phenomenon has not been investigated. In this article, the effect of pH on the kinetics of T conversion to its monoepoxide was studied from a mechanistic point of view. Also, the influence of boric acid on the reaction kinetics was examined. The rate constants observed for the activation of T (k obs ) in acetate, phosphate, and carbonate buffers satisfied the equation logk obs  = -7.48 + 0.96 pH. The reaction was inhibited in the excess of boric acid over T, and the k obs decreased with increasing borate buffer concentration. The experimental results were consistent with the inhibition model that included the formation of a tetrahedral, anionic T-boric acid monoester. To conclude, in nonborate buffers, the T activation to (2S,3S)-1,2-epoxybutane-3,4-diol 4-methanesulfonate follows IWR mechanism. A borate buffer changes the reaction kinetics and complicates kinetic analysis. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

4-((R)-2-{[6-((S)-3-Methoxypyrrolidin-1-yl)-2-phenylpyrimidine-4-carbonyl]amino}-3-phosphonopropionyl)piperazine-1-carboxylic Acid Butyl Ester (ACT-246475) and Its Prodrug (ACT-281959), a Novel P2Y12 Receptor Antagonist with a Wider Therapeutic Window in the Rat Than Clopidogrel.

PubMed

Caroff, Eva; Hubler, Francis; Meyer, Emmanuel; Renneberg, Dorte; Gnerre, Carmela; Treiber, Alexander; Rey, Markus; Hess, Patrick; Steiner, Beat; Hilpert, Kurt; Riederer, Markus A

2015-12-10

Recent post hoc analyses of several clinical trials with P2Y12 antagonists showed the need for new molecules being fully efficacious as antiplatelet agents and having a reduced propensity to cause major bleeding. We have previously reported the discovery of the 2-phenylpyrimidine-4-carboxamide analogs as P2Y12 antagonists with nanomolar potency in the disease-relevant platelet aggregation assay in human plasma. Herein we present the optimization steps that led to the discovery of clinical candidate ACT-246475 (30d). The key step was the replacement of the carboxylic acid functionality by a phosphonic acid group which delivered the most potent molecules of the program. In addition, low in vivo clearance in rat and dog was achieved for the first time. Since the bioavailability of 30d was low in rat and dog, we developed the bis((isopropoxycarbonyl)oxy)methyl ester prodrug (ACT-281959, 45). Compound 30d showed efficacy in the rat ferric chloride thrombosis model when administered intravenously as parent or orally as its prodrug 45. Moreover, 30d displays a wider therapeutic window as compared to clopidogrel in the rat surgical blood loss model.

Enzyme Prodrug Therapy Achieves Site-Specific, Personalized Physiological Responses to the Locally Produced Nitric Oxide

PubMed Central

2018-01-01

Nitric oxide (NO) is a highly potent but short-lived endogenous radical with a wide spectrum of physiological activities. In this work, we developed an enzymatic approach to the site-specific synthesis of NO mediated by biocatalytic surface coatings. Multilayered polyelectrolyte films were optimized as host compartments for the immobilized β-galactosidase (β-Gal) enzyme through a screen of eight polycations and eight polyanions. The lead composition was used to achieve localized production of NO through the addition of β-Gal–NONOate, a prodrug that releases NO following enzymatic bioconversion. The resulting coatings afforded physiologically relevant flux of NO matching that of the healthy human endothelium. The antiproliferative effect due to the synthesized NO in cell culture was site-specific: within a multiwell dish with freely shared media and nutrients, a 10-fold inhibition of cell growth was achieved on top of the biocatalytic coatings compared to the immediately adjacent enzyme-free microwells. The physiological effect of NO produced via the enzyme prodrug therapy was validated ex vivo in isolated arteries through the measurement of vasodilation. Biocatalytic coatings were deposited on wires produced using alloys used in clinical practice and successfully mediated a NONOate concentration-dependent vasodilation in the small arteries of rats. The results of this study present an exciting opportunity to manufacture implantable biomaterials with physiological responses controlled to the desired level for personalized treatment. PMID:29570264

Lisdexamfetamine: A pharmacokinetic review.

PubMed

Comiran, Eloisa; Kessler, Félix Henrique; Fröehlich, Pedro Eduardo; Limberger, Renata Pereira

2016-06-30

Lisdexamfetamine (LDX) is a d-amphetamine (d-AMPH) pro-drug used to treat Attention Deficit and Hyperactivity Disorder (ADHD) and Binge Eating Disorder (BED) symptoms. The in vivo pharmacodynamics of LDX is the same as that of its active product d-AMPH, although there are a few qualitative and quantitative differences due to pharmacokinetics. Due to the specific pharmacokinetics of the long-acting stimulants, this article revises the pharmacokinetic studies on LDX, the newest amphetamine pro-drug. The Medline/Pubmed, Science Direct and Biblioteca Virtual em Saúde (Lilacs and Ibecs) (2007-2016) databases were searched for articles and their list of references. As for basic pharmacokinetics studies, since LDX is a newly developed medication, there are few results concerning biotransformation, distribution and the use of different biological matrices for analysis. This is the first robust review on this topic, gathering data from all clinical pharmacokinetics studies available in the literature. The particular pharmacokinetics of LDX plays a major role in studying this pro-drug, since this knowledge was essential to understand some reports on clinical effects in literature, e.g. the small likelihood of reducing the effect by interactions, the effect of long duration use and the still questionable reduction of the potential for abuse. In general the already well-known pharmacokinetic properties of amphetamine make LDX relatively predictable, simplifying the use of LDX in clinical practice. Copyright © 2016 Elsevier B.V. All rights reserved.

Cargo-free nano-medicine with pH-sensitivity for co-delivery of DOX conjugated prodrug with SN38 to synergistically eradicate breast cancer stem cells.

PubMed

Sun, Na; Zhao, Chenyang; Cheng, Rui; Liu, Zerong; Li, Xian; Lu, Axin; Tian, Zhongmin; Yang, Zhe

2018-06-20

Due to their abilities of transforming into bulk cancer cells and resistance to radiotherapy and chemotherapy, cancer stem cells (CSCs) are currently considered as a major obstacle for cancer treatment. Application of multiple drugs using nano-carriers is a promising approach to simultaneously eliminate non-cancer stem cells (non-CSCs) and CSCs. Herein, to employ the advantages of nano-medicine while avoiding new excipients, pH-responsive pro-drug (PEG-CH=N-DOX) was employed as the surfactant to fabricate cargo-free nano-medicine for co-delivery of DOX conjugated prodrug with SN38 to synergistically eradicate breast cancer stem cells (bCSCs) and non-bCSCs. Through the intermolecular interaction between DOX and SN38, PEG-CH=N-DOX and SN38 were assembled together to form a stable nano-medicine. This nano-medicine not only dramatically enhanced drug accumulation efficiency at the tumor site, but also effectively eliminated bCSCs and non-bCSCs, which resulted in achieving a superior in vivo tumor inhibition activity. Additionally, the biosafety of this nano-medicine was systematically studied through immunohistochemistry, blood bio-chemistry assay, blood routine examination and metabolomics. The results revealed that this nano-medicine significantly reduced the adverse effects of DOX and SN38. Therefore, this simple yet efficient nano-medicine provided a promising strategy for future clinical applications.

Clinical pharmacokinetic drug interaction studies of gabapentin enacarbil, a novel transported prodrug of gabapentin, with naproxen and cimetidine

PubMed Central

Lal, Ritu; Sukbuntherng, Juthamas; Luo, Wendy; Vicente, Virna; Blumenthal, Robin; Ho, Judy; Cundy, Kenneth C

2010-01-01

AIM Gabapentin enacarbil, a transported prodrug of gabapentin, provides sustained, dose-proportional exposure to gabapentin. Unlike gabapentin, the prodrug is absorbed throughout the intestinal tract by high-capacity nutrient transporters, including mono-carboxylate transporter-1 (MCT-1). Once absorbed, gabapentin enacarbil is rapidly hydrolyzed to gabapentin, which is subsequently excreted by renal elimination via organic cation transporters (OCT2). To examine the potential for drug–drug interactions at these two transporters, the pharmacokinetics of gabapentin enacarbil were evaluated in healthy adults after administration alone or in combination with either naproxen (an MCT-1 substrate) or cimetidine (an OCT2 substrate). METHODS Subjects (n= 12 in each study) received doses of study drug until steady state was achieved; 1200 mg gabapentin enacarbil each day, followed by either naproxen (500 mg twice daily) or cimetidine (400 mg four times daily) followed by the combination. RESULTS When gabapentin enacarbil was co-administered with naproxen, gabapentin Css,max increased by, on average, 8% and AUC by, on average, 13%. When gabapentin enacarbil was co-administered with cimetidine, gabapentin AUCss increased by 24% and renal clearance of gabapentin decreased. Co-administration with gabapentin enacarbil did not affect naproxen or cimetidine exposure. Gabapentin enacarbil was generally well tolerated. CONCLUSIONS No gabapentin enacarbil dose adjustment is needed with co-administration of naproxen or cimetidine. PMID:20573085

JS-K, a Nitric Oxide Prodrug, Has Enhanced Cytotoxicity in Colon Cancer Cells with Knockdown of Thioredoxin Reductase 1

PubMed Central

Edes, Kornelia; Cassidy, Pamela; Shami, Paul J.; Moos, Philip J.

2010-01-01

Background The selenoenzyme thioredoxin reductase 1 has a complex role relating to cell growth. It is induced as a component of the cellular response to potentially mutagenic oxidants, but also appears to provide growth advantages to transformed cells by inhibiting apoptosis. In addition, selenocysteine-deficient or alkylated forms of thioredoxin reductase 1 have also demonstrated oxidative, pro-apoptotic activity. Therefore, a greater understanding of the role of thioredoxin reductase in redox initiated apoptotic processes is warranted. Methodology The role of thioredoxin reductase 1 in RKO cells was evaluated by attenuating endogenous thioredoxin reductase 1 expression with siRNA and then either inducing a selenium-deficient thioredoxin reductase or treatment with distinct redox challenges including, hydrogen peroxide, an oxidized lipid, 4-hydroxy-2-nonenol, and a nitric oxide donating prodrug. Thioredoxin redox status, cellular viability, and effector caspase activity were measured. Conclusions/Significance In cells with attenuated endogenous thioredoxin reductase 1, a stably integrated selenocysteine-deficient form of the enzyme was induced but did not alter either the thioredoxin redox status or the cellular growth kinetics. The oxidized lipid and the nitric oxide donor demonstrated enhanced cytotoxicity when thioredoxin reductase 1 was knocked-down; however, the effect was more pronounced with the nitric oxide prodrug. These results are consistent with the hypothesis that attenuation of the thioredoxin-system can promote apoptosis in a nitric oxide-dependent manner. PMID:20098717

Water-soluble benzodiazepine prodrug/enzyme combinations for intranasal rescue therapies.

PubMed

Siegel, Ronald A; Kapoor, Mamta; Cheryala, Narsihmulu; Georg, Gunda I; Cloyd, James C

2015-08-01

Benzodiazepines (BZDs), including diazepam (DZP) and midazolam (MDZ), are drugs of choice for rapid treatment of seizure emergencies. Current approved use of these drugs involves administration via either intravenous or rectal routes. The former requires trained medical personnel, while the latter is socially unacceptable for many patients and caregivers. In recent years, efforts have been made to formulate BZDs for nasal administration. Because of the low solubility of these molecules, organic vehicles have been used to solubilize the drugs in the nasal products under development. However, organic solvents are irritating, potentially resulting in injury to nasal tissue. Here we report preliminary studies supporting a strategy in which water-soluble BZD prodrugs and a suitable converting enzyme are coadministered in an aqueous vehicle. Diazepam and midazolam prodrugs were synthesized and were readily converted to their active forms by a protease from Aspergillus oryzae. Using a permeation assay based on monolayers of Madin-Darby canine kidney II-wild type cells, we found that enzymatically produced BZDs could be maintained at high degrees of supersaturation, enabling faster transport across the membrane than can be achieved using saturated solutions. This strategy not only obviates the need for organic solvents, but it also suggests more rapid absorption and earlier peak concentrations than can be otherwise achieved. This article is part of a Special Issue entitled "Status Epilepticus". Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis and antimalarial evaluation of prodrugs of novel fosmidomycin analogues.

PubMed

Faísca Phillips, Ana Maria; Nogueira, Fátima; Murtinheira, Fernanda; Barros, Maria Teresa

2015-01-01

The continuous development of drug resistance by Plasmodium falciparum, the agent responsible for the most severe forms of malaria, creates the need for the development of novel drugs to fight this disease. Fosmidomycin is an effective antimalarial and potent antibiotic, known to act by inhibiting the enzyme 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), essential for the synthesis of isoprenoids in eubacteria and plasmodia, but not in humans. In this study, novel constrained cyclic prodrug analogues of fosmidomycin were synthesized. One, in which the hydroxamate function is incorporated into a six-membered ring, was found have higher antimalarial activity than fosmidomycin against the chloroquine and mefloquine resistant P. falciparum Dd2 strain. In addition, it showed very low cytotoxicity against cultured human cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development and characterization of a long-acting nanoformulated abacavir prodrug

PubMed Central

Singh, Dhirender; McMillan, JoEllyn; Hilaire, James; Gautam, Nagsen; Palandri, Diana; Alnouti, Yazen; Gendelman, Howard E; Edagwa, Benson

2016-01-01

Aim: A myristoylated abacavir (ABC) prodrug was synthesized to extend drug half-life and bioavailability. Methods: Myristoylated ABC (MABC) was made by esterifying myristic acid to the drug's 5-hydroxy-cyclopentene group. Chemical composition, antiretroviral activity, cell uptake and retention and cellular trafficking of free MABC and poloxamer nanoformulations of MABC were assessed by proton nuclear magnetic resonance and tested in human monocyte-derived macrophages. Pharmacokinetics of ABC and nanoformulated MABC were evaluated after intramuscular injection into mice. Results: MABC antiretroviral activity in monocyte-derived macrophages was comparable to native drug. Encasement of MABC into poloxamer nanoparticles extended drug bioavailability for 2 weeks. Conclusion: MABC synthesis and encasement in polymeric nanoformulations improved intracellular drug accumulation and demonstrate translational potential as part of a long-acting antiretroviral regimen. PMID:27456759

Solid lipid nanoparticles by coacervation loaded with a methotrexate prodrug: preliminary study for glioma treatment.

PubMed

Battaglia, Luigi; Muntoni, Elisabetta; Chirio, Daniela; Peira, Elena; Annovazzi, Laura; Schiffer, Davide; Mellai, Marta; Riganti, Chiara; Salaroglio, Iris Chiara; Lanotte, Michele; Panciani, Pierpaolo; Capucchio, Maria Teresa; Valazza, Alberto; Biasibetti, Elena; Gallarate, Marina

2017-03-01

Methotrexate-loaded biocompatible nanoparticles were tested for preliminary efficacy in glioma treatment. Behenic acid nanoparticles, prepared by the coacervation method, were loaded with the ester prodrug didodecylmethotrexate, which was previously tested in vitro against glioblastoma human primary cultures. Nanoparticle conjugation with an ApoE mimicking chimera peptide was performed to obtain active targeting to the brain. Biodistribution studies in healthy rats assessed the superiority of ApoE-conjugated formulation, which was tested on an F98/Fischer glioma model. Differences were observed in tumor growth rate (measured by MRI) between control and treated rats. In vitro tests on F98 cultured cells assessed their susceptibility to treatment, with consequent apoptosis, and allowed us to explain the apoptosis observed in glioma models.

JS-K, a nitric oxide prodrug, induces cytochrome c release and caspase activation in HL-60 myeloid leukemia cells.

PubMed

Udupi, Vidya; Yu, Margaret; Malaviya, Swati; Saavedra, Joseph E; Shami, Paul J

2006-10-01

Nitric oxide (NO) induces differentiation and apoptosis in acute myelogenous leukemia (AML) cells. The NO prodrug O2-(2,4-dinitrophenyl)1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate, or JS-K, has potent antileukemic activity. JS-K induces apoptosis in HL-60 cells by a caspase-dependent mechanism. The purpose of this study was to determine the pathway through which JS-K induces apoptosis. We show that JS-K alters mitochondrial membrane potential (DeltaPsim) and induces cytochrome c release from mitochondria into the cytoplasm. Treatment with JS-K resulted in activation of Caspase (Casp) 9, Casp 3 and Casp 8. JS-K constitutes a promising lead for a new class of anti-leukemic agents.

Supramolecular gelation of a polymeric prodrug for its encapsulation and sustained release.

PubMed

Ma, Dong; Zhang, Li-Ming

2011-09-12

A polymeric prodrug, PEGylated indomethacin (MPEG-indo), was prepared and then used to interact with α-cyclodextrin (α-CD) in their aqueous mixed system. This process could lead to the formation of supramolecular hydrogel under mild conditions and simultaneous encapsulation of MPEG-indo in the hydrogel matrix. For the formed supramolecular hydrogel, its gelation kinetics, mechanical strength, shear-thinning behavior and thixotropic response were investigated with respect to the effects of MPEG-indo and α-CD amounts by dynamic and steady rheological tests. Meanwhile, the possibility of using this hydrogel matrix as injectable drug delivery system was also explored. By in vitro release and cell viability tests, it was found that the encapsulated MPEG-indo could exhibit a controlled and sustained release behavior as well as maintain its biological activity.

A prodrug micellar carrier assembled from polymers with pendant farnesyl thiosalicylic acid moieties for improved delivery of paclitaxel.

PubMed

Sun, Jingjing; Chen, Yichao; Li, Ke; Huang, Yixian; Fu, Xiaofeng; Zhang, Xiaolan; Zhao, Wenchen; Wei, Yuan; Xu, Liang; Zhang, Peijun; Venkataramanan, Raman; Li, Song

2016-10-01

In order to achieve enhanced and synergistic delivery of paclitaxel (PTX), a hydrophobic anticancer agent, two novel prodrug copolymers, POEG15-b-PFTS6 and POEG15-b-PFTS16 composed of hydrophilic poly(oligo(ethylene glycol) methacrylate) (POEG) and hydrophobic farnesylthiosalicylate (FTS, a nontoxic Ras antagonist) blocks, were synthesized. Both POEG-b-PFTS polymers were able to form micelles with intrinsic antitumor activity in vitro and in vivo. Employing these micelles as a carrier to load PTX, their drug loading capacity, stability, in vivo biodistribution and tumor inhibition effect were evaluated. PTX/POEG15-b-PFTS16 mixed micelles exhibited an excellent stability of 9days at 4°C with a PTX loading capacity of 8.2%, which was more effective than PTX/POEG15-b-PFTS6 mixed micelles. In vivo biodistribution data showed that DiR-loaded POEG-b-PFTS micelles were more effectively localized in the tumor than in other organs. Moreover, both PTX/POEG-b-PFTS micelles showed significantly higher antitumor activity than Taxol in a 4T1.2 murine breast tumor model, and the tumor inhibition and animal survival followed the order of PTX/POEG15-b-PFTS16>PTX/POEG15-b-PFTS6>POEG15-b-PFTS16>Taxol≈POEG15-b-PFTS6. Our data suggest that POEG-b-PFTS micelles are a promising anticancer drug carrier that warrants more studies in the future. Polymerization of drug-based monomer represents a facile and precise method to obtain well-defined polymeric prodrug amphiphiles. Currently, most reports largely focus on the synthesis methods and the biophysical properties. There is limited information about their anti-tumor activity and delivery function as prodrug carriers in vitro and in vivo. In this manuscript, we report the development of two novel prodrug copolymers, POEG15-b-PFTS6 and POEG15-b-PFTS16 composed of hydrophilic poly(oligo(ethylene glycol) methacrylate) (POEG) and hydrophobic farnesylthiosalicylate (FTS, a nontoxic Ras antagonist) blocks. Both POEG-b-PFTS polymers were able to self-assemble into nano-sized micelles with intrinsic antitumor activity in vitro and in vivo. More importantly, POEG-b-PFTS polymers were effective in forming stable mixed micelles with various anticancer agents including PTX, DOX, docetaxel, gefitinib, and imatinib. Delivery of PTX via our new carrier led to significantly improved antitumor activity, suggesting effective PTX/FTS combination therapy. We believe that our study shall be of broad interest to the readers in the fields of biomaterials and drug delivery. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Phase I study of replication-competent adenovirus-mediated double-suicide gene therapy in combination with conventional-dose three-dimensional conformal radiation therapy for the treatment of newly diagnosed, intermediate- to high-risk prostate cancer.

PubMed

Freytag, Svend O; Stricker, Hans; Pegg, Jan; Paielli, Dell; Pradhan, Deepak G; Peabody, James; DePeralta-Venturina, Mariza; Xia, Xueqing; Brown, Steve; Lu, Mei; Kim, Jae Ho

2003-11-01

The primary study objective was to determine the safety of intraprostatic administration of a replication-competent, oncolytic adenovirus containing a cytosine deaminase (CD)/herpes simplex virus thymidine kinase (HSV-1 TK) fusion gene concomitant with increasing durations of 5-fluorocytosine and valganciclovir prodrug therapy and conventional-dose three-dimensional conformal radiation therapy (3D-CRT) in patients with newly diagnosed, intermediate- to high-risk prostate cancer. Secondary objectives were to determine the persistence of therapeutic transgene expression in the prostate and to examine early posttreatment response. Fifteen patients in five cohorts received a single intraprostatic injection of 10(12) viral particles of the replication-competent Ad5-CD/TKrep adenovirus on day 1. Two days later, patients were administered 5-fluorocytosine and valganciclovir prodrug therapy for 1 (cohorts 1-3), 2 (cohort 4), or 3 (cohort 5) weeks along with 70-74 Gy 3D-CRT. Sextant needle biopsy of the prostate was obtained at 2 (cohort 1), 3 (cohort 2), and 4 (cohort 3) weeks for determination of the persistence of transgene expression. There were no dose-limiting toxicities and no significant treatment-related adverse events. Ninety-four percent of the adverse events observed were mild to moderate and self-limiting. Acute urinary and gastrointestinal toxicities were similar to those expected for conventional-dose 3D-CRT. Therapeutic transgene expression was found to persist in the prostate for up to 3 weeks after the adenovirus injection. As expected for patients receiving definitive radiation therapy, all patients experienced significant declines in prostate-specific antigen (PSA). The mean PSA half-life in patients administered more than 1 week of prodrug therapy was significantly shorter than that of patients receiving prodrugs for only 1 week (0.6 versus 2.0 months; P < 0.02) and markedly shorter than that reported previously for patients treated with conventional-dose 3D-CRT alone (2.4 months). With a median follow-up of only 9 months, 5 of 10 (50%) patients not treated with androgen-deprivation therapy achieved a serum PSA < or = 0.5 ng/ml. The results demonstrate that replication-competent adenovirus-mediated double-suicide gene therapy can be combined safely with conventional-dose 3D-CRT in patients with intermediate- to high-risk prostate cancer. The shorter than expected PSA half-life in patients receiving more than 1 week of prodrug therapy may suggest a possible interaction between the oncolytic adenovirus and/or double-suicide gene therapies and radiation therapy.

Targeting SVCT for enhanced drug absorption: Synthesis and in vitro evaluation of a novel vitamin C conjugated prodrug of saquinavir

PubMed Central

Luo, Shuanghui; Wang, Zhiying; Patel, Mitesh; Khurana, Varun; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim. K.

2015-01-01

In order to improve oral absorption, a novel prodrug of saquinavir (Saq), ascorbyl-succinic-saquinavir (AA-Su-Saq) targeting sodium dependent vitamin C transporter (SVCT) was synthesized and evaluated. Aqueous solubility, stability and cytotoxicity were determined. Affinity of AA-Su-Saq towards effluxpump P-glycoprotein (P-gp) and recognition of AA-Su-Saq by SVCT were studied. Transepithelial permeability across polarized MDCK-MDR1 and Caco-2 cells were determined. Metabolic stability of AA-Su-Saq in rat liver microsomes was investigated. AA-Su-Saq appears to be fairly stable in both DPBS and Caco-2 cells with half lives of 9.65 and 5.73 h, respectively. Uptake of [3H]Saquinavir accelerated by 2.7 and 1.9 fold in the presence of 50 μM Saq and AA-Su-Saq in MDCK-MDR1 cells. Cellular accumulation of [14C]AA diminished by about 50–70% relative to control in the presence of 200 μM AA-Su-Saq in MDCK-MDR1 and Caco-2 cells. Uptake of AA-Su-Saq was lowered by 27% and 34% in the presence of 5 mM AA in MDCK-MDR1 and Caco-2 cells, respectively. Absorptive permeability of AA-Su-Saq was elevated about 4-5 fold and efflux index reduced by about 13-15 fold across the polarized MDCK-MDR1 and Caco-2 cells. Absorptive permeability of AA-Su-Saq decreased 44% in the presence of 5 mM AA across MDCK-MDR1 cells. AA-Su-Saq was devoid of cytotoxicity over the concentration range studied. AA-Su-Saq significantly enhanced the metabolic stability but lowered the affinity towards CYP3A4. In conclusion, prodrug modification of Saq through conjugation to AA via a linker significantly raised the absorptive permeability and metabolic stability. Such modification also caused significant evading of P-gp mediated efflux and CYP3A4 mediated metabolism. SVCT targeted prodrug approach can be an attractive strategy to enhance the oral absorption and systemic bioavailability of anti-HIV protease inhibitors. PMID:21571053

Critical determinant of intestinal permeability and oral bioavailability of pegylated all trans-retinoic acid prodrug-based nanomicelles: Chain length of poly (ethylene glycol) corona.

PubMed

Li, Zhenbao; Han, Xiaopeng; Zhai, Yinglei; Lian, He; Zhang, Dong; Zhang, Wenjuan; Wang, Yongjun; He, Zhonggui; Liu, Zheng; Sun, Jin

2015-06-01

Pegylation method is widely used to prolong the blood circulation time of proteins and nanoparticles after intravenous administration, but the effect of surface poly (ethylene glycol) (PEG) chain length on oral absorption of the pegylated nanoparticles is poorly reported. The aim of our study was to investigate the influence of PEG corona chain length on membrane permeability and oral bioavailability of the amphiphilic pegylated prodrug-based nanomicelles, taking all trans-retinoic acid (ATRA) as a model drug. The amphiphilic ATRA-PEG conjugates were synthesized by esterification reaction between all trans-retinoic acid and mPEGs (mPEG500, mPEG1000, mPEG2000, and mPEG5000). The conjugates could self-assemble in aqueous medium to form nanomicelles by emulsion-solvent evaporation method. The resultant nanomicelles were in spherical shape with an average diameter of 13-20 nm. The drug loading efficiency of ATRA-PEG500, ATRA-PEG1000, ATRA-PEG2000, and ATRA-PEG5000 was about 38.4, 26.6, 13.1, and 5.68 wt%, respectively. With PEG chain length ranging from 500 to 5000, ATRA-PEG nanomicelles exhibited a bell shape of chemical stability in different pH buffers, intestinal homogenate and plasma. More importantly, they were all rapidly hydrolyzed into the parent drug in hepatic homogenate, with the half-time values being 0.3-0.4h. In comparison to ATRA solution and ATRA prodrug-based nanomicelles, ATRA-PEG1000 showed the highest intestinal permeability. After oral administration, ATRA-PEG2000 and ATRA-PEG5000 nanomicelles were not nearly absorbed, while the oral bioavailability of ATRA-PEG500 and ATRA-PEG1000 demonstrated about 1.2- and 2.0-fold higher than ATRA solution. Our results indicated that PEG1000 chain length of ATRA-PEG prodrug nanomicelles has the optimal oral bioavailability probably due to improved stability and balanced mucus penetration capability and cell binding, and that the PEG chain length on a surface of nanoparticles cannot exceed a key threshold with the purpose of enhancement in oral bioavailability. Copyright © 2015. Published by Elsevier B.V.

TIMP-2 mediates the anti-invasive effects of the nitric oxide-releasing prodrug JS-K in breast cancer cells.

PubMed

Simeone, Ann-Marie; McMurtry, Vanity; Nieves-Alicea, René; Saavedra, Joseph E; Keefer, Larry K; Johnson, Marcella M; Tari, Ana M

2008-01-01

Tumor invasion and metastasis remain a major cause of mortality in breast cancer patients. High concentrations of nitric oxide (NO) suppress tumor invasion and metastasis in vivo. NO prodrugs generate large amounts of NO upon metabolism by appropriate intracellular enzymes, and therefore could have potential in the prevention and therapy of metastatic breast cancer. The present study was designed to determine the effects of the NO-releasing prodrug O2-(2,4-dinitrophenyl) 1- [(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K) on breast cancer invasion and the mechanisms involved. MDA-MB-231, MDA-MB-231/F10, and MCF-7/COX-2 were the three breast cancer cell lines tested. NO levels were determined spectrophotometrically using a NO assay kit. Invasion and the expression of matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs were determined using Matrigel invasion assays, an MMP array kit and ELISAs. The activity and expression of extracellular signal-regulated kinase 1/2, p38, and c-Jun N-terminal kinase mitogen-activated protein kinases were determined using western blot analyses. Under conditions by which JS-K was not cytotoxic, JS-K significantly decreased (P < 0.05) the invasiveness of breast cancer cells across the Matrigel basement membrane, which was directly correlated with NO production. JS-43-126, a non-NO-releasing analog of JS-K, had no effect on NO levels or invasion. JS-K increased (P < 0.05) TIMP-2 production, and blocking TIMP-2 activity with a neutralizing antibody significantly increased (P < 0.05) the invasive activity of JS-K-treated cells across Matrigel. JS-K decreased p38 activity, whereas the activity and the expression of extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase were unaffected. We report the novel findings that JS-K inhibits breast cancer invasion across the Matrigel basement membrane, and NO production is vital for this activity. Upregulation of TIMP-2 production is one mechanism by which JS-K mediates its anti-invasive effects. JS-K and other NO prodrugs may represent an innovative biological approach in the prevention and treatment of metastatic breast cancer.

Therapeutic potential of a non-steroidal bifunctional anti-inflammatory and anti-cholinergic agent against skin injury induced by sulfur mustard

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Yoke-Chen; Wang, James D.; Hahn, Rita A.

Sulfur mustard (bis(2-chloroethyl) sulfide, SM) is a highly reactive bifunctional alkylating agent inducing edema, inflammation, and the formation of fluid-filled blisters in the skin. Medical countermeasures against SM-induced cutaneous injury have yet to be established. In the present studies, we tested a novel, bifunctional anti-inflammatory prodrug (NDH 4338) designed to target cyclooxygenase 2 (COX2), an enzyme that generates inflammatory eicosanoids, and acetylcholinesterase, an enzyme mediating activation of cholinergic inflammatory pathways in a model of SM-induced skin injury. Adult SKH-1 hairless male mice were exposed to SM using a dorsal skin vapor cup model. NDH 4338 was applied topically to themore » skin 24, 48, and 72 h post-SM exposure. After 96 h, SM was found to induce skin injury characterized by edema, epidermal hyperplasia, loss of the differentiation marker, keratin 10 (K10), upregulation of the skin wound marker keratin 6 (K6), disruption of the basement membrane anchoring protein laminin 322, and increased expression of epidermal COX2. NDH 4338 post-treatment reduced SM-induced dermal edema and enhanced skin re-epithelialization. This was associated with a reduction in COX2 expression, increased K10 expression in the suprabasal epidermis, and reduced expression of K6. NDH 4338 also restored basement membrane integrity, as evidenced by continuous expression of laminin 332 at the dermal–epidermal junction. Taken together, these data indicate that a bifunctional anti-inflammatory prodrug stimulates repair of SM induced skin injury and may be useful as a medical countermeasure. - Highlights: • Bifunctional anti-inflammatory prodrug (NDH4338) tested on SM exposed mouse skin • The prodrug NDH4338 was designed to target COX2 and acetylcholinesterase. • The application of NDH4338 improved cutaneous wound repair after SM induced injury. • NDH4338 treatment demonstrated a reduction in COX2 expression on SM injured skin. • Changes of skin repair markers are associated with NDH4438 treatment on SM injury.« less

Biotransformation Capacity of Carboxylesterase in Skin and Keratinocytes for the Penta-Ethyl Ester Prodrug of DTPA.

PubMed

Fu, Jing; Sadgrove, Matthew; Marson, Lesley; Jay, Michael

2016-08-01

The penta-ethyl ester prodrug of the chelating agent diethylene triamine pentaacetic acid (DTPA), referred to as C2E5, effectively accelerated clearance of americium after transdermal delivery. Carboxylesterases (CESs) play important roles in facilitating C2E5 hydrolysis. However, whether CESs in human skin hydrolyze C2E5 remains unknown. We evaluated the gene and protein expression of CESs in distinctive human epidermal cell lines: HEKa, HEKn, HaCaT, and A431. The substrates p-nitrophenyl acetate (pNPA) and 4-nitrophenyl valerate (4-NPV) were used to access esterase and CES activity. C2E5 hydrolysis was measured by radiometric high-performance liquid chromatography after incubation of [(14)C]C2E5 with supernatant fractions after centrifugation at 9000g (S9) prepared from skin cell lines. CES-specific inhibitors were used to access metabolism in human skin S9 fractions with analysis by liquid chromatography-tandem mass spectrometry. We identified the human carboxylesterase 1 and 2 (CES1 and CES2) bands in a Western blot. The gene expression of these enzymes was supported by a real-time polymerase chain reaction (qPCR). pNPA and 4-NPV assays demonstrated esterase and CES activity in all the cell lines that were comparable to human skin S9 fractions. The prodrug C2E5 was hydrolyzed by skin S9 fractions, resulting in a primary metabolite, C2E4. In human skin S9 fractions, inhibition of C2E5 hydrolysis was greatest with a pan-CES inhibitor (benzil). CES1 inhibition (troglitazone) was greater than CES2 (loperamide), suggesting a primary metabolic role for CES1. These results indicate that human keratinocyte cell lines are useful for the evaluation of human cutaneous metabolism and absorption of ester-based prodrugs. However, keratinocytes from skin provide a small contribution to the overall metabolism of C2E5. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Fabrication of Hyperbranched Block-Statistical Copolymer-Based Prodrug with Dual Sensitivities for Controlled Release.

PubMed

Zheng, Luping; Wang, Yunfei; Zhang, Xianshuo; Ma, Liwei; Wang, Baoyan; Ji, Xiangling; Wei, Hua

2018-01-17

Dendrimer with hyperbranched structure and multivalent surface is regarded as one of the most promising candidates close to the ideal drug delivery systems, but the clinical translation and scale-up production of dendrimer has been hampered significantly by the synthetic difficulties. Therefore, there is considerable scope for the development of novel hyperbranched polymer that can not only address the drawbacks of dendrimer but maintain its advantages. The reversible addition-fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP) technique has enabled facile preparation of segmented hyperbranched polymer (SHP) by using chain transfer monomer (CTM)-based double-head agent during the past decade. Meanwhile, the design and development of block-statistical copolymers has been proven in our recent studies to be a simple yet effective way to address the extracellular stability vs intracellular high delivery efficacy dilemma. To integrate the advantages of both hyperbranched and block-statistical structures, we herein reported the fabrication of hyperbranched block-statistical copolymer-based prodrug with pH and reduction dual sensitivities using RAFT-SCVP and post-polymerization click coupling. The external homo oligo(ethylene glycol methyl ether methacrylate) (OEGMA) block provides sufficient extracellularly colloidal stability for the nanocarriers by steric hindrance, and the interior OEGMA units incorporated by the statistical copolymerization promote intracellular drug release by facilitating the permeation of GSH and H + for the cleavage of the reduction-responsive disulfide bond and pH-liable carbonate link as well as weakening the hydrophobic encapsulation of drug molecules. The delivery efficacy of the target hyperbranched block-statistical copolymer-based prodrug was evaluated in terms of in vitro drug release and cytotoxicity studies, which confirms both acidic pH and reduction-triggered drug release for inhibiting proliferation of HeLa cells. Interestingly, the simultaneous application of both acidic pH and GSH triggers promoted significantly the cleavage and release of CPT compared to the exertion of single trigger. This study thus developed a facile approach toward hyperbranched polymer-based prodrugs with high therapeutic efficacy for anticancer drug delivery.

Targeting SVCT for enhanced drug absorption: synthesis and in vitro evaluation of a novel vitamin C conjugated prodrug of saquinavir.

PubMed

Luo, Shuanghui; Wang, Zhiying; Patel, Mitesh; Khurana, Varun; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim K

2011-07-29

In order to improve oral absorption, a novel prodrug of saquinavir (Saq), ascorbyl-succinic-saquinavir (AA-Su-Saq) targeting sodium dependent vitamin C transporter (SVCT) was synthesized and evaluated. Aqueous solubility, stability and cytotoxicity were determined. Affinity of AA-Su-Saq towards efflux pump P-glycoprotein (P-gp) and recognition of AA-Su-Saq by SVCT were studied. Transepithelial permeability across polarized MDCK-MDR1 and Caco-2 cells were determined. Metabolic stability of AA-Su-Saq in rat liver microsomes was investigated. AA-Su-Saq appears to be fairly stable in both DPBS and Caco-2 cells with half lives of 9.65 and 5.73 h, respectively. Uptake of [(3)H]Saquinavir accelerated by 2.7 and 1.9 fold in the presence of 50 μM Saq and AA-Su-Saq in MDCK-MDR1 cells. Cellular accumulation of [(14)C]AA diminished by about 50-70% relative to control in the presence of 200 μM AA-Su-Saq in MDCK-MDR1 and Caco-2 cells. Uptake of AA-Su-Saq was lowered by 27% and 34% in the presence of 5mM AA in MDCK-MDR1 and Caco-2 cells, respectively. Absorptive permeability of AA-Su-Saq was elevated about 4-5 fold and efflux index reduced by about 13-15 fold across the polarized MDCK-MDR1 and Caco-2 cells. Absorptive permeability of AA-Su-Saq decreased 44% in the presence of 5mM AA across MDCK-MDR1 cells. AA-Su-Saq was devoid of cytotoxicity over the concentration range studied. AA-Su-Saq significantly enhanced the metabolic stability but lowered the affinity towards CYP3A4. In conclusion, prodrug modification of Saq through conjugation to AA via a linker significantly raised the absorptive permeability and metabolic stability. Such modification also caused significant evading of P-gp mediated efflux and CYP3A4 mediated metabolism. SVCT targeted prodrug approach can be an attractive strategy to enhance the oral absorption and systemic bioavailability of anti-HIV protease inhibitors. Copyright © 2011 Elsevier B.V. All rights reserved.

Synergism of Selective Tumor Vascular Thrombosis and Protease Activated Prodrug

DTIC Science & Technology

2008-05-01

oxaloacetate , citrate, isocitrate), glycans, polyalkylene oxides, lower alkyl carboxylates, carboxyalkyls, carboxyalkylene carboxylates, charged... oxaloacetate , citrate, isocitrate), glycans, polyalkylene oxides, lower alkyl carboxylates, carboxyalkyls, carboxyalkylene carboxylates, and the like. 29

Treatment of infections due to resistant Staphylococcus aureus.

PubMed

Anstead, Gregory M; Cadena, Jose; Javeri, Heta

2014-01-01

This chapter reviews data on the treatment of infections caused by drug-resistant Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA). This review covers findings reported in the English language medical literature up to January of 2013. Despite the emergence of resistant and multidrug-resistant S. aureus, we have seven effective drugs in clinical use for which little resistance has been observed: vancomycin, quinupristin-dalfopristin, linezolid, tigecycline, telavancin, ceftaroline, and daptomycin. However, vancomycin is less effective for infections with MRSA isolates that have a higher MIC within the susceptible range. Linezolid is probably the drug of choice for the treatment of complicated MRSA skin and soft tissue infections (SSTIs); whether it is drug of choice in pneumonia remains debatable. Daptomycin has shown to be non-inferior to either vancomycin or β-lactams in the treatment of staphylococcal SSTIs, bacteremia, and right-sided endocarditis. Tigecycline was also non-inferior to comparator drugs in the treatment of SSTIs, but there is controversy about whether it is less effective than other therapeutic options in the treatment of more serious infections. Telavancin has been shown to be non-inferior to vancomycin in the treatment of SSTIs and pneumonia, but has greater nephrotoxicity. Ceftaroline is a broad-spectrum cephalosporin with activity against MRSA; it is non-inferior to vancomycin in the treatment of SSTIs. Clindamycin, trimethoprim-sulfamethoxazole, doxycycline, rifampin, moxifloxacin, and minocycline are oral anti-staphylococcal agents that may have utility in the treatment of SSTIs and osteomyelitis, but the clinical data for their efficacy is limited. There are also several drugs with broad-spectrum activity against Gm-positive organisms that have reached the phase II and III stages of clinical testing that will hopefully be approved for clinical use in the upcoming years: oritavancin, dalbavancin, omadacycline, tedizolid, delafloxacin, and JNJ-Q2. Thus, there are currently many effective drugs to treat resistant S. aureus infections and many promising agents in the pipeline. Nevertheless, S. aureus remains a formidable adversary, and despite our deep bullpen of potential therapies, there are still frequent treatment failures and unfortunate clinical outcomes. The following discussion summarizes the clinical challenges presented by MRSA, the clinical experience with our current anti-MRSA antibiotics, and the gaps in our knowledge on how to use these agents to most effectively combat MRSA infections.

N-Heterocyclic molecule-capped gold nanoparticles as effective antibiotics against multi-drug resistant bacteria

NASA Astrophysics Data System (ADS)

Feng, Yan; Chen, Wenwen; Jia, Yuexiao; Tian, Yue; Zhao, Yuyun; Long, Fei; Rui, Yukui; Jiang, Xingyu

2016-07-01

We demonstrate that N-heterocyclic molecule-capped gold nanoparticles (Au NPs) have broad-spectrum antibacterial activity. Optimized antibacterial activity can be achieved by using different initial molar ratios (1 : 1 and 10 : 1) of N-heterocyclic prodrugs and the precursor of Au NPs (HAuCl4). This work opens up new avenues for antibiotics based on Au NPs.We demonstrate that N-heterocyclic molecule-capped gold nanoparticles (Au NPs) have broad-spectrum antibacterial activity. Optimized antibacterial activity can be achieved by using different initial molar ratios (1 : 1 and 10 : 1) of N-heterocyclic prodrugs and the precursor of Au NPs (HAuCl4). This work opens up new avenues for antibiotics based on Au NPs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03317b

Dancing with chemical formulae of antivirals: a personal account.

PubMed

De Clercq, Erik

2013-09-15

A chemical structure is a joy forever, and this is how I perceived the chemical structures of a number of antiviral compounds with which I have been personally acquainted over the past 3 decades: (1) amino acid esters of acyclovir (i.e. valaciclovir); (2) 5-substituted 2'-deoxyuridines (i.e. brivudin); (3) 2',3'-dideoxynucleoside analogues (i.e. stavudine); (4) acyclic nucleoside phosphonates (ANPs) (i.e. cidofovir, adefovir); (5) tenofovir disoproxil fumarate (TDF) and drug combinations therewith; (6) tenofovir alafenamide (TAF, GS-7340), a new phosphonoamidate prodrug of tenofovir; (7) pro-prodrugs of PMEG (i.e. GS-9191 and GS-9219); (8) new ANPs: O-DAPy and 5-aza-C phosphonates; (9) non-nucleoside reverse transcriptase inhibitors (NNRTIs): HEPT and TIBO derivatives; and (10) bicyclam derivatives (i.e. AMD3100). Copyright © 2013 Elsevier Inc. All rights reserved.

Pathways and Progress in Improving Drug Delivery through the Intestinal Mucosa and Blood-Brain Barriers

PubMed Central

Laksitorini, Marlyn; Prasasty, Vivitri D.; Kiptoo, Paul K.; Siahaan, Teruna J.

2015-01-01

One of the major hurdles in developing therapeutic agents is the difficulty in delivering drugs through the intestinal mucosa and blood-brain barriers (BBB). The goal here is to describe the general structures of the biological barriers and the strategies to enhance drug delivery across these barriers. Prodrug methods used to improve drug penetration via the transcellular pathway have been successfully developed, and some prodrugs have been used to treat patients. The use of transporters to improve absorption of some drugs (e.g., antiviral agents) has also been successful in treating patients. Other methods, including (a) blocking the efflux pumps to improve transcellular delivery and (b) modulation of cell-cell adhesion in the intercellular junctions to improve paracellular delivery across biological barriers are still in the investigational stage. PMID:25418271

Selective ion exchange governed by the Irving-Williams series in K2Zn3[Fe(CN)6]2 nanoparticles: toward a designer prodrug for Wilson's disease.

PubMed

Kandanapitiye, Murthi S; Wang, Fan Jennifer; Valley, Benjamin; Gunathilake, Chamila; Jaroniec, Mietek; Huang, Songping D

2015-02-16

The principle of the Irving-Williams series is applied to the design of a novel prodrug based on K2Zn3[Fe(CN)6]2 nanoparticles (ZnPB NPs) for Wilson's disease (WD), a rare but fatal genetic disorder characterized by the accumulation of excess copper in the liver and other vital organs. The predetermined ion-exchange reaction rather than chelation between ZnPB NPs and copper ions leads to high selectivity of such NPs for copper in the presence of the other endogenous metal ions. Furthermore, ZnPB NPs are highly water-dispersible and noncytotoxic and can be readily internalized by cells to target intracellular copper ions for selective copper detoxification, suggesting their potential application as a new-generation treatment for WD.

Kidney-selective prodrugs of 6-mercaptopurine: biochemical basis of the kidney selectivity of S-(6-purinyl)-L-cysteine and metabolism of new analogs in rats.

PubMed

Hwang, I Y; Elfarra, A A

1991-07-01

Recently, we have reported that S-(6-purinyl)-L-cysteine (PC) is a kidney-selective prodrug of 6-mercaptopurine. In the present study, the in vivo metabolism of PC and the biochemical basis of its renal selectivity were further investigated. In addition, several PC analogs were synthesized and evaluated as prodrugs of 6-mercaptopurine by determining the concentrations of 6-mercaptopurine and its metabolites, 6-methylmercaptopurine and 6-thiouric acid, in urine after rats were given the analogs. At 30 min after PC treatments, kidney metabolite concentrations were dependent on the PC dose at 40 to 130 mumol/kg and were not increased when a 400 mumol PC/kg dose was given. At the 400 mumol PC/kg dose, metabolite concentrations in the kidneys were higher at 30 min than at 1 or 3 hr, and were nearly 2.5- and 100-fold higher than those in liver and plasma, respectively. Rates of PC in vitro metabolism by liver and kidney cytosolic cysteine conjugate beta-lyases (beta-lyases) were similar, but metabolism by renal mitochondrial beta-lyase occurred at a 3-fold higher rate than the rate obtained with hepatic mitochondrial beta-lyase. When rats were given aminooxyacetic acid (500 mumol/kg) or probenecid (270 mumol/kg) before PC (130 mumol/kg), total kidney metabolite concentrations were reduced by 55 and 36%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation Rate-Limited Pharmacokinetics of Biologically Active Epoxy Transformers of Prodrug Treosulfan.

PubMed

Romański, Michał; Kasprzyk, Anna; Karbownik, Agnieszka; Szałek, Edyta; Główka, Franciszek K

2016-05-01

A prodrug treosulfan (TREO) is being evaluated in clinical trials as a myeloablative agent before hematopoietic stem cell transplantation. The active derivatives of TREO, monoepoxide (EBDM), and diepoxide (DEB) are formed in a pH-dependent nonenzymatic reaction. The aim of the study was to investigate pharmacokinetics of the TREO epoxy transformers in a rabbit model and explain the causes of low plasma concentrations of EBDM and DEB observed in patients receiving high-dose TREO before hematopoietic stem cell transplantation. New Zealand white rabbits (n = 5 per cohort) received an intravenous infusion of TREO (group I), injection of DEB (group II), and injection of a solution containing EBDM (group III). When EBDM and DEB were administered to the rabbits, they underwent a very rapid elimination (half-life 0.069 and 0.046 h) associated with a high systemic clearance (10.0 and 14.0 L h(-1) kg(-1)). After administration of TREO, the t1/2 of EBDM was statistically equal to the t1/2 of the prodrug (1.6 h). To conclude, after administration of TREO, its epoxy transformers demonstrate a formation-limited elimination. Then EBDM and DEB have the same elimination half-life as TREO, but the levels of EBDM and DEB in the body, including plasma, are much lower than TREO on account of their inherently high clearance. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

The Evaluation Of Therapeutic Efficacy and Safety Profile of Simvastatin Prodrug Micelles in a Closed Fracture Mouse Model

PubMed Central

Zhang, Yijia; Jia, Zhenshan; Yuan, Hongjiang; Dusad, Anand; Ren, Ke; Wei, Xin; Fehringer, Edward V.; Purdue, P. Edward; Daluiski, Aaron; Goldring, Steven R.; Wang, Dong

2016-01-01

Purpose To evaluate the therapeutic efficiency of a micellar prodrug formulation of simvastatin (SIM/SIM-mPEG) and explore its safety in a closed femoral fracture mouse model. Methods The amphiphilic macromolecular prodrug of simvastatin (SIM-mPEG) was synthesized and formulated together with free simvastatin into micelles. It was also labeled with a near infrared dye for in vivo imaging purpose. A closed femoral fracture mouse model was established using a three-point bending device. The mice with established closed femoral fracture were treated with SIM/SIM-mPEG micelle, using free simvastatin and saline as controls. The therapeutic efficacy of the micelles was evaluated using a high-resolution micro-CT. Serum biochemistry and histology analyses were performed to explore the potential toxicity of the micelle formulation. Results Near Infrared Fluorescence (NIRF) imaging confirmed the passive targeting of SIM/SIM-mPEG micelles to the bone lesion of the mice with closed femoral fracture. The micelle was found to promote fracture healing with an excellent safety profile. In addition, the accelerated healing of the femoral fracture also helped to prevent disuse-associated same-side tibia bone loss accompanying the femur fracture. Conclusion SIM/SIM-mPEG micelle was found to be an effective and safe treatment for closed femoral fracture repair in mice. The evidence obtained in this study suggests that it may have the potential to be translated into a novel therapy for clinical management of skeletal fractures and non-union. PMID:27164897

A comparative evaluation of treatments with 17β-estradiol and its brain-selective prodrug in a double-transgenic mouse model of Alzheimer's disease.

PubMed

Tschiffely, Anna E; Schuh, Rosemary A; Prokai-Tatrai, Katalin; Prokai, Laszlo; Ottinger, Mary Ann

2016-07-01

Estrogens are neuroprotective and, thus, potentially useful for the therapy of Alzheimer's disease; however, clinical use of hormone therapy remains controversial due to adverse peripheral effects. The goal of this study was to investigate the benefits of treatment with 10β,17β-dihydroxyestra-1,4-dien-3-one (DHED), a brain-selective prodrug of 17β-estradiol, in comparison with the parent hormone using APPswe/PS1dE9 double transgenic mice to model the pathology of the disease. Ovariectomized and intact females were continuously treated with vehicle, 17β-estradiol, or DHED via subcutaneous osmotic pumps from 6 to 8months of age. We confirmed that this prolonged treatment with DHED did not stimulate uterine tissue, whereas 17β-estradiol treatment increased uterine weight. Amyloid precursor protein decreased in both treatment groups of intact, but not in ovariectomized double transgenic females in which ovariectomy already decreased the expression of this protein significantly. However, reduced brain amyloid-β peptide levels could be observed for both treatments. Consequently, double-transgenic ovariectomized and intact mice had higher cognitive performance compared to untreated control animals in response to both estradiol and DHED administrations. Overall, the tested brain-selective 17β-estradiol prodrug proved to be an effective early-stage intervention in an Alzheimer's disease-relevant mouse model without showing systemic impact and, thus, warrants further evaluation as a potential therapeutic candidate. Copyright © 2016 Elsevier Inc. All rights reserved.

Pro-drugs for indirect cannabinoids as therapeutic agents.

PubMed

Ashton, John

2008-10-01

Medicinal cannabis, cannabis extracts, and other cannabinoids are currently in use or under clinical trial investigation for the control of nausea, emesis and wasting in patients undergoing chemotherapy, the control of neuropathic pain and arthritic pain, and the control of the symptoms of multiple sclerosis. The further development of medicinal cannabinoids has been challenged with problems. These include the psychoactivity of cannabinoid CB1 receptor agonists and the lack of availability of highly selective cannabinoid receptor full agonists (for the CB1 or CB2 receptor), as well as problems of pharmacokinetics. Global activation of cannabinoid receptors is usually undesirable, and so enhancement of local endocannabinoid receptor activity with indirect cannabimimetics is an attractive strategy for therapeutic modulation of the endocannabinoid system. However, existing drugs of this type tend to be metabolized by the same enzymes as their target endocannabinoids and are not yet available in a form that is clinically useful. A potential solution to these problems may now have been suggested by the discovery that paracetamol (acetaminophen) exerts its analgesic (and probably anti-pyretic) effects by its degradation into an anandamide (an endocannabinoid) reuptake inhibitor (AM404) within the body, thus classifying it as pro-drug for an indirect cannabimimetic. Given the proven efficacy and safety of paracetamol, the challenge now is to develop related drugs, or entirely different substrates, into pro-drug indirect cannabimimetics with a similar safety profile to paracetamol but at high effective dose titrations.

Design of cellulose ether-based macromolecular prodrugs of ciprofloxacin for extended release and enhanced bioavailability.

PubMed

Amin, Muhammad; Abbas, Nazia Shahana; Hussain, Muhammad Ajaz; Sher, Muhammad; Edgar, Kevin J

2018-07-01

The present study reveals the syntheses of hydroxypropylcellulose‑(HPC) and hydroxyethylcellulose‑(HEC) based macromolecular prodrugs (MPDs) of ciprofloxacin (CIP) using homogeneous reaction methodology. Covalently loaded drug content (DC) of each prodrug was quantified using UV-Vis spectrophotometry to determine degree of substitution (DS). HPC-ciprofloxacin (HPC-CIP) conjugates showed DS of CIP in the range 0.87-1.15 whereas HEC-ciprofloxacin (HEC-CIP) conjugates showed DS range 0.51-0.75. Transmission electron microscopy revealed that HPC-CIP conjugate 2 and HEC-CIP conjugate 6 self-assembled into nanoparticles of 150-300 and 180-250nm, respectively. Size exclusion chromatography revealed HPC-CIP conjugate 2 and HEC-CIP conjugate 6 as monodisperse systems. In vitro drug release studies indicated 15 and 43% CIP release from HPC-CIP conjugate 2 after 6h in simulated gastric and simulated intestinal fluids (SGF and SIF), respectively. HEC-CIP conjugate 6 showed 16% and 46% release after 6h in SGF and SIF, respectively. HPC-CIP conjugate 2 and HEC-CIP conjugate 6 exhibited half-lives of 10.87 and 11.71h, respectively with area under the curve values of 164 and 175hμgmL -1 , respectively, indicating enhanced bioavailability and improved pharmacokinetic profiles in animal model. Equal antibacterial activities to that of unmodified CIP confirmed their competitive efficacies. Cytotoxicity studies supported their non-toxic nature and biocompatibility. Copyright © 2018 Elsevier B.V. All rights reserved.

Modeling of autocatalytic hydrolysis of adefovir dipivoxil in solid formulations.

PubMed

Dong, Ying; Zhang, Yan; Xiang, Bingren; Deng, Haishan; Wu, Jingfang

2011-04-01

The stability and hydrolysis kinetics of a phosphate prodrug, adefovir dipivoxil, in solid formulations were studied. The stability relationship between five solid formulations was explored. An autocatalytic mechanism for hydrolysis could be proposed according to the kinetic behavior which fits the Prout-Tompkins model well. For the classical kinetic models could hardly describe and predict the hydrolysis kinetics of adefovir dipivoxil in solid formulations accurately when the temperature is high, a feedforward multilayer perceptron (MLP) neural network was constructed to model the hydrolysis kinetics. The build-in approaches in Weka, such as lazy classifiers and rule-based learners (IBk, KStar, DecisionTable and M5Rules), were used to verify the performance of MLP. The predictability of the models was evaluated by 10-fold cross-validation and an external test set. It reveals that MLP should be of general applicability proposing an alternative efficient way to model and predict autocatalytic hydrolysis kinetics for phosphate prodrugs.

Biotin-Pt (IV)-indomethacin hybrid: A targeting anticancer prodrug providing enhanced cancer cellular uptake and reversing cisplatin resistance.

PubMed

Hu, Weiwei; Fang, Lei; Hua, Wuyang; Gou, Shaohua

2017-10-01

A Pt(IV) prodrug (2) composed of cancer-targeting biotin and nonsteroidal anti-inflammatory drug indomethacin in the axial positions of the six-coordinated octahedral geometry derived from cisplatin was developed, which could be highly accumulated in cancer cells more than normal ones and activated by endogenous reducing molecules to release cisplatin and indomethacin moieties simultaneously to inhibit tumor progression synergistically. In vitro assays revealed that 2 exhibited significantly selective inhibition to the tested cancer cell lines and sensitivity to cisplatin resistant cancer cells. Moreover, 2 presented cyclooxygenases inhibition properties to reduce tumor-associated inflammation, reduced the invasiveness of the highly aggressive PC-3 cells, and disrupted capillary-like tube formation in EA.hy926 cells. In all, this study offers a new strategy to enhance sensitivity and reduce toxicity of cisplatin. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis and biological evaluation of 6-substituted-5-fluorouridine ProTides.

PubMed

Slusarczyk, Magdalena; Ferla, Salvatore; Brancale, Andrea; McGuigan, Christopher

2018-02-01

A new family of thirteen phosphoramidate prodrugs (ProTides) of different 6-substituted-5-fluorouridine nucleoside analogues were synthesized and evaluated as potential anticancer agents. In addition, antiviral activity against Chikungunya (CHIKV) virus was evaluated using a cytopathic effect inhibition assay. Although a carboxypeptidase Y assay supported a putative mechanism of activation of ProTides built on 5-fluorouridine with such C6-modifications, the Hint docking studies revealed a compromised substrate-activity for the Hint phosphoramidase-type enzyme that is likely responsible for phosphoramidate bioactivation through P-N bond cleavage and free nucleoside 5'-monophosphate delivery. Our observations may support and explain to some extent the poor in vitro biological activity generally demonstrated by the series of 6-substituted-5-fluorouridine phosphoramidates (ProTides) and will be of guidance for the design of novel phosphoramidate prodrugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neuropharmacological and neurochemical properties of N-(2-cyanoethyl)-2-phenylethylamine, a prodrug of 2-phenylethylamine.

PubMed Central

Baker, G. B.; Coutts, R. T.; Rao, T. S.

1987-01-01

1 N-(2-cyanoethyl)-2-phenylethylamine (CEPEA) was examined as a possible prodrug of 2-phenylethylamine (PEA). 2 Pharmacokinetics of PEA and CEPEA were investigated in rat brain, blood and liver by gas chromatography with electron-capture detection (GC-ECD). Interactions of PEA and CEPEA with putative neurotransmitter amines were investigated by use of high performance liquid chromatography with electrochemical detection (h.p.l.c.-e.c.). 3 Administration of PEA caused transient increases in PEA concentrations which decreased rapidly in brain and blood and at a slower rate in liver. Administration of CEPEA caused sustained elevations of PEA concentrations and elimination of PEA was markedly decreased in these tissues relative to the situation after administration of PEA itself. 4 Administration of CEPEA caused more prolonged decreases in brain noradrenaline, dopamine and 5-hydroxytryptamine concentrations than those observed after PEA administration, although values increased to control levels eventually. PMID:2890391

Trimodal Therapy: Combining Hyperthermia with Repurposed Bexarotene and Ultrasound for Treating Liver Cancer.

PubMed

Misra, Santosh K; Ghoshal, Goutam; Gartia, Manas R; Wu, Zhe; De, Arun K; Ye, Mao; Bromfield, Corinne R; Williams, Emery M; Singh, Kuldeep; Tangella, Krishnarao V; Rund, Laurie; Schulten, Klaus; Schook, Lawrence B; Ray, Partha S; Burdette, Everette C; Pan, Dipanjan

2015-11-24

Repurposing of existing cancer drugs to overcome their physical limitations, such as insolubility, represents an attractive strategy to achieve enhanced therapeutic efficacy and broaden the range of clinical applications. Such an approach also promises to offer substantial cost savings in drug development efforts. Here we repurposed FDA-approved topical agent bexarotene (Targretin), currently in limited use for cutaneous manifestations of T-cell lymphomas, and re-engineer it for use in solid tumor applications by forming self-assembling nanobubbles. Physico-chemical characterization studies of the novel prodrug nanobubbles demonstrated their stability, enhanced target cell internalization capability, and highly controlled release profile in response to application of focused ultrasound energy. Using an in vitro model of hepatocellular carcinoma and an in vivo large animal model of liver ablation, we demonstrate the effectiveness of bexarotene prodrug nanobubbles when used in conjunction with catheter-based ultrasound, thereby highlighting the therapeutic promise of this trimodal approach.

Identification of a Potent Phosphoinositide 3‐Kinase Pan Inhibitor Displaying a Strategic Carboxylic Acid Group and Development of Its Prodrugs

PubMed Central

Pirali, Tracey; Ciraolo, Elisa; Aprile, Silvio; Massarotti, Alberto; Berndt, Alex; Griglio, Alessia; Serafini, Marta; Mercalli, Valentina; Landoni, Clarissa; Campa, Carlo Cosimo; Margaria, Jean Piero; Silva, Rangel L.; Grosa, Giorgio; Sorba, Giovanni; Williams, Roger

2017-01-01

Abstract Activation of the phosphoinositide 3‐kinase (PI3K) pathway is a key signaling event in cancer, inflammation, and other proliferative diseases. PI3K inhibitors are already approved for some specific clinical indications, but their systemic on‐target toxicity limits their larger use. In particular, whereas toxicity is tolerable in acute treatment of life‐threatening diseases, this is less acceptable in chronic conditions. In the past, the strategy to overcome this drawback was to block selected isoforms mainly expressed in leukocytes, but redundancy within the PI3K family members challenges the effectiveness of this approach. On the other hand, decreasing exposure to selected target cells represents a so‐far unexplored alternative to circumvent systemic toxicity. In this manuscript, we describe the generation of a library of triazolylquinolones and the development of the first prodrug pan‐PI3K inhibitor. PMID:28857471

Towards antibody-drug conjugates and prodrug strategies with extracellular stimuli-responsive drug delivery in the tumor microenvironment for cancer therapy.

PubMed

Joubert, Nicolas; Denevault-Sabourin, Caroline; Bryden, Francesca; Viaud-Massuard, Marie-Claude

2017-12-15

The design of innovative anticancer chemotherapies with superior antitumor efficacy and reduced toxicity continues to be a challenging endeavor. Recently, the success of Adcetris ® and Kadcyla ® made antibody-drug conjugates (ADCs) serious contenders to reach the envied status of Paul Ehrlich's "magic bullet". However, ADCs classically target overexpressed and internalizing antigens at the surface of cancer cells, and in solid tumors are associated with poor tumor penetration, insufficient targeting in heterogeneous tumors, and appearance of several resistance mechanisms. In this context, alternative non-internalizing ADCs and prodrugs have been developed to circumvent these limitations, in which the drug can be selectively released by an extracellular stimulus in the tumor microenvironment. Each strategy and method of activation will be discussed as potential alternatives to internalizing ADCs for cancer therapy. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Nano-palladium is a cellular catalyst for in vivo chemistry

NASA Astrophysics Data System (ADS)

Miller, Miles A.; Askevold, Bjorn; Mikula, Hannes; Kohler, Rainer H.; Pirovich, David; Weissleder, Ralph

2017-07-01

Palladium catalysts have been widely adopted for organic synthesis and diverse industrial applications given their efficacy and safety, yet their biological in vivo use has been limited to date. Here we show that nanoencapsulated palladium is an effective means to target and treat disease through in vivo catalysis. Palladium nanoparticles (Pd-NPs) were created by screening different Pd compounds and then encapsulating bis[tri(2-furyl)phosphine]palladium(II) dichloride in a biocompatible poly(lactic-co-glycolic acid)-b-polyethyleneglycol platform. Using mouse models of cancer, the NPs efficiently accumulated in tumours, where the Pd-NP activated different model prodrugs. Longitudinal studies confirmed that prodrug activation by Pd-NP inhibits tumour growth, extends survival in tumour-bearing mice and mitigates toxicity compared to standard doxorubicin formulations. Thus, here we demonstrate safe and efficacious in vivo catalytic activity of a Pd compound in mammals.

Liposomes assembled from a dual drug-tailed phospholipid for cancer therapy.

PubMed

Fang, Shuo; Niu, Yuge; Zhu, Wenjun; Zhang, Yemin; Yu, Liangli; Li, Xinsong

2015-05-01

We report a novel dual drug-tailed phospholipid which can form liposomes as a combination of prodrug and drug carrier. An amphiphilic dual chlorambucil-tailed phospholipid (DCTP) was synthesized by a straightforward esterification. With two chlorambucil molecules as hydrophobic tails and one glycerophosphatidylcholine molecule as a hydrophilic head, the DCTP, a phospholipid prodrug, undergoes assembly to form a liposome without any additives by the thin lipid film technique. The DCTP liposomes, as an effective carrier of chlorambucil, exhibited a very high loading capacity and excellent stability. The liposomes had higher cytotoxic effects to cancer cell lines than free DCTP and chlorambucil. The in vivo antitumor activity assessment indicated that the DCTP liposomes could inhibit the tumor growth effectively. This novel strategy of dual drug-tailed phospholipid liposomes may be also applicable to other hydrophobic anticancer drugs which have great potential in cancer therapy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of Purine-Derived 18F-Labeled Pro-drug Tracers for Imaging of MRP1 Activity with PET

PubMed Central

2014-01-01

Multidrug resistance-associated protein 1 (MRP1) is a drug efflux transporter that has been implicated in the pathology of several neurological diseases and is associated with development of multidrug resistance. To enable measurement of MRP1 function in the living brain, a series of 6-halopurines decorated with fluorinated side chains have been synthesized and evaluated as putative pro-drug tracers. The tracers were designed to undergo conjugation with glutathione within the brain and hence form the corresponding MRP1 substrate tracers in situ. 6-Bromo-7-(2-[18F]fluoroethyl)purine showed good brain uptake and rapid metabolic conversion. Dynamic PET imaging demonstrated a marked difference in brain clearance rates between wild-type and mrp1 knockout mice, suggesting that the tracer can allow noninvasive assessment of MRP1 activity in vivo. PMID:24456310

Amplifying the Red-Emission of Upconverting Nanoparticles for Biocompatible Clinically Used Prodrug-Induced Photodynamic Therapy

DOE PAGES

Punjabi, Amol; Wu, Xiang; Tokatli-Apollon, Amira; ...

2014-09-25

A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major stepmore » forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors.Lastly, it also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.« less

Mechanism of action for the cytotoxic effects of the nitric oxide prodrug JS-K in murine erythroleukemia cells.

PubMed

Kaczmarek, Monika Z; Holland, Ryan J; Lavanier, Stephen A; Troxler, Jami A; Fesenkova, Valentyna I; Hanson, Charlotte A; Cmarik, Joan L; Saavedra, Joseph E; Keefer, Larry K; Ruscetti, Sandra K

2014-03-01

The nitric oxide (NO) prodrug JS-K, a promising anti-cancer agent, consists of a diazeniumdiolate group necessary for the release of NO as well as an arylating ring. In this study, we research the mechanism by which JS-K kills a murine erythroleukemia cell line and determine the roles of NO and arylation in the process. Our studies indicate that JS-K inhibits the PI 3-kinase/Akt and MAP kinase pathways. This correlates with the activation of the tumor suppressor FoxO3a and increased expression of various caspases, leading to apoptosis. The arylating capability of JS-K appears to be sufficient for inducing these biological effects. Overall, these data suggest that JS-K kills tumor cells by arylating and inactivating signaling molecules that block the activation of a tumor suppressor. Published by Elsevier Ltd.

Synthesis and pharmacokinetics of valopicitabine (NM283), an efficient prodrug of the potent anti-HCV agent 2'-C-methylcytidine.

PubMed

Pierra, Claire; Amador, Agnès; Benzaria, Samira; Cretton-Scott, Erika; D'Amours, Marc; Mao, John; Mathieu, Steven; Moussa, Adel; Bridges, Edward G; Standring, David N; Sommadossi, Jean-Pierre; Storer, Richard; Gosselin, Gilles

2006-11-02

In our search for new therapeutic agents against chronic hepatitis C, a ribonucleoside analogue, 2'-C-methylcytidine, was discovered to be a potent and selective inhibitor in cell culture of a number of RNA viruses, including the pestivirus bovine viral diarrhea virus, a surrogate model for hepatitis C virus (HCV), and three flaviviruses, namely, yellow fever virus, West Nile virus, and dengue-2 virus. However, pharmacokinetic studies revealed that 2'-C-methylcytidine suffers from a low oral bioavailability. To overcome this limitation, we have synthesized the 3'-O-l-valinyl ester derivative (dihydrochloride form, valopicitabine, NM283) of 2'-C-methylcytidine. We detail herein for the first time the chemical synthesis and physicochemical characteristics of this anti-HCV prodrug candidate, as well as a comparative study of its pharmacokinetic parameters with those of its parent nucleoside analogue, 2'-C-methylcytidine.

Synthesis and in vitro evaluation of methotrexate conjugated O, N-carboxymethyl chitosan via peptidyl spacers

NASA Astrophysics Data System (ADS)

Li, Dan; Lu, Bo; Zhang, Hong; Huang, Zhijun; Xu, Peihu; Zheng, Hua; Yin, Yihua; Xu, Haixing; Liu, Xia; Lou, Yiceng; Zhang, Xueqiong; Xiong, Fuliang

2014-09-01

The use of methotrexate (MTX), an anticancer drug for the treatment of hematologic malignancies, has been limited in the clinical application due to its poor water solubility, high clearance rate, and lack of target specificity. To solve these problems, O, N-carboxymethyl chitosan-dipeptide-MTX conjugates have been synthesized and characterized by fourier transform infrared radiation spectroscopy and proton nuclear magnetic resonance (1H NMR). All polymeric conjugates showed satisfactory water solubility. The results of the study revealed that drug release and toxicity were affected by employing polymeric conjugation strategy and dipeptide spacers [glycylglycine (Gly-Gly), glycyl- l-phenylalanine (Gly-Phe), glycyl- l-tyrosine (Gly-Tyr)]. It has been found that drugs could be effectively loaded and released when polymeric prodrugs were combined with a dipeptide spacer. In conclusion, O, N-CMCS-dipeptide-MTX polymeric prodrugs could potentially be used as responsive drug delivery systems.

Tri-modal Therapy: Combining Hyperthermia with Repurposed Bexarotene and Ultrasound for Treating Liver Cancer

PubMed Central

Misra, Santosh K.; Ghoshal, Goutam; Bromfield, Corinne R.; Williams, Emery M.; Singh, Kuldeep; Tangella, Krishnarao V.; Rund, Laurie; Schulten, Klaus; Schook, Lawrence B.; Ray, Partha S.; Burdette, Everette C.; Pan, Dipanjan

2016-01-01

Repurposing of existing cancer drugs to overcome their physical limitations, such as insolubility, represents an attractive strategy to achieve enhanced therapeutic efficacy and broaden the range of clinical applications. Such an approach also promises to offer substantial cost savings in drug development efforts. Here we use repurposed FDA-approved topical agent bexarotene (Targretin™), currently in limited use for cutaneous manifestations of T-cell lymphomas, and re-engineer it for use in solid tumor applications by forming self-assembling nanobubbles. Physicochemical characterization studies of the novel prodrug nanobubbles demonstrated their stability, enhanced target cell-internalization capability and highly controlled release profile in response to application of focused ultrasound energy. Using an in vitro model of hepatocellular carcinoma and an in vivo large animal model of liver ablation, we demonstrate the effectiveness of bexarotene prodrug nanobubbles when used in conjunction with catheter-based ultrasound, thereby highlighting the therapeutic promise of this trimodal approach. PMID:26435333

Amplifying the red-emission of upconverting nanoparticles for biocompatible clinically used prodrug-induced photodynamic therapy.

PubMed

Punjabi, Amol; Wu, Xiang; Tokatli-Apollon, Amira; El-Rifai, Mahmoud; Lee, Hyungseok; Zhang, Yuanwei; Wang, Chao; Liu, Zhuang; Chan, Emory M; Duan, Chunying; Han, Gang

2014-10-28

A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP-PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major step forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors. It also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.

Amplifying the Red-Emission of Upconverting Nanoparticles for Biocompatible Clinically Used Prodrug-Induced Photodynamic Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Punjabi, Amol; Wu, Xiang; Tokatli-Apollon, Amira

A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in tumor was demonstrated in a deep-tissue (>1.2 cm) setting in vivo at a biocompatible laser power density. Furthermore, we show that our UCNP–PDT system with NIR irradiation outperforms clinically used red light irradiation in a deep tumor setting in vivo. This study marks a major stepmore » forward in photodynamic therapy utilizing UCNPs to effectively access deep-set tumors.Lastly, it also provides an opportunity for the wide application of upconverting red radiation in photonics and biophotonics.« less

Acyclic Immucillin Phosphonates. Second-Generation Inhibitors of Plasmodium falciparum Hypoxanthine- Guanine-Xanthine Phosphoribosyltransferase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazelton, Keith Z.; Ho, Meng-Chaio; Cassera, Maria B.

We found that Plasmodium falciparum is the primary cause of deaths from malaria. It is a purine auxotroph and relies on hypoxanthine salvage from the host purine pool. Purine starvation as an antimalarial target has been validated by inhibition of purine nucleoside phosphorylase. Hypoxanthine depletion kills Plasmodium falciparum in cell culture and in Aotus monkey infections. Hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT) from P. falciparum is required for hypoxanthine salvage by forming inosine 5'-monophosphate, a branchpoint for all purine nucleotide synthesis in the parasite. We present a class of HGXPRT inhibitors, the acyclic immucillin phosphonates (AIPs), and cell permeable AIP prodrugs. The AIPsmore » are simple, potent, selective, and biologically stable inhibitors. The AIP prodrugs block proliferation of cultured parasites by inhibiting the incorporation of hypoxanthine into the parasite nucleotide pool and validates HGXPRT as a target in malaria.« less

Pharmacokinetic drug interactions of morphine, codeine, and their derivatives: theory and clinical reality, Part II.

PubMed

Armstrong, Scott C; Cozza, Kelly L

2003-01-01

Pharmacokinetic drug-drug interactions with codeine, dihydrocodeine, hydrocodone, oxycodone, and buprenorphine are reviewed in this column. These compounds have a very similar chemical structure to morphine. Unlike morphine, which is metabolized chiefly through conjugation reactions with uridine diphosphate glucuronosyl transferase (UGT) enzymes, these five drugs are metabolized both through oxidative reactions by the cytochrome P450 (CYP450) enzyme and conjugation by UGT enzymes. There is controversy as to whether codeine, dihydrocodeine, and hydrocodone are actually prodrugs requiring activation by the CYP450 2D6 enzyme or UGT enzymes. Oxycodone and buprenorphine, however, are clearly not prodrugs and are metabolized by the CYP450 2D6 and 3A4 enzymes, respectively. Knowledge of this metabolism assists in the understanding for the potential of drug-drug interactions with these drugs. This understanding is important so that clinicians can choose the proper dosages for analgesia and anticipate potential drug-drug interactions.

Tumour-associated macrophages act as a slow-release reservoir of nano-therapeutic Pt(IV) pro-drug

PubMed Central

Miller, Miles A.; Zheng, Yao-Rong; Gadde, Suresh; Pfirschke, Christina; Zope, Harshal; Engblom, Camilla; Kohler, Rainer H.; Iwamoto, Yoshiko; Yang, Katherine S.; Askevold, Bjorn; Kolishetti, Nagesh; Pittet, Mikael; Lippard, Stephen J.; Farokhzad, Omid C.; Weissleder, Ralph

2015-01-01

Therapeutic nanoparticles (TNPs) aim to deliver drugs more safely and effectively to cancers, yet clinical results have been unpredictable owing to limited in vivo understanding. Here we use single-cell imaging of intratumoral TNP pharmacokinetics and pharmacodynamics to better comprehend their heterogeneous behaviour. Model TNPs comprising a fluorescent platinum(IV) pro-drug and a clinically tested polymer platform (PLGA-b-PEG) promote long drug circulation and alter accumulation by directing cellular uptake toward tumour-associated macrophages (TAMs). Simultaneous imaging of TNP vehicle, its drug payload and single-cell DNA damage response reveals that TAMs serve as a local drug depot that accumulates significant vehicle from which DNA-damaging Pt payload gradually releases to neighbouring tumour cells. Correspondingly, TAM depletion reduces intratumoral TNP accumulation and efficacy. Thus, nanotherapeutics co-opt TAMs for drug delivery, which has implications for TNP design and for selecting patients into trials. PMID:26503691

Conformational analysis of the anti-HIV Nikavir prodrug: comparisons with AZT and Thymidine, and establishment of structure-activity relationships/tendencies in other 6'-derivatives.

PubMed

El-Sayed, Ahmed A; Tamara Molina, A; Álvarez-Ros, M C; Alcolea Palafox, M

2015-01-01

A comprehensive theoretical conformational analysis of the anti-HIV Nikavir prodrug was carried out; this prodrug has noticeable advantage over the approved drug AZT. The whole conformational parameters (χ, α, β, γ, δ, ϕ, P and νmax) were analysed as well as the NBO natural atomic charges. The calculations were carried out by means of DFT/B3LYP and ab initio MP2 methods with full relaxation of all geometrical parameters. The search located at least 67 stable structures, 4 of which were within a 1 kcal/mol electronic energy range of the global minimum. By MP2 it corresponds to the calculated values of the exocyclic torsional angles χ=-108.0°, β=14.5°, γ=76.7° and ε=71.5°. The results obtained are in accordance to those found in related anti-HIV nucleoside analogues. Comparisons of the conformers with those determined in the common anti-HIV drug AZT were carried out. A detailed analysis of the lowest vibrations (<200 cm(-1)) in the best conformer of Nikavir was carried out. The most stable hydrated cluster of this conformer with 20 explicit water molecules was determined. Calculations in five of its 6'-derivatives were performed to identify structural trends that might correlate with the anti-HIV activity of these compounds. Ten structure-activity relationships/tendencies were established that can help for the design of new drugs. Several recommendations for this design were expressed.

In vitro and in vivo evaluation of the metabolism and pharmacokinetics of sebacoyl dinalbuphine.

PubMed

Pao, Li-Heng; Hsiong, Cheng-Huei; Hu, Oliver Yoa-Pu; Wang, Jhi-Jung; Ho, Shung-Tai

2005-03-01

A diester prodrug of nalbuphine, sebacoyl dinalbuphine (SDN), and its long-acting formulation are currently being developed to prolong the duration of nalbuphine. A comparative in vitro hydrolysis study was conducted for SDN in rat, rabbit, dog, and human blood. Both SDN and nalbuphine in blood or plasma were measured by high-performance liquid chromatography. The hydrolysis rates of SDN in blood were ranked as follows: rat > rabbit > human > dog. The rapid formation of nalbuphine in the blood accounted for almost 100% of the prodrug, which supported the contention that nalbuphine is the major metabolite after SDN hydrolysis. The hydrolysis profiles of SDN were similar both in plasma and in red blood cells when compared in the blood. In vitro release results of SDN long-acting formulation showed that the rate-limited step of SDN hydrolysis to nalbuphine in blood is the penetration of SDN from oil into the blood. After intravenous administration of SDN in sesame oil into rats, nalbuphine quickly appeared in plasma and, thereafter, exhibited monoexponential decay. Pharmaceutical dosage forms affecting the drug disposition kinetics were demonstrated after intravenous administration. The AUC of nalbuphine was significantly higher and clearance was significantly lower, without changes in the t(1/2) of nalbuphine after intravenous dosing of SDN in sesame oil when compared with that of intravenous dosing with nalbuphine HCl in rats. Overall, these results suggest that SDN fulfilled the original pro-soft drug design in which the prodrug can rapidly metabolize to nalbuphine, and no other unexpected compounds were apparent in the blood.

Hydrolyzable Poly[Poly(Ethylene Glycol) Methyl Ether Acrylate]-Colistin Prodrugs through Copper-Mediated Photoinduced Living Radical Polymerization.

PubMed

Zhu, Chongyu; Schneider, Elena K; Nikolaou, Vasiliki; Klein, Tobias; Li, Jian; Davis, Thomas P; Whittaker, Michael R; Wilson, Paul; Kempe, Kristian; Velkov, Tony; Haddleton, David M

2017-07-19

Through the recently developed copper-mediated photoinduced living radical polymerization (CP-LRP), a novel and well-defined polymeric prodrug of the antimicrobial lipopeptide colistin has been developed. A colistin initiator (Boc 5 -col-Br 2 ) was synthesized through the modification of colistin on both of its threonine residues using a cleavable initiator linker, 2-(2-bromo-2-methylpropanoyloxy) acetic acid (BMPAA), and used for the polymerization of acrylates via CP-LRP. Polymerization proceeds from both sites of the colistin initiator, and through the polymerization of poly(ethylene glycol) methyl ether acrylate (PEGA 480 ), three water-soluble polymer-colistin conjugates (col-PPEGA, having degrees of polymerization of 5, 10, and 20) were achieved with high yield (conversion of ≥93%) and narrow dispersities (Đ < 1.3) in 2-4 h. Little or no effect on the structure and activity of the colistin was observed during the synthesis, and most of the active colistin can be recovered from the conjugates in vitro within 2 days. Furthermore, in vitro biological analyses including disk diffusion, broth microdilution, and time-kill studies suggested that all of the conjugates have the ability to inhibit the growth of multidrug-resistant (MDR) Gram-negative bacteria, of which col-PPEGA DP5 and DP10 showed similar or better antibacterial performance compared to the clinically relevant colistin prodrug CMS, indicating their potential as an alternative antimicrobial therapy. Moreover, considering the control over the polymerization, the CP-LRP technique has the potential to provide an alternative platform for the development of polymer bioconjugates.

Intramuscular administration of paliperidone palmitate extended-release injectable microsuspension induces a subclinical inflammatory reaction modulating the pharmacokinetics in rats.

PubMed

Darville, Nicolas; van Heerden, Marjolein; Vynckier, An; De Meulder, Marc; Sterkens, Patrick; Annaert, Pieter; Van den Mooter, Guy

2014-07-01

The present study aims at elucidating the intricate nature of the drug release and absorption following intramuscular (i.m.) injection of sustained-release prodrug nanocrystals/microcrystals. A paliperidone palmitate (PPP) long-acting suspension was characterized with regard to particle size (Dv,50 = 1.09 μm) and morphology prior to i.m. injection in rats. The local disposition was rigorously investigated by means of (immuno)histochemistry and transmission electron microscopy while the concurrent multiphasic pharmacokinetics was linked to the microanatomy. A transient (24 h) trauma-induced inflammation promptly evolved into a subclinical but chronic granulomatous inflammatory reaction initiated by the presence of solid material. The dense inflammatory envelope (CD68(+) macrophages) led to particle agglomeration with subsequent drop in dissolution rate beyond 24 h postinjection. This was associated with a decrease in apparent paliperidone (PP) absorption (near-zero order) until 96 h and a delayed time of occurrence of observed maximum drug plasma concentration (168 h). The infiltrating macrophages phagocytosed large fractions of the depot, thereby influencing the (pro)drug release. Radial angiogenesis (CD31(+)) was observed throughout the inflammatory rim from 72 h onwards and presumably contributed to the sustained systemic PP concentrations by maintaining a sufficient absorptive capacity. No solid-state transitions of the retrieved formulation were recorded with X-ray diffraction analysis. In summary, the initial formulation-driven prodrug (PPP) dissolution and drug (PP) absorption were followed by a complex phase determined by the relative contribution of formulation factors and dynamic physiological variables. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Human transport protein carrier for controlled photoactivation of antitumor prodrug and real-time intracellular tumor imaging.

PubMed

Li, Xi; Mu, Jing; Liu, Fang; Tan, Eddy Wei Ping; Khezri, Bahareh; Webster, Richard D; Yeow, Edwin Kok Lee; Xing, Bengang

2015-05-20

Current anticancer chemotherapy often suffers from poor tumor selectivity and serious drug resistance. Proper vectors for targeted delivery and controlled drug release play crucial roles in improving the therapeutic selectivity to tumor areas and also overcoming the resistance of cancer cells. In this work, we developed a novel human serum albumin (HSA) protein-based nanocarrier system, which combines the photoactivatable Pt(IV) antitumor prodrug for realizing the controlled release and fluorescent light-up probe for evaluations of drug action and efficacy. The constructed Pt(IV)-probe@HSA platform can be locally activated by light irradiation to release the active Pt species, which results in enhanced cell death at both drug-sensitive A2780 and cisplatin-resistant A2780cis cell lines when compared to the free prodrug molecules. Simultaneously, the cytotoxicity caused by light controlled drug release would further lead to the cellular apoptosis and trigger the activation of caspases 3, one crucial protease enzyme in apoptotic process, which could cleave the recognition peptide moiety (DEVD) with a flanking fluorescent resonance energy transfer (FRET) pair containing near-infrared (NIR) fluorophore Cy5 and quencher Qsy21 on the HSA nanocarrier surface. The turn-on fluorescence in response to caspase-3 could be assessed by fluorescence microscopy and flow cytometry analysis. Our results supported the hypothesis that such a unique design may present a successful platform for multiple roles: (i) a biocompatible protein-based nanocarrier for drug delivery, (ii) the controlled drug release with strengthened therapeutic effects, (iii) real-time monitoring of antitumor drug efficacy at the earlier stage.

Hypoxia-Activated Prodrug TH-302 Targets Hypoxic Bone Marrow Niches in Preclinical Leukemia Models.

PubMed

Benito, Juliana; Ramirez, Marc S; Millward, Niki Zacharias; Velez, Juliana; Harutyunyan, Karine G; Lu, Hongbo; Shi, Yue-Xi; Matre, Polina; Jacamo, Rodrigo; Ma, Helen; Konoplev, Sergej; McQueen, Teresa; Volgin, Andrei; Protopopova, Marina; Mu, Hong; Lee, Jaehyuk; Bhattacharya, Pratip K; Marszalek, Joseph R; Davis, R Eric; Bankson, James A; Cortes, Jorge E; Hart, Charles P; Andreeff, Michael; Konopleva, Marina

2016-04-01

To characterize the prevalence of hypoxia in the leukemic bone marrow, its association with metabolic and transcriptional changes in the leukemic blasts and the utility of hypoxia-activated prodrug TH-302 in leukemia models. Hyperpolarized magnetic resonance spectroscopy was utilized to interrogate the pyruvate metabolism of the bone marrow in the murine acute myeloid leukemia (AML) model. Nanostring technology was used to evaluate a gene set defining a hypoxia signature in leukemic blasts and normal donors. The efficacy of the hypoxia-activated prodrug TH-302 was examined in the in vitro and in vivo leukemia models. Metabolic imaging has demonstrated increased glycolysis in the femur of leukemic mice compared with healthy control mice, suggesting metabolic reprogramming of hypoxic bone marrow niches. Primary leukemic blasts in samples from AML patients overexpressed genes defining a "hypoxia index" compared with samples from normal donors. TH-302 depleted hypoxic cells, prolonged survival of xenograft leukemia models, and reduced the leukemia stem cell pool in vivo In the aggressive FLT3/ITD MOLM-13 model, combination of TH-302 with tyrosine kinase inhibitor sorafenib had greater antileukemia effects than either drug alone. Importantly, residual leukemic bone marrow cells in a syngeneic AML model remain hypoxic after chemotherapy. In turn, administration of TH-302 following chemotherapy treatment to mice with residual disease prolonged survival, suggesting that this approach may be suitable for eliminating chemotherapy-resistant leukemia cells. These findings implicate a pathogenic role of hypoxia in leukemia maintenance and chemoresistance and demonstrate the feasibility of targeting hypoxic cells by hypoxia cytotoxins. ©2015 American Association for Cancer Research.

Combination of a fusogenic glycoprotein, prodrug activation, and oncolytic herpes simplex virus for enhanced local tumor control.

PubMed

Simpson, Guy R; Han, Ziqun; Liu, Binlei; Wang, Yibing; Campbell, Gregor; Coffin, Robert S

2006-05-01

We have previously developed an oncolytic herpes simplex virus-1 based on a clinical virus isolate, which was deleted for ICP34.5 to provide tumor selected replication and ICP47 to increase antigen presentation as well as tumor selective virus replication. A phase I/II clinical trial using a version of this virus expressing granulocyte macrophage colony-stimulating factor has shown promising results. The work reported here aimed to develop a version of this virus in which local tumor control was further increased through the combined expression of a highly potent prodrug activating gene [yeast cytosine deaminase/uracil phospho-ribosyltransferase fusion (Fcy::Fur)] and the fusogenic glycoprotein from gibbon ape leukemia virus (GALV), which it was hoped would aid the spread of the activated prodrug through the tumor. Viruses expressing the two genes individually or in combination were constructed and tested, showing (a) GALV and/or Fcy::Fur expression did not affect virus growth; (b) GALV expression causes cell fusion and increases the tumor cell killing at least 30-fold in vitro and tumor shrinkage 5- to 10-fold in vivo; (c) additional expression of Fcy::Fur combined with 5-fluorocytosine administration improves tumor shrinkage further. These results indicate, therefore, that the combined expression of the GALV protein and Fcy::Fur provides a highly potent oncolytic virus with improved capabilities for local tumor control. It is intended to enter the GALV/Fcy::Fur expressing virus into clinical development for the treatment of tumor types, such as pancreatic or lung cancer, where local control would be anticipated to be clinically advantageous.

Sulfur mustard induced mast cell degranulation in mouse skin is inhibited by a novel anti-inflammatory and anticholinergic bifunctional prodrug.

PubMed

Joseph, Laurie B; Composto, Gabriella M; Perez, Roberto M; Kim, Hong-Duck; Casillas, Robert P; Heindel, Ned D; Young, Sherri C; Lacey, Carl J; Saxena, Jaya; Guillon, Christophe D; Croutch, Claire R; Laskin, Jeffrey D; Heck, Diane E

2018-09-01

Sulfur mustard (SM, bis(2-chloroethyl sulfide) is a potent vesicating agent known to cause skin inflammation, necrosis and blistering. Evidence suggests that inflammatory cells and mediators that they generate are important in the pathogenic responses to SM. In the present studies we investigated the role of mast cells in SM-induced skin injury using a murine vapor cup exposure model. Mast cells, identified by toluidine blue staining, were localized in the dermis, adjacent to dermal appendages and at the dermal/epidermal junction. In control mice, 48-61% of mast cells were degranulated. SM exposure (1.4g/m 3 in air for 6min) resulted in increased numbers of degranulated mast cells 1-14days post-exposure. Treatment of mice topically with an indomethacin choline bioisostere containing prodrug linked by an aromatic ester-carbonate that targets cyclooxygenases (COX) enzymes and acetylcholinesterase (1% in an ointment) 1-14days after SM reduced skin inflammation and injury and enhanced tissue repair. This was associated with a decrease in mast cell degranulation from 90% to 49% 1-3days post SM, and from 84% to 44% 7-14days post SM. These data suggest that reduced inflammation and injury in response to the bifunctional indomethacin prodrug may be due, at least in part, to abrogating mast cell degranulation. The use of inhibitors of mast cell degranulation may be an effective strategy for mitigating skin injury induced by SM. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a Δ9-Tetrahydrocannabinol Amino Acid-Dicarboxylate Prodrug With Improved Ocular Bioavailability

PubMed Central

Adelli, Goutham R.; Bhagav, Prakash; Taskar, Pranjal; Hingorani, Tushar; Pettaway, Sara; Gul, Waseem; ElSohly, Mahmoud A.; Repka, Michael A.; Majumdar, Soumyajit

2017-01-01

Purpose The aim of the present study was to evaluate the utility of the relatively hydrophilic Δ9-tetrahydrocannabinol (THC) prodrugs, mono and di-valine esters (THC-Val and THC-Val-Val) and the amino acid (valine)-dicarboxylic acid (hemisuccinate) ester (THC-Val-HS), with respect to ocular penetration and intraocular pressure (IOP) lowering activity. THC, timolol, and pilocarpine eye drops were used as controls. Methods THC-Val, THC-Val-Val, and THC-Val-HS were synthesized and chemically characterized. Aqueous solubility and in vitro transcorneal permeability of THC and the prodrugs, in the presence of various surfactants and cyclodextrins, were determined. Two formulations were evaluated for therapeutic activity in the α-chymotrypsin induced rabbit glaucoma model, and the results were compared against controls comprising of THC emulsion and marketed timolol maleate and pilocarpine eye drops. Results THC-Val-HS demonstrated markedly improved solubility (96-fold) and in vitro permeability compared to THC. Selected formulations containing THC-Val-HS effectively delivered THC to the anterior segment ocular tissues in the anesthetized rabbits: 62.1 ng/100 μL of aqueous humor (AH) and 51.4 ng/50 mg of iris ciliary bodies (IC) (total THC). The duration and extent of IOP lowering induced by THC-Val-HS was 1 hour longer and 10% greater, respectively, than that obtained with THC and was comparable with the pilocarpine eye drops. Timolol ophthalmic drops, however, exhibited a longer duration of activity. Both THC and THC-Val-HS were detected in the ocular tissues following multiple dosing of THC-Val-HS in conscious animals. The concentration of THC in the iris-ciliary bodies at the 60- and 120-minute time points (53 and 57.4 ng/50 mg) were significantly greater than that of THC-Val-HS (24.2 and 11.3 ng/50 mg). Moreover, at the two time points studied, the concentration of THC was observed to increase or stay relatively constant, whereas THC-Val-HS concentration decreased by at least 50%. A similar trend was observed in the retina-choroid tissues. Conclusions A combination of prodrug derivatization and formulation development approaches significantly improved the penetration of THC into the anterior segment of the eye following topical application. Enhanced ocular penetration resulted in significantly improved IOP-lowering activity. PMID:28399267

Mesoporous silica coatings for cephalosporin active release at the bone-implant interface

NASA Astrophysics Data System (ADS)

Rădulescu, Dragoş; Voicu, Georgeta; Oprea, Alexandra Elena; Andronescu, Ecaterina; Grumezescu, Valentina; Holban, Alina Maria; Vasile, Bogdan Stefan; Surdu, Adrian Vasile; Grumezescu, Alexandru Mihai; Socol, Gabriel; Mogoantă, Laurenţiu; Mogoşanu, George Dan; Balaure, Paul Cătălin; Rădulescu, Radu; Chifiriuc, Mariana Carmen

2016-06-01

In this study, we investigated the potential of MAPLE-deposited coatings mesoporous silica nanoparticles (MSNs) to release Zinforo (ceftarolinum fosmil) in biologically active form. The MSNs were prepared by using a classic procedure with cetyltrimethylammonium bromide as sacrificial template and tetraethylorthosilicate as the monomer. The Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM) analyses revealed network-forming granules with diameters under 100 nm and an average pore diameter of 2.33 nm. The deposited films were characterized by SEM, TEM, XRD and IR. Microbiological analyses performed on ceftaroline-loaded films demonstrated that the antibiotic was released in an active form, decreasing the microbial adherence rate and colonization of the surface. Moreover, the in vitro and in vivo assays proved the excellent biodistribution and biocompatibility of the prepared systems. Our results suggest that the obtained bioactive coatings possess a significant potential for the design of drug delivery systems and antibacterial medical-use surfaces, with great applications in bone implantology.

The antibiotic pipeline for multi-drug resistant gram negative bacteria: what can we expect?

PubMed

Falagas, Matthew E; Mavroudis, Andreas D; Vardakas, Konstantinos Z

2016-08-01

A real concern in the medical community is the increasing resistance of bacteria, especially that of Gram-negative types. New antibiotics are currently under clinical development, promising to tackle severe infections caused, especially, by multi-drug resistant (MDR) bacteria and broaden the armamentarium of clinicians. We searched PUBMED and GOOGLE databases. Combinations of already approved β-lactams or monobactams with new β-lactamase inhibitors [imipenem-cilastatin/MK-7655 (relebactam), meropenem/RPX7009 (vaborbactam), ceftaroline/avibactam, aztreonam/avibactam], new β-lactams (S-649266, BAL30072), aminoglycosides (plazomicin), quinolones (finafloxacin) and tetracyclines (eravacycline) were included in the review. Expert commentary: For the majority of the upcoming antibiotics the currently available data is limited to their microbiology and pharmacokinetics. Their effectiveness and safety against infections due to MDR bacteria remain to be proved. Significant issues are also the impact of these antibiotics on the human intestinal microbiota and their possible co-administration with already-known antimicrobial agents in difficult-to-treat-infections; further studies should be conducted for these objectives.

Product development studies of amino acid conjugate of Aceclofenac.

PubMed

Singh, Ajay Pal; Ramadan, Wafa Mossa; Dahiya, Rajiv; Sarpal, A S; Pathak, Kamla

2009-04-01

The prodrugs designed by classical approach increase lipophilicity of the drug, which decreases the water solubility thus decreasing the concentration gradient, which controls drug absorption. To overcome the limitations of traditional prodrug approach, water soluble prodrugs can be designed by adding selected amino acid to the drug moiety that are the substrates for the enzyme located at the intestinal brush border thus overcoming pharmaceutical problem without compromising bioavailability. ACaa (Amino acid conjugate of Aceclofenac) was synthesized by conjugation with l-phenylalanine by conventional coupling method using N, N-dicyclohexylcarbodiimide and ACaa was characterized by melting point, TLC, photomicrograph, UV, FT-IR, FT-NMR, MS-FAB, XRD and DSC. As a part of product development study ACaa was subjected to studies like In-vivo in albino rats and in-vitro like ACaa reversion to AC (Aceclofenac) in aqueous buffers of pH 1.21, 2.38. 3.10, 6.22 and 7.41, at a constant concentration (0.05M), ionic strength (micro = 0.5) and at a temperature of 37 degrees C +/- 0.5 degrees C, ACaa showed negligible reversion (2.15 %) up to 24 hrs study at acidic pH thus suggesting stability in acidic environment of stomach, the rate of reversion increased as pH of medium increased. pH- partition profile, pH- solubility profile and micromeritic studies were also carried out in comparison to pure drug. The solubility and lipophilicity of ACaa exhibited higher values at all pH range when compared to AC. The micromeritic properties also evaluated in terms of particle shape and size, IQCS and kurtosis. Resulting IQCS value approached zero thus suggesting reducing in the degree of skewness.

Identification and characterization of N-tert-butoxycarbonyl-MDMA: a new MDMA precursor.

PubMed

Collins, Michael; Donnelly, Christopher; Cameron, Shane; Tahtouh, Mark; Salouros, Helen

2017-03-01

In September 2015, 80 litres of a viscous, light-red liquid, described as hair product, was seized by the Australian Border Force (ABF). Initial testing by ABF indicated that the liquid was the 3,4-methylenedioxymethamphetamine (MDMA) precursor chemical safrole and custody of the material was transferred to the Australian Federal Police (AFP) who coordinated all subsequent investigations. Initial gas chromatography-mass spectrometry (GC-MS) analysis by the AFP indicated that the material was not safrole and samples of the liquid were transferred to the National Measurement Institute Australia (NMIA) for identification. Using a combination of nuclear magnetic resonance spectroscopy (NMR), GC-MS, infrared spectroscopy, and synthesis, the unknown substance was identified as N-tert.-butoxycarbonyl-MDMA (t-BOC-MDMA). The substance was also converted in high yield to MDMA (aqueous HCl, 80 °C, 30 min). The possibility that the t-BOC-MDMA may act as a pro-drug following ingestion was explored by exposure to simulated gastric juice (pH 1.5) and monitored by NMR (37 °C) at various intervals. The majority of t-BOC-MDMA was converted to MDMA after 305 min, which suggested that this derivatized form might serve as a pro-drug in vivo. An investigation into the chemistry of potential pro-drugs showed that t-BOC derivatives of methamphetamine, pseudoephedrine and 4-methylmethcahtinone (mephedrone) could also be prepared using di-tert.-butyl dicarbonate. The appearance of t-BOC-derivatives on the drug market requires further monitoring. © 2016 Commonwealth of Australia. Drug Testing and Analysis © 2016 John Wiley & Sons, Ltd. © 2016 Commonwealth of Australia. Drug Testing and Analysis © 2016 John Wiley & Sons, Ltd.

Selective tissue factor/factor VIIa Inhibitor, ER-410660, and its prodrug, E5539, have anti-venous and anti-arterial thrombotic effects with a low risk of bleeding.

PubMed

Nagakura, Tadashi; Tabata, Kimiyo; Kira, Kazunobu; Hirota, Shinsuke; Clark, Richard; Matsuura, Fumiyoshi; Hiyoshi, Hironobu

2013-08-01

Many anticoagulant drugs target factors common to both the intrinsic and extrinsic coagulation pathways, which may lead to bleeding complications. Since the tissue factor (TF)/factor VIIa complex is associated with thrombosis onset and specifically activates the extrinsic coagulation pathway, compounds that inhibit this complex may provide therapeutic and/or prophylactic benefits with a decreased risk of bleeding. The in vitro enzyme profile and anticoagulation selectivity of the TF/VIIa complex inhibitor, ER-410660, and its prodrug E5539 were assessed using enzyme inhibitory and plasma clotting assays. In vivo effects of ER-410660 and E5539 were determined using a TF-induced, thrombin generation rhesus monkey model; a stasis-induced, venous thrombosis rat model; a photochemically induced, arterial thrombosis rat model; and a rat tail-cut bleeding model. ER-410660 selectively prolonged prothrombin time, but had a less potent anticoagulant effect on the intrinsic pathway. It also exhibited a dose-dependent inhibitory effect on thrombin generation caused by TF-injection in the rhesus monkey model. ER-410660 also reduced venous thrombus weights in the TF-administered, stasis-induced, venous thrombosis rat model and prolonged the occlusion time induced by arterial thrombus formation after vascular injury. The compound was capable of doubling the total bleeding time in the rat tail-cut model, albeit with a considerably higher dose compared to the effective dose in the venous and arterial thrombosis models. Moreover, E5539, an orally available ER-410660 prodrug, reduced the thrombin-anti-thrombin complex levels, induced by TF-injection, in a dose-dependent manner. Selective TF/VIIa inhibitors have potential as novel anticoagulants with a lower propensity for enhancing bleeding. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biological and Mechanistic Characterization of Novel Prodrugs of Green Tea Polyphenol Epigallocatechin Gallate Analogs in Human Leiomyoma Cell Lines.

PubMed

Ahmed, Reda Saber Ibrahim; Liu, Gang; Renzetti, Andrea; Farshi, Pershang; Yang, Huanjie; Soave, Claire; Saed, Ghassan; El-Ghoneimy, Ashraf Ahmed; El-Banna, Hossny Awad; Foldes, Robert; Chan, Tak-Hang; Dou, Q Ping

2016-10-01

Uterine fibroids (leiomyomas) are very common benign tumors grown on the smooth muscle layer of the uterus, present in up to 75% of reproductive-age women and causing significant morbidity in a subset of this population. Although the etiology and biology of uterine fibroids are unclear, strong evidence supports that cell proliferation, angiogenesis and fibrosis are involved in their formation and growth. Currently the only cure for uterine fibroids is hysterectomy; the available alternative therapies have limitations. Thus, there is an urgent need for developing a novel strategy for treating this condition. The green tea polyphenol epigallocatechin gallate (EGCG) inhibits the growth of uterine leiomyoma cells in vitro and in vivo, and the use of a green tea extract (containing 45% EGCG) has demonstrated clinical activity without side effects in women with symptomatic uterine fibroids. However, EGCG has a number of shortcomings, including low stability, poor bioavailability, and high metabolic transformations under physiological conditions, presenting challenges for its development as a therapeutic agent. We developed a prodrug of EGCG (Pro-EGCG or 1) which shows increased stability, bioavailability and biological activity in vivo as compared to EGCG. We also synthesized prodrugs of EGCG analogs, compounds 2a and 4a, in order to potentially reduce their susceptibility to methylation/inhibition by catechol-O-methyltransferase. Here, we determined the effect of EGCG, Pro-EGCG, and 2a and 4a on cultured human uterine leiomyoma cells, and found that 2a and 4a have potent antiproliferative, antiangiogenic, and antifibrotic activities. J. Cell. Biochem. 117: 2357-2369, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Enhanced Intratumoral Delivery of SN38 as a Tocopherol Oxyacetate Prodrug Using Nanoparticles in a Neuroblastoma Xenograft Model.

PubMed

Nguyen, Ferro; Alferiev, Ivan; Guan, Peng; Guerrero, David T; Kolla, Venkatadri; Moorthy, Ganesh S; Chorny, Michael; Brodeur, Garrett M

2018-06-01

Purpose: Currently, <50% of high-risk pediatric solid tumors like neuroblastoma can be cured, and many survivors experience serious or life-threatening toxicities, so more effective, less toxic therapy is needed. One approach is to target drugs to tumors using nanoparticles, which take advantage of the enhanced permeability of tumor vasculature. Experimental Design: SN38, the active metabolite of irinotecan (CPT-11), is a potent therapeutic agent that is readily encapsulated in polymeric nanoparticles. Tocopherol oxyacetate (TOA) is a hydrophobic mitocan that was linked to SN38 to significantly increase hydrophobicity and enhance nanoparticle retention. We treated neuroblastomas with SN38-TOA nanoparticles and compared the efficacy with the parent prodrug CPT-11 using a mouse xenograft model. Results: Nanoparticle treatment induced prolonged event-free survival (EFS) in most mice, compared with CPT-11. This was shown for both SH-SY5Y and IMR-32 neuroblastoma xenografts. Enhanced efficacy was likely due to increased and sustained drug levels of SN38 in the tumor compared with conventional CPT-11 delivery. Interestingly, when recurrent CPT-11-treated tumors were re-treated with SN38-TOA nanoparticles, the tumors transformed from undifferentiated neuroblastomas to maturing ganglioneuroblastomas. Furthermore, these tumors were infiltrated with Schwann cells of mouse origin, which may have contributed to the differentiated histology. Conclusions: Nanoparticle delivery of SN38-TOA produced increased drug delivery and prolonged EFS compared to conventional delivery of CPT-11. Also, lower total dose and drug entrapment in nanoparticles during circulation should decrease toxicity. We propose that nanoparticle-based delivery of a rationally designed prodrug is an attractive approach to enhance chemotherapeutic efficacy in pediatric and adult tumors. Clin Cancer Res; 24(11); 2585-93. ©2018 AACR . ©2018 American Association for Cancer Research.

Application of homology modeling to generate CYP1A1 mutants with enhanced activation of the cancer chemotherapeutic prodrug dacarbazine.

PubMed

Lewis, Benjamin C; Mackenzie, Peter I; Miners, John O

2011-11-01

The chemotherapeutic prodrug dacarbazine (DTIC) has limited efficacy in human malignancies and exhibits numerous adverse effects that arise from systemic exposure to the cytotoxic metabolite. DTIC is activated by CYP1A1 and CYP1A2 catalyzed N-demethylation. However, structural features of these enzymes that confer DTIC N-demethylation have not been characterized. A validated homology model of CYP1A1 was employed to elucidate structure-activity relationships and to engineer CYP1A1 enzymes with altered DTIC activation. In silico docking demonstrated that DTIC orientates proximally to Ser122, Phe123, Asp313, Ala317, Ile386, Tyr259, and Leu496 of human CYP1A1. The site of metabolism is positioned 5.6 Å from the heme iron at an angle of 105.3°. Binding in the active site is stabilized by H-bonding between Tyr259 and the N(2) position of the imidazole ring. Twenty-seven CYP1A1 mutants were generated and expressed in Escherichia coli in yields ranging from 9 to 225 pmol P450/mg. DTIC N-demethylation by the E161K, E256K, and I458V mutants exhibited Michaelis-Menten kinetics, with decreases in K(m) (183-249 μM) that doubled the catalytic efficiency (p < 0.05) relative to wild-type CYP1A1 (K(m), 408 ± 43 μM; V(max), 28 ± 4 pmol · min(-1) · pmol of P450(-1)). The generation of enzymes with catalytically enhanced DTIC activation highlights the potential use of mutant CYP1A1 proteins in P450-based gene-directed enzyme prodrug therapy for the treatment of metastatic malignant melanoma.

Sulforaphane Preconditioning Sensitizes Human Colon Cancer Cells towards the Bioreductive Anticancer Prodrug PR-104A.

PubMed

Erzinger, Melanie M; Bovet, Cédric; Hecht, Katrin M; Senger, Sabine; Winiker, Pascale; Sobotzki, Nadine; Cristea, Simona; Beerenwinkel, Niko; Shay, Jerry W; Marra, Giancarlo; Wollscheid, Bernd; Sturla, Shana J

2016-01-01

The chemoprotective properties of sulforaphane (SF), derived from cruciferous vegetables, are widely acknowledged to arise from its potent induction of xenobiotic-metabolizing and antioxidant enzymes. However, much less is known about the impact of SF on the efficacy of cancer therapy through the modulation of drug-metabolizing enzymes. To identify proteins modulated by a low concentration of SF, we treated HT29 colon cancer cells with 2.5 μM SF. Protein abundance changes were detected by stable isotope labeling of amino acids in cell culture. Among 18 proteins found to be significantly up-regulated, aldo-keto reductase 1C3 (AKR1C3), bioactivating the DNA cross-linking prodrug PR-104A, was further characterized. Preconditioning HT29 cells with SF reduced the EC50 of PR-104A 3.6-fold. The increase in PR-104A cytotoxicity was linked to AKR1C3 abundance and activity, both induced by SF in a dose-dependent manner. This effect was reproducible in a second colon cancer cell line, SW620, but not in other colon cancer cell lines where AKR1C3 abundance and activity were absent or barely detectable and could not be induced by SF. Interestingly, SF had no significant influence on PR-104A cytotoxicity in non-cancerous, immortalized human colonic epithelial cell lines expressing either low or high levels of AKR1C3. In conclusion, the enhanced response of PR-104A after preconditioning with SF was apparent only in cancer cells provided that AKR1C3 is expressed, while its expression in non-cancerous cells did not elicit such a response. Therefore, a subset of cancers may be susceptible to combined food-derived component and prodrug treatments with no harm to normal tissues.

Selective and augmented β-glucuronidase expression combined with DOX-GA3 application elicits the potent suppression of prostate cancer.

PubMed

Wang, Longxin; Dong, Jie; Wei, Ming; Wen, Weihong; Gao, Jianping; Zhang, Zhengyu; Qin, Weijun

2016-03-01

The present study was carried out to evaluate the specific and amplified β-glucuronidase (βG) expression in prostate cancer cells by using a prostate‑specific antigen (PSA) promoter-controlled bicistronic adenovirus and to evaluate the specific killing of prostate cancer cells after the application of the prodrug DOX‑GA3. Bicistronic adenoviral expression vectors were constructed, and the effectiveness of specific and amplified expression was evaluated using luciferase and EGFP as reporter genes. βG expression was detected in LNCaP cells after they were infected with the βG‑expressing PSA promoter-controlled bicistronic adenovirus. MTT assays were conducted to evaluate the cytoxicity on the infected cells after the application of the prodrug DOX‑GA3. Tumor growth inhibition was also evaluated in nude mice after treatment with the βG‑expressing adenovirus and DOX‑GA3. Selective and amplified expression was observed in the PSA-producing LNCaP cells, but not in the PSA‑non‑producing DU145 cells. Potent cytotoxity and a strong bystander effect were observed in the LNCaP cells after infection with the βG‑expressing adenovirus and the application of DOX‑GA3. Intravenous injection of a GAL4 regulated bicistronic adenovirus vector constructed to express βG under the control of the PSA promoter (Ad/PSAP‑GV16‑βG) and the application of DOX‑GA3 strongly inhibited tumor growth and prolonged the survival time of tumor‑bearing nude mice. Selective and amplified βG expression together with the prodrug DOX‑GA3 had an increased antitumor effect, showing great potential for prostate cancer therapy.

The bumetanide prodrug BUM5, but not bumetanide, potentiates the antiseizure effect of phenobarbital in adult epileptic mice.

PubMed

Erker, Thomas; Brandt, Claudia; Töllner, Kathrin; Schreppel, Philipp; Twele, Friederike; Schidlitzki, Alina; Löscher, Wolfgang

2016-05-01

The loop diuretic bumetanide has been reported to potentiate the antiseizure activity of phenobarbital in rodent models of neonatal seizures, most likely as a result of inhibition of the chloride importer Na-K-Cl cotransporter isoform 1 (NKCC1) in the brain. In view of the intractability of neonatal seizures, the preclinical findings prompted a clinical trial in neonates on bumetanide as an add-on to phenobarbital, which, however, had to be terminated because of ototoxicity and lack of efficacy. We have recently shown that bumetanide penetrates only poorly into the brain, so that we developed lipophilic prodrugs such as BUM5, the N,N-dimethylaminoethylester of bumetanide, which penetrate more easily into the brain and are converted to bumetanide. In the present study, we used a new strategy to test whether BUM5 is more potent than bumetanide in potentiating the antiseizure effect of phenobarbital. Adult mice were made epileptic by pilocarpine, and the antiseizure effects of bumetanide, BUM5, and phenobarbital alone or in combination were determined by the maximal electroshock seizure threshold test. In nonepileptic mice, only phenobarbital exerted seizure threshold-increasing activity, and this was not potentiated by the NKCC1 inhibitors. In contrast, a marked potentiation of phenobarbital by BUM5, but not bumetanide, was determined in epileptic mice. Thus, bumetanide is not capable of potentiating phenobarbital's antiseizure effect in an adult mouse model, which, however, can be overcome by using the prodrug BUM5. These data substantiate that BUM5 is a promising tool compound for target validation and proof-of-concept studies on the role of NKCC1 in brain diseases. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

Lysosome-oriented, dual-stage pH-responsive polymeric micelles for β-Lapachone delivery.

PubMed

Zhou, Yinjian; Dong, Ying; Huang, Gang; Wang, Yiguang; Huang, Xiaonan; Zhang, Fayun; Boothman, David A; Gao, Jinming; Liang, Wei

2016-12-14

β-Lapachone (β-lap), a novel anticancer agent, is bioactivated by NADP(H):quinone oxidoreductase 1 (NQO1), an enzyme over-expressed in numerous tumors, including lung, pancreas, breast, and prostate cancers. Fast renal clearance and methemaglobinemia / hemolytic side-effects from the clinical formulation (β-lap-hydroxyl propyl-β-cyclodextrin complex) hindered its clinical translation. Here, we investigated a dual model pH responsive polymers for β-lap delivery. Three pH-sensitive linkages, including acylhydrazone, ketal and imine bonds for β-lap prodrug syntheses result in an aryl imine linkage the most optimal linkage. The conversion to β-lap was 2.8%, 4.5% and 100% at pH 7.4, 6.5 and 5.0 in 8 h, respectively. β-lap aryl imine prodrug conjugated ultra pH-sensitive (UPS) polymer reached high β-lap loading density (8.3%) and exhibited dual-stages responsiveness to pH variation. In pHs under pH t , at stage I, micelle immediately dissociation and subsequently entering stage II, micelles start quickly release β-lap. In vitro release study showed that the micelles constantly release β-lap (14.9 ± 0.1%) at pHs above pH t in 72 h, whereas boosted release of β-lap (79.4 ± 1.2%) at pH 5.0. Micelle intracellular distribution predominantly in the lysosome organelle guaranteed their pH responsive dissociation and subsequently β-lap controlled release. The M-P micelles retained NQO1-dependent cytotoxicity in A549 lung cancer cells, similar to free drug in both efficacy and mechanism of cell death. The lysosome-oriented dual-stage ultra pH responsive β-lap prodrug micelles potentially offer an alternative nanotherapeutic strategy for lung, as well as other NQO1+ cancer therapies.

Dual targeting luminescent gold nanoclusters for tumor imaging and deep tissue therapy.

PubMed

Chen, Dan; Li, Bowen; Cai, Songhua; Wang, Peng; Peng, Shuwen; Sheng, Yuanzhi; He, Yuanyuan; Gu, Yueqing; Chen, Haiyan

2016-09-01

Dual targeting towards both extracellular and intracellular receptors specific to tumor is a significant approach for cancer diagnosis and therapy. In the present study, a novel nano-platform (AuNC-cRGD-Apt) with dual targeting function was initially established by conjugating gold nanocluster (AuNC) with cyclic RGD (cRGD) that is specific to αvβ3integrins over-expressed on the surface of tumor tissues and aptamer AS1411 (Apt) that is of high affinity to nucleolin over-expressed in the cytoplasm and nucleus of tumor cells. Then, AuNC-cRGD-Apt was further functionalized with near infrared (NIR) fluorescence dye (MPA), giving a NIR fluorescent dual-targeting probe AuNC-MPA-cRGD-Apt. AuNC-MPA-cRGD-Apt displays low cytotoxicity and favorable tumor-targeting capability at both in vitro and in vivo level, suggesting its clinical potential for tumor imaging. Additionally, Doxorubicin (DOX), a widely used clinical chemotherapeutic drug that kill cancer cells by intercalating DNA in cellular nucleus, was immobilized onto AuNC-cRGD-Apt forming a pro-drug, AuNC-DOX-cRGD-Apt. The enhanced tumor affinity, deep tumor penetration and improved anti-tumor activity of this pro-drug were demonstrated in different tumor cell lines, tumor spheroid and tumor-bearing mouse models. Results in this study suggest not only the prospect of non-toxic AuNC modified with two targeting ligands for tumor targeted imaging, but also confirm the promising future of dual targeting AuNC as a core for the design of prodrug in the field of cancer therapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Nitric Oxide Prodrug JS-K Is Effective against Non–Small-Cell Lung Cancer Cells In Vitro and In Vivo: Involvement of Reactive Oxygen SpeciesS⃞

PubMed Central

Chakrapani, Harinath; Saavedra, Joseph E.; Morris, Nicole L.; Holland, Ryan J.; Kosak, Ken M.; Shami, Paul J.; Anderson, Lucy M.; Keefer, Larry K.

2011-01-01

Non–small-cell lung cancer is among the most common and deadly forms of human malignancies. Early detection is unusual, and there are no curative therapies in most cases. Diazeniumdiolate-based nitric oxide (NO)-releasing prodrugs are a growing class of promising NO-based therapeutics. Here, we show that O2-(2,4-dinitrophenyl)-1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K) is a potent cytotoxic agent against a subset of human non–small-cell lung cancer cell lines both in vitro and as xenografts in mice. JS-K treatment led to 75% reduction in the growth of H1703 lung adenocarcinoma cells in vivo. Differences in sensitivity to JS-K in different lung cancer cell lines seem to be related to their endogenous levels of reactive oxygen species (ROS)/reactive nitrogen species (RNS). Other related factors, levels of peroxiredoxin 1 (PRX1) and 8-oxo-deoxyguanosine glycosylase (OGG1), also correlated with drug sensitivity. Treatment of the lung adenocarcinoma cells with JS-K resulted in oxidative/nitrosative stress in cells with high basal levels of ROS/RNS, which, combined with the arylating properties of the compound, was reflected in glutathione depletion and alteration in cellular redox potential, mitochondrial membrane permeabilization, and cytochrome c release. Inactivation of manganese superoxide dismutase by nitration was associated with increased superoxide and significant DNA damage. Apoptosis followed these events. Taken together, the data suggest that diazeniumdiolate-based NO-releasing prodrugs may have application as a personalized therapy for lung cancers characterized by high levels of ROS/RNS. PRX1 and OGG1 proteins, which can be easily measured, could function as biomarkers for identifying tumors sensitive to the therapy. PMID:20962031

The nitric oxide prodrug JS-K is effective against non-small-cell lung cancer cells in vitro and in vivo: involvement of reactive oxygen species.

PubMed

Maciag, Anna E; Chakrapani, Harinath; Saavedra, Joseph E; Morris, Nicole L; Holland, Ryan J; Kosak, Ken M; Shami, Paul J; Anderson, Lucy M; Keefer, Larry K

2011-02-01

Non-small-cell lung cancer is among the most common and deadly forms of human malignancies. Early detection is unusual, and there are no curative therapies in most cases. Diazeniumdiolate-based nitric oxide (NO)-releasing prodrugs are a growing class of promising NO-based therapeutics. Here, we show that O(2)-(2,4-dinitrophenyl)-1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K) is a potent cytotoxic agent against a subset of human non-small-cell lung cancer cell lines both in vitro and as xenografts in mice. JS-K treatment led to 75% reduction in the growth of H1703 lung adenocarcinoma cells in vivo. Differences in sensitivity to JS-K in different lung cancer cell lines seem to be related to their endogenous levels of reactive oxygen species (ROS)/reactive nitrogen species (RNS). Other related factors, levels of peroxiredoxin 1 (PRX1) and 8-oxo-deoxyguanosine glycosylase (OGG1), also correlated with drug sensitivity. Treatment of the lung adenocarcinoma cells with JS-K resulted in oxidative/nitrosative stress in cells with high basal levels of ROS/RNS, which, combined with the arylating properties of the compound, was reflected in glutathione depletion and alteration in cellular redox potential, mitochondrial membrane permeabilization, and cytochrome c release. Inactivation of manganese superoxide dismutase by nitration was associated with increased superoxide and significant DNA damage. Apoptosis followed these events. Taken together, the data suggest that diazeniumdiolate-based NO-releasing prodrugs may have application as a personalized therapy for lung cancers characterized by high levels of ROS/RNS. PRX1 and OGG1 proteins, which can be easily measured, could function as biomarkers for identifying tumors sensitive to the therapy.

Amino acid derivatives of 5-ASA as novel prodrugs for intestinal drug delivery.

PubMed

Clerici, C; Gentili, G; Boschetti, E; Santucci, C; Aburbeh, A G; Natalini, B; Pellicciari, R; Morelli, A

1994-12-01

In an attempt to obtain site-specific delivery of 5-ASA in the intestinal tract, we have determined the extent of absorption and metabolism of a number of novel 5-ASA derivatives, namely, (N-L-glutamyl)-amino-2-salicylic acid (1), (N-L-aspartyl)-amino-2-salicylic-acid (2), 5-aminosalicyl-L-proline-L-leucine (3), and 5-(N-L-glutamyl)-aminosalicyl-L-proline-L-leucine (4), which are selectively cleaved by intestinal brush border aminopeptidase A and carboxypeptidases. These novel prodrugs, 5-ASA, and sulfasalazine were administered to adult Fisher rats (N = 30) and to animals that had undergone prior colostomy (N = 30). Urine and feces were collected at timed intervals for 48 hr and the metabolites, 5-ASA, and N-acetyl-5-ASA were measured by high-performance liquid chromatography. The absorption and metabolism of all compounds were essentially identical in colostomized and normal animals. 5-ASA exhibited a rapid proximal intestinal absorption as evidenced by the high cumulative urinary excretion (> 65%) and low fecal excretion. Sulfasalazine, as expected, exhibited a lower urinary recovery (< 35%) and higher fecal excretion of 5-ASA and its metabolite. The novel glutamate and aspartate derivatives (1 and 2) behaved similarly to sulfasalazine, while administration of the proline-leucine derivative (3) resulted in urinary and fecal recovery values intermediate with respect to those observed with 5-ASA and sulfasalazine. 5-(N-L-Glutamyl)-aminosalicyl-L-proline-L-leucine yielded the highest fecal recovery of 5-ASA and its N-acetyl derivative, indicating a more efficient delivery to the distal bowel. Amino acid derivatives of 5-ASA appear to be potentially useful prodrugs for the site-specific delivery of 5-ASA to different regions of the intestinal tract.

Determination of prodrug treosulfan and its biologically active monoepoxide in rat plasma, liver, lungs, kidneys, muscle, and brain by HPLC-ESI-MS/MS method.

PubMed

Romański, Michał; Kasprzyk, Anna; Teżyk, Artur; Widerowska, Agnieszka; Żaba, Czesław; Główka, Franciszek

2017-06-05

A prodrug treosulfan (TREO) is currently investigated in clinical trials for conditioning prior to hematopoietic stem cell transplantation. Bioanalysis of TREO and its active derivatives, monoepoxide (S,S-EBDM) and diepoxide, in plasma and urine underlay the pharmacokinetic studies of these compounds but cannot explain an organ pharmacological action or toxicity. Recently, distribution of TREO and S,S-EBDM into brain, cerebrospinal fluid, and aqueous humor of the eye has been investigated in animal models and the obtained results presented clinical relevance. In this paper, a selective and rapid HPLC-ESI-MS/MS method was elaborated and validated for the studies of disposition of TREO and S,S-EBDM in rat plasma, liver, lungs, kidneys, muscle, and brain. The two analytes and codeine, internal standard (IS), were isolated from 50μL of plasma and 100μL of supernatants of the tissues homogenates using ultrafiltration Amicon vials. Chromatographic resolution was accomplished on C18 column with isocratic elution. The limits of quantitation of TREO and S,S-EBDM in the studied matrices ranged from 0.11 to 0.93μM. The HPLC-MS/MS method was adequately precise and accurate within and between runs. The IS-normalized matrix effect differed among the tissues and was the most pronounced in a liver homogenate supernatant (approximately 0.55 for TREO and 0.35 for S,S-EBDM). Stability of the analytes in experimental samples was also established. The validated method for the first time enabled determination of TREO and S,S-EBDM in the six life-important tissues in rats following administration of the prodrug. Copyright © 2017 Elsevier B.V. All rights reserved.

Pharmacokinetics and Abuse Potential of Benzhydrocodone, a Novel Prodrug of Hydrocodone, After Intranasal Administration in Recreational Drug Users.

PubMed

Mickle, Travis C; Guenther, Sven M; Barrett, Andrew C; Roupe, Kathryn Ann; Zhou, Jing; Dickerson, Daniel; Webster, Lynn R

2017-10-28

Developing an acetaminophen-free, immediate-release hydrocodone product remains an unmet medical need; however, new opioid analgesics should not introduce new abuse risks. Benzhydrocodone is a prodrug of hydrocodone that must be metabolized into hydrocodone by enzymes in the intestinal tract to optimally deliver its pharmacologic effects. This study evaluated the intranasal pharmacokinetics and abuse potential of benzhydrocodone active pharmaceutical ingredient (API) compared with hydrocodone bitartrate (HB) API. Single-center, randomized, double-blind, crossover study. Clinical research site. Healthy adult, nondependent, recreational opioid users. Subjects (N = 51 Completers) were randomized to receive 13.34 mg of intranasal benzhydrocodone API and 15.0 mg of intranasal HB API (molar-equivalent doses of hydrocodone). Blood samples were taken, and Drug Liking scores (assessed on a bipolar visual analog scale) were obtained throughout each dosing interval. Nasal irritation and safety were assessed. Peak hydrocodone plasma concentration (Cmax) was 36.0% lower, and total hydrocodone exposures (AUClast and AUCinf) were 20.3% and 19.5% lower, respectively, for benzhydrocodone API compared with HB API (P < 0.0001). All partial AUC values were lower for benzhydrocodone API, with a ≥ 75% reduction in hydrocodone exposure at all time intervals up to one hour postdose (P < 0.0001). Median Tmax of hydrocodone following benzhydrocodone API was delayed by more than one hour compared with HB. Drug Liking score, as assessed by maximal liking (Emax), was significantly lower for benzhydrocodone API vs HB API (P = 0.004), with 45% of subjects showing a ≥ 30% reduction in Drug Liking Emax. Reductions in hydrocodone exposure and associated decreases in Drug Liking relative to HB suggest that the prodrug benzhydrocodone may deter intranasal abuse. © 2017 American Academy of Pain Medicine.

Lisdexamfetamine for treatment of attention-deficit/hyperactivity disorder.

PubMed

Cowles, Brian J

2009-04-01

To review the pharmacology, pharmacokinetics, efficacy, and safety of the prodrug lisdexamfetamine for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children and adults and describe its potential place in therapy. Primary literature published between January 1, 1990, and August 1, 2008, was selected from PubMed using the search key words lisdexamfetamine, Vyvanse, and NRP104. References of selected publications were also reviewed. Posters and abstracts of research presented at national meetings were reviewed when available. The product labeling for Vyvanse was also used. Preference was given to published, randomized, and controlled research describing the pharmacokinetics, efficacy, and safety of lisdexamfetamine. Noncontrolled studies, postmarketing reports, and poster presentations were considered secondly. All published studies were included. Lisdexamfetamine is a prodrug of dextroamphetamine covalently bound to l-lysine, which is activated during first-pass metabolism. The unique pharmacokinetic profile owing to lisdexamfetamine's prodrug design and rate-limited enzymatic biotransformation allows for once-daily dosing with a duration of activity of approximately 12 hours. Lisdexamfetamine has been proven to reduce the symptoms of ADHD both in children aged 6-12 years and adults aged 18-55 years, decreasing ADHD rating scale scores by approximately 27 and 19 points, respectively. Adverse effects with an incidence greater than 10% during preclinical trials included appetite suppression, insomnia, and headache. Lisdexamfetamine's unique pharmacokinetic properties may provide additional safety with regard to reducing abuse potential. As with other central nervous system (CNS) stimulants, concerns regarding sudden cardiac death and adverse effects on growth also apply to lisdexamfetamine. Lisdexamfetamine provides another amphetamine-based CNS stimulant option for treatment of children and adults with ADHD. However, its use may be limited by a lack of significant differentiation when compared with currently used stimulants and a lack of evidence to support its use in adolescents.

Pharmacokinetics of Hydroxymethylnitrofurazone, a Promising New Prodrug for Chagas' Disease Treatment

PubMed Central

Serafim, Eliana Ometto Pavan; Silva, Antonio Távora de Albuquerque e; Moreno, Andréia de Haro; Vizioli, Ednir de Oliveira; Ferreira, Elizabeth Igne; Ribeiro, Maria Lucia

2013-01-01

Hydroxymethylnitrofurazone (NFOH) is a trypanocidal prodrug of nitrofurazone (NF), devoid of mutagenic toxicity. The purpose of this work was to study the chemical conversion of NFOH into NF in sodium acetate buffer (pH 1.2 and 7.4) and in human plasma and to determine preclinical pharmacokinetic parameters in rats. At pH 1.2, the NFOH was totally transformed into NF, the parent drug, after 48 h, while at pH 7.4, after the same period, the hydrolysis rate was 20%. In human plasma, 50% of NFOH was hydrolyzed after 24 h. In the investigation of kinetic disposition, the concentration of drug in serum versus time curve was used to calculate the pharmacokinetic parameters after a single-dose regimen. NFOH showed a time to maximum concentration of drug in serum (Tmax) as 1 h, suggesting faster absorption than NF (4 h). The most important results observed were the volume of distribution (V) of NFOH through the tissues, which showed a rate that is 20-fold higher (337.5 liters/kg of body weight) than that of NF (17.64 liters/kg), and the concentration of NF obtained by in vivo metabolism of NFOH, which was about four times lower (maximum concentration of drug in serum [Cmax] = 0.83 μg/ml; area under the concentration-time curve from 0 to 12 h [AUC0–12] = 5.683 μg/ml · h) than observed for administered NF (Cmax = 2.78 μg/ml; AUC0–12 = 54.49 μg/ml · h). These findings can explain the superior activity and lower toxicity of the prodrug NFOH in relation to its parent drug and confirm NFOH as a promising anti-Chagas' disease drug candidate. PMID:24080661

Colistin Methanesulfonate Is an Inactive Prodrug of Colistin against Pseudomonas aeruginosa

PubMed Central

Bergen, Phillip J.; Li, Jian; Rayner, Craig R.; Nation, Roger L.

2006-01-01

There is a dearth of information on the pharmacodynamics of “colistin,” despite its increasing use as a last line of defense for treatment of infections caused by multidrug-resistant gram-negative organisms. The antimicrobial activities of colistin and colistin methanesulfonate (CMS) were investigated by studying the time-kill kinetics of each against a type culture of Pseudomonas aeruginosa in cation-adjusted Mueller-Hinton broth. The appearance of colistin from CMS spiked at 8.0 and 32 mg/liter was measured by high-performance liquid chromatography, which generated colistin concentration-time profiles. These concentration-time profiles were subsequently mimicked in other incubations, independent of CMS, by incrementally spiking colistin. When the cultures were spiked with CMS at either concentration, there was a substantial delay in the onset of the killing effect which was not evident until the concentrations of colistin generated from the hydrolysis of CMS had reached approximately 0.5 to 1 mg/liter (i.e., ∼0.5 to 1 times the MIC for colistin). The time course of the killing effect was similar when colistin was added incrementally to achieve the same colistin concentration-time course observed from the hydrolysis of CMS. Given that the killing kinetics of CMS can be accounted for by the appearance of colistin, CMS is an inactive prodrug of colistin with activity against P. aeruginosa. This is the first study to demonstrate the formation of colistin in microbiological media containing CMS and to demonstrate that CMS is an inactive prodrug of colistin. These findings have important implications for susceptibility testing involving “colistin,” in particular, for MIC measurement and for microbiological assays and pharmacokinetic and pharmacodynamic studies. PMID:16723551

Leinamycin E1 acting as an anticancer prodrug activated by reactive oxygen species.

PubMed

Huang, Sheng-Xiong; Yun, Bong-Sik; Ma, Ming; Basu, Hirak S; Church, Dawn R; Ingenhorst, Gudrun; Huang, Yong; Yang, Dong; Lohman, Jeremy R; Tang, Gong-Li; Ju, Jianhua; Liu, Tao; Wilding, George; Shen, Ben

2015-07-07

Leinamycin (LNM) is a potent antitumor antibiotic produced by Streptomyces atroolivaceus S-140, featuring an unusual 1,3-dioxo-1,2-dithiolane moiety that is spiro-fused to a thiazole-containing 18-membered lactam ring. Upon reductive activation in the presence of cellular thiols, LNM exerts its antitumor activity by an episulfonium ion-mediated DNA alkylation. Previously, we have cloned the lnm gene cluster from S. atroolivaceus S-140 and characterized the biosynthetic machinery responsible for the 18-membered lactam backbone and the alkyl branch at C3 of LNM. We now report the isolation and characterization of leinamycin E1 (LNM E1) from S. atroolivacues SB3033, a ΔlnmE mutant strain of S. atroolivaceus S-140. Complementary to the reductive activation of LNM by cellular thiols, LNM E1 can be oxidatively activated by cellular reactive oxygen species (ROS) to generate a similar episulfonium ion intermediate, thereby alkylating DNA and leading to eventual cell death. The feasibility of exploiting LNM E1 as an anticancer prodrug activated by ROS was demonstrated in two prostate cancer cell lines, LNCaP and DU-145. Because many cancer cells are under higher cellular oxidative stress with increased levels of ROS than normal cells, these findings support the idea of exploiting ROS as a means to target cancer cells and highlight LNM E1 as a novel lead for the development of anticancer prodrugs activated by ROS. The structure of LNM E1 also reveals critical new insights into LNM biosynthesis, setting the stage to investigate sulfur incorporation, as well as the tailoring steps that convert the nascent hybrid peptide-polyketide biosynthetic intermediate into LNM.

Pt(IV) complexes as prodrugs for cisplatin.

PubMed

Shi, Yi; Liu, Shu-An; Kerwood, Deborah J; Goodisman, Jerry; Dabrowiak, James C

2012-02-01

The antitumor effects of platinum(IV) complexes, considered prodrugs for cisplatin, are believed to be due to biological reduction of Pt(IV) to Pt(II), with the reduction products binding to DNA and other cellular targets. In this work we used pBR322 DNA to capture the products of reduction of oxoplatin, c,t,c-[PtCl(2)(OH)(2)(NH(3))(2)], 3, and a carboxylate-modified analog, c,t,c-[PtCl(2)(OH)(O(2)CCH(2)CH(2)CO(2)H)(NH(3))(2)], 4, by ascorbic acid (AsA) or glutathione (GSH). Since carbonate plays a significant role in the speciation of platinum complexes in solution, we also investigated the effects of carbonate on the reduction/DNA-binding process. In pH 7.4 buffer in the absence of carbonate, both 3 and 4 are reduced by AsA to cisplatin (confirmed using ((195))Pt NMR), which binds to and unwinds closed circular DNA in a manner consistent with the formation of the well-known 1, 2 intrastrand DNA crosslink. However, when GSH is used as the reducing agent for 3 and 4, ((195))Pt NMR shows that cisplatin is not produced in the reaction medium. Although the Pt(II) products bind to closed circular DNA, their effect on the mobility of Form I DNA is different from that produced by cisplatin. When physiological carbonate is present in the reduction medium, ((13))C NMR shows that Pt(II) carbonato complexes form which block or impede platinum binding to DNA. The results of the study vis-à-vis the ability of the Pt(IV) complexes to act as prodrugs for cisplatin are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

A germination bioassay as a toxicological screening system for studying the effects of potential prodrugs of naproxen.

PubMed

Gonzalez-de la Parra, M; Ramos-Mundo, C; Jimenez-Estrada, M; Ponce-de Leon, C; Castillo, R; Tejeda, V; Cuevas, K G; Enriquez, R G

1998-01-01

A germination bioassay with radish (Raphanus sativus L.) seeds was developed as a toxicological screening system for assessing the effects of new potential prodrugs of naproxen, as an alternative to animals and animal cell toxicity screens. Both enantiomers of naproxen (6-methoxy-α-methyl-2-naphthaleneacetic acid) and naproxol (6-methoxy-β-2-naphthaleneethanol), and their racemic mixtures, inhibited the radicle growth of R. sativus at a concentration of 1mM, while only (R)-(+ )-naproxol and racemic naproxol inhibited the hypocotyl growth of R. sativus at the same concentration. Four novel combinatorial esters, naproxen naproxyl esters (6-methoxy-β-methyl-2-naphthaleneethyl 6-methoxy-α-methyl-2-naphthaleneacetate), resulting from the combinatorial chemistry of the esterification reaction between naproxen and naproxol, were synthesised and then tested in the germination bioassay, at a concentration of 0.5mM. It was found that they did not inhibit either the radicle or the hypocotyl growth of R. sativus. 1998 FRAME.

Poly(glycerol adipate) - indomethacin drug conjugates - synthesis and in vitro characterization.

PubMed

Wersig, T; Hacker, M C; Kressler, J; Mäder, K

2017-10-05

The linear biodegradable polyester poly(glycerol adipate) (PGA) was synthesized via enzymatic polycondensation using lipase B from Candida antarctica (CAL-B). Every monomer unit of PGA possesses a pendant hydroxyl group which is responsible for the hydrophilic character and moisture swelling. These OH groups were esterified to different degrees with the anti-inflammatory drug indomethacin in order to create a prodrug with a pH-sensitive linker for modified drug release. The structure of the conjugates was determined via ATR FT-IR spectroscopy, NMR spectroscopy, GPC and UV/VIS spectroscopy. The physical properties of polymers with different drug load were investigated using DSC, contact angle measurements and oscillatory rheology. Drug release was monitored over one month in vitro. A very slow, but continuous release was observed in PBS. Slightly acidic conditions and lipase activity are accelerating the indomethacin release. Therefore, poly(glycerol adipate) - indomethacin conjugates are promising prodrugs for the local sustained release of indomethacin. Copyright © 2017 Elsevier B.V. All rights reserved.

Engineering a prostate-specific membrane antigen-activated tumor endothelial cell prodrug for cancer therapy.

PubMed

Denmeade, Samuel R; Mhaka, Annastasiah M; Rosen, D Marc; Brennen, W Nathaniel; Dalrymple, Susan; Dach, Ingrid; Olesen, Claus; Gurel, Bora; Demarzo, Angelo M; Wilding, George; Carducci, Michael A; Dionne, Craig A; Møller, Jesper V; Nissen, Poul; Christensen, S Brøgger; Isaacs, John T

2012-06-27

Heterogeneous expression of drug target proteins within tumor sites is a major mechanism of resistance to anticancer therapies. We describe a strategy to selectively inhibit, within tumor sites, the function of a critical intracellular protein, the sarcoplasmic/endoplasmic reticulum calcium adenosine triphosphatase (SERCA) pump, whose proper function is required by all cell types for viability. To achieve targeted inhibition, we took advantage of the unique expression of the carboxypeptidase prostate-specific membrane antigen (PSMA) by tumor endothelial cells within the microenvironment of solid tumors. We generated a prodrug, G202, consisting of a PSMA-specific peptide coupled to an analog of the potent SERCA pump inhibitor thapsigargin. G202 produced substantial tumor regression against a panel of human cancer xenografts in vivo at doses that were minimally toxic to the host. On the basis of these data, a phase 1 dose-escalation clinical trial has been initiated with G202 in patients with advanced cancer.

Synthesis and Pharmacokinetic Evaluation of Siderophore Biosynthesis Inhibitors for Mycobacterium tuberculosis

PubMed Central

Nelson, Kathryn M.; Viswanathan, Kishore; Dawadi, Surendra; Duckworth, Benjamin P.; Boshoff, Helena I.; Barry, Clifton E.; Aldrich, Courtney C.

2015-01-01

MbtA catalyzes the first committed biosynthetic step of the mycobactins, which are important virulence factors associated with iron acquisition in Mycobacterium tuberculosis. MbtA is a validated therapeutic target for antitubercular drug development. 5′-O-[N-(salicyl)sulfamoyl]adenosine (1) is a bisubstrate inhibitor of MbtA and exhibits exceptionally potent biochemical and antitubercular activity. However, 1 suffers from sub-optimal drug disposition properties resulting in a short half-life (t1/2), low exposure (AUC), and low bioavailability (F). Four strategies were pursued to address these liabilities including the synthesis of prodrugs, increasing the pKa of the acyl-sulfonyl moiety, modulation of the lipophilicity, and strategic introduction of fluorine into 1. Complete pharmacokinetic (PK) analysis of all compounds was performed. The most successful modifications involved fluorination of the nucleoside that provided substantial improvements in t1/2 and AUC. Increasing the pKa of the acyl-sulfonyl linker yielded incremental enhancements while modulation of the lipophilicity and prodrug approaches led to substantially poorer PK parameters. PMID:26110337

Electrochemical Detection of Platinum(IV) Prodrug Satraplatin in Serum.

PubMed

Wu, Yao; Lai, Rebecca Y

2015-11-03

We report the design and fabrication of a reagentless and reusable electrochemical sensor for detection of satraplatin (SAT), a platinum(IV) prodrug. The detection strategy is based on the electrocatalytic reaction between the Pt(IV) center of SAT and surface-immobilized methylene blue. We systematically evaluated the effect of passivating diluent chain length on the overall sensor performance. Our results show that the use of a shorter diluent like 2-mercaptoethanol is more advantageous than using a longer and more passivating diluent such as 6-mercapto-1-hexanol. Independent of the use of cyclic voltammetry or chronoamperometry as the sensor interrogation technique, all three sensors, each passivated with a different alkanethiol diluent, have been demonstrated to be sensitive; the limit of detection is in the range of 1-10 μM. They are also highly specific and do not respond to Pt(II) drugs such as cisplatin and carboplatin. More importantly, they are selective enough to be employed directly in 50% serum. This sensing strategy has potential applications in clinical pharmacokinetics studies.

Delivery of Therapeutic Proteins via Extracellular Vesicles: Review and Potential Treatments for Parkinson's Disease, Glioma, and Schwannoma.

PubMed

Hall, Justin; Prabhakar, Shilpa; Balaj, Leonora; Lai, Charles P; Cerione, Richard A; Breakefield, Xandra O

2016-04-01

Extracellular vesicles present an attractive delivery vehicle for therapeutic proteins. They intrinsically contain many proteins which can provide information to other cells. Advantages include reduced immune reactivity, especially if derived from the same host, stability in biologic fluids, and ability to target uptake. Those from mesenchymal stem cells appear to be intrinsically therapeutic, while those from cancer cells promote tumor progression. Therapeutic proteins can be loaded into vesicles by overexpression in the donor cell, with oligomerization and membrane sequences increasing their loading. Examples of protein delivery for therapeutic benefit in pre-clinical models include delivery of: catalase for Parkinson's disease to reduce oxidative stress and thus help neurons to survive; prodrug activating enzymes which can convert a prodrug which crosses the blood-brain barrier into a toxic chemotherapeutic drug for schwannomas and gliomas; and the apoptosis-inducing enzyme, caspase-1 under a Schwann cell specific promoter for schwannoma. This therapeutic delivery strategy is novel and being explored for a number of diseases.

Identification of a Potent Phosphoinositide 3-Kinase Pan Inhibitor Displaying a Strategic Carboxylic Acid Group and Development of Its Prodrugs.

PubMed

Pirali, Tracey; Ciraolo, Elisa; Aprile, Silvio; Massarotti, Alberto; Berndt, Alex; Griglio, Alessia; Serafini, Marta; Mercalli, Valentina; Landoni, Clarissa; Campa, Carlo Cosimo; Margaria, Jean Piero; Silva, Rangel L; Grosa, Giorgio; Sorba, Giovanni; Williams, Roger; Hirsch, Emilio; Tron, Gian Cesare

2017-09-21

Activation of the phosphoinositide 3-kinase (PI3K) pathway is a key signaling event in cancer, inflammation, and other proliferative diseases. PI3K inhibitors are already approved for some specific clinical indications, but their systemic on-target toxicity limits their larger use. In particular, whereas toxicity is tolerable in acute treatment of life-threatening diseases, this is less acceptable in chronic conditions. In the past, the strategy to overcome this drawback was to block selected isoforms mainly expressed in leukocytes, but redundancy within the PI3K family members challenges the effectiveness of this approach. On the other hand, decreasing exposure to selected target cells represents a so-far unexplored alternative to circumvent systemic toxicity. In this manuscript, we describe the generation of a library of triazolylquinolones and the development of the first prodrug pan-PI3K inhibitor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Novel Tumor-Activated Prodrug Strategy Targeting Ferrous Iron Is Effective in Multiple Preclinical Cancer Models

PubMed Central

2016-01-01

Here we describe a new approach for tumor targeting in which augmented concentrations of Fe(II) in cancer cells and/or the tumor microenvironment triggers drug release from an Fe(II)-reactive prodrug conjugate. The 1,2,4-trioxolane scaffold developed to enable this approach can in principle be applied to a broad range of cancer therapeutics and is illustrated here with Fe(II)-targeted forms of a microtubule toxin and a duocarmycin-class DNA-alkylating agent. We show that the intrinsic reactivity/toxicity of the duocarmycin analog is masked in the conjugated form and this greatly reduced toxicity in mice. This in turn permitted elevated dosing levels, leading to higher systemic exposure and a significantly improved response in tumor xenograft models. Overall our results suggest that Fe(II)-dependent drug delivery via trioxolane conjugates could have significant utility in expanding the therapeutic index of a range of clinical and preclinical stage cancer chemotherapeutics. PMID:27936709

Nonaqueous gel for the transdermal delivery of a DTPA penta-ethyl ester prodrug.

PubMed

Zhang, Yong; Sadgrove, Matthew P; Sueda, Katsuhiko; Yang, Yu-Tsai; Pacyniak, Erik K; Kagel, John R; Braun, Brenda A; Zamboni, William C; Mumper, Russell J; Jay, Michael

2013-04-01

Diethylenetriamine pentaacetic acid penta-ethyl ester, designated as C2E5, was successfully incorporated into a nonaqueous gel for transdermal delivery. The thermal and rheological properties of a formulation containing 40% C2E5, 20% ethyl cellulose, and 40% Miglyol 840® prepared using the solvent evaporation method demonstrated that the gel had acceptable content uniformity and flow properties. In vitro studies showed that C2E5 was steadily released from the gel at a rate suitable for transdermal delivery. Topical application of the gel at a 200 mg C2E5/kg dose level in rats achieved significantly higher plasma exposures of several active metabolites compared with neat C2E5 oil at the same dose level. The results suggest that transdermal delivery of a chelator prodrug is an effective radionuclide decorporation strategy by delivering chelators to the circulation with a pharmacokinetic profile that is more consistent with the biokinetic profile of transuranic elements in contaminated individuals.

Target engagement and drug residence time can be observed in living cells with BRET

PubMed Central

Robers, Matthew B.; Dart, Melanie L.; Woodroofe, Carolyn C.; Zimprich, Chad A.; Kirkland, Thomas A.; Machleidt, Thomas; Kupcho, Kevin R.; Levin, Sergiy; Hartnett, James R.; Zimmerman, Kristopher; Niles, Andrew L.; Ohana, Rachel Friedman; Daniels, Danette L.; Slater, Michael; Wood, Monika G.; Cong, Mei; Cheng, Yi-Qiang; Wood, Keith V.

2015-01-01

The therapeutic action of drugs is predicated on their physical engagement with cellular targets. Here we describe a broadly applicable method using bioluminescence resonance energy transfer (BRET) to reveal the binding characteristics of a drug with selected targets within intact cells. Cell-permeable fluorescent tracers are used in a competitive binding format to quantify drug engagement with the target proteins fused to Nanoluc luciferase. The approach enabled us to profile isozyme-specific engagement and binding kinetics for a panel of histone deacetylase (HDAC) inhibitors. Our analysis was directed particularly to the clinically approved prodrug FK228 (Istodax/Romidepsin) because of its unique and largely unexplained mechanism of sustained intracellular action. Analysis of the binding kinetics by BRET revealed remarkably long intracellular residence times for FK228 at HDAC1, explaining the protracted intracellular behaviour of this prodrug. Our results demonstrate a novel application of BRET for assessing target engagement within the complex milieu of the intracellular environment. PMID:26631872

Nanomedicines for Inflammatory Arthritis: Head-To-Head Comparison of Glucocorticoid-Containing Polymers, Micelles and Liposomes

PubMed Central

Crielaard, Bart J.; Dusad, Anand; Lele, Subodh M.; Rijcken, Cristianne J. F.; Metselaar, Josbert M; Kostková, Hana; Etrych, Tomáš; Ulbrich, Karel; Kiessling, Fabian; Mikuls, Ted R.; Hennink, Wim E.; Storm, Gert; Lammers, Twan; Wang, Dong

2014-01-01

As an emerging research direction, nanomedicine has been increasingly utilized to treat inflammatory diseases. In this head-to-head comparison study, four established nanomedicine formulations of dexamethasone, including liposomes (L-Dex), core-crosslinked micelles (M-Dex), slow releasing polymeric prodrugs (P-Dex-slow) and fast releasing polymeric prodrugs (P-Dex-fast), were evaluated in an adjuvant-induced arthritis rat model with an equivalent dose treatment design. It was found that after a single i.v. injection, the formulations with the slower drug release kinetics (i.e. M-Dex and P-Dex-slow) maintained longer duration of therapeutic activity than those with relatively faster drug release kinetics, resulting in better joint protection. This finding will be instructional in the future development and optimization of nanomedicines for the clinical management of rheumatoid arthritis. The outcome of this study also illustrates the value of such head-to-head comparison studies in translational nanomedicine research. PMID:24341611

Beta-lactamase targeted enzyme activatable photosensitizers for antimicrobial PDT

NASA Astrophysics Data System (ADS)

Zheng, Xiang; Verma, Sarika; Sallum, Ulysses W.; Hasan, Tayyaba

2009-06-01

Photodynamic therapy (PDT) as a treatment modality for infectious disease has shown promise. However, most of the antimicrobial photosensitizers (PS) non-preferentially accumulate in both bacteria and host tissues, causing host tissue phototoxicity during treatment. We have developed a new antimicrobial PDT strategy which exploits beta-lactam resistance mechanism, one of the major drug-resistance bacteria evolved, to achieve enhanced target specificity with limited host damage. Our strategy comprises a prodrug construct with a PS and a quencher linked by beta-lactam ring, resulting in a diminished phototoxicity. This construct, beta-lactamase enzyme-activated-photosensitizer (beta-LEAP), can only be activated in the presence of both light and bacteria, and remains inactive elsewhere such as mammalian tissue. Beta-LEAP construct had shown specific cleavage by purified beta-lactamase and by beta-lactamase over-expressing methicillin resistant Staphylococcus aureus (MRSA). Specific photodynamic toxicity was observed towards MRSA, while dark and light toxicity were equivalent to reference strains. The prodrug design, synthesis and photophysical properties will be discussed.

Targeting hypoxic microenvironment of pancreatic xenografts with the hypoxia-activated prodrug TH-302.

PubMed

Lohse, Ines; Rasowski, Joanna; Cao, Pinjiang; Pintilie, Melania; Do, Trevor; Tsao, Ming-Sound; Hill, Richard P; Hedley, David W

2016-06-07

Previous reports have suggested that the hypoxic microenvironment provides a niche that supports tumor stem cells, and that this might explain clinical observations linking hypoxia to metastasis. To test this, we examined the effects of a hypoxia-activated prodrug, TH-302, on the tumor-initiating cell (TIC) frequency of patient-derived pancreatic xenografts (PDX).The frequencies of TIC, measured by limiting dilution assay, varied widely in 11 PDX models, and were correlated with rapid growth but not with the levels of hypoxia. Treatment with either TH-302 or ionizing radiation (IR), to target hypoxic and well-oxygenated regions, respectively, reduced TIC frequency, and the combination of TH-302 and IR was much more effective in all models tested. The combination was also more effective than TH-302 or IR alone controlling tumor growth, particularly treating the more rapidly-growing/hypoxic models. These findings support the clinical utility of hypoxia targeting in combination with radiotherapy to treat pancreatic cancers, but do not provide strong evidence for a hypoxic stem cell niche.

Design and Synthesis of Neuroprotective Methylthiazoles and Modification as NO-Chimeras for Neurodegenerative Therapy

PubMed Central

Qin, Zhihui; Luo, Jia; VandeVrede, Lawren; Tavassoli, Ehsan; Fa’, Mauro; Teich, Andrew; Arancio, Ottavio; Thatcher, Gregory R. J.

2012-01-01

Learning and memory deficits in Alzheimer’s disease (AD) result from synaptic failure and neuronal loss, the latter caused in part by excitotoxicity and oxidative stress. A therapeutic approach is described, which uses NO-chimeras directed at restoration of both synaptic function and neuroprotection. 4-Methylthiazole (MZ) derivatives were synthesized, based upon a lead neuroprotective pharmacophore acting in part by GABAA receptor potentiation. MZ derivatives were assayed for protection of primary neurons against oxygen-glucose deprivation and excitotoxicity. Selected neuroprotective derivatives were incorporated into NO-chimera prodrugs, coined nomethiazoles. To provide proof of concept for the nomethiazole drug class, selected examples were assayed for: restoration of synaptic function in hippocampal slices from AD-transgenic mice; reversal of cognitive deficits; and, brain bioavailability of the prodrug and its neuroprotective MZ metabolite. Taken together the assay data suggest that these chimeric nomethiazoles may be of use in treatment of multiple components of neurodegenerative disorders, such as AD. PMID:22779770

Diels Alder-mediated release of gemcitabine from hybrid nanoparticles for enhanced pancreatic cancer therapy.

PubMed

Oluwasanmi, Adeolu; Al-Shakarchi, Wejdan; Manzur, Ayesha; Aldebasi, Mohammed H; Elsini, Rayan S; Albusair, Malek K; Haxton, Katherine J; Curtis, Anthony D M; Hoskins, Clare

2017-11-28

Hybrid nanoparticles (HNPs) have shown huge potential as drug delivery vehicles for pancreatic cancer. Currently, the first line treatment, gemcitabine, is only effective in 23.8% of patients. To improve this, a thermally activated system was developed by introducing a linker between HNPs and gemcitabine. Whereby, heat generation resulting from laser irradiation of the HNPs promoted linker breakdown resulting in prodrug liberation. In vitro evaluation in pancreatic adenocarcinoma cells, showed the prodrug was 4.3 times less cytotoxic than gemcitabine, but exhibited 11-fold improvement in cellular uptake. Heat activation of the formulation led to a 56% rise in cytotoxicity causing it to outperform gemcitabine by 26%. In vivo the formulation outperformed free gemcitabine with a 62% reduction in tumor weight in pancreatic xenografts. This HNP formulation is the first of its kind and has displayed superior anti-cancer activity as compared to the current first line drug gemcitabine after heat mediated controlled release. Copyright © 2017 Elsevier B.V. All rights reserved.

Gastroprotective [6]-Gingerol Aspirinate as a Novel Chemopreventive Prodrug of Aspirin for Colon Cancer

PubMed Central

Zhu, Yingdong; Wang, Fang; Zhao, Yantao; Wang, Pei; Sang, Shengmin

2017-01-01

A growing body of research suggests daily low-dose aspirin (ASA) reduces heart diseases and colorectal cancers. However, the major limitation to the use of aspirin is its side effect to cause ulceration and bleeding in the gastrointestinal tract. Preclinical studies have shown that ginger constituents ameliorate ASA-induced gastric ulceration. We here report the design and synthesis of a novel prodrug of aspirin, [6]-gingerol aspirinate (GAS). Our data show that GAS exerts enhanced anti-cancer properties in vitro and superior gastroprotective effects in mice. GAS was also able to survive stomach acid and decomposed in intestinal linings or after absorption to simultaneously release ASA and [6]-gingerol. We further present that GAS inactivates both COX-1 and COX-2 equally. Our results demonstrate the enhanced anticancer properties along with gastroprotective effects of GAS, suggesting that GAS can be a therapeutic equivalent for ASA in inflammatory and proliferative diseases without the deleterious effects on stomach mucosa. PMID:28067282

Slow self-activation enhances the potency of viridin prodrugs.

PubMed

Blois, Joseph; Yuan, Hushan; Smith, Adam; Pacold, Michael E; Weissleder, Ralph; Cantley, Lewis C; Josephson, Lee

2008-08-14

When the viridin wortmannin (Wm) is modified by reaction with certain nucleophiles at the C20 position, the compounds obtained exhibit an improved antiproliferative activity even though a covalent reaction between C20 and a lysine in the active site of PI3 kinase is essential to Wm's ability to inhibit this enzyme. Here we show that this improved potency results from an intramolecular attack by the C6 hydroxyl group that slowly converts these inactive prodrugs to the active species Wm over the 48 h duration of the antiproliferative assay. Our results provide a guide for selecting Wm-like compounds to maximize kinase inhibition with the variety of protocols used to assess the role of PI3 kinase in biological systems, or for achieving optimal therapeutic effects in vivo . In addition, the slow self-activation of WmC20 derivatives provides a mechanism that can be exploited to obtain kinase inhibitors endowed with physical and pharmacokinetic properties far different from man-made kinase inhibitors because they do not bind to kinase active sites.

Sensation seeking and adolescent drug use: the mediating role of association with deviant peers and pro-drug discussions.

PubMed

Yanovitzky, Itzhak

2005-01-01

In this study, I examined direct and indirect influences of sensation seeking, a personality trait, on adolescent drug use. I hypothesized that some or even most of the contribution of sensation seeking to drug use by adolescents is mediated through association with deviant peers and communication with peers that is favorable toward drug use. I examined the role of additional risk or protective factors in facilitating or impeding association with deviant peers, pro-drug communication, and marijuana use as well. The results of analyzing nationally representative cross-sectional data from the evaluation of the National Youth Anti-Drug Media Campaign support the study's hypotheses and suggest that different factors may protect high sensation-seeking adolescents from using drugs or engaging in activities (e.g., association with deviant peers) that may increase their risk for drug use. I discuss the theoretical, methodological, and practical implications of these findings to the design of health communication interventions.

Synthesis and Chemical and Biological Comparison of Nitroxyl and Nitric Oxide Releasing Diazeniumdiolate-based Aspirin Derivatives

PubMed Central

Basudhar, Debashree; Bharadwaj, Gaurav; Cheng, Robert Y.; Jain, Sarthak; Shi, Sa; Heinecke, Julie L.; Holland, Ryan J.; Ridnour, Lisa A.; Caceres, Viviane M.; Spadari-Bratfisch, Regina C.; Paolocci, Nazareno; Velázquez-Martínez, Carlos A.; Wink, David A.; Miranda, Katrina M.

2013-01-01

Structural modifications of non-steroidal anti-inflammatory drugs (NSAIDs) have successfully reduced the side effect of gastrointestinal ulceration without affecting anti-inflammatory activity, but may increase risk of myocardial infarction with chronic use. That nitroxyl (HNO) reduces platelet aggregation, preconditions against myocardial infarction and enhances contractility led us to synthesize a diazeniumdiolate-based HNO releasing aspirin and to compare it to an NO-releasing analogue. Here, the decomposition mechanisms are described for these compounds. In addition to protection against stomach ulceration, these prodrugs also exhibited significantly enhanced cytotoxcity compared to either aspirin or the parent diazeniumdiolate toward non-small cell lung carcinoma cells (A549) but were not appreciably toxic toward endothelial cells (HUVECs). The HNO-NSAID prodrug inhibited cylcooxgenase-2 and glyceraldehyde 3-phosphate dehydrogenase activity and triggered significant sarcomere shortening compared to control on murine ventricular myocytes. Together, these anti-inflammatory, anti-neoplasic and contractile properties suggest the potential of HNO-NSAIDs in the treatment of inflammation, cancer or heart failure. PMID:24102516

Supramolecular nanofibers of triamcinolone acetonide for uveitis therapy

NASA Astrophysics Data System (ADS)

Li, Xingyi; Wang, Yuqin; Yang, Chengbiao; Shi, Shuai; Jin, Ling; Luo, Zichao; Yu, Jing; Zhang, Zhaoliang; Yang, Zhimou; Chen, Hao

2014-11-01

Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular compatibility in rats, as indicated by the optical coherence tomography (OCT) images, HE observation, and glial fibrillary acidic protein (GFAP) and vimentin immuno-staining assays of the retinas. Our TA hydrogel showed a decreased efficacy to inhibit ocular inflammation in the rat's experiment autoimmune uveitis (EAU) model compared to the commercial TA suspension (Transton®), but without causing complications such as high intraocular pressure and cataracts. These promising properties of the hydrogel indicated its great potential for the treatment of eye diseases.Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular compatibility in rats, as indicated by the optical coherence tomography (OCT) images, HE observation, and glial fibrillary acidic protein (GFAP) and vimentin immuno-staining assays of the retinas. Our TA hydrogel showed a decreased efficacy to inhibit ocular inflammation in the rat's experiment autoimmune uveitis (EAU) model compared to the commercial TA suspension (Transton®), but without causing complications such as high intraocular pressure and cataracts. These promising properties of the hydrogel indicated its great potential for the treatment of eye diseases. Electronic supplementary information (ESI) available: Synthesis and characterization of the STA agent. SEM image of TA suspension (Transton®). See DOI: 10.1039/c4nr04761c

Bioactivation antioxidant and transglycating properties of N-acetylcarnosine autoinduction prodrug of a dipeptide L-carnosine in mucoadhesive drug delivery eye-drop formulation: powerful eye health application technique and therapeutic platform.

PubMed

Babizhayev, Mark A

2012-06-01

A considerable interest in N-acetylcarnosine ocular drug design for eye health is based on clinical strategies to improve ocular drug delivery through metabolic enzymatic activation. Human biology aspects of ocular N-acetylcarnosine deacetylation during its pass through the cornea to the aqueous humor and dipeptide hydrolyzing enzymes are characterized. Novel approaches to ocular drug delivery increasing intraocular bioavailability of N-acetylcarnosine biologically activated metabolite carnosine become an integral development ensuring prolonged retention of the medication in the mucoadhesive precorneal area and facilitating transcorneal penetration of the natural dipeptide with the corneal promoters. A comprehensive list of techniques for peptide drug design, synthesis, purification, and biological analyses was considered: liquid chromatography (LC), high performance liquid chromatography (HPLC), (1) H and (13) C nuclear magnetic resonance (NMR), electrospray ionization (ESI) mass spectroscopy, and spectrophotometry. The antioxidant activity of therapeutics-targeted molecules was studied in aqueous solution and in a lipid membrane environment. A deglycation therapeutic system was developed involving removal, by transglycation of sugar or aldehyde moieties from Schiff bases by histidyl-hydrazide compounds or aldehyde scavenger L-carnosine. Clinical studies included ophthalmoscopy, visual acuity (VA), halometer disability glare tests, slit-image, and retro-illumination photography. N-acetylcarnosine 1% lubricant eye drops are considered as an auto-induction prodrug and natural ocular redox state balance therapies with implications in prevention and treatment of serious eye diseases that involve pathways of continuous oxidative damage to ocular tissues(cataracts, primary open-angle glaucoma, age-related macular degeneration) and sight-threatening glycosylation processes (diabetic retinopathy and consequent visual impairment) important for public health. The results of the study document that the therapeutic benefit in clinical trials is associated with the bioactivation universal antioxidant and transglycating properties of N-acetylcarnosine acting as the ophthalmic prodrug of L-carnosine, and depends on the nature of the specific drug delivery lubricant eye-drop formulation applied as the topical solution. The research highlights findings in N-acetylcarnosine prodrug activation, transport mechanisms, drug-to-drug interactions, and formulations in order to unlock the optimization of complicated ocular pharmacology of N-acetylcarnosine. Patented N-acetylcarnosine lubricant eye-drop formula was marketed as numerous human biological brands reaching important distribution networks on over 550 000 bottles sold. Nature Does Nothing Uselessly. -Aristotle Copyright © 2011 John Wiley & Sons, Ltd.

Evaluation of carbohydrate-cysteamine thiazolidines as pro-drugs for the treatment of cystinosis

USDA-ARS?s Scientific Manuscript database

Cystinosis is a genetic disorder caused by malfunction of cystinosin and is characterized by accumulation of cystine. Cysteamine, the medication used in cystinosis, causes halitosis resulting in poor patient compliance. Halitosis is mainly caused by the formation of dimethylsulfide as the final prod...

Targeting the S1P Axis and Development of a Novel Therapy for Obesity-Related Triple-Negative Breast Cancer

DTIC Science & Technology

2015-09-01

Catherine I. Dumur, Zara Zelenko, Emily J. Gallagher, Derek Leroith, Sheldon Milstien1, Kazuaki Takabe and Sarah Spiegel. The Phosphorylated Prodrug...Akimitsu Yamada, Masayuki Nagahashi, Tomoyoshi Aoyagi, Hiroaki Aoki, Catherine I. Dumur, Zara Zelenko, Emily J. Gallagher, Derek Leroith, Sheldon

Application of a Microfluidic Reactor for Screening Cancer Prodrug Activation Using Silica-Immobilized Nitrobenzene Nitroreductase

DTIC Science & Technology

2006-01-01

molecules18 can mediate an analogous reaction15 that combines the advantages of silica encapsulation with a signifi- cant reduction in cost... Alltech , Deerfield, IL) with a mobile phase of acetonitrile and water (containing 0.05% and 0.1% trifluoroacetic acid, respectively). The concentration

Legubicin a Tumor-activated Prodrug for Breast Cancer Therapy

DTIC Science & Technology

2008-04-01

slides were incubated with a cocktail of first primary antibodies for overnight (biotin-conjugeted rat anti-mouse CD68 at 1:100 dilution and sheep anti... sheep (green) (Vector Laboratories) for 40 minutes. Nuclear staining was performed DEPI (10ug/ml) for 10 minutes, then mount cover slip with anti-fade

Recombinant Platform for Prioritizing Aerolysin Molecular Grenades for Metastatic Prostate Cancer

DTIC Science & Technology

2015-10-01

hydrolysis occurring between glycine and phenylalanine (2)); Fibroblast activated protein (FAP) (i.e., ASGPAGPA] with hydrolysis occurring after the proline...PROBLEMS Nothing to Report ! 14! PRODUCTS 1. Recombinant Prodrug HSA/PA-PSA 2. C19-PSA LUC2 cell line ! 15! PARTICIPANTS & OTHER COLLABORATING ORGANIZATIONS Freddie L . Pruitt – NO CHANGE

Self-Assembled Nanoparticles from Phenolic Derivatives for Cancer Therapy.

PubMed

Dai, Yunlu; Guo, Junling; Wang, Ting-Yi; Ju, Yi; Mitchell, Andrew J; Bonnard, Thomas; Cui, Jiwei; Richardson, Joseph J; Hagemeyer, Christoph E; Alt, Karen; Caruso, Frank

2017-08-01

Therapeutic nanoparticles hold clinical promise for cancer treatment by avoiding limitations of conventional pharmaceuticals. Herein, a facile and rapid method is introduced to assemble poly(ethylene glycol) (PEG)-modified Pt prodrug nanocomplexes through metal-polyphenol complexation and combined with emulsification, which results in ≈100 nm diameter nanoparticles (PtP NPs) that exhibit high drug loading (0.15 fg Pt per nanoparticle) and low fouling properties. The PtP NPs are characterized for potential use as cancer therapeutics. Mass cytometry is used to quantify uptake of the nanoparticles and the drug concentration in individual cells in vitro. The PtP NPs have long circulation times, with an elimination half-life of ≈18 h in healthy mice. The in vivo antitumor activity of the PtP NPs is systematically investigated in a human prostate cancer xenograft mouse model. Mice treated with the PtP NPs demonstrate four times better inhibition of tumor growth than either free prodrug or cisplatin. This study presents a promising strategy to prepare therapeutic nanoparticles for biomedical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two-step polymer- and liposome-enzyme prodrug therapies for cancer: PDEPT and PELT concepts and future perspectives.

PubMed

Scomparin, Anna; Florindo, Helena F; Tiram, Galia; Ferguson, Elaine L; Satchi-Fainaro, Ronit

2017-09-01

Polymer-directed enzyme prodrug therapy (PDEPT) and polymer enzyme liposome therapy (PELT) are two-step therapies developed to provide anticancer drugs site-selective intratumoral accumulation and release. Nanomedicines, such as polymer-drug conjugates and liposomal drugs, accumulate in the tumor site due to extravasation-dependent mechanism (enhanced permeability and retention - EPR - effect), and further need to cross the cellular membrane and release their payload in the intracellular compartment. The subsequent administration of a polymer-enzyme conjugate able to accumulate in the tumor tissue and to trigger the extracellular release of the active drug showed promising preclinical results. The development of polymer-enzyme, polymer-drug conjugates and liposomal drugs had undergone a vast advancement over the past decades. Several examples of enzyme mimics for in vivo therapy can be found in the literature. Moreover, polymer therapeutics often present an enzyme-sensitive mechanism of drug release. These nanomedicines can thus be optimal substrates for PDEPT and this review aims to provide new insights and stimuli toward the future perspectives of this promising combination. Copyright © 2017 Elsevier B.V. All rights reserved.

Dipeptides as effective prodrugs of the unnatural amino acid (+)-2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (LY354740), a selective group II metabotropic glutamate receptor agonist.

PubMed

Bueno, Ana Belén; Collado, Iván; de Dios, Alfonso; Domínguez, Carmen; Martín, José Alfredo; Martín, Luisa M; Martínez-Grau, María Angeles; Montero, Carlos; Pedregal, Concepción; Catlow, John; Coffey, D Scott; Clay, Michael P; Dantzig, Anne H; Lindstrom, Terry; Monn, James A; Jiang, Haiyan; Schoepp, Darryle D; Stratford, Robert E; Tabas, Linda B; Tizzano, Joseph P; Wright, Rebecca A; Herin, Marc F

2005-08-11

(+)-2-Aminobicyclo[3.1.0]hexane-2,6-dicarboxylic acid (1), also known as LY354740, is a highly potent and selective agonist for group II metabotropic glutamate receptors (mGlu receptors 2 and 3) tested in clinical trials. It has been shown to block anxiety in the fear-potentiated startle model. Its relatively low bioavailability in different animal species drove the need for an effective prodrug form that would produce a therapeutic response at lower doses for the treatment of anxiety disorders. We have investigated the increase of intestinal absorption of this compound by targeting the human peptide transporter hPepT1 for active transport of di- and tripeptides derived from 1. We have found that oral administration of an N dipeptide derivative of 1 (12a) in rats shows up to an 8-fold increase in drug absorption and a 300-fold increase in potency in the fear-potentiated startle model in rats when compared with the parent drug 1.

An Interactive Lesson in Acid/Base and Pro-Drug Chemistry Using Sodium Gamma-Hydroxybutyrate and Commercial Test Coasters

PubMed Central

Page, Nathaniel A.; Paganelli, Meaghan; Boje, Kathleen M.K.

2007-01-01

Objective To develop a classroom activity that applied pertinent pharmaceutical concepts to examine the use and limitations of a commercially available test drink coaster in detecting the presence of a date-rape drug, sodium γ-hydroxybutyrate (NaGHB), in beverages. Design An activity exercise involving a combination of self-study, hands on participation, and classroom discussion was developed. Topics incorporated into the activity were drug-assisted rape, the concepts of false positives and negatives, and prodrug and pH chemistry. Assessment Based on questionnaires completed by the students, the intended concepts were reinforced and students demonstrated an increased awareness of the potential shortcomings of the commercial test devices. The activity was well received by the majority of students. Conclusion The developed activity stimulated student awareness and interest in several principles relevant in pharamceutical education, including drug-assisted rape, consumer-based drug testing of NaGHB, and the chemical basis for its limitations. The activity requires no special equipment other than the drink coasters and can be easily completed in one 2-hour classroom session. PMID:17619654

An interactive lesson in acid/base and pro-drug chemistry using sodium gamma-hydroxybutyrate and commercial test coasters.

PubMed

Page, Nathaniel A; Paganelli, Meaghan; Boje, Kathleen M K; Fung, Ho-Leung

2007-06-15

To develop a classroom activity that applied pertinent pharmaceutical concepts to examine the use and limitations of a commercially available test drink coaster in detecting the presence of a date-rape drug, sodium gamma-hydroxybutyrate (NaGHB), in beverages. An activity exercise involving a combination of self-study, hands on participation, and classroom discussion was developed. Topics incorporated into the activity were drug-assisted rape, the concepts of false positives and negatives, and prodrug and pH chemistry. Based on questionnaires completed by the students, the intended concepts were reinforced and students demonstrated an increased awareness of the potential shortcomings of the commercial test devices. The activity was well received by the majority of students. The developed activity stimulated student awareness and interest in several principles relevant in pharmaceutical education, including drug-assisted rape, consumer-based drug testing of NaGHB, and the chemical basis for its limitations. The activity requires no special equipment other than the drink coasters and can be easily completed in one 2-hour classroom session.

Design of Enzymatically Cleavable Prodrugs of a Potent Platinum-Containing Anticancer Agent

PubMed Central

Ding, Song; Pickard, Amanda J.; Kucera, Gregory L.

2014-01-01

Using a versatile synthetic approach, a new class of potential ester prodrugs of highly potent, but systemically too toxic, platinum–acridine anticancer agents was generated. The new hybrids contain a hydroxyl group, which has been masked with a cleavable lipophilic acyl moiety. Both butanoic (butyric) and bulkier 2-propanepentanoic (valproic) esters were introduced. The goals of this design were to improve the drug-like properties (e.g., logD) and to reduce the systemic toxicity of the pharmacophore. Two distinct pathways by which the target compounds undergo effective ester hydrolysis, the proposed activating step, have been confirmed: platinum-assisted, self-immolative ester cleavage in a low-chloride environment (LC-ESMS, NMR spectroscopy) and enzymatic cleavage by human carboxylesterase-2 (hCES-2) (LC-ESMS). The valproic acid ester derivatives are the first example of a metal-containing agent cleavable by the pro-drug-converting enzyme. They show excellent chemical stability and reduced systemic toxicity. Preliminary results from screening in lung adenocarcinoma cell lines (A549, NCI-H1435) suggest that the mechanism of the valproic esters may involve intracellular deesterification. PMID:25303639

Glutathione S-conjugates as prodrugs to target drug-resistant tumors

PubMed Central

Ramsay, Emma E.; Dilda, Pierre J.

2014-01-01

Living organisms are continuously exposed to xenobiotics. The major phase of enzymatic detoxification in many species is the conjugation of activated xenobiotics to reduced glutathione (GSH) catalyzed by the glutathione-S-transferase (GST). It has been reported that some compounds, once transformed into glutathione S-conjugates, enter the mercapturic acid pathway whose end products are highly reactive and toxic for the cell responsible for their production. The cytotoxicity of these GSH conjugates depends essentially on GST and gamma-glutamyl transferases (γGT), the enzymes which initiate the mercapturic acid synthesis pathway. Numerous studies support the view that the expression of GST and γGT in cancer cells represents an important factor in the appearance of a more aggressive and resistant phenotype. High levels of tumor GST and γGT expression were employed to selectively target tumor with GST- or γGT-activated drugs. This strategy, explored over the last two decades, has recently been successful using GST-activated nitrogen mustard (TLK286) and γGT-activated arsenic-based (GSAO and Darinaparsin) prodrugs confirming the potential of GSH-conjugates as anticancer drugs. PMID:25157234

Synthesis and functional evaluation of a peptide derivative of 1-beta-D-arabinofuranosylcytosine.

PubMed

Balajthy, Z; Aradi, J; Kiss, I T; Elödi, P

1992-09-04

We have synthesized a peptidyl prodrug derivative of 1-beta-D-arabinofuranosylcytosine (1) designed to be a selective substrate of plasmin. D-Val-Leu-Lys-ara-C (2) was obtained by coupling the protected peptide Cbz-D-Val-Leu-(N6-Cbz)Lys-OH and ara-C (1) by a water-soluble carbodiimide (EDCI), followed by the removal of the Cbz groups by using catalytic hydrogenolysis over Pd/C. The kinetic constant of hydrolysis of 2 in the presence of plasmin demonstrated effective release of 1. The amino group of 1, which is sensitive to the removal by cytidine deaminase, is protected in 2 by the formation of the amide bond resulting in a prolonged half-life of 2 in biological milieu. The antiproliferative efficiency of 2 against L1210 leukemic cells was significantly higher than that of 1. The activity of 2 was abolished in the presence of serine proteinase inhibitor, (4-amidinopheny)methanesulfonyl fluoride. These data indicate that 2 is a prodrug form of 1 in systems generating plasmin.

Mitochondrial Uncoupler Prodrug of 2,4-Dinitrophenol, MP201, Prevents Neuronal Damage and Preserves Vision in Experimental Optic Neuritis

PubMed Central

Khan, Reas S.; Geisler, John G.

2017-01-01

The ability of novel mitochondrial uncoupler prodrug of 2,4-dinitrophenol (DNP), MP201, to prevent neuronal damage and preserve visual function in an experimental autoimmune encephalomyelitis (EAE) model of optic neuritis was evaluated. Optic nerve inflammation, demyelination, and axonal loss are prominent features of optic neuritis, an inflammatory optic neuropathy often associated with the central nervous system demyelinating disease multiple sclerosis. Currently, optic neuritis is frequently treated with high-dose corticosteroids, but treatment fails to prevent permanent neuronal damage and associated vision changes that occur as optic neuritis resolves, thus suggesting that additional therapies are required. MP201 administered orally, once per day, attenuated visual dysfunction, preserved retinal ganglion cells (RGCs), and reduced RGC axonal loss and demyelination in the optic nerves of EAE mice, with limited effects on inflammation. The prominent mild mitochondrial uncoupling properties of MP201, with slow elimination of DNP, may contribute to the neuroprotective effect by modulating the entire mitochondria's physiology directly. Results suggest that MP201 is a potential novel treatment for optic neuritis. PMID:28680531

Development of a Hypoxic Radiosensitizer-Prodrug Liposome Delivery DNA Repair Inhibitor Dbait Combination with Radiotherapy for Glioma Therapy.

PubMed

Liu, Hongmei; Cai, Yifan; Zhang, Yafei; Xie, Yandong; Qiu, Hui; Hua, Lei; Liu, Xuejiao; Li, Yuling; Lu, Jun; Zhang, Longzhen; Yu, Rutong

2017-06-01

Gliomas are highly radioresistant tumors, mainly due to hypoxia in the core region of the gliomas and efficient DNA double-strand break repair. However, the design of a radiosensitizer incorporating the two above mechanisms is difficult and has rarely been reported. Thus, this study develops a hypoxic radiosensitizer-prodrug liposome (MLP) to deliver the DNA repair inhibitor Dbait (MLP/Dbait) to achieve the simultaneous entry of radiosensitizers with two different mechanisms into the glioma. MLP/Dbait effectively sensitizes glioma cells to X-ray radiotherapy (RT). Histological and microscopic examinations of dissected brain tissue confirm that MLP effectively delivers Dbait into the glioma. Furthermore, the combination of MLP/Dbait with RT significantly inhibits growth of the glioma, as assessed by in vivo bioluminescence imaging. These findings suggest that MLP is a promising candidate as a Dbait delivery system to enhance the effect of RT on glioma, owing to the synergistic effects of the two different radiosensitizers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrating Dynamic Positron Emission Tomography and Conventional Pharmacokinetic Studies to Delineate Plasma and Tumor Pharmacokinetics of FAU, a Prodrug Bioactivated by Thymidylate Synthase.

PubMed

Li, Jing; Kim, Seongho; Shields, Anthony F; Douglas, Kirk A; McHugh, Christopher I; Lawhorn-Crews, Jawana M; Wu, Jianmei; Mangner, Thomas J; LoRusso, Patricia M

2016-11-01

FAU, a pyrimidine nucleotide analogue, is a prodrug bioactivated by intracellular thymidylate synthase to form FMAU, which is incorporated into DNA, causing cell death. This study presents a model-based approach to integrating dynamic positron emission tomography (PET) and conventional plasma pharmacokinetic studies to characterize the plasma and tissue pharmacokinetics of FAU and FMAU. Twelve cancer patients were enrolled into a phase 1 study, where conventional plasma pharmacokinetic evaluation of therapeutic FAU (50-1600 mg/m 2 ) and dynamic PET assessment of 18 F-FAU were performed. A parent-metabolite population pharmacokinetic model was developed to simultaneously fit PET-derived tissue data and conventional plasma pharmacokinetic data. The developed model enabled separation of PET-derived total tissue concentrations into the parent drug and metabolite components. The model provides quantitative, mechanistic insights into the bioactivation of FAU and retention of FMAU in normal and tumor tissues and has potential utility to predict tumor responsiveness to FAU treatment. © 2016, The American College of Clinical Pharmacology.

Targeting hypoxic microenvironment of pancreatic xenografts with the hypoxia-activated prodrug TH-302

PubMed Central

Lohse, Ines; Rasowski, Joanna; Cao, Pinjiang; Pintilie, Melania; Do, Trevor; Tsao, Ming-Sound; Hill, Richard P.; Hedley, David W.

2016-01-01

Previous reports have suggested that the hypoxic microenvironment provides a niche that supports tumor stem cells, and that this might explain clinical observations linking hypoxia to metastasis. To test this, we examined the effects of a hypoxia-activated prodrug, TH-302, on the tumor-initiating cell (TIC) frequency of patient-derived pancreatic xenografts (PDX). The frequencies of TIC, measured by limiting dilution assay, varied widely in 11 PDX models, and were correlated with rapid growth but not with the levels of hypoxia. Treatment with either TH-302 or ionizing radiation (IR), to target hypoxic and well-oxygenated regions, respectively, reduced TIC frequency, and the combination of TH-302 and IR was much more effective in all models tested. The combination was also more effective than TH-302 or IR alone controlling tumor growth, particularly treating the more rapidly-growing/hypoxic models. These findings support the clinical utility of hypoxia targeting in combination with radiotherapy to treat pancreatic cancers, but do not provide strong evidence for a hypoxic stem cell niche. PMID:27248663

Hypoxia-activated prodrug TH-302 decreased survival rate of canine lymphoma cells under hypoxic condition.

PubMed

Yamazaki, Hiroki; Lai, Yu-Chang; Tateno, Morihiro; Setoguchi, Asuka; Goto-Koshino, Yuko; Endo, Yasuyuki; Nakaichi, Munekazu; Tsujimoto, Hajime; Miura, Naoki

2017-01-01

We tested the hypotheses that hypoxic stimulation enhances growth potentials of canine lymphoma cells by activating hypoxia-inducible factor 1α (HIF-1α), and that the hypoxia-activated prodrug (TH-302) inhibits growth potentials in the cells. We investigated how hypoxic culture affects the growth rate, chemoresistance, and invasiveness of canine lymphoma cells and doxorubicin (DOX)-resistant lymphoma cells, and influences of TH-302 on survival rate of the cells under hypoxic conditions. Our results demonstrated that hypoxic culture upregulated the expression of HIF-1α and its target genes, including ATP-binding cassette transporter B1 (ABCB1), ATP-binding cassette transporter G2 (ABCG2), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and survivin, and enhanced the growth rate, DOX resistance, and invasiveness of the cells. Additionally, TH-302 decreased the survival rate of the cells under hypoxic condition. Our studies suggest that hypoxic stimulation may advance the tumorigenicity of canine lymphoma cells, favoring malignant transformation. Therefore, the data presented may contribute to the development of TH-302-based hypoxia-targeting therapies for canine lymphoma.

An Efficient Buchwald-Hartwig/Reductive Cyclization for the Scaffold Diversification of Halogenated Phenazines: Potent Antibacterial Targeting, Biofilm Eradication, and Prodrug Exploration.

PubMed

Garrison, Aaron T; Abouelhassan, Yasmeen; Kallifidas, Dimitris; Tan, Hao; Kim, Young S; Jin, Shouguang; Luesch, Hendrik; Huigens, Robert W

2018-05-10

Bacterial biofilms are surface-attached communities comprised of nonreplicating persister cells housed within a protective extracellular matrix. Biofilms display tolerance toward conventional antibiotics, occur in ∼80% of infections, and lead to >500000 deaths annually. We recently identified halogenated phenazine (HP) analogues which demonstrate biofilm-eradicating activities against priority pathogens; however, the synthesis of phenazines presents limitations. Herein, we report a refined HP synthesis which expedited the identification of improved biofilm-eradicating agents. 1-Methoxyphenazine scaffolds were generated through a Buchwald-Hartwig cross-coupling (70% average yield) and subsequent reductive cyclization (68% average yield), expediting the discovery of potent biofilm-eradicating HPs (e.g., 61: MRSA BAA-1707 MBEC = 4.69 μM). We also developed bacterial-selective prodrugs (reductively activated quinone-alkyloxycarbonyloxymethyl moiety) to afford HP 87, which demonstrated excellent antibacterial and biofilm eradication activities against MRSA BAA-1707 (MIC = 0.15 μM, MBEC = 12.5 μM). Furthermore, active HPs herein exhibit negligible cytotoxic or hemolytic effects, highlighting their potential to target biofilms.

Prodrug Strategy for PSMA-targeted Delivery of TGX-221 to Prostate Cancer Cells

PubMed Central

Zhao, Yunqi; Duan, Shaofeng; Zeng, Xing; Liu, Chunjing; Davies, Neal M.; Li, Benyi; Forrest, M. Laird

2013-01-01

TGX-221 is a potent, selective, and cell membrane permeable inhibitor of the PI3K p110β catalytic subunit. Recent studies showed that TGX-221 has anti-proliferative activity against PTEN-deficient tumor cell lines including prostate cancers. The objective of this study was to develop an encapsulation system for parenterally delivering TGX-221 to the target tissue through a prostate-specific membrane aptamer (PSMAa10) with little or no side effects. In this study, PEG-PCL micelles were formulated to encapsulate the drug, and a prodrug strategy was pursued to improve the stability of the carrier system. Fluorescence imaging studies demonstrated that the cellular uptake of both drug and nanoparticles were significantly improved by targeted micelles in a PSMA positive cell line. The area under the plasma concentration time curve of the micelle formulation in nude mice was 2.27-fold greater than the naked drug, and the drug clearance rate was 17.5-fold slower. These findings suggest a novel formulation approach for improving site-specific drug delivery of a molecular-targeted prostate cancer treatment. PMID:22494444

Novel Antihypertensive Prodrug from Grape Seed Proanthocyanidin Extract via Acid-Mediated Depolymerization in the Presence of Captopril: Synthesis, Process Optimization, and Metabolism in Rats.

PubMed

Cui, Can; Shi, Ailong; Bai, Shuang; Yan, Pengyu; Li, Qing; Bi, Kaishun

2018-04-11

Grape seed extract contains a high content of proanthocyanidins that can be depolymerized into C-4-substituted (epi)catechin derivatives in the presence of nucleophiles. However, the biological and medicinal values of depolymerization products have been rarely investigated. Recently, we developed a novel depolymerization product (-)-epicatechin-4β- S-captopril methyl ester (ECC) derived from the reaction of grape seed proanthocyanidin extract with captopril in the presence of acidified methanol. A central composite design was employed to select the most appropriate depolymerization temperature and time to obtain the target product ECC with a high yield. A total of 16 metabolites of ECC in rat urine, feces, and plasma were identified using liquid chromatography quadrupole time-of-flight tandem mass spectrometry. The in vivo results suggested that ECC could release captopril methyl ester and epicatechin, followed by the generation of further metabolites captopril and epicatechin sulfate conjugates. Therefore, ECC may be used as a potential prodrug with synergistic or additive hypotensive effects.

Synthesis and Characterization of a Novel Phenolic Lipid for Use as Potential Lipophilic Antioxidant and as a Prodrug of Butyric Acid.

PubMed

Kaki, Shiva Shanker; Kunduru, Konda Reddy; Kanjilal, Sanjit; Narayana Prasad, Rachapudi Badari

2015-01-01

Ferulic acid was modified to produce a novel phenolipid containing butyl chains. Ferulic acid was esterified with butanol to produce butyl ferulate which was further dihydroxylated followed by esterification with butyric anhydride to produce the phenolipid containing butyric acid. IR, NMR and MS techniques confirmed the structure of the synthesized structured lipophilic phenolic compound. The synthesized compound was tested for in vitro antioxidant and antimicrobial activities. The produced phenolipid showed moderate antioxidant activity in DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging assay but in linoleic acid oxidation method, it exhibited good activity compared with the parent compound and the reference compounds. The prepared derivative could find applications as antioxidant in lipophilic systems and also as a potential prodrug of butyric acid. It also showed antibacterial effect against the four bacterial strains studied. The drug-likeness properties of the prepared molecule calculated were in the acceptable ranges according to Lipinski's rule of 5 and suggest that it has potential to cross the blood-brain barrier.

Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy

NASA Astrophysics Data System (ADS)

Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

2014-06-01

Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes and shapes, high drug loadings, ease of surface modification and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48±3 wt% cisplatin prodrug and 45±5 wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4±2.9 and 12.0±3.9 h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumour xenograft models evaluated, including CT26 colon cancer, H460 lung cancer and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared with free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumour activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy.

Self-assembly behaviour of colistin and its prodrug colistin methanesulfonate: implications for solution stability and solubilization

PubMed Central

Wallace, Stephanie J.; Li, Jian; Nation, Roger L.; Prankerd, Richard J.; Velkov, Tony; Boyd, Ben J.

2010-01-01

Colistin is an amphiphilic antibiotic that has re-emerged into clinical use due to the increasing prevalence of difficult-to-treat Gram-negative infections. The existence of self-assembling colloids in solutions of colistin and its derivative prodrug, colistin methanesulfonate (CMS) was investigated. Colistin and CMS reduced the air-water interfacial tension, and dynamic light scattering (DLS) studies showed the existence of 2.07 ± 0.3 nm aggregates above 1.5 mM for colistin, and of 1.98 ± 0.36 nm aggregates for CMS above 3.5 mM (mean ± SD). Above the respective critical micelle concentrations (CMC) the solubility of azithromycin, a hydrophobic antibiotic, increased approximately linearly with increasing surfactant concentration (5:1 mol ratio colistin:azithromycin), suggestive of hydrophobic domains within the micellar cores. Rapid conversion of CMS to colistin occurred below the CMC (60 % over 48 hr), while conversion above the CMC was less than 1 %. The formation of colistin and CMS micelles demonstrated in this study is the proposed mechanism for solubilization of azithromycin and the concentration-dependent stability of CMS. PMID:20302384

Virus-directed enzyme prodrug therapy and the assessment of the cytotoxic impact of some benzimidazole derivatives.

PubMed

Szewczuk, Michał; Boguszewska, Karolina; Żebrowska, Marta; Balcerczak, Ewa; Stasiak, Marta; Świątkowska, Maria; Błaszczak-Świątkiewicz, Katarzyna

2017-07-01

Virus-directed enzyme prodrug therapy is one of the major strategy of increasing cytotoxicity of bioreductive agents. This research intended to examine new selected benzimidazole derivatives as a substrate for nitroreductase, the enzyme involved in nitroreduction which is responsible to the production of cytotoxic metabolites. In this way, the selectivity and strength of cytotoxicity can be raised. The effect of benzimidazoles on virus transfected cells and non-virus transfected cells A549 cell line was established by Annexin V + propidium iodide test, western blot, and polymerase chain reaction analysis of specific pro- and anti-apoptotic proteins in the corresponding gene expression and additionally nitroreductase gene expression. Our results proved the pro-apoptotic properties of all tested compounds in normoxia and hypoxia, especially according to virused A549 cells where the time of exposition was reduced from 48 to 4 h. In this shorten period of time, the strongest activity was shown by N-oxide compounds with nitro-groups. The apoptosis was confirmed by generation of BAX gene and protein and reduction of BCL2 gene and protein.

When sepsis persists: a review of MRSA bacteraemia salvage therapy.

PubMed

Kullar, Ravina; Sakoulas, George; Deresinski, Stan; van Hal, Sebastiaan J

2016-03-01

MRSA bacteraemia (MRSAB), including infective endocarditis, carries a high mortality rate, with up to 50% of patients failing initial therapy with vancomycin and requiring salvage therapy. Persistent MRSAB can be difficult to successfully eliminate, especially when source control is not possible due to an irremovable focus or the bacteraemia still persists despite surgical intervention. Although vancomycin and daptomycin are the only two antibiotics approved by the US FDA for the treatment of patients with MRSAB as monotherapy, the employment of novel strategies is required to effectively treat patients with persistent MRSAB and these may frequently involve combination drug therapy. Treatment strategies that are reviewed in this manuscript include vancomycin combined with a β-lactam, daptomycin-based therapy, ceftaroline-based therapy, linezolid-based therapy, quinupristin/dalfopristin, telavancin, trimethoprim/sulfamethoxazole-based therapy and fosfomycin-based therapy. We recommend that combination antibiotic therapy be considered for use in MRSAB salvage treatment. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Anti-MRSA beta-lactams in development, with a focus on ceftobiprole: the first anti-MRSA beta-lactam to demonstrate clinical efficacy.

PubMed

Bush, Karen; Heep, Markus; Macielag, Mark J; Noel, Gary J

2007-04-01

Ceftobiprole is the first of the investigational beta-lactam antibiotics with in vitro activity against methicillin-resistant staphylococci to reach and complete Phase III therapeutic trials. Its antibacterial spectrum includes methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, penicillin-resistant streptococci and many Gram-negative pathogens. It has demonstrated in vivo activity against many experimental infections caused by these pathogens. Ceftobiprole has completed Phase III clinical trials for complicated skin and skin structure infections, is being studied in Phase III pneumonia trials and has demonstrated non-inferiority compared with vancomycin in a Phase III complicated skin and skin structure infections trial, resulting in > 90% clinical cures of infections caused by MRSA. Other anti-MRSA beta-lactams in therapeutic clinical trials include the carbapenem CS-023/RO-4908463 and the cephalosporin ceftaroline (PPI-0903). The future of all of these agents will depend on their clinical efficacy, safety and their ability to be accepted as beta-lactams for the reliable treatment of a broad spectrum of infections, including those caused by MRSA.

Bioorthogonal Catalysis: A General Method To Evaluate Metal-Catalyzed Reactions in Real Time in Living Systems Using a Cellular Luciferase Reporter System.

PubMed

Hsu, Hsiao-Tieh; Trantow, Brian M; Waymouth, Robert M; Wender, Paul A

2016-02-17

The development of abiological catalysts that can function in biological systems is an emerging subject of importance with significant ramifications in synthetic chemistry and the life sciences. Herein we report a biocompatible ruthenium complex [Cp(MQA)Ru(C3H5)](+)PF6(-) 2 (Cp = cyclopentadienyl, MQA = 4-methoxyquinoline-2-carboxylate) and a general analytical method for evaluating its performance in real time based on a luciferase reporter system amenable to high throughput screening in cells and by extension to evaluation in luciferase transgenic animals. Precatalyst 2 activates alloc-protected aminoluciferin 4b, a bioluminescence pro-probe, and releases the active luminophore, aminoluciferin (4a), in the presence of luciferase-transfected cells. The formation and enzymatic turnover of 4a, an overall process selected because it emulates pro-drug activation and drug turnover by an intracellular target, is evaluated in real time by photon counting as 4a is converted by intracellular luciferase to oxyaminoluciferin and light. Interestingly, while the catalytic conversion (activation) of 4b to 4a in water produces multiple products, the presence of biological nucleophiles such as thiols prevents byproduct formation and provides almost exclusively luminophore 4a. Our studies show that precatalyst 2 activates 4b extracellularly, exhibits low toxicity at concentrations relevant to catalysis, and is comparably effective in two different cell lines. This proof of concept study shows that precatalyst 2 is a promising lead for bioorthogonal catalytic activation of pro-probes and, by analogy, similarly activatable pro-drugs. More generally, this study provides an analytical method to measure abiological catalytic activation of pro-probes and, by analogy with our earlier studies on pro-Taxol, similarly activatable pro-drugs in real time using a coupled biological catalyst that mediates a bioluminescent readout, providing tools for the study of imaging signal amplification and of targeted therapy.

Activity of the HIV-1 Attachment Inhibitor BMS-626529, the Active Component of the Prodrug BMS-663068, against CD4-Independent Viruses and HIV-1 Envelopes Resistant to Other Entry Inhibitors

PubMed Central

Li, Zhufang; Zhou, Nannan; Sun, Yongnian; Ray, Neelanjana; Lataillade, Max; Hanna, George J.

2013-01-01

BMS-626529 is a novel small-molecule HIV-1 attachment inhibitor active against both CCR5- and CXCR4-tropic viruses. BMS-626529 functions by preventing gp120 from binding to CD4. A prodrug of this compound, BMS-663068, is currently in clinical development. As a theoretical resistance pathway to BMS-663068 could be the development of a CD4-independent phenotype, we examined the activity of BMS-626529 against CD4-independent viruses and investigated whether resistance to BMS-626529 could be associated with a CD4-independent phenotype. Finally, we evaluated whether cross-resistance exists between BMS-626529 and other HIV-1 entry inhibitors. Two laboratory-derived envelopes with a CD4-independent phenotype (one CXCR4 tropic and one CCR5 tropic), five envelopes from clinical isolates with preexisting BMS-626529 resistance, and several site-specific mutant BMS-626529-resistant envelopes were examined for their dependence on CD4 for infectivity or susceptibility to BMS-626529. Viruses resistant to other entry inhibitors (enfuvirtide, maraviroc, and ibalizumab) were also examined for susceptibility to BMS-626529. Both CD4-independent laboratory isolates retained sensitivity to BMS-626529 in CD4− cells, while HIV-1 envelopes from viruses resistant to BMS-626529 exhibited no evidence of a CD4-independent phenotype. BMS-626529 also exhibited inhibitory activity against ibalizumab- and enfuvirtide-resistant envelopes. While there appeared to be some association between maraviroc resistance and reduced susceptibility to BMS-626529, an absolute correlation cannot be presumed, since some CCR5-tropic maraviroc-resistant envelopes remained sensitive to BMS-626529. Clinical use of the prodrug BMS-663068 is unlikely to promote resistance via generation of CD4-independent virus. No cross-resistance between BMS-626529 and other HIV entry inhibitors was observed, which could allow for sequential or concurrent use with different classes of entry inhibitors. PMID:23774428

[Killing effects of PWZL plasmid-mediated double suicide gene on human lens epithelium cells].

PubMed

Yan, Xiao-ran; Wu, Hong; Yu, Hai-tao; Wang, Xiu; Zhang, Yu

2008-04-01

To investigate the killing efficiency of PWZL plasmid-mediated herpes simplex virus-thymidine kinase (TK) and E. coli cytosine deaminase (CD) on human lens epithelium cells followed by the treatment of prodrugs. PWZL plasmid was used as a vehicle, to transduce double suicide genes into the human lens epithelium in vitro, then the cells were treated with fluorocytosine (5-FC) and/or ganciclovir (GCV) at different concentrations. The cell growth of the lens epithelium cells was observed by light microscope. MTT analysis was used to estimate the cell survival rate and the bystander effect was analyzed simultaneously. The significance of difference between each group was treated by statistical tests. The CD and TK gene could be joined into PWZL plasmid successfully, and did not have any special effect on normal cells. There was no significant difference in cell viability between CD-TK transfected cells and control cells. Cell viability in cells treated with prodrugs was decreased in a time-dependent manner. At the end of the experiment, cell viability was lowest in GCV 10 mg/L +5-FC 60 mg/L group, GCV 10 mg/L + 5-FC 100 mg/L group and GCV 100 mg/L + 5-FC 100 mg/L group. There were no significant differences between these three groups (X2 = 1.25 , P > 0.01). Analysis of bystander effect indicated that the cell viability in GCV 100 mg/L + 5-FC 100 mg/L group and GCV 10 mg/L +5-FC 60 mg/L group was significantly lower than that in the controls (t = 10.26, 13.16; P < 0.01). PWZL plasmid can transfect the CD and TK genes into lens epithelium cells successfully and efficiently. CD and TK genes can be expressed steadily. Transfection of double suicide gene reduces the dosage of prodrugs required for killing cells. The combination of 5-FC with GCV shows the greatest killing effect and also has the bystander effect.

Determination of the mitigating effect of colon-specific bioreversible codrugs of mycophenolic acid and aminosugars in an experimental colitis model in Wistar rats

PubMed Central

Chopade, Shakuntala Santosh; Dhaneshwar, Suneela Sunil

2018-01-01

AIM To design colon-targeted codrugs of mycophenolic acid (MPA) and aminosugars as a safer option to mycophenolate mofetil (MMF) in the management of inflammatory bowel disease. METHODS Codrugs were synthesized by coupling MPA with aminosugars (D-glucosamine and D-galactosamine) using EDCI coupling. The structures were confirmed by infrared radiation, nuclear magnetic resonance, mass spectroscopy and elemental analysis. The release profile of codrugs was extensively studied in aqueous buffers, upper gastrointestinal homogenates, faecal matter and caecal homogenates (in vitro) and rat blood (in vitro). Anti-colitic activity was assessed in 2,4,6-trinitrobezenesulfonic acid-induced colitis in Wistar rats by the estimation of various demarcating parameters. Statistical evaluation was performed by applying one-way and two-way ANOVA when compared with the disease control. RESULTS The prodrugs resisted activation in HCl buffer (pH 1.2) and stomach homogenates of rats with negligible hydrolysis in phosphate buffer (pH 7.4) and intestinal homogenates. Incubation with colon homogenates (in vitro) produced 76% to 89% release of MPA emphasizing colon-specific activation of codrugs and the release of MPA and aminosugars at the site of action. In the in vitro studies, the prodrug of MPA with D-glucosamine (MGLS) was selected which resulted in 68% release of MPA in blood. in vitro studies on MGLS revealed its colon-specific activation after a lag time of 8 h which could be ascribed to the hydrolytic action of N-acyl amidases found in the colon. The synthesized codrugs markedly diminished disease activity score and revived the disrupted architecture of the colon that was comparable to MMF but superior to MPA. CONCLUSION The significant attenuating effect of prodrugs and individual aminosugars on colonic inflammation proved that the rationale of the codrug approach is valid. PMID:29563754

Biotransformations of Antidiabetic Vanadium Prodrugs in Mammalian Cells and Cell Culture Media: A XANES Spectroscopic Study

PubMed Central

2016-01-01

The antidiabetic activities of vanadium(V) and -(IV) prodrugs are determined by their ability to release active species upon interactions with components of biological media. The first X-ray absorption spectroscopic study of the reactivity of typical vanadium (V) antidiabetics, vanadate ([VVO4]3–, A) and a vanadium(IV) bis(maltolato) complex (B), with mammalian cell cultures has been performed using HepG2 (human hepatoma), A549 (human lung carcinoma), and 3T3-L1 (mouse adipocytes and preadipocytes) cell lines, as well as the corresponding cell culture media. X-ray absorption near-edge structure data were analyzed using empirical correlations with a library of model vanadium(V), -(IV), and -(III) complexes. Both A and B ([V] = 1.0 mM) gradually converged into similar mixtures of predominantly five- and six-coordinate VV species (∼75% total V) in a cell culture medium within 24 h at 310 K. Speciation of V in intact HepG2 cells also changed with the incubation time (from ∼20% to ∼70% VIV of total V), but it was largely independent of the prodrug used (A or B) or of the predominant V oxidation state in the medium. Subcellular fractionation of A549 cells suggested that VV reduction to VIV occurred predominantly in the cytoplasm, while accumulation of VV in the nucleus was likely to have been facilitated by noncovalent bonding to histone proteins. The nuclear VV is likely to modulate the transcription process and to be ultimately related to cell death at high concentrations of V, which may be important in anticancer activities. Mature 3T3-L1 adipocytes (unlike for preadipocytes) showed a higher propensity to form VIV species, despite the prevalence of VV in the medium. The distinct V biochemistry in these cells is consistent with their crucial role in insulin-dependent glucose and fat metabolism and may also point to an endogenous role of V in adipocytes. PMID:25906315

Rp-cAMPS Prodrugs Reveal the cAMP Dependence of First-Phase Glucose-Stimulated Insulin Secretion

PubMed Central

Schwede, Frank; Chepurny, Oleg G.; Kaufholz, Melanie; Bertinetti, Daniela; Leech, Colin A.; Cabrera, Over; Zhu, Yingmin; Mei, Fang; Cheng, Xiaodong; Manning Fox, Jocelyn E.; MacDonald, Patrick E.; Genieser, Hans-G.; Herberg, Friedrich W.

2015-01-01

cAMP-elevating agents such as the incretin hormone glucagon-like peptide-1 potentiate glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells. However, a debate has existed since the 1970s concerning whether or not cAMP signaling is essential for glucose alone to stimulate insulin secretion. Here, we report that the first-phase kinetic component of GSIS is cAMP-dependent, as revealed through the use of a novel highly membrane permeable para-acetoxybenzyl (pAB) ester prodrug that is a bioactivatable derivative of the cAMP antagonist adenosine-3′,5′-cyclic monophosphorothioate, Rp-isomer (Rp-cAMPS). In dynamic perifusion assays of human or rat islets, a step-wise increase of glucose concentration leads to biphasic insulin secretion, and under these conditions, 8-bromoadenosine-3′,5′-cyclic monophosphorothioate, Rp-isomer, 4-acetoxybenzyl ester (Rp-8-Br-cAMPS-pAB) inhibits first-phase GSIS by up to 80%. Surprisingly, second-phase GSIS is inhibited to a much smaller extent (≤20%). Using luciferase, fluorescence resonance energy transfer, and bioluminescence resonance energy transfer assays performed in living cells, we validate that Rp-8-Br-cAMPS-pAB does in fact block cAMP-dependent protein kinase activation. Novel effects of Rp-8-Br-cAMPS-pAB to block the activation of cAMP-regulated guanine nucleotide exchange factors (Epac1, Epac2) are also validated using genetically encoded Epac biosensors, and are independently confirmed in an in vitro Rap1 activation assay using Rp-cAMPS and Rp-8-Br-cAMPS. Thus, in addition to revealing the cAMP dependence of first-phase GSIS from human and rat islets, these findings establish a pAB-based chemistry for the synthesis of highly membrane permeable prodrug derivatives of Rp-cAMPS that act with micromolar or even nanomolar potency to inhibit cAMP signaling in living cells. PMID:26061564

Enhancement of hypoxia-activated prodrug TH-302 anti-tumor activity by Chk1 inhibition.

PubMed

Meng, Fanying; Bhupathi, Deepthi; Sun, Jessica D; Liu, Qian; Ahluwalia, Dharmendra; Wang, Yan; Matteucci, Mark D; Hart, Charles P

2015-05-21

The hypoxia-activated prodrug TH-302 is reduced at its nitroimidazole group and selectively under hypoxic conditions releases the DNA cross-linker bromo-isophosphoramide mustard (Br-IPM). Here, we have explored the effect of Chk1 inhibition on TH-302-mediated pharmacological activities. We employed in vitro cell viability, DNA damage, cellular signaling assays and the in vivo HT29 human tumor xenograft model to study the effect of Chk1inhibition on TH-302 antitumor activities. TH-302 cytotoxicity is greatly enhanced by Chk1 inhibition in p53-deficient but not in p53-proficient human cancer cell lines. Chk1 inhibitors reduced TH-302-induced cell cycle arrest via blocking TH-302-induced decrease of phosphorylation of histone H3 and increasing Cdc2-Y15 phosphorylation. Employing the single-cell gel electrophoresis (comet) assay, we observed a potentiation of the TH-302 dependent tail moment. TH-302 induced γH2AX and apoptosis were also increased upon the addition of Chk1 inhibitor. Potentiation of TH-302 cytotoxicity by Chk1 inhibitor was only observed in cell lines proficient in, but not deficient in homology-directed DNA repair. We also show that combination treatment led to lowering of Rad51 expression levels as compared to either agent alone. In vivo data demonstrate that Chk1 inhibitor enhances TH-302 anti-tumor activity in p53 mutant HT-29 human tumor xenografts, supporting the hypothesis that these in vitro results can translate to enhanced in vivo efficacy of the combination. TH-302-mediated in vitro and in vivo anti-tumor activities were greatly enhanced by the addition of Chk1 inhibitors. The preclinical data presented in this study support a new approach for the treatment of p53-deficient hypoxic cancers by combining Chk1 inhibitors with the hypoxia-activated prodrug TH-302.

Effects of JS-K, a novel anti-cancer nitric oxide prodrug, on gene expression in human hepatoma Hep3B cells.

PubMed

Dong, Ray; Wang, Xueqian; Wang, Huan; Liu, Zhengyun; Liu, Jie; Saavedra, Joseph E

2017-04-01

JS-K is a novel anticancer nitric oxide (NO) prodrug effective against a variety of cancer cells, including the inhibition of AM-1 hepatoma cell growth in rats. To further evaluate anticancer effects of JS-K, human hepatoma Hep3B cells were treated with JS-K and the compound control JS-43-126 at various concentrations (0-100μM) for 24h, and cytotoxicity was determined by the MTS assay. The compound control JS-43-126 was not cytotoxic to Hep3B cells at concentrations up to 100μM, while the LC 50 for JS-K was about 10μM. To examine the molecular mechanisms of antitumor effects of JS-K, Hep3B cells were treated with 1-10μM of JS-K for 24h, and then subjected to gene expression analysis via real time RT-PCR and protein immunostain via confocal images. JS-K is a GST-α targeting NO prodrug, and decreased immunostaining for GST-α was associated with JS-K treatment. JS-K activated apoptosis pathways in Hep3B cells, including induction of caspase-3, caspase-9, Bax, TNF-α, and IL-1β, and immunostaining for caspase-3 was intensified. The expressions of thrombospondin-1 (TSP-1) and the tissue inhibitors of metalloproteinase-1 (TIMP-1) were increased by JS-K at both transcript and protein levels. JS-K treatment also increased the expression of differentiation-related genes CD14 and CD11b, and depressed the expression of c-myc in Hep3B cells. Thus, multiple molecular events appear to be associated with anticancer effects of JS-K in human hepatoma Hep3B cells, including activation of genes related to apoptosis and induction of genes involved in antiangiogenesis and tumor cell migration. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Dual-targeted and pH-sensitive Doxorubicin Prodrug-Microbubble Complex with Ultrasound for Tumor Treatment

PubMed Central

Luo, Wanxian; Wen, Ge; Yang, Li; Tang, Jiao; Wang, Jianguo; Wang, Jihui; Zhang, Shiyu; Zhang, Li; Ma, Fei; Xiao, Liling; Wang, Ying; Li, Yingjia

2017-01-01

In this study, we investigated the potential of a dual-targeted pH-sensitive doxorubicin prodrug-microbubble complex (DPMC) in ultrasound (US)-assisted antitumor therapy. The doxorubicin prodrug (DP) consists of a succinylated-heparin carrier conjugated with doxorubicin (DOX) via hydrazone linkage and decorated with dual targeting ligands, folate and cRGD peptide. Combination of microbubble (MB) and DP, generated via avidin-biotin binding, promoted intracellular accumulation and improved therapeutic efficiency assisted by US cavitation and sonoporation. Aggregates of prepared DP were observed with an inhomogeneous size distribution (average diameters: 149.6±29.8 nm and 1036.2±38.8 nm, PDI: 1.0) while DPMC exhibited a uniform distribution (average diameter: 5.804±2.1 μm), facilitating its usage for drug delivery. Notably, upon US exposure, DPMC was disrupted and aggregated DP dispersed into homogeneous small-sized nanoparticles (average diameter: 128.6±42.3 nm, PDI: 0.21). DPMC could target to angiogenic endothelial cells in tumor region via αvβ3-mediated recognition and subsequently facilitate its specific binding to tumor cells mediated via recognition of folate receptor (FR) after US exposure. In vitro experiments showed higher tumor specificity and killing ability of DPMC with US than free DOX and DP for breast cancer MCF-7 cells. Furthermore, significant accumulation and specificity for tumor tissues of DPMC with US were detected using in vivo fluorescence and ultrasound molecular imaging, indicating its potential to integrate tumor imaging and therapy. In particular, through inducing apoptosis, inhibiting cell proliferation and antagonizing angiogenesis, DPMC with US produced higher tumor inhibition rates than DOX or DPMC without US in MCF-7 xenograft tumor-bearing mice while inducing no obvious body weight loss. Our strategy provides an effective platform for the delivery of large-sized or aggregated particles to tumor sites, thereby extending their therapeutic applications in vivo. PMID:28255342

Protein Nanoscaffolds for Delivering Toxic Inorganic Cargo to Cancer Cells

NASA Astrophysics Data System (ADS)

Cioloboc, Daniela

Targeted delivery of anticancer drugs or prodrugs to tumors can minimize systemic toxicity and side effects. This study develops platforms for targeted delivery of two potentially less systemically toxic prodrugs by exploiting the native and/or bioinorganic properties of two ferritins, both of which function naturally as iron storage proteins. Two delivery approaches were investigated. The first system was designed to serve as either an enhancement or alternative to traditional photodynamic therapy by generating hydroxyl radical in addition to singlet oxygen as the toxic reactive oxygen species. This system used Escherichia coli bacterioferritin (Bfr) loaded with 2,500 irons and multiple zinc-porphyrin (ZnP) photosensitizers. Ferrous iron was released by photoreduction of ferric iron stored within the Bfr protein shell. Hydroxyl radicals were generated via the Fenton reaction between hydrogen peroxide and the released ferrous iron. The outer surface of the Bfr protein shell was coated with peptides that specifically bind to a receptor known to be overexpressed in many tumor cells and tumor vasculature. The iron-loaded peptide-ZnP-Bfr was endocytosed by melanoma cells, where it showed photo-triggered release of iron and light-dependent cytotoxicity. The second system, built around human heavy chain ferritin (HFn), was loaded with arsenate as a less toxic "prodrug" and designed to release arsenic in its toxic, therapeutically effective reduced form, arsenic trioxide (ATO). The Hfn shell was coated with peptides targeting receptors that are hyperexpressed in triple negative breast cancers. The arsenate/iron-loaded-Hfn was endocytosed by a breast cancer cell line and showed cytotoxicity equivalent to that of free ATO on an arsenic basis, whereas the "empty" or iron-only loaded Hfn showed no cytotoxicity. Although HFn has previously been used to deliver organic drugs and imaging agents, these new results demonstrate that both Bfr and HFn can be manipulated to function as 'Trojan horse' nanocarriers for inorganic drugs.

An on-spot internal standard addition approach for accurately determining colistin A and colistin B in dried blood spots using ultra high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Tsai, I-Lin; Kuo, Ching-Hua; Sun, Hsin-Yun; Chuang, Yu-Chung; Chepyala, Divyabharathi; Lin, Shu-Wen; Tsai, Yun-Jung

2017-10-25

Outbreaks of multidrug-resistant Gram-negative bacterial infections have been reported worldwide. Colistin, an antibiotic with known nephrotoxicity and neurotoxicity, is now being used to treat multidrug-resistant Gram-negative strains. In this study, we applied an on-spot internal standard addition approach coupled with an ultra high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify colistin A and B from dried blood spots (DBSs). Only 15μL of whole blood was required for each sample. An internal standard with the same yield of extraction recoveries as colistin was added to the spot before sample extraction for accurate quantification. Formic acid in water (0.15%) with an equal volume of acetonitrile (50:50v/v) was used as the extraction solution. With the optimized extraction process and LC-MS/MS conditions, colistin A and B could be quantified from a DBS with respective limits of quantification of 0.13 and 0.27μgmL -1 , and the retention times were < 2min. The relative standard deviations of within-run and between-run precisions for peak area ratios were all < 17.3%. Accuracies were 91.5-111.2% for lower limit of quantification, low, medium, and high QC samples. The stability of the easily hydrolyzed prodrug, colistin methanesulfonate, was investigated in DBSs. Less than 4% of the prodrug was found to be hydrolyzed in DBSs at room temperature after 48h. The developed method applied an on-spot internal standard addition approach which benefited the precision and accuracy. Results showed that DBS sampling coupled with the sensitive LC-MS/MS method has the potential to be an alternative approach for colistin quantification, where the bias of prodrug hydrolysis in liquid samples is decreased. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemotherapy of Second Stage Human African Trypanosomiasis: Comparison between the Parenteral Diamidine DB829 and Its Oral Prodrug DB868 in Vervet Monkeys

PubMed Central

Thuita, John K.; Wolf, Kristina K.; Murilla, Grace A.; Bridges, Arlene S.; Boykin, David W.; Mutuku, James N.; Liu, Qiang; Jones, Susan K.; Gem, Charles O.; Ching, Shelley; Tidwell, Richard R.; Wang, Michael Z.; Paine, Mary F.; Brun, Reto

2015-01-01

Human African trypanosomiasis (HAT, sleeping sickness) ranks among the most neglected tropical diseases based on limited availability of drugs that are safe and efficacious, particularly against the second stage (central nervous system [CNS]) of infection. In response to this largely unmet need for new treatments, the Consortium for Parasitic Drug Development developed novel parenteral diamidines and corresponding oral prodrugs that have shown cure of a murine model of second stage HAT. As a rationale for selection of one of these compounds for further development, the pharmacokinetics and efficacy of intramuscular (IM) active diamidine 2,5-bis(5-amidino-2-pyridyl)furan (DB829; CPD-0802) and oral prodrug2,5-bis[5-(N-methoxyamidino)-2-pyridyl]furan (DB868) were compared in the vervet monkey model of second stage HAT. Treatment was initiated 28 days post-infection of monkeys with T. b. rhodesiense KETRI 2537. Results showed that IM DB829 at 5 mg/kg/day for 5 consecutive days, 5 mg/kg/day every other day for 5 doses, or 2.5 mg/kg/day for 5 consecutive days cured all monkeys (5/5). Oral DB868 was less successful, with no cures (0/2) at 3 mg/kg/day for 10 days and cure rates of 1/4 at 10 mg/kg/day for 10 days and 20 mg/kg/day for 10 days; in total, only 2/10 monkeys were cured with DB868 dose regimens. The geometric mean plasma Cmax of IM DB829 at 5 mg/kg following the last of 5 doses was 25-fold greater than that after 10 daily oral doses of DB868 at 20 mg/kg. These data suggest that the active diamidine DB829, administered IM, should be considered for further development as a potential new treatment for second stage HAT. PMID:25654243

Preclinical Assessment of Lisdexamfetamine as an Agonist Medication Candidate for Cocaine Addiction: Effects in Rhesus Monkeys Trained to Discriminate Cocaine or to Self-Administer Cocaine in a Cocaine Versus Food Choice Procedure

PubMed Central

Hutsell, Blake A.; Blough, Bruce E.; Poklis, Justin L.; Negus, S. Stevens

2015-01-01

Background: Chronic amphetamine treatment decreases cocaine consumption in preclinical and human laboratory studies and in clinical trials. Lisdexamfetamine is an amphetamine prodrug in which L-lysine is conjugated to the terminal nitrogen of d-amphetamine. Prodrugs may be advantageous relative to their active metabolites due to slower onsets and longer durations of action; however, lisdexamfetamine treatment’s efficacy in decreasing cocaine consumption is unknown. Methods: This study compared lisdexamfetamine and d-amphetamine effects in rhesus monkeys using two behavioral procedures: (1) a cocaine discrimination procedure (training dose = 0.32mg/kg cocaine, i.m.); and (2) a cocaine-versus-food choice self-administration procedure. Results: In the cocaine-discrimination procedure, lisdexamfetamine (0.32–3.2mg/kg, i.m.) substituted for cocaine with lower potency, slower onset, and longer duration of action than d-amphetamine (0.032–0.32mg/kg, i.m.). Consistent with the function of lisdexamfetamine as an inactive prodrug for amphetamine, the time course of lisdexamfetamine effects was related to d-amphetamine plasma levels by a counter-clockwise hysteresis loop. In the choice procedure, cocaine (0–0.1mg/kg/injection, i.v.) and food (1g banana-flavored pellets) were concurrently available, and cocaine maintained a dose-dependent increase in cocaine choice under baseline conditions. Treatment for 7 consecutive days with lisdexamfetamine (0.32–3.2mg/kg/day, i.m.) or d-amphetamine (0.032–0.1mg/kg/h, i.v.) produced similar dose-dependent rightward shifts in cocaine dose-effect curves and decreases in preference for 0.032mg/kg/injection cocaine. Conclusions: Lisdexamfetamine has a slower onset and longer duration of action than amphetamine but retains amphetamine’s efficacy to reduce the choice of cocaine in rhesus monkeys. These results support further consideration of lisdexamfetamine as an agonist-based medication candidate for cocaine addiction. PMID:25618405

New Enzyme Prodrug and Methionine-Depletion Combination Therapy of Breast Cancer Designed for Effective Delivery to the Tumor

DTIC Science & Technology

2012-10-01

arabinofuranosyl-2-fluoroadenine 5’-phosphate in mice and dogs , Cancer Treat. Rep. 67 (1983) 445-456. 9. X. Huang, M. Bennett, P.E. Thorpe, A...infections, and gastrointestinal tox ici t ies such as stromatitis, nausea, vomiting, and diarrhea [3 ]. To * Corresponding author. Address: School

Persuader Sex Differences and Peer Pressure Effects on Attitudes Toward Drug Abuse.

ERIC Educational Resources Information Center

Stone, Christopher I.; Shute, Robert E.

This experiment was performed to assess the effects of the experimental confederates' sex and contrived group peer pressure on the drug attitudes of male college students. Subjects were exposed to all male or all female groups of experimental confederates (persuaders) who expressed either extremely pro-drug or anti-drug sentiments in a guided…

Modifying Pro-Drug Risk Factors in Adolescents: Results from Project ALERT

ERIC Educational Resources Information Center

Ghosh-Dastidar, Bonnie; Longshore, Douglas L.; Ellickson, Phyllis L.; McCaffrey, Daniel F.

2004-01-01

The objective of this study was to evaluate the impact of a revised state-of-the-art drug prevention program, Project ALERT, on risk factors for drug use in mostly rural midwestern schools and communities. Fifty-five middle schools from South Dakota were randomly assigned to treatment or control conditions. Treatment-group students received 11…

Legubicin, a Tumor-Activated Prodrug for Breast Cancer Therapy

DTIC Science & Technology

2007-04-01

carcinomas, leukemias, lymphomas, melanomas, fibrosarcomas , neuroblastoma, and the like. The cancer can, for example, be autoimmune deficiency syndrome...their analogs. (a) 4-Nitrophenyl chloroformate, Py, CH2Cl2, 0°C; (b) (i) OsO4 ( cat ), NMO, citric acid, CH2Cl2-H2O (10:1), RT, (ii) NaIO4, THF- H2O (1:1

Anti-cancer agents based on 6-trifluoromethoxybenzimidazole derivatives and method of making

DOEpatents

Gakh, Andrei A.; Vovk, Mykhaylo V.; Mel'nychenko, Nina V.; Sukach, Volodymyr A.

2012-08-14

The present disclosure relates to novel compounds having the structural Formulas (1a,1b), stereoisomers, tautomers, racemics, prodrugs, metabolites thereof, or pharmaceutically acceptable salt and/or solvate thereof as chemotherapy agents for treating of cancer, particularly androgen-independent prostate cancer. The disclosure also relates to methods for preparing said compounds, and to pharmaceutical compositions comprising said compounds.

Anti-cancer agents based on 6-trifluoromethoxybenzimidazole derivatives and method of making

DOEpatents

Gakh, Andrei A; Vovk, Mykhaylo V; Mel& #x27; nychenko, Nina V; Sukach, Volodymyr A

2012-10-23

The present disclosure relates to novel compounds having the structural Formulas (1a,1b), stereoisomers, tautomers, racemics, prodrugs, metabolites thereof, or pharmaceutically acceptable salt and/or solvate thereof as chemotherapy agents for treating of cancer, particularly androgen-independent prostate cancer. The disclosure also relates to methods for preparing said compounds, and to pharmaceutical compositions comprising said compounds.

Photoacoustic molecular imaging of angiogenesis using theranostic ανβ3-targeted copper nanoparticles incorporating a sn-2 lipase-labile fumagillin prodrug

NASA Astrophysics Data System (ADS)

Zhang, Ruiying; Cai, Xin; Yang, Xiaoxia; Senpan, Angana; Allen, John S.; Pan, Dipanjan; Lanza, Gregory M.; Wang, Lihong V.

2014-03-01

Photoacoustic (PA) tomography imaging is an emerging, versatile, and noninvasive imaging modality, which combines the advantages of both optical imaging and ultrasound imaging. It opens up opportunities for noninvasive imaging of angiogenesis, a feature of skin pathologies including cancers and psoriasis. In this study, high-density copper oleate encapsulated within a phospholipid surfactant (CuNPs) generated a soft nanoparticle with PA contrast comparable to gold. Within the near-infrared window, the copper nanoparticles can provide a signal more than 7 times higher that of blood. ανβ3-targeted of CuNPs in a Matrigel mouse model demonstrated prominent PA contrast enhancement of the neovasculature compared to mice given nontargeted or competitively inhibited CuNPs. Incorporation of a sn-2 lipase-labile fumagillin prodrug into the CuNPs produced marked antiangiogenesis in the same model, demonstrating the theranostic potential of a PA agent for the first time in vivo. With a PA signal comparable to gold-based nanoparticles yet a lower cost and demonstrated drug delivery potential, ανβ3-targeted CuNPs hold great promise for the management of skin pathologies with neovascular features.