Note: This page contains sample records for the topic micelle-based drug delivery from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Biodegradable Stereocomplex Micelles Based on Dextran-block-polylactide as Efficient Drug Deliveries.  

PubMed

Biodegradable stereocomplex micelles (SCMs) based on amphiphilic dextran-block-polylactide (Dex-b-PLA) were designed and used for efficient intracellular drug deliveries. The Dex-b-PLA copolymers were successfully synthesized by click reaction. The structures of the resultant copolymers were verified by (1)H NMR and FT-IR spectra. The formation of stable micelles through self-assembly driven by the stereocomplexation between enantiomeric l- and d-PLA blocks was characterized by transmission electron microscopy (TEM), dynamic laser scattering (DLS), and fluorescence techniques. It was interesting to observe that the SCMs showed lower critical micelle concentration values (CMCs) because of the stereocomplex interaction between PLLA and PDLA. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis provided information on the thermal and crystal properties of the copolymers and SCMs. The improved stability of SCMs should be attractive for intracellular drug delivery. Thus, a model anticancer drug doxorubicin (DOX) was loaded into micelles, and the in vitro drug release in was also studied. The release kinetics of DOX showed DOX-loaded SCMs exhibited slower DOX release. Confocal laser scanning microscopy (CLSM) and flow cytometry studies also showed that the DOX-loaded SCMs exhibited a slower drug release behavior. Meanwhile, the MTT assay demonstrated that DOX-loaded SCMs show lower cellular proliferation inhibition against HepG2. In sum, the micelles through self-assembly driven by stereocomplex interaction would have great potential to be used as stable delivery vehicles for pharmaceutical and biomedical applications. PMID:24112037

Zhao, Ziwei; Zhang, Zhe; Chen, Li; Cao, Yue; He, Chaoliang; Chen, Xuesi

2013-10-10

2

Hydrotropic polymeric mixed micelles based on functional hyperbranched polyglycerol copolymers as hepatoma-targeting drug delivery system.  

PubMed

Mixed copolymer nanoparticles (NPs) self-assembled from ?-cyclodextrin-grafted hyperbranched polyglycerol (HPG-g-CD) and lactobionic acid (LA)-grafted hyperbranched polyglycerol (HPG-g-LA) were applied as carriers for a hydrophobic antitumor drug, paclitaxel (PTX), achieving hepatocellular carcinoma-targeted delivery. The resulting NPs exhibited high drug loading capacity and substantial stability in aqueous solution. In vitro drug release studies demonstrated a controlled drug release profile with increased release at acidic pH. Remarkably, tumor proliferation assays showed that PTX-loaded mixed copolymer NPs inhibited asialoglycoprotein (ASGP) receptor positive HepG2 cell proliferation in a concentration-dependent manner in comparison with ASGP receptor negative BGC-823 cells. Moreover, the competition assay demonstrated that the small molecular LA inhibited the cellular uptake of the PTX-loaded mixed copolymer NPs, indicating the ASGP receptor-mediated endocytosis in HepG2 cells. In addition, the intracellular uptake tests by confocal laser scanning microscopy showed that the mixed copolymer NPs were more efficiently taken up by HepG2 cells compared with HPG-g-CD NPs. These results suggest a feasible application of the mixed copolymer NPs as nanocarriers for hepatoma-targeted delivery of potent antitumor drugs. PMID:23132353

Zhang, Xuejiao; Zhang, Xinge; Yu, Peien; Han, Yucai; Li, Yangguang; Li, Chaoxing

2012-11-06

3

Solubilization of poorly water-soluble drugs by mixed micelles based on hydrogenated phosphatidylcholine.  

PubMed

A remarkable part of newly developed active pharmaceutical ingredients is rejected in early phase development and will never find a way to a patient because of poor water solubility which is often paired with poor bioavailability. Considering such arising solubility problems the development of application vehicles like mixed micelles (MM) is a challenging research topic in pharmaceutical technology. While known classical MM systems are composed of phosphatidylcholine and bile salts, it was the aim of this study to investigate if alternatively developed MM systems were superior in solubilization of different hydrophobic drugs. The novel MM were also comprised of phosphatidylcholine and (contrarily to bile salts) different other suitable surfactants forming binary MM. As model water-insoluble drug substances two benzodiazepines, diazepam and tetrazepam, and the steroid estradiol were chosen. In this study the solubilization capacities of newly developed MM were compared to those of classical lecithin/bile salt MM systems and different other surfactant containing systems. The MM system with sucrose laurate and hydrogenated PC (hPC) at a weight fraction of 0.5 was found to be superior in drug solubilization of all investigated drugs compared to the classical lecithin/bile salt mixed micelles. Further, a polysorbate 80 solution, also at 5%, was inferior with regard to solubilize the investigated hydrophobic drugs. The MM sizes of the favorite developed MM system, before and after drug incorporation, were analysed by dynamic light scattering (DLS) to evaluate the influence of the drug incorporation. Here, the particle sizes, before and after drug incorporation, remained constant, indicating a stable formation of the solubilizate. Further the critical micelle concentration (CMC) of MM before and after drug incorporation was analysed by three different determination techniques. Constant CMC-values could be obtained regardless if diazepam was encapsulated within the MM or unloaded MM were analysed. PMID:20580793

Rupp, Christopher; Steckel, Hartwig; Müller, Bernd W

2010-05-24

4

Advances in Drug Delivery  

NASA Astrophysics Data System (ADS)

In this article, we review critical aspects in the area of drug delivery. Specifically, delivery of siRNA, remote-controlled delivery, noninvasive delivery, and nanotechnology in drug delivery are reviewed.

Timko, Brian P.; Whitehead, Kathryn; Gao, Weiwei; Kohane, Daniel S.; Farokhzad, Omid; Anderson, Daniel; Langer, Robert

2011-08-01

5

Transdermal drug delivery  

Microsoft Academic Search

Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, noncavitational ultrasound and iontophoresis have also resulted

Mark R Prausnitz; Robert Langer

2008-01-01

6

Polymeric micelles based on poly(ethylene glycol) block poly(racemic amino acids) hybrid polypeptides: conformation-facilitated drug-loading behavior and potential application as effective anticancer drug carriers.  

PubMed

In this work, racemic hybrid polypeptides poly(ethylene glycol) (PEG)-b-poly(racemic-leucine) (PRL) copolymers with different leucine residues have been synthesized and characterized. Using docetaxel as a model molecule, the high drug-loaded spherical micelles based on PEG-PRL were prepared successfully using dialysis, with a tunable particle size from 170 nm to 250 nm obtained by changing the length of the hydrophobic blocks. Facilitated drug-loading behavior (higher drug-loading ability and easier drug-loading process) of PEG-PRL compared with their corresponding levo forms (PEG-b-poly[levo leucine]) was observed and clarified for the first time. With this facilitation, the highest drug-loading content and efficiency of PEG-PRL micelles can achieve 11.2% ± 0.4% and 67.2% ± 2.4%, respectively. All drug-loaded PEG-PRL micelles exhibit a similar release behavior with a sustained release up to 72 hours. The PEG-PRL was shown to be nontoxic against MCF-7 and human umbilical vein endothelial cells up to a concentration of 100 ?g/mL, displaying a good biocompatibility. Also, the docetaxel-loaded PEG-PRL micelles were more toxic than the free drug against MCF-7 human breast cancer cells - both dose and time dependent. Therefore, these high docetaxel-loaded micelles based on racemic hybrid polypeptides appear to be a novel promising nanomedicine for anticancer therapy. PMID:22275827

Gu, Peng Fei; Xu, Hui; Sui, Bo Wen; Gou, Jing Xin; Meng, Ling Kuo; Sun, Feng; Wang, Xiu Jun; Qi, Na; Zhang, Yu; He, Hai Bing; Tang, Xing

2012-01-05

7

Intracochlear Drug Delivery Systems  

PubMed Central

Introduction Advances in molecular biology and in the basic understanding of the mechanisms associated with sensorineural hearing loss and other diseases of the inner ear, are paving the way towards new approaches for treatments for millions of patients. However, the cochlea is a particularly challenging target for drug therapy, and new technologies will be required to provide safe and efficacious delivery of these compounds. Emerging delivery systems based on microfluidic technologies are showing promise as a means for direct intracochlear delivery. Ultimately, these systems may serve as a means for extended delivery of regenerative compounds to restore hearing in patients suffering from a host of auditory diseases. Areas covered in this review Recent progress in the development of drug delivery systems capable of direct intracochlear delivery is reviewed, including passive systems such as osmotic pumps, active microfluidic devices, and systems combined with currently available devices such as cochlear implants. The aim of this article is to provide a concise review of intracochlear drug delivery systems currently under development, and ultimately capable of being combined with emerging therapeutic compounds for the treatment of inner ear diseases. Expert Opinion Safe and efficacious treatment of auditory diseases will require the development of microscale delivery devices, capable of extended operation and direct application to the inner ear. These advances will require miniaturization and integration of multiple functions, including drug storage, delivery, power management and sensing, ultimately enabling closed-loop control and timed-sequence delivery devices for treatment of these diseases.

Borenstein, Jeffrey T.

2011-01-01

8

PECTIN IN CONTROLLED DRUG DELIVERY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Controlled drug delivery remains a research focus for public health to enhance patient compliance, drug efficiency and to reduce the side effects of drugs. Pectin, an edible plant polysaccharide, has shown potential for the construction of drug delivery systems for site-specific drug delivery. Sev...

9

Mucoadhesive drug delivery systems  

PubMed Central

Mucoadhesion is commonly defined as the adhesion between two materials, at least one of which is a mucosal surface. Over the past few decades, mucosal drug delivery has received a great deal of attention. Mucoadhesive dosage forms may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. Application of dosage forms to mucosal surfaces may be of benefit to drug molecules not amenable to the oral route, such as those that undergo acid degradation or extensive first-pass metabolism. The mucoadhesive ability of a dosage form is dependent upon a variety of factors, including the nature of the mucosal tissue and the physicochemical properties of the polymeric formulation. This review article aims to provide an overview of the various aspects of mucoadhesion, mucoadhesive materials, factors affecting mucoadhesion, evaluating methods, and finally various mucoadhesive drug delivery systems (buccal, nasal, ocular, gastro, vaginal, and rectal).

Shaikh, Rahamatullah; Raj Singh, Thakur Raghu; Garland, Martin James; Woolfson, A David; Donnelly, Ryan F.

2011-01-01

10

Cyclodextrins in nasal drug delivery  

Microsoft Academic Search

Nasal drug delivery is an attractive approach for the systemic delivery of high potency drugs with a low oral bioavailability due to extensive gastrointestinal breakdown and high hepatic first-pass effect. For lipophilic drugs nasal delivery is possible if they can be dissolved in the dosage form. Peptide and protein drugs often have a low nasal bioavailability because of their large

F. W. H. M Merkus; J. C Verhoef; E Marttin; S. G Romeijn; P. H. M van der Kuy; W. A. J. J Hermens; N. G. M Schipper

1999-01-01

11

Chronotherapeutic drug delivery.  

PubMed

Living organisms follow a circadian rhythm in which physiological processes such as hormonal secretion, metabolism, heart rate, and renal output are affected by the time of day. Chronotherapy coordinates drug delivery with the circadian rhythm to enhance effectiveness and mitigate adverse effects and is achieved by delivering a drug when the system is most susceptible. Cancer is a chronotherapeutic disorder. Cancer treatment requires high doses of intravenous medication to kill cancerous cells; however, normal cells are also killed, creating intolerable side effects. This review shows that chronotherapy can play a vital role in the quality of life and survival rate for oncology patients. PMID:22955155

Librodo, Paul; Buckley, Mitchell; Luk, Marilyn; Bisso, Andrea

12

Transdermal Drug Delivery  

Microsoft Academic Search

\\u000a Transdermal drug delivery is a validated technology contributing significantly to global pharmaceutical care. Since 1980,\\u000a impressive growth in this field has been observed with many commercial successes; importantly, a new chemical entity was recently\\u000a developed and approved for transdermal administration without having first been given as an injectable or oral dosage form.\\u000a The progress achieved has been based on the

Richard H. Guy

13

Photomechanical drug delivery  

NASA Astrophysics Data System (ADS)

Photomechanical waves (PW) are generated by Q-switched or mode-locked lasers. Ablation is a reliable method for generating PWs with consistent characteristics. Depending on the laser wavelength and target material, PWs with different parameters can be generated which allows the investigation of PWs with cells and tissue. PWs have been shown to permeabilize the stratum corneum (SC) in vivo and facilitate the transport of drugs into the skin. Once a drug has diffused into the dermis it can enter the vasculature, thus producing a systemic effect. Fluorescence microscopy of biopsies show that 40-kDa molecules can be delivered to a depth of > 300 micrometers into the viable skin of rats. Many important drugs such as insulin, and erythropoietin are smaller or comparable in size, making the PWs attractive for transdermal drug delivery. There are three possible pathways through the SC: Transappendageal via hair follicles or other appendages, transcellular through the corneocytes, and intercellular via the extracellular matrix. The intracellular route appears to be the most likely pathway of drug delivery through the SC.

Doukas, Apostolos G.; Lee, Shun

2000-05-01

14

Suprachoroidal and Intrascleral Drug Delivery  

Microsoft Academic Search

\\u000a Local drug delivery to the eye minimizes systemic side effects and targets specific ocular tissue. In preclinical studies,\\u000a transscleral and suprachoroidal delivery appear to achieve therapeutic drug tissue levels that target specific tissues, such\\u000a as the choroid and macula. These routes allow minimally invasive sustained delivery of drugs to the ocular posterior segment\\u000a while minimizing systemic drug levels and the

Timothy W. Olsen; Brian C. Gilger

15

Ultrasound and transdermal drug delivery  

Microsoft Academic Search

Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Application of ultrasound to the skin increases its permeability (sonophoresis) and enables the delivery of various substances into and through the skin. This review presents

Ilana Lavon; Joseph Kost

2004-01-01

16

Drug delivery to damaged brain  

Microsoft Academic Search

Drug delivery to the brain poses unique challenges. Specialized anatomic and physiological features of the cerebrovasculature and cerebral tissue fluids result in barriers which significantly restrict delivery of a wide range of possible therapeutic agents. In addition to these normal restrictions to brain drug delivery, pathophysiological features and sequelae of acute brain injury will also impact upon the efficiency of

Eng H. Lo; Aneesh B. Singhal; Vladimir P. Torchilin; N. Joan Abbott

2001-01-01

17

MRI in ocular drug delivery  

PubMed Central

Conventional pharmacokinetic methods for studying ocular drug delivery are invasive and cannot be conveniently applied to humans. The advancement of MRI technology has provided new opportunities in ocular drug-delivery research. MRI provides a means to non-invasively and continuously monitor ocular drug-delivery systems with a contrast agent or compound labeled with a contrast agent. It is a useful technique in pharmacokinetic studies, evaluation of drug-delivery methods, and drug-delivery device testing. Although the current status of the technology presents some major challenges to pharmaceutical research using MRI, it has a lot of potential. In the past decade, MRI has been used to examine ocular drug delivery via the subconjunctival route, intravitreal injection, intrascleral injection to the suprachoroidal space, episcleral and intravitreal implants, periocular injections, and ocular iontophoresis. In this review, the advantages and limitations of MRI in the study of ocular drug delivery are discussed. Different MR contrast agents and MRI techniques for ocular drug-delivery research are compared. Ocular drug-delivery studies using MRI are reviewed.

Li, S. Kevin; Lizak, Martin J.; Jeong, Eun-Kee

2008-01-01

18

New Methods of Drug Delivery  

Microsoft Academic Search

Conventional forms of drug administration generally rely on pills, eye drops, ointments, and intravenous solutions. Recently, a number of novel drug delivery approaches have been developed. These approaches include drug modification by chemical means, drug entrapment in small vesicles that are injected into the bloodstream, and drug entrapment within pumps or polymeric materials that are placed in desired bodily compartments

Robert Langer

1990-01-01

19

Bioresponsive matrices in drug delivery  

Microsoft Academic Search

For years, the field of drug delivery has focused on (1) controlling the release of a therapeutic and (2) targeting the therapeutic to a specific cell type. These research endeavors have concentrated mainly on the development of new degradable polymers and molecule-labeled drug delivery vehicles. Recent interest in biomaterials that respond to their environment have opened new methods to trigger

Jin-Oh You; Dariela Almeda; George JC Ye; Debra T Auguste

2010-01-01

20

Transdermal drug delivery: Microfabrication insights  

Microsoft Academic Search

The paper presented an enhancement solution for transdermal drug delivery using microneedles array with biodegradable tips. The microneedles array was fabricated by using deep reactive ion etching (DRIE) and the biodegradable tips were made to be porous by electrochemical etching process. The porous silicon microneedle tips can greatly enhance the transdermal drug delivery in a minimum invasion, painless, and convenient

Ciprian Iliescu; Bangtao Chen; Jiashen Wei; Zhilian Yue

2009-01-01

21

PECTIN BASED DRUG DELIVERY SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two drug delivery systems have been developed from pectin recently in our laboratory. (I) Pectin gel formulations for controlled fragrance release and (II) pectin/zein hydrogels for oral drug delivery. By altering the molecular characteristics or modifying the pectin hydrogel networks, the release ...

22

Microneedles for transdermal drug delivery  

Microsoft Academic Search

The success of transdermal drug delivery has been severely limited by the inability of most drugs to enter the skin at therapeutically useful rates. Recently, the use of micron-scale needles in increasing skin permeability has been proposed and shown to dramatically increase transdermal delivery, especially for macromolecules. Using the tools of the microelectronics industry, microneedles have been fabricated with a

Mark R Prausnitz

2004-01-01

23

Nanotechnology-based drug delivery systems  

Microsoft Academic Search

Nanoparticles hold tremendous potential as an effective drug delivery system. In this review we discussed recent developments in nanotechnology for drug delivery. To overcome the problems of gene and drug delivery, nanotechnology has gained interest in recent years. Nanosystems with different compositions and biological properties have been extensively investigated for drug and gene delivery applications. To achieve efficient drug delivery

Sarabjeet Singh Suri; Hicham Fenniri; Baljit Singh

2007-01-01

24

Nanosuspension Technology for Drug Delivery  

Microsoft Academic Search

The poor water solubility of drugs is major problem for drug formulation. To date, nanoscale systems for drug delivery have gained much interest as a way to improve the solubility problems. The reduction of drug particles into the sub-micron range leads to a significant increase in the dissolution rate and therefore enhances bioavailability. Nanosuspensions are promising candidates that can be

Jiraporn CHINGUNPITUK

25

Drug delivery to the ear.  

PubMed

Drug delivery to the ear is used to treat conditions of the middle and inner ear such as acute and chronic otitis media, Ménière's disease, sensorineural hearing loss and tinnitus. Drugs used include antibiotics, antifungals, steroids, local anesthetics and neuroprotective agents. A literature review was conducted searching Medline (1966-2012), Embase (1988-2012), the Cochrane Library and Ovid (1966-2012), using search terms 'drug delivery', 'middle ear', 'inner ear' and 'transtympanic'. There are numerous methods of drug delivery to the middle ear, which can be categorized as topical, systemic (intravenous), transtympanic and via the Eustachian tube. Localized treatments to the ear have the advantages of targeted drug delivery allowing higher therapeutic doses and minimizing systemic side effects. The ideal scenario would be a carrier system that could cross the intact tympanic membrane loaded with drugs or biochemical agents for the treatment of middle and inner ear conditions. PMID:23323784

Hoskison, E; Daniel, M; Al-Zahid, S; Shakesheff, K M; Bayston, R; Birchall, J P

2013-01-01

26

Transmucosal macromolecular drug delivery.  

PubMed

Mucosal surfaces are the most common and convenient routes for delivering drugs to the body. However, macromolecular drugs such as peptides and proteins are unable to overcome the mucosal barriers and/or are degraded before reaching the blood stream. Among the approaches explored so far in order to optimize the transport of these macromolecules across mucosal barriers, the use of nanoparticulate carriers represents a challenging but promising strategy. The present paper aims to compare the characteristics and potential of nanostructures based on the mucoadhesive polysaccharide chitosan (CS). These are CS nanoparticles, CS-coated oil nanodroplets (nanocapsules) and CS-coated lipid nanoparticles. The characteristics and behavior of CS nanoparticles and CS-coated lipid nanoparticles already reported [A. Vila, A. Sanchez, M. Tobio, P. Calvo, M.J. Alonso, Design of biodegradable particles for protein delivery, J. Control. Rel. 78 (2002) 15-24; R. Fernandez-Urrusuno, P. Calvo, C. Remunan-Lopez, J.L. Vila-Jato, M.J. Alonso, Enhancement of nasal absorption of insulin using chitosan nanoparticles, Pharm. Res. 16 (1999) 1576-1581; M. Garcia-Fuentes, D. Torres, M.J. Alonso, New surface-modified lipid nanoparticles as delivery vehicles for salmon calcitonin (submitted for publication).] are compared with those of CS nanocapsules originally reported here. The three types of systems have a size in the nanometer range and a positive zeta potential that was attributed to the presence of CS on their surface. They showed an important capacity for the association of peptides such as insulin, salmon calcitonin and proteins, such as tetanus toxoid. Their mechanism of interaction with epithelia was investigated using the Caco-2 model cell line. The results showed that CS-coated systems caused a concentration-dependent reduction in the transepithelial resistance of the cell monolayer. Moreover, within the range of concentrations investigated, these systems were internalized in the monolayer in a concentration-dependent manner. This uptake was slightly enhanced by the presence of the CS coating but, as compared with previously published results [M. Garcia-Fuentes, C. Prego, D. Torres, M.J. Alonso, Triglyceride-chitosan nanostructures for oral calcitonin delivery: evaluation in the Caco-2 cell model and in vivo (submitted for publication)], highly dependent on the nature of the lipid core. Nevertheless, these differences in the uptake of the CS-coated systems (solid lipid core or oily core) by the Caco-2 cells did not have a consequence in the in vivo behaviour. Indeed, both CS-coated systems (nanocapsules and CS-coated nanoparticles) showed an important capacity to enhance the intestinal absorption of the model peptide, salmon calcitonin, as shown by the important and long-lasting decrease in the calcemia levels observed in rats. PMID:15588901

Prego, C; García, M; Torres, D; Alonso, M J

2005-01-01

27

Bioresponsive matrices in drug delivery  

PubMed Central

For years, the field of drug delivery has focused on (1) controlling the release of a therapeutic and (2) targeting the therapeutic to a specific cell type. These research endeavors have concentrated mainly on the development of new degradable polymers and molecule-labeled drug delivery vehicles. Recent interest in biomaterials that respond to their environment have opened new methods to trigger the release of drugs and localize the therapeutic within a particular site. These novel biomaterials, usually termed "smart" or "intelligent", are able to deliver a therapeutic agent based on either environmental cues or a remote stimulus. Stimuli-responsive materials could potentially elicit a therapeutically effective dose without adverse side effects. Polymers responding to different stimuli, such as pH, light, temperature, ultrasound, magnetism, or biomolecules have been investigated as potential drug delivery vehicles. This review describes the most recent advances in "smart" drug delivery systems that respond to one or multiple stimuli.

2010-01-01

28

Bioresponsive matrices in drug delivery.  

PubMed

For years, the field of drug delivery has focused on (1) controlling the release of a therapeutic and (2) targeting the therapeutic to a specific cell type. These research endeavors have concentrated mainly on the development of new degradable polymers and molecule-labeled drug delivery vehicles. Recent interest in biomaterials that respond to their environment have opened new methods to trigger the release of drugs and localize the therapeutic within a particular site. These novel biomaterials, usually termed "smart" or "intelligent", are able to deliver a therapeutic agent based on either environmental cues or a remote stimulus. Stimuli-responsive materials could potentially elicit a therapeutically effective dose without adverse side effects. Polymers responding to different stimuli, such as pH, light, temperature, ultrasound, magnetism, or biomolecules have been investigated as potential drug delivery vehicles. This review describes the most recent advances in "smart" drug delivery systems that respond to one or multiple stimuli. PMID:21114841

You, Jin-Oh; Almeda, Dariela; Ye, George Jc; Auguste, Debra T

2010-11-29

29

COLON TARGETED DRUG DELIVERY SYSTEMS  

Microsoft Academic Search

Colon targeted drug delivery systems have the potential to deliver drugs for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. In recent years, various pharmaceutical approaches have been developed for targeting the drugs to the colon include, formation of prodrugs, coating of pH-sensitive polymers, use of colon

Ceyda Tuba

30

Cellulose esters in drug delivery  

Microsoft Academic Search

Cellulose esters have played a vital role in the development of modern drug delivery technology. They possess properties that\\u000a are not only well-suited to the needs of pharmaceutical applications, but that enable construction of drug delivery systems\\u000a that address critical patient needs. These properties include very low toxicity, endogenous and\\/or dietary decomposition products,\\u000a stability, high water permeability, high T\\u000a g,

Kevin J. Edgar

2007-01-01

31

Nanosuspensions in drug delivery  

Microsoft Academic Search

A surprisingly large proportion of new drug candidates emerging from drug discovery programmes are water insoluble, and therefore poorly bioavailable, leading to abandoned development efforts. These so-called 'brickdust' candidates can now be rescued by formulating them into crystalline nanosuspensions. In the process of overcoming issues involving solubility, additional pharmacokinetic benefits of the drugs so formulated have come to be appreciated.

Barrett E. Rabinow

2004-01-01

32

Drug delivery from jet nebulisers  

Microsoft Academic Search

Maximising the rate of drug delivered in particles small enough to reach the lower respiratory tract from jet nebulisers may allow treatment times to be reduced and thus improve the acceptability of this form of treatment, particularly in very young patients. The role of various technical factors such as driving gas flow (DGF) in determining the rate of drug delivery

M L Everard; A R Clark; A D Milner

1992-01-01

33

Transmucosal macromolecular drug delivery  

Microsoft Academic Search

Mucosal surfaces are the most common and convenient routes for delivering drugs to the body. However, macromolecular drugs such as peptides and proteins are unable to overcome the mucosal barriers and\\/or are degraded before reaching the blood stream. Among the approaches explored so far in order to optimize the transport of these macromolecules across mucosal barriers, the use of nanoparticulate

C. Prego; M. García; D. Torres; M. J. Alonso

2005-01-01

34

Biodegradable Polymers for Ocular Drug Delivery  

Microsoft Academic Search

A variety of ocular drug delivery systems, including a controlled release of the drug, drug targeting, and penetration enhancement of the drug, have been investigated. Biodegradable polymers have been widely used as the drug carrier for controlled-release systems. Biodegradable polymers release the drug as they themselves degrade and are finally absorbed within the body. Several ocular drug delivery systems using

Hideya Kimura; Yuichiro Ogura

2001-01-01

35

Developments in macromolecular drug delivery.  

PubMed

Macromolecular drugs hold great promise as novel therapeutics of several major disorders, such as cancer and cardiovascular disease. However, their use is limited by lack of efficient, safe, and specific delivery strategies. Successful development of such strategies requires interdisciplinary collaborations involving researchers with expertise on, e.g., polymer chemistry, cell biology, nanotechnology, systems biology, advanced imaging methods, and clinical medicine. This not only poses obvious challenges to the scientific community but also provides opportunities for the unexpected at the interface between different disciplines. This introductory chapter summarizes and gives references to studies on macromolecular delivery that should be of interest to a broad scientific audience involved in macromolecular drug synthesis as well as in vitro and in vivo drug delivery studies. PMID:19085127

Belting, Mattias; Wittrup, Anders

2009-01-01

36

Microneedles for transdermal drug delivery.  

PubMed

The success of transdermal drug delivery has been severely limited by the inability of most drugs to enter the skin at therapeutically useful rates. Recently, the use of micron-scale needles in increasing skin permeability has been proposed and shown to dramatically increase transdermal delivery, especially for macromolecules. Using the tools of the microelectronics industry, microneedles have been fabricated with a range of sizes, shapes and materials. Most drug delivery studies have emphasized solid microneedles, which have been shown to increase skin permeability to a broad range of molecules and nanoparticles in vitro. In vivo studies have demonstrated delivery of oligonucleotides, reduction of blood glucose level by insulin, and induction of immune responses from protein and DNA vaccines. For these studies, needle arrays have been used to pierce holes into skin to increase transport by diffusion or iontophoresis or as drug carriers that release drug into the skin from a microneedle surface coating. Hollow microneedles have also been developed and shown to microinject insulin to diabetic rats. To address practical applications of microneedles, the ratio of microneedle fracture force to skin insertion force (i.e. margin of safety) was found to be optimal for needles with small tip radius and large wall thickness. Microneedles inserted into the skin of human subjects were reported as painless. Together, these results suggest that microneedles represent a promising technology to deliver therapeutic compounds into the skin for a range of possible applications. PMID:15019747

Prausnitz, Mark R

2004-03-27

37

Biodegradable microspheres in drug delivery.  

PubMed

General aspects of biodegradable microspheres prepared from natural and synthesized polymers used in drug delivery systems are reviewed first from various viewpoints: characteristics of biodegradable polymers (physicochemical properties, bioerosion mechanism, biocompatibility), preparation method for the microspheres, drug release from parenteral products and briefly nonparenteral products. The relationship between release pattern and pharmacological activity of therapeutic peptides and proteins and rational controlled release design are also discussed. In the latter half, successful sustained release depot formulations of peptides, leuprorelin acetate, and thyrotropin-releasing hormone (TRH), utilizing poly(lactic acid) (PLA) and poly(lactic/glycolic acid) (PLGA) microspheres are reviewed with respect to preparation, drug release, biocompatibility, pharmacological effects, and results of clinical studies. Thereafter, studies on antitumor therapy by chemoembolization using PLGA microspheres containing an angiogenesis inhibitor (TNP-470) are described as an example of targeted drug delivery with biodegradable microspheres. PMID:8521523

Okada, H; Toguchi, H

1995-01-01

38

Nanocarriers and Drug Delivery  

Microsoft Academic Search

Nanoparticles may serve, among other techniques, as a useful tool for achieving the main objective of regional cancer therapy:\\u000a they can deliver a higher concentration of the agent to the tumor and expose the tumor to active drug for longer periods than\\u000a safely possible with conventional formulations. These carriers combine many advantages, such as a potential for selective\\u000a targeting and

Svetlana Gelperina

39

Hydrogel nanoparticles in drug delivery  

Microsoft Academic Search

Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system (e.g., hydrophilicity and extremely high water content) with a nanoparticle (e.g., very small size). Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based

Mehrdad Hamidi; Amir Azadi; Pedram Rafiei

2008-01-01

40

Drug delivery by lipid cochleates.  

PubMed

Drug delivery technology has brought additional benefits to pharmaceuticals such as reduction in dosing frequency and side effects, as well as the extension of patient life. To address this need, cochleates, a precipitate obtained as a result of the interaction between phosphatidylserine and calcium, have been developed and proved to have potential in encapsulating and delivering small molecule drugs. This chapter discusses the molecules that can be encapsulated in a cochleate system and describes in detail the methodology that can be used to encapsulate and characterize hydrophobic drugs such as amphotericin B, a potent antifungal agent. Some efficacy data in animal models infected with candidiasis or aspergillosis are described as well. PMID:15721389

Zarif, Leila

2005-01-01

41

Gelatin Used for Drug Delivery  

NSDL National Science Digital Library

In this activity, learners discover how gelatin can be used as a medium for drug delivery. Learners create colored gelatin and then cut out pieces of the gelatin to simulate medicine (pills). Learners then put their simulated pills in a pan of hot water. Since gelatin is a thermoreversible or cold-setting polymer, gelatin will convert back to a liquid if put in a hot environment. As the gelatin returns to its liquid form, it releases its embedded dye. The dye eventually diffuses completely out of the gelatin which simulates the slow release of a drug from a pill. From this activity, learners learn more about diffusion and drug delivery. Adult supervision recommended.

Mississippi, University O.

2003-01-01

42

Microfabricated injectable drug delivery system  

DOEpatents

A microfabricated, fully integrated drug delivery system capable of secreting controlled dosages of multiple drugs over long periods of time (up to a year). The device includes a long and narrow shaped implant with a sharp leading edge for implantation under the skin of a human in a manner analogous to a sliver. The implant includes: 1) one or more micromachined, integrated, zero power, high and constant pressure generating osmotic engine; 2) low power addressable one-shot shape memory polymer (SMP) valves for switching on the osmotic engine, and for opening drug outlet ports; 3) microfabricated polymer pistons for isolating the pressure source from drug-filled microchannels; 4) multiple drug/multiple dosage capacity, and 5) anisotropically-etched, atomically-sharp silicon leading edge for penetrating the skin during implantation. The device includes an externally mounted controller for controlling on-board electronics which activates the SMP microvalves, etc. of the implant.

Krulevitch, Peter A. (Pleasanton, CA); Wang, Amy W. (Oakland, CA)

2002-01-01

43

Peptide and protein delivery using new drug delivery systems.  

PubMed

Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery. PMID:23662604

Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

2013-01-01

44

Biosensing and Drug Delivery at the Microscale  

Microsoft Academic Search

\\u000a The book chapter “Biosensing and Drug Delivery at the Microscale: Novel Devices for a Controlled and Responsive Drug Delivery”\\u000a published in the Handbook of Experimental Pharmacology vol. 197: Drug Delivery has been retracted. For further details see Erratum.

Andrea A. Robitzki; Randy Kurz

45

Protease-mediated drug delivery  

NASA Astrophysics Data System (ADS)

Drugs used in disease treatment can cause damage to both malignant and normal tissue. This toxicity limits the maximum therapeutic dose. Drug targeting is of high interest to increase the therapeutic efficacy of the drug without increasing systemic toxicity. Certain tissue abnormalities, disease processes, cancers, and infections are characterized by high levels of activity of specific extracellular and/or intracellular proteases. Abnormally high activity levels of specific proteases are present at sites of physical or chemical trauma, blood clots, malignant tumors, rheumatoid arthritis, inflammatory bowel disease, gingival disease, glomerulonerphritis, and acute pancreatitis. Abnormal protease activity is suspected in development of liver thrombosis, pulmonary emphysema, atherosclerosis, and muscular dystrophy. Inactiviating disease-associated proteases by the administration of appropriate protease inhibitors has had limited success. Instead, one could use such proteases to target drugs to treat the condition. Protease mediated drug delivery offers such a possibility. Solubilizing groups are attached to insoluble drugs via a polypeptide chain which is specifically cleavable by certian proteases. When the solubilized drug enounters the protease, the solubilizing moieties are cleaved, and the drug precipitates at the disease location. Thus, a smaller systemic dosage could result in a therapeutic drug concentration at the treatment site with less systemic toxicity.

Dickson, Eva F.; Goyan, Rebecca L.; Kennedy, James C.; Mackay, M.; Mendes, M. A. K.; Pottier, Roy H.

2003-12-01

46

Nanostructured Devices Based on Block Copolymer Assemblies for Drug Delivery: Designing Structures for Enhanced Drug Function  

Microsoft Academic Search

Block copolymers spontaneously assemble into nanoscaled polymeric micelles, which have significant\\u000a potential as drug carriers. Following much work in related fields over the last decade, a drug\\u000a carrier based on polymeric micelles has been created. Advances in polymer chemistry have significantly\\u000a contributed to progress in polymeric micelle-based drug carrier research, because the micelle parameters\\u000a that are most important to successful drug

Nobuhiro Nishiyama; Kazunori Kataoka

47

Orotransmucosal drug delivery systems: A review  

Microsoft Academic Search

Oral mucosal drug delivery is an alternative method of systemic drug delivery that offers several advantages over both injectable and enteral methods and also enhances drug bioavailability because the mucosal surfaces are usually rich in blood supply, providing the means for rapid drug transport to the systemic circulation and avoiding, in most cases, degradation by first-pass hepatic metabolism. The systems

N. V. Satheesh Madhav; Ashok K. Shakya; Pragati Shakya; Kuldeep Singh

2009-01-01

48

Enhanced anticancer drug delivery using electrical pulses  

Microsoft Academic Search

Many drugs that have the potential to treat cancers have had limited success due to their lack of efficient and safe delivery mechanisms that allow the drug molecules to cross cell membranes. Electrical pulses-mediated drug delivery, known as electroporation, is gaining attention as a possible approach to enhance uptake of chemotherapy. It delivers anticancer drugs with enhanced efficacy and fewer

Funian Xiao

2009-01-01

49

Drug delivery across the skin.  

PubMed

Since the introduction of the first through the skin (TTS) therapeutic in 1980, a total of 34 TTS products have been marketed and numerous drugs have been tested by more than 50 commercial organisations for their suitability for TTS delivery. Most of the agents which have been tested have had low molecular weights, due to the impermeability of the skin barrier. This barrier resides in the outermost skin layer, the stratum corneum. It is mechanical, anatomical, as well as chemical in nature; laterally overlapping cell multi-layers are sealed by tightly packed, intercellular, lipid multi-lamellae. Chemical skin permeation enhancers increase the transport across the barrier by partly solubilising or extracting the skin lipids and by creating hydrophobic pores. This is often irritating and not always well-tolerated. The TTS approach allows drugs (< 400 kDa in size) to permeate through the resulting pores in the skin, with a short lag-time and subsequent steady-state period. Drug bioavailability for TTS delivery is typically below 50%, avoiding the first pass effect. Wider, hydrophilic channels can be generated by skin poration, with the aid of a small electrical current (> 0.4 mA/cm2) across the skin (iontophoresis) or therapeutic ultrasound (few W/cm2; sonoporation). High-voltage (> 150 V, electroporation) widens the pores even more and often irreversibly. These standard poration methods require experience and equipment and are therefore, not practical; at best, charged/small molecules (< or = 4000 kDa in size) can be delivered efficiently across the skin. In spite of the potential harm of gadget-driven skin poration, this method is used to deliver molecules which conventional TTS patches are unable to deliver, especially polypeptides. Lipid-based drug carriers (liposomes, niosomes, nanoparticle microemulsions, etc.) were proposed as alternative, low-risk delivery vehicles. Such suspensions provide an improved drug reservoir on the skin, but the aggregates remain confined to the surface. Conventional carrier suspensions increase skin hydration and/or behave as skin permeation enhancers. The recently developed carriers; Transferomes, comprise pharmaceutically-acceptable, established compounds and are thought to penetrate the skin barrier along the naturally occurring transcutaneous moisture gradient. Transfersomes are believed to penetrate the hydrophilic (virtual) channels in the skin and widen the former after non-occlusive administration. Both small and large hydrophobic and hydrophilic molecules are deliverable across the stratum after conjugation with Transfersomes. Drug distribution after transdermal delivery probably proceeds via the lymph. This results in quasi-zero order kinetics with significant systemic drug levels reached after a lag-time of up to a few hours. The relative efficiency of TTS drug delivery with Transfersomes is typically above 50 %; with the added possibility of regional drug targeting. PMID:15989590

Cevc, G

1997-12-01

50

Technique for Drug and Chemical Delivery.  

National Technical Information Service (NTIS)

The invention relates generally to a technique for delivering drugs and/or chemicals, and, more particularly, to effecting such delivery by means of microwave-stimulation of drug containing liposomes. By subjecting liposome encapsulated drugs to microwave...

R. P. Liburdy

1986-01-01

51

Microbially triggered drug delivery to the colon  

Microsoft Academic Search

Increasing acceptance of protein- and peptide-based drugs necessitates an investigation into the suitability of various sites for their administration. Colon is being investigated for delivery of such molecules. Colon-specific drug delivery is designed to target drug molecules specifically to this area. Development of site-specific delivery systems may exploit a specific property of the target site for drug activation\\/release. The gastrointestinal

V. R Sinha; Rachna Kumria

2003-01-01

52

Advancing the field of drug delivery  

Microsoft Academic Search

Drug delivery systems for cancer therapeutics have now been used by millions of patients and have resulted in the creation of new therapies as well as significantly improving existing ones. Here we discuss a number of the drug delivery systems that have been approved by regulatory authorities and that are currently in clinical use, such as controlled delivery of cancer

Marsha A Moses; Henry Brem; Robert Langer

2003-01-01

53

Magnetizable implants for targeted drug delivery  

Microsoft Academic Search

The capability to deliver high effective dosages to specific sites in the human body has become the holy grail of drug delivery research. Drugs with proven effectiveness under in vitro investigation often reach a major roadblock under in vivo testing due to a lack of an effective delivery strategy. In addition, many clinical scenarios require delivery of agents that are

Zachary Graham Forbes

2005-01-01

54

Drug delivery systems from nose to brain.  

PubMed

The treatment of brain disorders is particularly challenging due to the presence of a variety of formidable obstacles to deliver drugs selectively and effectively to the brain. Blood-brain-barrier (BBB) constitutes the major obstacle to the uptake of drugs into the brain following systemic administration. Intranasal delivery offers a non-invasive and convenient method to bypass the BBB and delivery of therapeutics directly to the brain. The review discusses the potential of intranasal route to deliver drugs to the brain, the mechanisms and pathways of direct nose to brain drug transport, the various factors influencing transnasal drug absorption, the conventional and novel intranasal drug delivery systems, the various intranasal drug delivery techniques and devices, and examples of brain drug transport that have been feasible in treating various brain disorders. Moreover, products on the market, investigational drugs, and the author's perceptions about the prospect of intranasal delivery for treating brain disorders are also been discussed. PMID:23016642

Misra, Ambikanandan; Kher, Gitanjali

2012-09-01

55

Cyclodextrins in drug delivery: An updated review  

Microsoft Academic Search

The purpose of this review is to discuss and summarize some of the interesting findings and applications of cyclodextrins\\u000a (CDs) and their derivatives in different areas of drug delivery, particularly in protein and peptide drug delivery and gene\\u000a delivery. The article highlights important CD applications in the design of various novel delivery systems like liposomes,\\u000a microspheres, microcapsules, and nanoparticles. In

Rajeswari Challa; Alka Ahuja; Javed Ali; R. K. Khar

2005-01-01

56

Nanoparticle drug delivery system for restenosis  

Microsoft Academic Search

Restenosis, an arterial reobstruction occurring in thirty to fifty percent of patients undergoing coronary angioplasty, because of its localized nature can possibly be best treated by local drug therapy. In recent years, several local drug delivery strategies have been investigated for the prevention of restenosis. In this review we discuss the therapeutic potential of nanoparticles as a drug delivery system

Vinod Labhasetwar; Cunxian Song; Robert J. Levy

1997-01-01

57

Moving smaller in drug discovery and delivery  

Microsoft Academic Search

Advances in new micro- and nanotechnologies are accelerating the identification and evaluation of drug candidates, and the development of new delivery technologies that are required to transform biological potential into medical reality. This article will highlight the emerging micro- and nanotechnology tools, techniques and devices that are being applied to advance the fields of drug discovery and drug delivery. Many

David A. LaVan; David M. Lynn; Robert Langer

2002-01-01

58

The rise and rise of drug delivery  

Microsoft Academic Search

Drug delivery has typically focused on optimizing marketed compounds, improving their effectiveness or tolerability, and simplifying their administration. This role now includes the first biopharmaceuticals as well as more conventional drugs. As drug-delivery technologies come into play earlier in the development cycle, however, they can also enhance the screening and evaluation of new compounds and 'rescue' failed compounds, such as

Howard Rosen; Thierry Abribat

2005-01-01

59

Colloidal drug delivery systems in vaccine delivery.  

PubMed

Vaccines play a vital role in the field of community medicine to combat against several diseases of human existence. Vaccines primarily trigger the acquired immune system to develop long-lasting immunity against pathogens. Conventional approaches for vaccine delivery lacks potential to target a particular antigen to develop acquired immunity by specific antibodies. Recent advancements in vaccine delivery showed that inclusion of adjuvants in vaccine formulations or delivery of them in a carrier helps in achieving desired targeting ability, reducing the immunogenicity and significant augmentation in the immune response. Colloidal carriers (liposomes, niosomes, microspheres, proteosomes, virosomes and virus like particles (VLPs), antigen cochleates, dendrimers and carbon nanotubes) have been widely explored for vaccine delivery. Further, surface engineering of these carriers with ligands, functional moieties and monoclonal antibodies tend to enhance the immune recognition potential of vaccines by differentiation of antigen specific memory T-cells. The current review, therefore, provides an updated account on the recent advancements in various colloidal delivery systems in vaccine delivery, outlining the mechanism of immune response initiated by them along with potential applications and marketed instances in an explicit manner. PMID:23072326

Beg, Sarwar; Samad, Abdus; Nazish, Iram; Sultana, Ruksar; Rahman, Mahfoozur; Ahmad, Md Zaki; Akbar, Md

2013-01-01

60

Physically facilitating drug-delivery systems  

PubMed Central

Facilitated/modulated drug-delivery systems have emerged as a possible solution for delivery of drugs of interest to pre-allocated sites at predetermined doses for predefined periods of time. Over the past decade, the use of different physical methods and mechanisms to mediate drug release and delivery has grown significantly. This emerging area of research has important implications for development of new therapeutic drugs for efficient treatments. This review aims to introduce and describe different modalities of physically facilitating drug-delivery systems that are currently in use for cancer and other diseases therapy. In particular, delivery methods based on ultrasound, electrical, magnetic and photo modulations are highlighted. Current uses and areas of improvement for these different physically facilitating drug-delivery systems are discussed. Furthermore, the main advantages and drawbacks of these technologies reviewed are compared. The review ends with a speculative viewpoint of how research is expected to evolve in the upcoming years.

Rodriguez-Devora, Jorge I; Ambure, Sunny; Shi, Zhi-Dong; Yuan, Yuyu; Sun, Wei; Xu, Tao

2012-01-01

61

Polymeric conjugates for drug delivery  

PubMed Central

The field of polymer therapeutics has evolved over the past decade and has resulted in the development of polymer-drug conjugates with a wide variety of architectures and chemical properties. Whereas traditional non-degradable polymeric carriers such as poly(ethylene glycol) (PEG) and N-(2-hydroxypropyl methacrylamide) (HPMA) copolymers have been translated to use in the clinic, functionalized polymer-drug conjugates are increasingly being utilized to obtain biodegradable, stimuli-sensitive, and targeted systems in an attempt to further enhance localized drug delivery and ease of elimination. In addition, the study of conjugates bearing both therapeutic and diagnostic agents has resulted in multifunctional carriers with the potential to both “see and treat” patients. In this paper, the rational design of polymer-drug conjugates will be discussed followed by a review of different classes of conjugates currently under investigation. The design and chemistry used for the synthesis of various conjugates will be presented with additional comments on their potential applications and current developmental status.

Larson, Nate; Ghandehari, Hamidreza

2012-01-01

62

Polymers for colon targeted drug delivery.  

PubMed

The colon targeted drug delivery has a number of important implications in the field of pharmacotherapy. Oral colon targeted drug delivery systems have recently gained importance for delivering a variety of therapeutic agents for both local and systemic administration. Targeting of drugs to the colon via oral administration protect the drug from degradation or release in the stomach and small intestine. It also ensures abrupt or controlled release of the drug in the proximal colon. Various drug delivery systems have been designed that deliver the drug quantitatively to the colon and then trigger the release of drug. This review will cover different types of polymers which can be used in formulation of colon targeted drug delivery systems. PMID:21969739

Rajpurohit, H; Sharma, P; Sharma, S; Bhandari, A

2010-11-01

63

CCMR: Controlled Drug Delivery From New Biomaterials  

NSDL National Science Digital Library

The development of controlled release systems for drug delivery is an area that has generated considerable research interest over the past decade. Biodegradable polymers, which degrade naturally via hydrolysis or enzymatic digestion, have demonstrated great potential for use in the preparation of controlled drug delivery systems. Biodegradable polymeric drug delivery systems hold several distinct advantages over more conventional oral and inhalation routes, including enhanced site specificity of drug delivery, reduced side effects, improved patient compliance, and greater overall efficacy. The primary objective of this work was to synthesize biodegradable polyesters based on a locked dimer of dihydroxyacetone (DHA).

Rhodes, Steven D.

2005-08-17

64

Monolithic maleic anhydride drug delivery systems  

US Patent & Trademark Office Database

Erodible bioadhesive drug delivery vehicles for use in delivering pharmaceutical compounds to the eye and similar physiological environments are disclosed. The drug delivery vehicles are formed of a homopolymer or copolymer of maleic anhydride or lower alkyl maleic anhydride incorporating a pharmaceutical compound in either a monolithic matrix or encapsulated form. The bioadhesive erodible drug delivery vehicles are configured to be retained in the eye following administration while providing specific erosion profiles allowing convenient drug delivery schedules ranging from hourly to daily or weekly intervals.

1995-12-12

65

Therapeutic applications of implantable drug delivery systems  

Microsoft Academic Search

In the past, drugs were frequently administered orally, as liquids or in powder forms. To avoid problems incurred through the utilization of the oral route of drug administration, new dosage forms containing the drug(s) were introduced. As time progressed, there was a need for delivery systems that could maintain a steady release of drug to the specific site of action.

AlekhaK Dash; GreggreyC Cudworth

1998-01-01

66

Image Guided Biodistribution of Drugs and Drug Delivery  

PubMed Central

Image guided technique is playing an increasingly important role in the investigation of the biodistribution and pharmacokinetics of drugs or drug delivery systems. The application of these new materials and techniques with combined properties of diagnosis and therapy can benefit the development of targeted drug delivery system and modern personalized medicine This special issue provides an up-to-date collection of original research articles and review on the development of novel targeted drug and drug delivery systems combining with non-invasive image guided techniques for chemotherapeutic reagents or DNA delivery.

Ding, Hong; Wu, Fang

2012-01-01

67

Membranes and Barriers: Targeted Drug Delivery.  

National Technical Information Service (NTIS)

Contents: Retrometabolic Approaches to Drug Targeting; Vector-Mediated Delivery of Opioid Peptides to the Brain; Conformationally Constrained Peptide Drugs Targeted at the Blood-Brain Barrier; Passive and Facilitative Transport of Nucleobases, Nucleosides...

R. S. Rapaka

1995-01-01

68

Microfabrication Technologies for Oral Drug Delivery  

PubMed Central

Micro-/nanoscale technologies such as lithographic techniques and microfluidics offer promising avenues to revolutionalize the fields of tissue engineering, drug discovery, diagnostics and personalized medicine. Microfabrication techniques are being explored for drug delivery applications due to their ability to combine several features such as precise shape and size into a single drug delivery vehicle. They also offer to create unique asymmetrical features incorporated into single or multiple reservoir systems maximizing contact area with the intestinal lining. Combined with intelligent materials, such microfabricated platforms can be designed to be bioadhesive and stimuli-responsive. Apart from drug delivery devices, microfabrication technologies offer exciting opportunities to create biomimetic gastrointestinal tract models incorporating physiological cell types, flow patterns and brush-border like structures. Here we review the recent developments in this field with a focus on the applications of microfabrication in the development of oral drug delivery devices and biomimetic gastrointestinal tract models that can be used to evaluate the drug delivery efficacy.

Sant, Shilpa; Tao, Sarah L.; Fisher, Omar; Xu, Qiaobing; Peppas, Nicholas A.; Khademhosseini, Ali

2012-01-01

69

MEMS-based Implantable Drug Delivery System  

Microsoft Academic Search

Implantable devices are currently used regularly for chronic pain relief, cardiac pacemakers, arterial infusion for cancer and insulin delivery. A MEMS based implantable drug delivery system (IDDS) integrating a subcutaneous reservoir, an in plane silicon pump and associated circuitry for local or centralized delivery of therapeutic agents for chemotherapy is proposed. System configurations, flow rate analysis and applications are presented.

Smitha M. N. Rao; Amit Mhatre; Dan O. Popa; C. Chiao; Jeongsik Sin; Harry E. Stephanou

2005-01-01

70

Cubic phase gels as drug delivery systems  

Microsoft Academic Search

Lipids have been used extensively for drug delivery in various forms such as liposomes, and solid-matrices. The focus of this review is evaluation of liquid crystalline cubic phases, spontaneously formed when amphiphilic lipids are placed in aqueous environment, for drug delivery. Cubic phases have an interesting thermodynamically stable structure consisting of curved bicontinuous lipid bilayer in three dimensions, separating two

Jaymin C Shah; Yogesh Sadhale; Dakshina Murthy Chilukuri

2001-01-01

71

Bioadhesive Dosage Forms for Esophageal Drug Delivery  

Microsoft Academic Search

No Heading The esophagus as a site for drug delivery has been much overlooked in comparison to the remainder of the gastrointestinal tract. The low permeability and transient nature of the esophagus means that it is unsuitable for delivery of drugs for systemic action. However, esophageal disorders including fungal infection, cancers, motility dysfunction, and damage due to gastric reflux may

Hannah Batchelor

2005-01-01

72

Optically generated ultrasound for enhanced drug delivery  

Microsoft Academic Search

High frequency acoustic waves, analogous to ultrasound, can enhance the delivery of therapeutic compounds into cells. The compounds delivered may be chemotherapeutic drugs, antibiotics, photodynamic drugs or gene therapies. The therapeutic compounds are administered systemically, or preferably locally to the targeted site. Local delivery can be accomplished through a needle, cannula, or through a variety of vascular catheters, depending on

Steven R. Visuri; Heather L. Campbell; Luiz Da Silva

2002-01-01

73

Nanoparticles for intracellular-targeted drug delivery  

NASA Astrophysics Data System (ADS)

Nanoparticles (NPs) are very promising for the intracellular delivery of anticancer and immunomodulatory drugs, stem cell differentiation biomolecules and cell activity modulators. Although initial studies in the area of intracellular drug delivery have been performed in the delivery of DNA, there is an increasing interest in the use of other molecules to modulate cell activity. Herein, we review the latest advances in the intracellular-targeted delivery of short interference RNA, proteins and small molecules using NPs. In most cases, the drugs act at different cellular organelles and therefore the drug-containing NPs should be directed to precise locations within the cell. This will lead to the desired magnitude and duration of the drug effects. The spatial control in the intracellular delivery might open new avenues to modulate cell activity while avoiding side-effects.

Paulo, Cristiana S. O.; Pires das Neves, Ricardo; Ferreira, Lino S.

2011-12-01

74

Recent advances in ocular drug delivery.  

PubMed

Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist. Recent research has focused on the characteristic advantages and limitations of the various drug delivery systems, and further research will be required before the ideal system can be developed. Administration of drugs to the ocular region with conventional delivery systems leads to short contact time of the formulations on the epithelium and fast elimination of drugs. This transient residence time involves poor bioavailability of drugs which can be explained by the tear production, non-productive absorption and impermeability of corneal epithelium. Anatomy of the eye is shortly presented and is connected with ophthalmic delivery and bioavailability of drugs. In the present update on ocular dosage forms, chemical delivery systems such as prodrugs, the use of cyclodextrins to increase solubility of various drugs, the concept of penetration enhancers and other ocular drug delivery systems such as polymeric gels, bioadhesive hydrogels, in-situ forming gels with temperature-, pH-, or osmotically induced gelation, combination of polymers and colloidal systems such as liposomes, niosomes, cubosomes, microemulsions, nanoemulsions and nanoparticles are discussed. Novel ophthalmic delivery systems propose the use of many excipients to increase the viscosity or the bioadhesion of the product. New formulations like gels or colloidal systems have been tested with numerous active substances by in vitro and in vivo studies. Sustained drug release and increase in drug bioavailability have been obtained, offering the promise of innovation in drug delivery systems for ocular administration. Combining different properties of pharmaceutical formulations appears to offer a genuine synergy in bioavailability and sustained release. Promising results are obtained with colloidal systems which present very comfortable conditions of use and prolonged action. PMID:23153114

Achouri, Djamila; Alhanout, Kamel; Piccerelle, Philippe; Andrieu, Véronique

2012-11-16

75

Ultrasound-mediated micellar drug delivery.  

PubMed

During the last decade, nanomedicine has emerged as a new field of medicine that utilises nanoscale materials for delivery of drugs, genes and imaging agents. The efficiency of drug delivery may be enhanced by the application of directed energy, which provides for drug targeting and enhanced intracellular uptake. In this paper, we present a review of recent advances in the ultrasound-mediated drug delivery with the emphasis on polymeric micelles as tumour-targeted drug carriers. This new modality of drug targeting to tumours is based on the drug encapsulation in polymeric micelles followed by a localised release at the tumour site triggered by focused ultrasound. The rationale behind this approach is that drug encapsulation in micelles decreases systemic concentration of free drug and provides for a passive drug targeting to tumours via the enhanced permeability and retention (EPR) effect, therefore reducing unwanted drug interactions with healthy tissues. Ultrasound affects micellar drug delivery on various levels. Mild hyperthermia induced by ultrasound may enhance micelle extravasation into tumour tissue; mechanical action of ultrasound results in drug release from micelles and enhances the intracellular uptake of both released and encapsulated drug. In addition, polymeric micelles sensitise multidrug resistant (MDR) cells to the action of drugs. PMID:22621738

Rapoport, Natalya

2012-01-01

76

Self-Emulsifying Drug Delivery Systems: Strategy for Improving Oral Delivery of Poorly Soluble Drugs  

Microsoft Academic Search

Drugs are most often administered by the oral route. However, more than 40% of new chemical entities exhibit poor aqueous solubility, resulting in unsatisfactory oral drug delivery. Recently, much attention has been focused on self- emulsifying drug delivery systems (SEDDS) to improve the oral bioavailability of poorly aqueous soluble drugs. SEDDS are isotropic mixtures of oil, surfactants, solvents and co-solvents\\/surfactants.

Jing-ling Tang; Jin Sun; Zhong-Gui He

2007-01-01

77

Formulating Drug Delivery Systems by Spray Drying  

Microsoft Academic Search

The knowledge of the potential use of the spray-drying technology to prepare microparticulate drug delivery systems—microspheres and microcapsules—has been strongly improved over the last years. Various microparticulate spray drying systems used as vehicles for drug encapsulation and delivery that have been investigated for different purposes are presented here, including spray-dried powders formulated with hydrophilic polymers allowing controlled drug release, biodegradable

Maria-Inês Ré

2006-01-01

78

Biologically responsive polymeric nanoparticles for drug delivery.  

PubMed

Responsive nanoparticles that release their drug cargo in accordance with a change in pH or oxidative stress are of significant clinical interest as this approach offers the opportunity to link drug delivery to a specific location or disease state. This research news article reviews the current state of this field by examining a series of published articles that highlight the novelty and benefits of using responsive polymeric particles to achieve functionally-targeted drug delivery. PMID:22988558

Colson, Yolonda L; Grinstaff, Mark W

2012-07-24

79

Magnetic nanoparticles for gene and drug delivery  

PubMed Central

Investigations of magnetic micro- and nanoparticles for targeted drug delivery began over 30 years ago. Since that time, major progress has been made in particle design and synthesis techniques, however, very few clinical trials have taken place. Here we review advances in magnetic nanoparticle design, in vitro and animal experiments with magnetic nanoparticle-based drug and gene delivery, and clinical trials of drug targeting.

McBain, Stuart C; Yiu, Humphrey HP; Dobson, Jon

2008-01-01

80

Applying models of targeted drug delivery to gene delivery.  

PubMed

Gene delivery requires targeted delivery systems. Exploratory simulations using models of targeted drug delivery helps one assess the worthiness of such systems, and helps quantify the expected therapeutic benefits of the systems. The drug targeting index (DTI), a ratio of availabilities, is a measure of pharmacokinetic benefit of the delivery device, based on a combination of a physiologically-based pharmacokinetic model and a single pharmacodynamic Emaxmodel. Pharmacodynamic outcomes are quantified by the degree of separation between the dose-response and dose-toxicity curves (SRT). Simulations are undertaken to investigate the potential linkage of DTI and SRT, a pharmacodynamic outcome. A significant positive linear relationship is found between the DTI and SRT. The relationship can be translated into a minimum pharmacokinetic requirement that can be used to guide making decisions regarding whether or not further pursue the development of a candidate gene-delivery device as a therapeutic agent. PMID:17271053

Lam, Tai Ning; Hunt, C Anthony

2004-01-01

81

Magnetic nanovectors for drug delivery.  

PubMed

Nanotechnology holds the promise of novel and more effective treatments for vexing human health issues. Among these are the use of nanoparticle platforms for site-specific delivery of therapeutics to tumors, both by passive and active mechanisms; the latter includes magnetic vectoring of magnetically responsive nanoparticles (MNP) that are functionalized to carry a drug payload that is released at the tumor. The conceptual basis, which actually dates back a number of decades, resides in physical (magnetic) enhancement, with magnetic field gradients aligned non-parallel to the direction of flow in the tumor vasculature, of existing passive mechanisms for extravasation and accumulation of MNP in the tumor interstitial fluid, followed by MNP internalization. In this review, we will assess the most recent developments and current status of this approach, considering MNP that are composed of one or more of the three elements that are ferromagnetic at physiological temperature: nickel, cobalt and iron. The effects on cellular functions in vitro, the ability to successfully vector the platform in vivo, the anti-tumor effects of such localized nano-vectors, and any associated toxicities for these MNP will be presented. The merits and shortcomings of nanomaterials made of each of the three elements will be highlighted, and a roadmap for moving this long-established approach forward to clinical evaluation will be put forth. PMID:22640907

Klostergaard, Jim; Seeney, Charles E

2012-05-26

82

Transfersomes for transdermal drug delivery.  

PubMed

Transfersomes (Idea AG) are a form of elastic or deformable vesicle, which were first introduced in the early 1990s. Elasticity is generated by incorporation of an edge activator in the lipid bilayer structure. The original composition of these vesicles was soya phosphatidyl choline incorporating sodium cholate and a small concentration of ethanol. Transfersomes are applied in a non-occluded method to the skin and have been shown to permeate through the stratum corneum lipid lamellar regions as a result of the hydration or osmotic force in the skin. They have been used as drug carriers for a range of small molecules, peptides, proteins and vaccines, both in vitro and in vivo. It has been claimed by Idea AG that intact Transfersomes penetrate through the stratum corneum and the underlying viable skin into the blood circulation. However, this has not been substantiated by other research groups who have extensively probed the mechanism of penetration and interaction of elastic vesicles in the skin. Structural changes in the stratum corneum have been identified, and intact elastic vesicles visualised within the stratum corneum lipid lamellar regions, but no intact vesicles have been ascertained in the viable tissues. Using the principle of incorporating an edge-activator agent into a bilayer structure, a number of other elastic vesicle compositions have been evaluated. This review describes the research into the development and evaluation of Transfersomes and elastic vesicles as topical and transdermal delivery systems. PMID:17076595

Benson, Heather A E

2006-11-01

83

Tumor-Targeted Drug Delivery with Aptamers  

PubMed Central

Cancer is one of the leading causes of death around the world. Tumor-targeted drug delivery is one of the major areas in cancer research. Aptamers exhibit many desirable properties for tumor-targeted drug delivery, such as ease of selection and synthesis, high binding affinity and specificity, low immunogenicity, and versatile synthetic accessibility. Over the last several years, aptamers have quickly become a new class of targeting ligands for drug delivery applications. In this review, we will discuss in detail about aptamer-based delivery of chemotherapy drugs (e.g. doxorubicin, docetaxel, daunorubicin, and cisplatin), toxins (e.g. gelonin and various photodynamic therapy agents), and a variety of small interfering RNAs. Although the results are promising which warrants enthusiasm for aptamer-based drug delivery, tumor homing of aptamer-based conjugates after systemic injection has only been achieved in one report. Much remains to be done before aptamer-based drug delivery can reach clinical trials and eventually the day-to-day management of cancer patients. Therefore, future directions and challenges in aptamer-based drug delivery are also discussed.

Zhang, Yin; Hong, Hao; Cai, Weibo

2011-01-01

84

Drug Delivery Using Platelet Cancer Cell Interaction.  

PubMed

PURPOSE: To develop an efficient biocompatible and targeted drug delivery system in which platelets, an essential blood component having a natural affinity for cancer cells, are used as carrier of anticancer drug as delivery of drug to the targeted site is crucial for cancer treatment. METHODS: Doxorubicin hydrochloride, a potent anti cancer drug, was delivered in lung adenocarcinoma cell line (A549) using platelet as a delivery agent. This delivery mode was also tested in Ehrlich ascites carcinoma (EAC) bearing mice in presence and absence of platelets. RESULTS: The results show that platelets can uptake the drug and release the same upon activation. The efficiency of drug loaded platelets in inducing cytotoxicity was significantly higher in both in vitro and in vivo model, as compared to the free drug. CONCLUSIONS: The proposed drug delivery strategy may lead to clinical improvement in the management of cancer treatment as lower drug concentration can be used in a targeted mode. Additionally the method can be personalized as patient's own platelet can be used for deliver various drugs. PMID:23739991

Sarkar, Sounik; Alam, Mohammed Aftab; Shaw, Jyoti; Dasgupta, Anjan Kr

2013-06-01

85

Ophthalmic drug delivery systems—Recent advances  

Microsoft Academic Search

Eye-drops are the conventional dosage forms that account for 90% of currently accessible ophthalmic formulations. Despite the excellent acceptance by patients, one of the major problems encountered is rapid precorneal drug loss. To improve ocular drug bioavailability, there is a significant effort directed towards new drug delivery systems for ophthalmic administration.This chapter will focus on three representative areas of ophthalmic

Chrystèle Le Bourlais; Liliane Acar; Hosein Zia; Pierre A. Sado; Thomas Needham; Roger Leverge

1998-01-01

86

Liposomes in drug delivery: Progress and limitations  

Microsoft Academic Search

Liposomes are microparticulate lipoidal vesicles which are under extensive investigation as drug carriers for improving the delivery of therapeutic agents. Due to new developments in liposome technology, several liposome- based drug formulations are currently in clinical trial, and recently some of them have been approved for clinical use. Reformulation of drugs in liposomes has provided an opportunity to enhance the

Amarnath Sharma; Uma S. Sharma

1997-01-01

87

Biodegradable polymeric nanoparticles as drug delivery devices  

Microsoft Academic Search

This review presents the most outstanding contributions in the field of biodegradable polymeric nanoparticles used as drug delivery systems. Methods of preparation, drug loading and drug release are covered. The most important findings on surface modification methods as well as surface characterization are covered from 1990 through mid-2000.

Kumaresh S Soppimath; Tejraj M Aminabhavi; Anandrao R Kulkarni; Walter E Rudzinski

2001-01-01

88

Multiscale modeling of transdermal drug delivery  

Microsoft Academic Search

This study addresses the modeling of transdermal diffusion of drugs, to better understand the permeation of molecules through the skin, and especially the stratum corneum, which forms the main permeation barrier of the skin. In transdermal delivery of systemic drugs, the drugs diffuse from a patch placed on the skin through the epidermis to the underlying blood vessels. The epidermis

Jee Eun Rim

2006-01-01

89

NANOMAGNETIC PARTICLES FOR TRANSDERMAL DRUG DELIVERY  

Microsoft Academic Search

Nowadays drug administration through the transdermal route has emphasized for comfort of patient and easy application. However, the limitations of transdermal drug delivery are governed largely by high impermeability of the human skin, which acts as a natural selective barrier impeding the penetration of foreign molecules and minimizing water losses. Recent advances on improvement of drug transport through the skin

M. H. A. Santana; R. M. Barbosa

90

Device-directed therapeutic drug delivery systems  

Microsoft Academic Search

To increase the therapeutic effectiveness of device-directed drug delivery systems for diseased cardiovascular tissues and cancerous tissues, new devices and new functional biomaterials were devised to meet the requirements as listed below: drug-infusible balloon catheter, drug-releasable and covered stents, and in situ hydrogelation on and in cancerous tissues. New therapeutic strategies based on these devices were discussed.

Takehisa Matsuda

2002-01-01

91

Intracellular Delivery of Drugs to Macrophages  

Microsoft Academic Search

Toxic side effects which often complicate successful therapy in a number of diseases possibly arise due to the fact that at therapeutically effective concentrations the non-target cells in the body are also exposed to the cytotoxic effects of the drugs. Minimization of such adverse reactions might be feasible through drug delivery modalities that would reduce the uptake of the drugs

Amitabha Mukhopadhyay; Sandip K. Basu

92

Drug delivery system for zero order, zero order-biphasic, ascending or descending drug delivery  

US Patent & Trademark Office Database

The invention is directed to a drug delivery device for controlled release of a drug, comprising a core that has a cylindrical plug embedded therein; and a coating that at least partially surrounds the core. The core is comprised of a drug and excipients. The coating surrounding the core is essentially impermeable to the drug. The cylindrical plug, which is embedded in the core, may be hollow or solid. The drug delivery device enables zero-order drug release profiles as well as more complicated release profiles to be obtained. The invention is also directed to a method of making the drug delivery device.

2007-03-27

93

Perspectives on transdermal ultrasound mediated drug delivery  

PubMed Central

The use of needles for multiple injection of drugs, such as insulin for diabetes, can be painful. As a result, prescribed drug noncompliance can result in severe medical complications. Several noninvasive methods exist for transdermal drug delivery. These include chemical mediation using liposomes and chemical enhancers or physical mechanisms such as microneedles, iontophoresis, electroporation, and ultrasound. Ultrasound enhanced transdermal drug delivery offers advantages over traditional drug delivery methods which are often invasive and painful. A broad review of the transdermal ultrasound drug delivery literature has shown that this technology offers promising potential for noninvasive drug administration. From a clinical perspective, few drugs, proteins or peptides have been successfully administered transdermally because of the low skin permeability to these relatively large molecules, although much work is underway to resolve this problem. The proposed mechanism of ultrasound has been suggested to be the result of cavitation, which is discussed along with the bioeffects from therapeutic ultrasound. For low frequencies, potential transducers which can be used for drug delivery are discussed, along with cautions regarding ultrasound safety versus efficacy.

Smith, Nadine Barrie

2007-01-01

94

Inner ear drug delivery for auditory applications.  

PubMed

Many inner ear disorders cannot be adequately treated by systemic drug delivery. A blood-cochlear barrier exists, similar physiologically to the blood-brain barrier, which limits the concentration and size of molecules able to leave the circulation and gain access to the cells of the inner ear. However, research in novel therapeutics and delivery systems has led to significant progress in the development of local methods of drug delivery to the inner ear. Intratympanic approaches, which deliver therapeutics to the middle ear, rely on permeation through tissue for access to the structures of the inner ear, whereas intracochlear methods are able to directly insert drugs into the inner ear. Innovative drug delivery systems to treat various inner ear ailments such as ototoxicity, sudden sensorineural hearing loss, autoimmune inner ear disease, and for preserving neurons and regenerating sensory cells are being explored. PMID:18848590

Swan, Erin E Leary; Mescher, Mark J; Sewell, William F; Tao, Sarah L; Borenstein, Jeffrey T

2008-09-21

95

Inner Ear Drug Delivery for Auditory Applications  

PubMed Central

Many inner ear disorders cannot be adequately treated by systemic drug delivery. A blood-cochlear barrier exists, similar physiologically to the blood-brain barrier, which limits the concentration and size of molecules able to leave the circulation and gain access to the cells of the inner ear. However, research in novel therapeutics and delivery systems has led to significant progress in the development of local methods of drug delivery to the inner ear. Intratympanic approaches, which deliver therapeutics to the middle ear, rely on permeation through tissue for access to the structures of the inner ear, whereas intracochlear methods are able to directly insert drugs into the inner ear. Innovative drug delivery systems to treat various inner ear ailments such as ototoxicity, sudden sensorineural hearing loss, autoimmune inner ear disease, and for preserving neurons and regenerating sensory cells are being explored.

Swan, Erin E. Leary; Mescher, Mark J.; Sewell, William F.; Tao, Sarah L.; Borenstein, Jeffrey T.

2008-01-01

96

Elongated supramolecular assemblies in drug delivery.  

PubMed

This review presents different lipid-based elongated microstructures: tubules, cochleate cylinders and ribbons. Their composition, process of preparation and the mechanism behind their formation is discussed as well as their use as a drug delivery system. PMID:11992674

Zarif, Leila

2002-05-17

97

Inner ear drug delivery for auditory applications  

Microsoft Academic Search

Many inner ear disorders cannot be adequately treated by systemic drug delivery. A blood-cochlear barrier exists, similar physiologically to the blood-brain barrier, which limits the concentration and size of molecules able to leave the circulation and gain access to the cells of the inner ear. However, research in novel therapeutics and delivery systems has led to significant progress in the

Erin E. Leary Swan; Mark J. Mescher; William F. Sewell; Sarah L. Tao; Jeffrey T. Borenstein

2008-01-01

98

Intra-Arterial Catheter for Drug Delivery.  

National Technical Information Service (NTIS)

The present invention provides a catheter, a drug delivery system and methods for the localized delivery of therapeutic or diagnostic agent to a target location in a subject and methods for the treatment of a pathological disorder in a subject using the s...

S. Joshi

2004-01-01

99

Microsystems for drug and gene delivery  

Microsoft Academic Search

Microneedles and other structures have been developed for introducing therapeutic agents into tissues and cells. Microstructures for transdermal delivery hold the promise of pain-free drug injection. Electrodes integrated with microneedles can sense and monitor the effects of injected materials on tissues. Microprobes have been shown to be effective in transfecting cells through the delivery of DNA in experiments with both

MICHAEL L. REED; WHYE-KEI LYE

2004-01-01

100

Chitosan Microspheres in Novel Drug Delivery Systems  

PubMed Central

The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

Mitra, Analava; Dey, Baishakhi

2011-01-01

101

Ask the Experts: Transdermal drug delivery.  

PubMed

Transdermal drug delivery, an arena currently worth several billions of US dollars, is a highly favored route of drug administration due to its convenience for patients and medical professionals alike. However, given the high costs in bringing new technologies to the market, as well as the technical issues of delivering drugs past the stratum corneum, the transdermal field needs to overcome a number of obstacles before it can realize its true potential. James Potticary, Assistant Commissioning Editor, spoke with three experts, discussing the challenges faced within the transdermal community, their motivations for becoming involved in the field and their visions for the future of transdermal drug delivery. PMID:24116908

2013-10-01

102

Novel Platforms for Oral Drug Delivery  

Microsoft Academic Search

The aim of this review is to provide the reader general and inspiring prospects on recent and promising fields of innovation\\u000a in oral drug delivery. Nowadays, inventive drug delivery systems vary from geometrically modified and modular matrices, more\\u000a close to “classic” pharmaceutical manufacturing processes, to futuristic bio micro-electro-mechanical systems (bioMEMS), based\\u000a on manufacturing techniques borrowed from electronics and other fields.

P. Colombo; F. Sonvico; G. Colombo; R. Bettini

2009-01-01

103

Transdermal drug delivery system: patent reviews.  

PubMed

Transdermal drug delivery represents one of the most rapidly advancing areas of novel drug delivery. Although the concept of transdermal drug delivery has been known since 1924, it took until 1979, as FDA approved the transdermal delivery of scopolamine, that transdermal delivery systems [TDDS] received broad attention as novel tool for controlled release. These drug delivery systems are designed for controlled release of drug through the skin into systemic circulation maintaining consistent efficacy and reducing dose of the drug and its related side effects. More than 200 patents have been granted by the United State patent alone, of which more than 35 TDD products have now been approved for sale in the US, and approximately 16 active ingredients have been approved for use globally. Statistics reveal a market of $ 12.7 billion in the year 2005 which is expected to increase by $ 21.5 billion in the year 2010 and $ 31.5 billion in the year 2015. Almost all major and minor pharmaceutical companies are developing TDDS. There is not a single review article which describes patents on different types of TDDS. Thus this review is designed for patents on the different type of TDDS which would be helpful for the researcher in the field of TDDS. PMID:19519574

Samad, Abdus; Ullah, Zabih; Alam, Mohammad I; Wais, Mohd; Shams, Mohammad Shabaz

2009-06-01

104

Calcium phosphate ceramics in drug delivery  

NASA Astrophysics Data System (ADS)

Calcium phosphate (CaP) particulates, cements and scaffolds have attracted significant interest as drug delivery vehicles. CaP systems, including both hydroxyapaptite and tricalcium phosphates, possess variable stoichiometry, functionality and dissolution properties which make them suitable for cellular delivery. Their chemical similarity to bone and thus biocompatibility, as well as variable surface charge density contribute to their controlled release properties. Among specific research areas, nanoparticle size, morphology, surface area due to porosity, and chemistry controlled release kinetics are the most active. This article discusses CaP systems in their particulate, cements, and scaffold forms for drug, protein, and growth factor delivery toward orthopedic and dental applications.

Bose, Susmita; Tarafder, Solaiman; Edgington, Joe; Bandyopadhyay, Amit

2011-04-01

105

Microneedles for drug and vaccine delivery  

PubMed Central

Microneedles were first conceptualized for drug delivery many decades ago, but only became the subject of significant research starting in the mid-1990’s when microfabrication technology enabled their manufacture as (i) solid microneedles for skin pretreatment to increase skin permeability, (ii) microneedles coated with drug that dissolves off in the skin, (iii) polymer microneedles that encapsulate drug and fully dissolve in the skin and (iv) hollow microneedles for drug infusion into the skin. As shown in more than 350 papers now published in the field, microneedles have been used to deliver a broad range of different low molecular weight drugs, biotherapeutics and vaccines, including published human studies with a number of small-molecule and protein drugs and vaccines. Influenza vaccination using a hollow microneedle is in widespread clinical use and a number of solid microneedle products are sold for cosmetic purposes. In addition to applications in the skin, microneedles have also been adapted for delivery of bioactives into the eye and into cells. Successful application of microneedles depends on device function that facilitates microneedle insertion and possible infusion into skin, skin recovery after microneedle removal, and drug stability during manufacturing, storage and delivery, and on patient outcomes, including lack of pain, skin irritation and skin infection, in addition to drug efficacy and safety. Building off a strong technology base and multiple demonstrations of successful drug delivery, microneedles are poised to advance further into clinical practice to enable better pharmaceutical therapies, vaccination and other applications.

Kim, Yeu-Chun; Park, Jung-Hwan; Prausnitz, Mark R.

2012-01-01

106

Hydrogen peroxide mediated transvaginal drug delivery.  

PubMed

Simple, safe and effective permeability enhancers are crucial for successful non-invasive drug delivery methods. We seek local permeability augmentation mechanisms for integration into passive or active architectures in order to enable novel therapeutic delivery routes of the target drug while minimizing drug formulation challenges. This study explores the efficacy of hydrogen peroxide (HP) as a permeability enhancer for transmucosal delivery of macromolecules. HP at low concentrations (2–8 mM) is an effective permeability enhancer that is locally metabolized and safe. HP improves drug permeation through mucosa by altering tight junctions (TJ) between cells and oxidizing enzymes that function to degrade the foreign species. Results from trans-epithelial electrical resistance measurements and cell viability assay show reversible disassembly of TJ with minimal cell damage demonstrating the feasibility of HP as a safe permeability enhancer for drug delivery. Permeation studies show that HP treatment of cell cultured vaginal mucosa significantly enhances the permeability to insulin by more than an order of magnitude. This work lays foundation for the development of a drug delivery platform that administers drug doses by enhancing the permeability of local epithelial tissue via a separate HP treatment step. PMID:21498011

Fatakdawala, Hussain; Uhland, Scott A

2011-05-16

107

Cyclodextrins in ophthalmic drug delivery  

Microsoft Academic Search

Most ocular diseases are treated by topical drug application in the form of aqueous eye drop solutions. Recent studies have shown that cyclodextrins are useful additives in ophthalmic formulations for increasing the aqueous solubility, aqueous stability and bioavailability of ophthalmic drugs, and to decrease drug irritation. However, these studies have also shown that there are some basic differences between ophthalmic

Thorsteinn Loftssona; Tomi Järvinen

1999-01-01

108

Multiparticulate Formulation .. Approach to Colon Specific Drug Delivery: Current Perspectives  

Microsoft Academic Search

Colon specific drug delivery has gained increased importance not just for the delivery of drugs for the treatment of local diseases associated with the colon but also as potential site for the systemic delivery of therapeutic peptide and proteins. To achieve successful colon targeted drug delivery, a drug needs to be protected from degradation, release and\\/or absorption in the upper

Laila Fatima; Ali Asghar; Sajeev Chandran

109

Molecularly imprinted polymers for drug delivery  

Microsoft Academic Search

Molecular imprinting technology has an enormous potential for creating satisfactory drug dosage forms. Although its application in this field is just at an incipient stage, the use of MIPs in the design of new drug delivery systems (DDS) and devices useful in closely related fields, such as diagnostic sensors, is receiving increasing attention. Examples of MIP-based DDS can be found

Carmen Alvarez-Lorenzo; Angel Concheiro

2004-01-01

110

Transdermal drug delivery by localized intervention  

Microsoft Academic Search

Both field-confined skin electroporation and microscissioning offer minimally invasive methods for delivering drugs across skin and nail with minimal sensation. Both methods create high permeability pathways in a pain-free manner. These openings are similar in dimension to commonly experienced scratches and nicks on the skin. These localized openings provide pathways for sustained delivery of drugs either passively using a patch

T. R. Gowrishankar; T. O. Herndon; J. C. Weaver

2009-01-01

111

Tuberculosis chemotherapy: current drug delivery approaches  

Microsoft Academic Search

Tuberculosis is a leading killer of young adults worldwide and the global scourge of multi-drug resistant tuberculosis is reaching epidemic proportions. It is endemic in most developing countries and resurgent in developed and developing countries with high rates of human immunodeficiency virus infection. This article reviews the current situation in terms of drug delivery approaches for tuberculosis chemotherapy. A number

Lisa Claire du Toit; Viness Pillay; Michael Paul Danckwerts

2006-01-01

112

Nanotech approaches to drug delivery and imaging.  

PubMed

Nanotechnology, a multidisciplinary scientific undertaking, involves creation and utilization of materials, devices or systems on the nanometer scale. The field of nanotechnology is currently undergoing explosive development on many fronts. The technology is expected to create innovations and play a critical role in various biomedical applications, not only in drug delivery, but also in molecular imaging, biomarkers and biosensors. Target-specific drug therapy and methods for early diagnosis of pathologies are the priority research areas where nanotechnology would play a vital role. This review considers different nanotechnology-based drug delivery and imaging approaches, and their economic impact on pharmaceutical and biomedical industries. PMID:14678737

Sahoo, Sanjeeb K; Labhasetwar, Vinod

2003-12-15

113

Emulsion forming drug delivery system for lipophilic drugs.  

PubMed

In the recent years, there is a growing interest in the lipid-based formulations for delivery of lipophilic drugs. Due to their potential as therapeutic agents, preferably these lipid soluble drugs are incorporated into inert lipid carriers such as oils, surfactant dispersions, emulsions, liposomes etc. Among them, emulsion forming drug delivery systems appear to be a unique and industrially feasible approach to overcome the problem of low oral bioavailability associated with the BCS class II drugs. Self-emulsifying formulations are ideally isotropic mixtures of oils, surfactants and co-solvents that emulsify to form fine oil in water emulsions when introduced in aqueous media. Fine oil droplets would pass rapidly from stomach and promote wide distribution of drug throughout the GI tract, thereby overcome the slow dissolution step typically observed with solid dosage forms. Recent advances in drug carrier technologies have promulgated the development of novel drug carriers such as control release self-emulsifying pellets, microspheres, tablets, capsules etc. that have boosted the use of "self-emulsification" in drug delivery. This article reviews the different types of formulations and excipients used in emulsion forming drug delivery system to enhance the bioavailability of lipophilic drugs. PMID:22568032

Wadhwa, Jyoti; Nair, Anroop; Kumria, Rachna

114

Ultrasonic Drug Delivery - A General Review  

PubMed Central

Ultrasound (US) has an ever-increasing role in the delivery of therapeutic agents including genetic material, proteins, and chemotherapeutic agents. Cavitating gas bodies such as microbubbles are the mediators through which the energy of relatively non-interactive pressure waves is concentrated to produce forces that permeabilize cell membranes and disrupt the vesicles that carry drugs. Thus the presence of microbubbles enormously enhances delivery of genetic material, proteins and smaller chemical agents. Delivery of genetic material is greatly enhanced by ultrasound in the presence of microbubbles. Attaching the DNA directly to the microbubbles or to gas-containing liposomes enhances gene uptake even further. US-enhanced gene delivery has been studied in various tissues including cardiac, vascular, skeletal muscle, tumor and even fetal tissue. US-enhanced delivery of proteins has found most application in transdermal delivery of insulin. Cavitation events reversibly disrupt the structure of the stratus corneum to allow transport of these large molecules. Other hormones and small proteins could also be delivered transdermally. Small chemotherapeutic molecules are delivered in research settings from micelles and liposomes exposed to ultrasound. Cavitation appears to play two roles: it disrupts the structure of the carrier vesicle and releases the drug; it also makes the cell membranes and capillaries more permeable to drugs. There remains a need to better understand the physics of cavitation of microbubbles and the impact that such cavitation has upon cells and drug-carrying vesicles.

Pitt, William G.; Husseini, Ghaleb A.; Staples, Bryant J.

2006-01-01

115

Drug delivery to the Lungs 21.  

PubMed

Drug Delivery to the Lungs 21 was focused exclusively on delivery technologies of medicines for the treatment of diseases that are 'local' to the respiratory tract or for wider 'systemic' distribution. Therefore, the range of diseases that can be treated via delivering drugs to the lungs is large and diverse. This diversity means that the delivery technologies (device and/or formulation) are also very varied. Moreover, the patient is critically involved when using drug-delivery technologies to the lungs as their inhalation and 'user' characteristics are pivotal in ensuring that the correct dose is given and reaches the appropriate part of the respiratory tract. Thus, Drug Delivery to the Lungs 21 was a wide-ranging conference, ideal for an overview of current and future inhaled-delivery technologies. The conference was split into various themed sections and supported by approximately 65 posters. Furthermore, the conference was preceded by a workshop organized by the European Pharmaceutical Aerosol Group on abbreviated impactor measurement, which is a tool currently of much interest in assessing aerosol products (see separate summary). The conference initiated a number of innovations this year, including a Facebook page on which delegates and organizers could follow and 'chat' about conference proceedings. PMID:22834000

Mitchell, Jolyon P; Nichols, Steve C

2011-03-01

116

Inhaled Drug Delivery for Tuberculosis Therapy  

Microsoft Academic Search

One third of the world population is infected with tuberculosis (TB), and new infections occur at a rate of one per second.\\u000a The recent increase in the emergence of drug-resistant strains of Mycobacterium tuberculosis and the dearth of anti-TB drugs is threatening the future containment of TB. New drugs or delivery systems that will stop\\u000a the spread of TB and

Pavan Muttil; Chenchen Wang; Anthony J. Hickey

2009-01-01

117

Local drug delivery system using biodegradable polymers  

Microsoft Academic Search

For last five years, we are developing the novel local drug delivery devices using biodegradable polymers, especially polylactide\\u000a (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) due to its relatively good biocompatibility, easily controlled biodegradability, good processability and\\u000a only FDA approved synthetic degradable polymers. The relationship between various kinds of drug [water soluble small molecule\\u000a drugs : gentamicin sulfate (GS), fentanyl citrate (FC), BCNU,

Gilson Khang; John M. Rhee; Je Kyo Jeong; Jeong Sik Lee; Moon Suk Kim; Sun Hang Cho; Hai Bang Lee

2003-01-01

118

A biodegradable filament for controlled drug delivery  

Microsoft Academic Search

Biodegradable filaments (diameters of 250–300 ?m) for the controlled delivery of dexamethasone or levofloxacin are described. Filaments are prepared by wet-spinning solutions of poly(lactide-co-glycolide) (PLGA) and drug dissolved in dimethyl sulfoxide (DMSO) into a coagulation bath of water. Compositional analyses of the filaments by independent measurements of drug, DMSO, water, and polymer give drug loadings up to 40% of filament mass

Brendan C. Mack; Kenneth W. Wright; Mark E. Davis

2009-01-01

119

Intracellular Delivery of Drugs to Macrophages  

Microsoft Academic Search

Toxic side effects which often complicate successful therapy in a number of diseases possibly arise due to the fact that at\\u000a therapeutically effective concentrations the non-target cells in the body are also exposed to the cytotoxic effects of the\\u000a drugs. Minimization of such adverse reactions might be feasible through drug delivery modalities that would reduce the uptake\\u000a of the drugs

Amitabha Mukhopadhyay; Sandip Basu

120

Floating drug delivery systems: an approach to oral controlled drug delivery via gastric retention  

Microsoft Academic Search

In recent years scientific and technological advancements have been made in the research and development of rate-controlled oral drug delivery systems by overcoming physiological adversities, such as short gastric residence times (GRT) and unpredictable gastric emptying times (GET). Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems (FDDS), also known as hydrodynamically balanced

Brahma N. Singh; Kwon H. Kim

2000-01-01

121

Nanoporous Implants for Controlled Drug Delivery  

Microsoft Academic Search

\\u000a Over the last three decades considerable advances have marked the field of drug delivery technology, resulting in many breakthroughs\\u000a in clinical medicine. However, major unmet needs remain. Among these are broad categories of: 1) Continuous release of therapeutic\\u000a agents over extended time periods and in accordance to a pre-determined temporal profile [38, 60]; 2) Local delivery at a constant rate

Tejal A. Desai; Sadhana Sharma; Robbie J. Walczak; Anthony Boiarski; Michael Cohen; John Shapiro; Teri West; Kristie Melnik; Carlo Cosentino; Piyush M. Sinha; Mauro Ferrari

122

Nanoparticles in the ocular drug delivery  

PubMed Central

Ocular drug transport barriers pose a challenge for drug delivery comprising the ocular surface epithelium, the tear film and internal barriers of the blood-aqueous and blood-retina barriers. Ocular drug delivery efficiency depends on the barriers and the clearance from the choroidal, conjunctival vessels and lymphatic. Traditional drug administration reduces the clinical efficacy especially for poor water soluble molecules and for the posterior segment of the eye. Nanoparticles (NPs) have been designed to overcome the barriers, increase the drug penetration at the target site and prolong the drug levels by few internals of drug administrations in lower doses without any toxicity compared to the conventional eye drops. With the aid of high specificity and multifunctionality, DNA NPs can be resulted in higher transfection efficiency for gene therapy. NPs could target at cornea, retina and choroid by surficial applications and intravitreal injection. This review is concerned with recent findings and applications of NPs drug delivery systems for the treatment of different eye diseases.

Zhou, Hong-Yan; Hao, Ji-Long; Wang, Shuang; Zheng, Yu; Zhang, Wen-Song

2013-01-01

123

Transport Barriers in Transscleral Drug Delivery for Retinal Diseases  

Microsoft Academic Search

Transscleral delivery has emerged as an attractive method for treating retinal disorders because it offers localized delivery of drugs as a less invasive method compared to intravitreal administration. Numerous novel transscleral drug delivery systems ranging from microparticles to implants have been reported. However, transscleral delivery is currently not as clinically effective as intravitreal delivery in the treatment of retinal diseases.

Stephanie H. Kim; Robert J. Lutz; Nam Sun Wang; Michael R. Robinson

2007-01-01

124

Self-emulsifying drug delivery systems (SEDDS) for improved oral delivery of lipophilic drugs  

Microsoft Academic Search

The oral delivery of hydrophobic drugs presents a major challenge because of the low aqueous solubility of such compounds. Self-emulsifying drug delivery systems (SEDDS), which are isotropic mixtures of oils, surfactants, solvents and co-solvents\\/surfactants, can be used for the design of formulations in order to improve the oral absorption of highly lipophilic drug compounds. SEDDS can be orally administered in

R Neslihan Gursoy; Simon Benita

2004-01-01

125

Comparison of local intravascular drug-delivery catheter systems  

Microsoft Academic Search

Systemic and local delivery on the photosensitive drug Photofrin polyporphyrin was investigated in normal porcine arteries (n = 192). A macroporous balloon and a novel needle injection catheter were used for local drug delivery and compared with systemic delivery. Fluorescence microscopy combined with digital image analysis was used to quantify the drug-related fluorescence. Systemic delivery showed a maximum in the

Peter Gonschior; Clemens Pahl; Tanya Y. Huehns; Florian Gerheuser; Aysel Erdemci; Katharina Larisch; Marc Dellian; Stefan Deil; Alwin-E. Goetz; Hans A. Lehr; Berthold Höfling

1995-01-01

126

Drug delivery and nanoparticles: Applications and hazards  

PubMed Central

The use of nanotechnology in medicine and more specifically drug delivery is set to spread rapidly. Currently many substances are under investigation for drug delivery and more specifically for cancer therapy. Interestingly pharmaceutical sciences are using nanoparticles to reduce toxicity and side effects of drugs and up to recently did not realize that carrier systems themselves may impose risks to the patient. The kind of hazards that are introduced by using nanoparticles for drug delivery are beyond that posed by conventional hazards imposed by chemicals in classical delivery matrices. For nanoparticles the knowledge on particle toxicity as obtained in inhalation toxicity shows the way how to investigate the potential hazards of nanoparticles. The toxicology of particulate matter differs from toxicology of substances as the composing chemical(s) may or may not be soluble in biological matrices, thus influencing greatly the potential exposure of various internal organs. This may vary from a rather high local exposure in the lungs and a low or neglectable exposure for other organ systems after inhalation. However, absorbed species may also influence the potential toxicity of the inhaled particles. For nanoparticles the situation is different as their size opens the potential for crossing the various biological barriers within the body. From a positive viewpoint, especially the potential to cross the blood brain barrier may open new ways for drug delivery into the brain. In addition, the nanosize also allows for access into the cell and various cellular compartments including the nucleus. A multitude of substances are currently under investigation for the preparation of nanoparticles for drug delivery, varying from biological substances like albumin, gelatine and phospholipids for liposomes, and more substances of a chemical nature like various polymers and solid metal containing nanoparticles. It is obvious that the potential interaction with tissues and cells, and the potential toxicity, greatly depends on the actual composition of the nanoparticle formulation. This paper provides an overview on some of the currently used systems for drug delivery. Besides the potential beneficial use also attention is drawn to the questions how we should proceed with the safety evaluation of the nanoparticle formulations for drug delivery. For such testing the lessons learned from particle toxicity as applied in inhalation toxicology may be of use. Although for pharmaceutical use the current requirements seem to be adequate to detect most of the adverse effects of nanoparticle formulations, it can not be expected that all aspects of nanoparticle toxicology will be detected. So, probably additional more specific testing would be needed.

De Jong, Wim H; Borm, Paul JA

2008-01-01

127

Local Inner Ear Drug Delivery and Pharmacokinetics  

PubMed Central

Summary A number of drugs are in widespread clinical use for the treatment of inner ear disorders by applying them directly to the inner ear. Many new substances and drug delivery systems specific to the inner ear are under development, and in some cases are undergoing evaluations in animal experiments and in clinical studies. The pharmacokinetics of drugs in the inner ear, however, is not well defined and the field is plagued by technical problems in obtaining pure samples of the inner ear fluids for analysis. Nevertheless, a basic understanding of the mechanisms of drug dispersal in the inner ear has emerged that facilitates the design and interpretation of future pharmacokinetic studies.

Salt, Alec N.; Plontke, Stefan K.R.

2008-01-01

128

Pulmonary drug delivery: medicines for inhalation.  

PubMed

Mankind has inhaled substances for medical and other reasons for thousands of years, notably resulting in the cultural manifestations of tobacco and opium smoking. Over the course of time concepts of pulmonary application, including inhalation devices and drug formulations, have been and still are being continuously developed. State of the art instruments even allow for individualized drug application by adaptation of the inhalation procedure to the breathing pattern of the patient. Pulmonary drug delivery offers promising advantages in comparison to "classical" drug administration via the oral or transcutaneous routes, which is also reflected by an increasing interest and number of marketed products for inhalation therapy. However, the lungs' efficient clearance mechanisms still limit the benefit of many therapeutic concepts. In consequence the objective of current research and development in pulmonary drug delivery is to overcome and to control drug clearance from the intended target site. Here, several of the most auspicious future drug delivery concepts are presented and discussed in order to give the reader an insight into this emerging field of medicine. PMID:20217530

Henning, Andreas; Hein, Stephanie; Schneider, Marc; Bur, Michael; Lehr, Claus-Michael

2010-01-01

129

Polysaccharides for colon targeted drug delivery.  

PubMed

Colon targeted drug delivery has the potential to deliver bioactive agents for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. Various strategies, currently available to target the release of drugs to colon, include formation of prodrug, coating of pH-sensitive polymers, use of colon-specific biodegradable polymers, timed released systems, osmotic systems, and pressure controlled drug delivery systems. Among the different approaches to achieve targeted drug release to the colon, the use of polymers especially biodegradable by colonic bacteria holds great promise. Polysaccharidases are bacterial enzymes that are available in sufficient quantity to be exploited in colon targeting of drugs. Based on this approach, various polysaccharides have been investigated for colon-specific drug release. These polysaccharides include pectin, guar gum, amylose, inulin, dextran, chitosan, and chondroitin sulphate. This family of natural polymers has an appeal to drug delivery as it is comprised of polymers with a large number of derivatizable groups, a wide range of molecular weights, varying chemical compositions, and, for the most part, low toxicity and biodegradability yet high stability. The most favorable property of these materials is their approval as pharmaceutical excipients. PMID:15200012

Chourasia, M K; Jain, S K

130

Systemic delivery of antihypertensive drugs via skin.  

PubMed

Hypertension is a chronic disease with one of the highest chances of causing death, and long-term treatment is required. The antihypertensive drugs used in the treatment are generally administered orally. The limitations of the oral route make transdermal delivery of drugs more attractive. The transdermal route offers numerous advantages including avoidance of systemic first-pass metabolism and high patient compliance. The transdermal therapeutic systems, popularly known as 'patches', deliver drugs across the skin with a constant release rate. However, skin is a unique membrane having excellent barrier properties. Either chemical enhancers or physical methods such as iontophoresis and electroporation have been used to provide effective plasma drug concentrations. This review article focuses on the approaches to enhance skin permeability of antihypertensive drugs for the optimization of transdermal therapeutic systems of these drugs and the research studies intended for the optimization of transdermal dosage forms of antihypertensive drugs are summarized. PMID:23035594

Güngör, Sevgi; Ozsoy, Yildiz

2012-09-01

131

Porous polysulfone coatings for enhanced drug delivery.  

PubMed

The synthesis of a porous polysulfone (PSU) coating for use in drug delivery applications is presented. PSU can serve as a functional surface coating for drug delivery vehicles, such as intraocular biomicrorobots. The coatings can be applied using spin coating or dip coating. The porosity is introduced by selectively dissolving calcium carbonate nanoparticles embedded in the bulk polymer. The network of pores thus formed increases by a factor of thirty the amount of Rhodamine B (model drug) that can be loaded and by a factor of fifteen the amount that can be released. The films do not affect cell viability and exhibit poor cell adhesion. The straightforward synthesis and predictability of porosity enables the tuning of the amount of drug that can be loaded. PMID:22391877

Sivaraman, Kartik M; Kellenberger, Christoph; Pané, Salvador; Ergeneman, Olgaç; Lühmann, Tessa; Luechinger, Norman A; Hall, Heike; Stark, Wendelin J; Nelson, Bradley J

2012-06-01

132

Colonic Drug Delivery: Prodrug Approach  

Microsoft Academic Search

The colon is largely being investigated as a site for administration of protein and peptides, which are degraded by digestive enzymes in the upper GIT. Also for local diseases of the colon, drug administration to the site of action can not only reduce the dose to be administered, but also decrease the side effects. One of the approaches used for

V. R. Sinha; Rachna Kumria

2001-01-01

133

Nano-Sized Carriers for Drug Delivery  

Microsoft Academic Search

Drug delivery is an important issue, especially with a new generation of therapeutics, which are either unstable in the biological\\u000a environment, have poor transport properties across biological membranes, are insoluble in water, or have very low bioavailability.\\u000a Nano-sized drug carriers can address some of the above issues and enhance their therapeutic efficacy. Different types of nano-sized\\u000a carriers, such as nanoparticles,

Sanjeeb K. Sahoo; Tapan K. Jain; Maram K. Reddy; Vinod Labhasetwar

134

Endocytic mechanisms for targeted drug delivery.  

PubMed

Advances in the delivery of targeted drug systems have evolved to enable highly regulated site specific localization to subcellular organelles. Targeting therapeutics to individual intracellular compartments has resulted in benefits to therapies associated with these unique organelles. Endocytosis, a mechanism common to all cells in the body, internalizes macromolecules and retains them in transport vesicles which traffic along the endolysosomal scaffold. An array of vesicular internalization mechanisms exist, therefore understanding the key players specific to each pathway has allowed researchers to bioengineer macromolecular complexes for highly specialized delivery. Membrane specific receptors most frequently enter the cell through endocytosis following the binding of a high affinity ligand. High affinity ligands interact with membrane receptors, internalize in membrane bound vesicles, and traffic through cells in different manners to allow for accumulation in early endosomal fractions or lysosomally associated fractions. Although most drug delivery complexes aim to avoid lysosomal degradation, more recent studies have shown the clinical utility in directed protein delivery to this environment for the enzymatic release of therapeutics. Targeting nanomedicine complexes to the endolysosomal pathway has serious potential for improving drug delivery for the treatment of lysosomal storage diseases, cancer, and Alzheimer's disease. Although several issues remain for receptor specific targeting, current work is investigating a synthetic receptor approach for high affinity binding of targeted macromolecules. PMID:17659804

Bareford, Lisa M; Swaan, Peter W

2007-06-28

135

Ion Exchange Resins Transforming Drug Delivery Systems.  

PubMed

Ion-exchange resins are light, porous, three-dimensional high molecular weight cross -linked matrix of hydrocarbon chains carrying positively or negatively charged sites that can attract an ion of opposite charge from the surrounding medium. There is stoichiometric exchange of mobile ions between the solid and the solution called as Ion-exchange which does not lead to any radical change in the properties and structure of the solid. Depending upon the type of Ionexchanged it can be either Cation-exchange or Anion-exchange. They are prepared in the form of granules, beads or sheets. As drug delivery systems they have received considerable attention after the 1950s due to their inertness, freedom from side effects, high drug loading capacity, ease of sterilization and the fact that their structure can be easily altered to achieve the desired drug release characteristics. Their use is revolutionizing all traditional delivery systems namely- oral, nasal, ophthalmic and parenteral. Ion- exchange resins have been used for the development of novel drug delivery systems (NDDSs), to modify the characteristics of the dosage form and various other biomedical applications. The present article deals with the varied applications of ion-exchange resins for taste making, as resinates (simple and microencapsulated or coated), Pennkinetic systems, in selective recovery of pharmaceuticals, in pH and ionic strength responsive systems, in gastro-retentive systems, in hollow fiber systems, as sigmoidal release systems, as site specific delivery systems and as inotophoretically assisted transdermal drug delivery systems. They also have an immense importance when used as disintegrants/ superdisintegrants in formulation of orodispersible tablets, powder processing aids and in the dissolution and stabilization of drugs. PMID:20497105

Gupta, Shweta; Benien, Parul; Sahoo, P K

2010-05-24

136

Ion Exchange Resins Transforming Drug Delivery Systems.  

PubMed

Ion-exchange resins are light, porous, three-dimensional high molecular weight cross -linked matrix of hydrocarbon chains carrying positively or negatively charged sites that can attract an ion of opposite charge from the surrounding medium. There is stoichiometric exchange of mobile ions between the solid and the solution called as Ion-exchange which does not lead to any radical change in the properties and structure of the solid. Depending upon the type of Ion-exchanged it can be either Cation-exchange or Anion-exchange. They are prepared in the form of granules, beads or sheets. As drug delivery systems they have received considerable attention after the 1950s due to their inertness, freedom from side effects, high drug loading capacity, ease of sterilization and the fact that their structure can be easily altered to achieve the desired drug release characteristics. Their use is revolutionizing all traditional delivery systems namely- oral, nasal, ophthalmic and parenteral. Ion- exchange resins have been used for the development of novel drug delivery systems (NDDSs), to modify the characteristics of the dosage form and various other biomedical applications. The present article deals with the varied applications of ion-exchange resins for taste making, as resinates (simple and microencapsulated or coated), Pennkinetic systems, in selective recovery of pharmaceuticals, in pH and ionic strength responsive systems, in gastro-retentive systems, in hollow fiber systems, as sigmoidal release systems, as site specific delivery systems and as inotophoretically assisted transdermal drug delivery systems. They also have an immense importance when used as disintegrants / superdisintegrants in formulation of orodispersible tablets, powder processing aids and in the dissolution and stabilization of drugs. PMID:20158479

Gupta, Shweta; Parul; Sahoo, P K

2010-02-17

137

Kinetics of reciprocating drug delivery to the inner ear  

Microsoft Academic Search

Reciprocating drug delivery is a means of delivering soluble drugs directly to closed fluid spaces in the body via a single cannula without an accompanying fluid volume change. It is ideally suited for drug delivery into small, sensitive and unique fluid spaces such as the cochlea. We characterized the pharmacokinetics of reciprocating drug delivery to the scala tympani within the

Erin E. Leary Pararas; Zhiqiang Chen; Jason Fiering; Mark J. Mescher; Ernest S. Kim; Michael J. McKenna; Sharon G. Kujawa; Jeffrey T. Borenstein; William F. Sewell

2011-01-01

138

Ultrasound-enhanced drug and gene delivery: A review  

Microsoft Academic Search

Optimization of drug and gene delivery is currently a topic of great interest. This optimization can be achieved via site-specific (targeted) delivery, controlled drug release, and by finding ways to deliver more of the drug into tissues of interest (despite various barriers). Targeted delivery can serve to lower the required drug dose and minimize toxic side effects, which is crucial

Vesna Zderic

2008-01-01

139

Micro- and nano-fabricated implantable drug-delivery systems  

PubMed Central

Implantable drug-delivery systems provide new means for achieving therapeutic drug concentrations over entire treatment durations in order to optimize drug action. This article focuses on new drug administration modalities achieved using implantable drug-delivery systems that are enabled by micro- and nano-fabrication technologies, and microfluidics. Recent advances in drug administration technologies are discussed and remaining challenges are highlighted.

Meng, Ellis; Hoang, Tuan

2013-01-01

140

Optically generated ultrasound for enhanced drug delivery  

DOEpatents

High frequency acoustic waves, analogous to ultrasound, can enhance the delivery of therapeutic compounds into cells. The compounds delivered may be chemotherapeutic drugs, antibiotics, photodynamic drugs or gene therapies. The therapeutic compounds are administered systemically, or preferably locally to the targeted site. Local delivery can be accomplished through a needle, cannula, or through a variety of vascular catheters, depending on the location of routes of access. To enhance the systemic or local delivery of the therapeutic compounds, high frequency acoustic waves are generated locally near the target site, and preferably near the site of compound administration. The acoustic waves are produced via laser radiation interaction with an absorbing media and can be produced via thermoelastic expansion, thermodynamic vaporization, material ablation, or plasma formation. Acoustic waves have the effect of temporarily permeabilizing the membranes of local cells, increasing the diffusion of the therapeutic compound into the cells, allowing for decreased total body dosages, decreased side effects, and enabling new therapies.

Visuri, Steven R. (Livermore, CA); Campbell, Heather L. (Baltimore, MD); Da Silva, Luiz (Danville, CA)

2002-01-01

141

Phototriggering of liposomal drug delivery systems  

Microsoft Academic Search

Over the past several years, photodynamic therapy (PDT) has been approved for the treatment of various cancers. Additional applications of photochemical processes for triggering site-specific drug delivery are in early stages of development at this time. This review focuses on the literature appearing between January 1996–June 2001 that describe new and ongoing studies of phototriggering mechanisms that may ultimately find

Pochi Shum; Jong-Mok Kim; David H Thompson

2001-01-01

142

Cell Penetrating Peptides in Drug Delivery  

Microsoft Academic Search

Protein transduction domains (PTDs) are small cationic peptides that can facilitate the uptake of large, biologically active molecules into mammalian cells. Recent reports have suggested that PTDs may be able to mediate the delivery of cargo to tissues throughout a living organism. Such technology could eliminate the size restrictions on usable drugs, enabling previously unavailable large molecules to modulate in

Eric L. Snyder; Steven F. Dowdy

2004-01-01

143

Endocytic mechanisms for targeted drug delivery  

Microsoft Academic Search

Advances in the delivery of targeted drug systems have evolved to enable highly regulated site specific localization to subcellular organelles. Targeting therapeutics to individual intracellular compartments has resulted in benefits to therapies associated with these unique organelles. Endocytosis, a mechanism common to all cells in the body, internalizes macromolecules and retains them in transport vesicles which traffic along the endolysosomal

Lisa M. Bareford; Peter W. Swaan

2007-01-01

144

REVIEW NANOPARTICLES IN DELIVERY OF CARDIOVASCULAR DRUGS  

Microsoft Academic Search

Everything in nature is built upward from the atomic level to define limits and structures to everything. Nanomedicines marked the field of medicine from nanobiotechnology, biological micro-electromechanical systems, microfluidics, biosensors, drug delivery, microarrays to tissue microengineering. Since then nanoparticles has overcome many challenges from blood brain barrier to targeting tumors. Where solid biodegradable nanoparticles were a step up liposome, targeting

M. SAEED ARAYNE; NAJMA SULTANA; FAIZA QURESHI

145

Mathematical modelling of magnetically targeted drug delivery  

Microsoft Academic Search

A mathematical model for targeted drug delivery using magnetic particles is developed. This includes a diffusive flux of particles arising from interactions between erythrocytes in the microcirculation. The model is used to track particles in a vessel network. Magnetic field design is discussed and we show that it is impossible to specifically target internal regions using an externally applied field.

Andrew D. Grief; Giles Richardson

2005-01-01

146

Echogenic Lipsomes for Targeted Drug Delivery  

Microsoft Academic Search

Echogenic immunoliposomes (ELIP) are under development to enable ultrasound-controlled drug delivery. Mechanistic studies in vitro have revealed that stable cavitation is correlated with enhanced recombinant tissue Plasminogen Activator (rt-PA) thrombolysis, yet strategies to optimize the occurrence of such bubble activity and avoid potential harmful bioeffects have yet to be identified. Stable cavitation is characterized by bubbles pulsating gently in response

Christy K. Holland; David D. McPherson

2009-01-01

147

Electroporation apparatus for transdermal drug delivery  

Microsoft Academic Search

The apparatus described is applicable to transdermal drug delivery (TDD) by electroporation in vitro. It is a pulse generator which uses capacitor discharge to produce a series of controlled exponential pulses to the skin. The unit is capable of producing selected pulse amounts from 1 to 9 with continuous regulable pulse intensity of 70-400 V and selected pulse rates of

Bao Jiali; Lang Wenquan; Hu Qiaohong; Gao Jianqing

1998-01-01

148

Nanotech approaches to drug delivery and imaging  

Microsoft Academic Search

Nanotechnology, a multidisciplinary scientific undertaking, involves creation and utilization of materials, devices or systems on the nanometer scale. The field of nanotechnology is currently undergoing explosive development on many fronts. The technology is expected to create innovations and play a critical role in various biomedical applications, not only in drug delivery, but also in molecular imaging, biomarkers and biosensors. Target-specific

Sanjeeb K. Sahoo; Vinod Labhasetwar

2003-01-01

149

Micromechanical devices for intravascular drug delivery  

Microsoft Academic Search

Microfabrication technology, more commonly applied to the manufacture of integrated circuits, can be used to build devices useful for mechanical delivery of drugs and genes. Microprobes fabricated using silicon micromachining have been used to deliver DNA into cells as an alternative to bombardment and microinjection. This idea can be extended to intravascular stents with integrated microprobes capable of piercing compressed

Michael L. Reed; Clarence Wu; James Kneller; Simon Watkins; David A. Vorp; Ahmed Nadeem; Lee E. Weiss; Keith Rebello; Mark Mescher; A. J. Conrad Smith; Warren Rosenblum; Marc D. Feldman

1998-01-01

150

Environment-sensitive hydrogels for drug delivery.  

PubMed

Environmentally sensitive hydrogels have enormous potential in various applications. Some environmental variables, such as low pH and elevated temperatures, are found in the body. For this reason, either pH-sensitive and/or temperature-sensitive hydrogels can be used for site-specific controlled drug delivery. Hydrogels that are responsive to specific molecules, such as glucose or antigens, can be used as biosensors as well as drug delivery systems. Light-sensitive, pressure-responsive and electro-sensitive hydrogels also have the potential to be used in drug delivery and bioseparation. While the concepts of these environment-sensitive hydrogels are sound, the practical applications require significant improvements in the hydrogel properties. The most significant weakness of all these external stimuli-sensitive hydrogels is that their response time is too slow. Thus, fast-acting hydrogels are necessary, and the easiest way of achieving that goal is to make thinner and smaller hydrogels. This usually makes the hydrogel systems too fragile and they do not have mechanical strength necessary in many applications. Environmentally sensitive hydrogels for drug delivery applications also require biocompatibility. Synthesis of new polymers and crosslinkers with more biocompatibility and better biodegradability would be essential for successful applications. Development of environmentally sensitive hydrogels with such properties is a formidable challenge. If the achievements of the past can be extrapolated into the future, however, it is highly likely that responsive hydrogels with a wide array of desirable properties can be made. PMID:11744175

Qiu, Y; Park, K

2001-12-31

151

Control-relevant modeling in drug delivery  

Microsoft Academic Search

The development of control-relevant models for a variety of biomedical engineering drug delivery problems is reviewed in this paper. A summary of each control problem is followed by a review of relevant patient models from literature, an examination of the control approaches taken to solve the problem, and a discussion of the control-relevance of the models used in each case.

Robert S. Parker; Francis J. Doyle

2001-01-01

152

Microdialysis in mice for drug delivery research  

Microsoft Academic Search

Intracerebral microdialysis was first performed in the mouse at the end of the 1980s. Most microdialysis studies on mice were confined to neuropharmacology and changes in neurotransmitter concentrations up to 1995, although pharmacological studies were done on other tissues like the skin, kidney and implanted tumors. The use of microdialysis in mice for pharmacokinetic and drug delivery studies owes much

Gabrielle Boschi; Jean-Michel Scherrmann

2000-01-01

153

New Approaches to Targeted Drug Delivery  

NASA Astrophysics Data System (ADS)

For targeted drug delivery, one of the primary drawbacks lies with the inability to design a delivery system that can be loaded with a variety of drugs and biomolecules. Motivated by this challenge, we will present data showing 400 nm liposomes loaded via the novel method of lysenin pores. These pores are approximately 3 nm in diameter and can be closed with divalent and trivalent ions in addition to charged polymers. This new method allows for the controllable passage of large biomolecules such as DNA and protein without the inherent problems common to active and passive loading methods. We will show proof-of-concept results of this method using fluorescent calcein as a drug simulator. Furthermore, data demonstrating current attempts at loading DNA will also be presented.

Cooper, James; Oliver, William; Fologea, Daniel

2013-03-01

154

Matrix metalloproteases: Underutilized targets for drug delivery  

PubMed Central

Pathophysiological molecules in the extracellular environment offer excellent targets that can be exploited for designing drug targeting systems. Matrix metalloproteases (MMPs) are a family of extracellular proteolytic enzymes that are characterized by their overexpression or overactivity in several pathologies. Over the last two decades, the MMP literature reveals heightened interest in the research involving MMP biology, pathology, and targeting. This review describes various strategies that have been designed to utilize MMPs for targeting therapeutic entities. Key factors that need to be considered in the successful design of such systems have been identified based on the analyses of these strategies. Development of targeted drug delivery using MMPs has been steadily pursued; however, drug delivery efforts using these targets need to be intensified and focused to realize the clinical application of the fast developing fundamental MMP research.

Vartak, Deepali G.; Gemeinhart, Richard A.

2013-01-01

155

Intestinal lymphatic transport for drug delivery.  

PubMed

Intestinal lymphatic transport has been shown to be an absorptive pathway following oral administration of lipids and an increasing number of lipophilic drugs, which once absorbed, diffuse across the intestinal enterocyte and while in transit associate with secretable enterocyte lipoproteins. The chylomicron-associated drug is then secreted from the enterocyte into the lymphatic circulation, rather than the portal circulation, thus avoiding the metabolically-active liver, but still ultimately returning to the systemic circulation. Because of this parallel and potentially alternative absorptive pathway, first-pass metabolism can be reduced while increasing lymphatic drug exposure, which opens the potential for novel therapeutic modalities and allows the implementation of lipid-based drug delivery systems. This review discusses the physiological features of the lymphatics, enterocyte uptake and metabolism, links between drug transport and lipid digestion/re-acylation, experimental model (in vivo, in vitro, and in silico) of lymphatic transport, and the design of lipid- or prodrug-based drug delivery systems for enhancing lymphatic drug transport. PMID:21689702

Yáñez, Jaime A; Wang, Stephen W J; Knemeyer, Ian W; Wirth, Mark A; Alton, Kevin B

2011-06-13

156

Fate of polymeric nanocarriers for oral drug delivery  

Microsoft Academic Search

This review will focus on two polymeric nanocarriers: nanoparticles and micelles that have been studied for oral drug delivery at preclinical level. Their potential for oral drug delivery will first be illustrated. Then their mechanisms of uptake and their fate after oral delivery will be discussed. Future directions for oral delivery with nanocarriers will be analyzed with a special emphasis

Laurence Plapied; Nicolas Duhem; Anne des Rieux; Véronique Préat

2011-01-01

157

Organic–Inorganic Composites for Bone Drug Delivery  

Microsoft Academic Search

This review paper attempts to provide an overview in the fabrication and application of organic–inorganic based composites\\u000a in the field of local drug delivery for bone. The concept of local drug delivery exists for a few decades. However, local\\u000a drug delivery in bone and specially application of composites for delivery of drugs to bone is an area for potential research

Chidambaram Soundrapandian; Biswanath Sa; Someswar Datta

2009-01-01

158

A thermally responsive biopolymer for intra-articular drug delivery  

Microsoft Academic Search

Intra-articular drug delivery is the preferred standard for targeting pharmacologic treatment directly to joints to reduce undesirable side effects associated with systemic drug delivery. In this study, a biologically based drug delivery vehicle was designed for intra-articular drug delivery using elastin-like polypeptides (ELPs), a biopolymer composed of repeating pentapeptides that undergo a phase transition to form aggregates above their transition

Helawe Betre; Wenge Liu; Michael R. Zalutsky; Ashutosh Chilkoti; Virginia B. Kraus; Lori A. Setton

2006-01-01

159

Novel drug delivery systems in pain therapy.  

PubMed

Pain is an unpleasant sensory experience resulting from damage to bodily tissues. It is considered a significant public health problem because it affects 1/5 of the world population and causes loss of great amounts of money. Pain reflects a mixture of pathological, psychological and genetic conditions that need deep understanding to be efficiently treated. If under-treated, pain results in serious immune and metabolic problems. Pain management faces many problems that limit its control. For instance, efficiency of pain killers is limited, pain killers give rise to serious side effects and inability of drug administration methods to help in pain control. Technology can overcome some of these problems and the introduction of implantable controlled drug delivery systems (CDDS), manufactured from biodegradable materials, offers a solution. Implantable CDDS provide good level of pain control, as they continuously provide drug, reduce side effects and improve patients' compliance. Biodegradable type of implantable CDDS are polymer based devices that are fabricated to locally deliver drugs in a pre-designed manner. They are currently a focus of research in the field of pain therapy in order to explore their chance to offer an alternative to the conventional methods for drug delivery. This paper aims to highlight the dimensions of pain issue and to overview the basics of drug release from polymers used for CDDS in pain management. In addition, it discusses the recent advances in the technologically designed drug delivery systems in the field of pain medicine and their clinical applications. Future perspectives are also presented. PMID:17159768

Al Malyan, M; Becchi, C; Boncinelli, S; Ashammakhi, N

2006-12-12

160

Microfabricated Drug Delivery Systems: Concepts to Improve Clinical Benefit  

Microsoft Academic Search

Important classes of drugs have yet to benefit from advances in drug delivery technology. Strategies to provide reasonable oral bioavailability of peptide and proteins drugs remain elusive, for example. Systemic cancer drugs produce dose-limiting toxicities largely due to their lack of selectivity. Although delivery systems such as immunotoxins and liposomes improve selectivity of a few cancer drugs, current technology is

Frank J. Martin; Carl Grove

2001-01-01

161

Fluorescence techniques for drug delivery research: theory and practice  

Microsoft Academic Search

Advances in drug delivery require an understanding of drug design, drug stability and metabolism together with the complexities imposed by the biological system such as cell\\/tissue penetration, drug-target interaction, and the pharmacodynamic consequences. Fluorescence microscopy provides a comprehensive tool for investigating many of these aspects of drug delivery in single cells and whole tissue. This review presents the fundamental concepts

Nick S. White; Rachel J. Errington

2005-01-01

162

Bharatbook.com - Drug Delivery Systems forecasts for 2012 & 2017  

Microsoft Academic Search

Oral drug delivery systems will remain the largest method used for drug delivery. Orally disintegrating tablets and transmucosal drugs will generate strong growth opportunities in the delivery of pain control and other critical care medication. Ease of administration advantages will promote the widening use of chewable tablet dosages for nutritional, respiratory and central nervous system agents, especially pediatric preparations. Better

2008-01-01

163

Nanobiotechnology-Based Drug Delivery to the Central Nervous System  

Microsoft Academic Search

Background: Drug delivery across the blood-brain barrier (BBB) is a major limitation in the treatment of central nervous system (CNS) disorders. Several approaches are being investigated to improve drug delivery across the BBB. Objective\\/Methods: This review deals with the role of nanobiotechnology in CNS drug delivery. The small size of the nanoparticles enables them to penetrate the BBB and facilitate

K. K. Jain

2007-01-01

164

Liposomes and Niosomes as Topical Drug Delivery Systems  

Microsoft Academic Search

The skin acts as a major target as well as a principle barrier for topical\\/transdermal (TT) drug delivery. The stratum corneum plays a crucial role in barrier function for TT drug delivery. Despite major research and development efforts in TT systems and the advantages of these routes, low stratum corneum permeability limits the usefulness of topical drug delivery. To overcome

M. J. Choi; H. I. Maibach

2005-01-01

165

Polymeric multilayer capsules in drug delivery.  

PubMed

Recent advances in medicine and biotechnology have prompted the need to develop nanoengineered delivery systems that can encapsulate a wide variety of novel therapeutics such as proteins, chemotherapeutics, and nucleic acids. Moreover, these delivery systems should be "intelligent", such that they can deliver their payload at a well-defined time, place, or after a specific stimulus. Polymeric multilayer capsules, made by layer-by-layer (LbL) coating of a sacrificial template followed by dissolution of the template, allow the design of microcapsules in aqueous conditions by using simple building blocks and assembly procedures, and provide a previously unmet control over the functionality of the microcapsules. Polymeric multilayer capsules have recently received increased interest from the life science community, and many interesting systems have appeared in the literature with biodegradable components and biospecific functionalities. In this Review we give an overview of the recent breakthroughs in their application for drug delivery. PMID:20645362

De Cock, Liesbeth J; De Koker, Stefaan; De Geest, Bruno G; Grooten, Johan; Vervaet, Chris; Remon, Jean Paul; Sukhorukov, Gleb B; Antipina, Maria N

2010-09-17

166

Transdermal drug delivery: from micro to nano.  

PubMed

Delivery across skin offers many advantages compared to oral or intravenous routes of drug administration. Skin however is highly impermeable to most molecules on the basis of size, hydrophilicity, lipophilicity and charge. For this reason it is often necessary to temporarily alter the barrier properties of skin for effective administration. This can be done by applying chemical enhancers, which alter the lipid structure of the top layer of skin (the stratum corneum, SC), by applying external forces such as electric currents and ultrasounds, by bypassing the stratum corneum via minimally invasive microneedles or by using nano-delivery vehicles that can cross and deliver their payload to the deeper layers of skin. Here we present a critical summary of the latest technologies used to increase transdermal delivery. PMID:22334401

Pegoraro, Carla; MacNeil, Sheila; Battaglia, Giuseppe

2012-02-15

167

Nanotechnology approaches for ocular drug delivery.  

PubMed

Blindness is a major health concern worldwide that has a powerful impact on afflicted individuals and their families, and is associated with enormous socio-economical consequences. The Middle East is heavily impacted by blindness, and the problem there is augmented by an increasing incidence of diabetes in the population. An appropriate drug/gene delivery system that can sustain and deliver therapeutics to the target tissues and cells is a key need for ocular therapies. The application of nanotechnology in medicine is undergoing rapid progress, and the recent developments in nanomedicine-based therapeutic approaches may bring significant benefits to address the leading causes of blindness associated with cataract, glaucoma, diabetic retinopathy and retinal degeneration. In this brief review, we highlight some promising nanomedicine-based therapeutic approaches for drug and gene delivery to the anterior and posterior segments. PMID:23580849

Xu, Qingguo; Kambhampati, Siva P; Kannan, Rangaramanujam M

168

Viruses as nanomaterials for drug delivery.  

PubMed

Virus delivery vectors are one among the many nanomaterials that are being developed as drug delivery materials. This chapter focuses on methods utilizing plant virus nanoparticles (PVNs) synthesized from the Red clover necrotic mosaic virus (RCNMV). A successful vector must be able to effectively carry and subsequently deliver a drug cargo to a specific target. In the case of the PVNs, we describe two types of ways cargo can be loaded within these structures: encapsidation and infusion. Several targeting approaches have been used for PVNs based on bioconjugate chemistry. Herein, examples of such approaches will be given that have been used for RCNMV as well as for other PVNs in the literature. Further, we describe characterization of PVNs, in vitro cell studies that can be used to test the efficacy of a targeting vector, and potential routes for animal administration. PMID:21424452

Lockney, Dustin; Franzen, Stefan; Lommel, Steven

2011-01-01

169

Nanotechnology Approaches for Ocular Drug Delivery  

PubMed Central

Blindness is a major health concern worldwide that has a powerful impact on afflicted individuals and their families, and is associated with enormous socio-economical consequences. The Middle East is heavily impacted by blindness, and the problem there is augmented by an increasing incidence of diabetes in the population. An appropriate drug/gene delivery system that can sustain and deliver therapeutics to the target tissues and cells is a key need for ocular therapies. The application of nanotechnology in medicine is undergoing rapid progress, and the recent developments in nanomedicine-based therapeutic approaches may bring significant benefits to address the leading causes of blindness associated with cataract, glaucoma, diabetic retinopathy and retinal degeneration. In this brief review, we highlight some promising nanomedicine-based therapeutic approaches for drug and gene delivery to the anterior and posterior segments.

Xu, Qingguo; Kambhampati, Siva P.; Kannan, Rangaramanujam M.

2013-01-01

170

ECHOGENIC LIPSOMES FOR TARGETED DRUG DELIVERY.  

PubMed

Echogenic immunoliposomes (ELIP) are under development to enable ultrasound-controlled drug delivery. Mechanistic studies in vitro have revealed that stable cavitation is correlated with enhanced recombinant tissue Plasminogen Activator (rt-PA) thrombolysis, yet strategies to optimize the occurrence of such bubble activity and avoid potential harmful bioeffects have yet to be identified. Stable cavitation is characterized by bubbles pulsating gently in response to the time-varying acoustic pressure in an ultrasound field. A review of in vitro sonothrombolysis studies utilizing commercial US contrast agent or echogenic liposomes loaded with rt-PA to nucleate stable cavitation will be presented. Strategies for the development of ultrasound-enhanced thrombolysis and drug delivery will be discussed. PMID:20383294

Holland, Christy K; McPherson, David D

2009-06-28

171

Protein-Based Nanomedicine Platforms for Drug Delivery  

SciTech Connect

Drug delivery systems have been developed for many years, however some limitations still hurdle the pace of going to clinical phase, for example, poor biodistribution, drug molecule cytotoxicity, tissue damage, quick clearance from the circulation system, solubility and stability of drug molecules. To overcome the limitations of drug delivery, biomaterials have to be developed and applied to drug delivery to protect the drug molecules and to enhance the drug’s efficacy. Protein-based nanomedicine platforms for drug delivery are platforms comprised of naturally self-assembled protein subunits of the same protein or a combination of proteins making up a complete system. They are ideal for drug delivery platforms due to their biocompatibility and biodegradability coupled with low toxicity. A variety of proteins have been used and characterized for drug delivery systems including the ferritin/apoferritin protein cage, plant derived viral capsids, the small Heat shock protein (sHsp) cage, albumin, soy and whey protein, collagen, and gelatin. There are many different types and shapes that have been prepared to deliver drug molecules using protein-based platforms including the various protein cages, microspheres, nanoparticles, hydrogels, films, minirods and minipellets. There are over 30 therapeutic compounds that have been investigated with protein-based drug delivery platforms for the potential treatment of various cancers, infectious diseases, chronic diseases, autoimmune diseases. In protein-based drug delivery platforms, protein cage is the most newly developed biomaterials for drug delivery and therapeutic applications. Their uniform sizes, multifunctions, and biodegradability push them to the frontier for drug delivery. In this review, the recent strategic development of drug delivery has been discussed with a special emphasis upon the polymer based, especially protein-based nanomedicine platforms for drug delivery. The advantages and disadvantages are also discussed for each type of protein based drug delivery system.

Ma Ham, Aihui; Tang, Zhiwen; Wu, Hong; Wang, Jun; Lin, Yuehe

2009-08-03

172

Intratumoral Drug Delivery with Nanoparticulate Carriers  

PubMed Central

Stiff extracellular matrix, elevated interstitial fluid pressure, and the affinity for the tumor cells in the peripheral region of a solid tumor mass have long been recognized as significant barriers to diffusion of small-molecular-weight drugs and antibodies. However, their impacts on nanoparticle-based drug delivery have begun to receive due attention only recently. This article reviews biological features of many solid tumors that influence transport of drugs and nanoparticles and properties of nanoparticles relevant to their intratumoral transport, studied in various tumor models. We also discuss several experimental approaches employed to date for enhancement of intratumoral nanoparticle penetration. The impact of nanoparticle distribution on the effectiveness of chemotherapy remains to be investigated and should be considered in the design of new nanoparticulate drug carriers.

Holback, Hillary

2011-01-01

173

Biosensing and drug delivery at the microscale : novel devices for controlled and responsive drug delivery.  

PubMed

An overall objective of pharmaceutical research is the controlled release or delivery of drugs at the biological target site in a therapeutically and pharmacodynamically optimal amount. In relation to "intelligent" drug delivery, several basic aspects are important, i.e., release of active pharmaceutical ingredients from the formulation, transport to and penetration across biological barriers, and subsequent biotransformation depending on a controlled release process. Future development of advanced and/or controlled drug releasing systems, e.g. polymeric or particulate drug targeting systems, nano-carbon tube related and/or nano-pillar based drug release, or electronically mediated molecule delivery, is expected to take advantage of progress in molecular cell biology, cell and tissue engineering, membrane nano-biophysics, and bioelectronic properties (Bramstedt et al. 2005; Gardner et al. 2006). In this chapter novel aspects of the development of innovative drug delivery systems described and are categorized into polymeric, lipid-based or electronically mediated delivery systems (De la Heras et al. 2004). PMID:20217527

Robitzki, Andrea A; Kurz, Randy

2010-01-01

174

[Drug delivery systems for intraocular applications].  

PubMed

Numerous drug delivery systems (DDSs) can be used as intraocular tools to provide a sustained and calibrated release for a specific drug. Great progress has been made on the design, biocompatibility, bioavailability, and efficacy of DDSs. Although several of them are undergoing clinical trials, a few are already on the market and could be of a routine use in clinical practice. Moreover, miniaturization of the implants makes them less and less traumatic for the eye tissues and some DDSs are now able to target certain cells or tissues specifically. An overview of ocular implants with therapeutic application potentials is provided. PMID:18268450

Bourges, J-L; Touchard, E; Kowalczuk, L; Berdugo, M; Thomas-Doyle, A; Bochot, A; Gomez, A; Azan, F; Gurny, R; Behar-Cohen, F

2007-12-01

175

Nanoemulsions as delivery systems for lipophilic drugs.  

PubMed

Nanoemulsions have received a growing attention as colloidal drug carriers for pharmaceutical applications. Their advantages over conventional formulations include drug enhanced solubility and bioavailability, protection from toxicity, improved pharmacological activity and stability, more sustained delivery and protection from physical and chemical degradation. Nanoemulsions can be prepared by two major techniques, high-energy and low-energy emulsification. Both these emulsification methods have proved to be efficient to obtain stable nanoemulsions with small and highly uniform droplets. Further research into nanoemulsions is important to develop novel liquid formulations with more efficient results in therapeutic. PMID:22755138

de Campos, Vania E B; Ricci-Júnior, Eduardo; Mansur, Claudia R E

2012-03-01

176

Floating drug delivery systems: A review  

Microsoft Academic Search

The purpose of writing this review on floating drug delivery systems (FDDS) was to compile the recent literature with special\\u000a focus on the principal mechanism of floatation to achieve gastric retention. The recent developments of FDDS including the\\u000a physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating\\u000a systems, and their classification and formulation aspects are

Shweta Arora; Javed Ali; Alka Ahuja; Roop K. Khar; Sanjula Baboota

2005-01-01

177

Recent advances in transdermal drug delivery  

Microsoft Academic Search

Transdermal delivery of pharmacologically active agents has been extensively studied for the past 40 years. Despite the strong\\u000a efforts, currently, only about 40 products are in market on about 20 drug molecules, due to the requirements that the patch\\u000a area should be small enough for the patients to feel comfortable, and to the barrier properties of the stratum corneum. Various

Robhash Kusam Subedi; Seaung Youl Oh; Myung-Kwan Chun; Hoo-Kyun Choi

2010-01-01

178

A microneedle roller for transdermal drug delivery  

Microsoft Academic Search

Microneedle rollers have been used to treat large areas of skin for cosmetic purposes and to increase skin permeability for drug delivery. In this study, we introduce a polymer microneedle roller fabricated by inclined rotational UV lithography, replicated by micromolding hydrophobic polylactic acid and hydrophilic carboxy-methyl-cellulose. These microneedles created micron-scale holes in human and porcine cadaver skin that permitted entry

Jung-Hwan Park; Seong-O Choi; Soonmin Seo; Young Bin Choy; Mark R. Prausnitz

2010-01-01

179

[Intraocular lens as a drug delivery device].  

PubMed

The development of an intraocular lens (IOL) as a drug delivery device has been the purpose of numerous preclinical studies and might become a future technology in cataract surgery. There are three techniques of pharmacological IOL modification: surface modification (coating), optic modification (soaking) or haptic modification with a slow-release-system. The therapeutic goals are endophthalmitis, postoperative inflammation and posterior capsule opacification. PMID:23933838

Eibl-Lindner, K H; Liegl, R; Wertheimer, C; Kampik, A

2013-10-01

180

Environment-sensitive hydrogels for drug delivery  

Microsoft Academic Search

Environmentally sensitive hydrogels have enormous potential in various applications. Some environmental variables, such as low pH and elevated temperatures, are found in the body. For this reason, either pH-sensitive and\\/or temperature-sensitive hydrogels can be used for site-specific controlled drug delivery. Hydrogels that are responsive to specific molecules, such as glucose or antigens, can be used as biosensors as well as

Yong Qiu

2001-01-01

181

Protein microspheres for pulmonary drug delivery  

Microsoft Academic Search

A new supercritical fluid (SCF) technique was developed for the preparation of microspheres for pulmonary drug delivery (PDD).\\u000a This technique, based on the anti-solvent process, has incorporated advanced engineering design features to enable improved\\u000a control of the particle formation process. Human recombinant insulin (HRI) was used as a model compound to evaluate the efficiency\\u000a of this SCF process. An aqueous

Yongda Sun

2010-01-01

182

Strategy for effective brain drug delivery.  

PubMed

Blood-brain barrier (BBB) together with enzymes restricts the entry of substances for maintaining the internal milieu of the brain. Because of the presence of multiple endogenous transporters, BBB allows a selective entry of nutrients and minerals across it and limits the entry of foreign substances like drugs as well as neuropharmaceutical agents. This makes the CNS treatment ineffective. The conventional drug delivery systems which release drug into general circulation fail to deliver drugs effectively to brain and is therefore not very useful in treating certain diseases that affect CNS including Alzheimer's disease, dementia, Parkinson's disease, mood disorder, AIDS, viral and bacterial meningitis. Therefore there is a need to develop and design approaches which specifically target to brain in a better and effective way. The present review enlightens about several novel approaches including nanotechnology based approach like nanoparticles, liposomes, antibody mediated delivery approach and application of genomics in brain drug targeting that would give an insight to the researchers, academia and industrialists. PMID:20497904

Alam, M Intakhab; Beg, Sarwar; Samad, Abdus; Baboota, Sanjula; Kohli, Kanchan; Ali, Javed; Ahuja, Alka; Akbar, M

2010-05-16

183

A model of axonal transport drug delivery  

NASA Astrophysics Data System (ADS)

In this paper a model of targeted drug delivery by means of active (motor-driven) axonal transport is developed. The model is motivated by recent experimental research by Filler et al. (A.G. Filler, G.T. Whiteside, M. Bacon, M. Frederickson, F.A. Howe, M.D. Rabinowitz, A.J. Sokoloff, T.W. Deacon, C. Abell, R. Munglani, J.R. Griffiths, B.A. Bell, A.M.L. Lever, Tri-partite complex for axonal transport drug delivery achieves pharmacological effect, Bmc Neuroscience 11 (2010) 8) that reported synthesis and pharmacological efficiency tests of a tri-partite complex designed for axonal transport drug delivery. The developed model accounts for two populations of pharmaceutical agent complexes (PACs): PACs that are transported retrogradely by dynein motors and PACs that are accumulated in the axon at the Nodes of Ranvier. The transitions between these two populations of PACs are described by first-order reactions. An analytical solution of the coupled system of transient equations describing conservations of these two populations of PACs is obtained by using Laplace transform. Numerical results for various combinations of parameter values are presented and their physical significance is discussed.

Kuznetsov, Andrey V.

2011-12-01

184

Protein and Peptide Drug Delivery: Oral Approaches  

PubMed Central

Till recent, injections remained the most common means for administering therapeutic proteins and peptides because of their poor oral bioavailability. However, oral route would be preferred to any other route because of its high levels of patient acceptance and long term compliance, which increases the therapeutic value of the drug. Designing and formulating a polypeptide drug delivery through the gastro intestinal tract has been a persistent challenge because of their unfavorable physicochemical properties, which includes enzymatic degradation, poor membrane permeability and large molecular size. The main challenge is to improve the oral bioavailability from less than 1% to at least 30-50%. Consequently, efforts have intensified over the past few decades, where every oral dosage form used for the conventional small molecule drugs has been used to explore oral protein and peptide delivery. Various strategies currently under investigation include chemical modification, formulation vehicles and use of enzyme inhibitors, absorption enhancers and mucoadhesive polymers. This review summarizes different pharmaceutical approaches which overcome various physiological barriers that help to improve oral bioavailability that ultimately achieve formulation goals for oral delivery.

Shaji, Jessy; Patole, V.

2008-01-01

185

Local drug delivery to the inner ear using biodegradable materials.  

PubMed

The lack of an effective method of drug delivery has been a considerable obstacle in the development of novel therapeutics for inner ear diseases. However, several strategies have been investigated to achieve drug delivery to the inner ear, particularly for local application. Here, we review recent advances in the development of inner ear drug-delivery systems, focusing on biodegradable materials. Both synthetic and natural biodegradable materials have shown efficacy for inner ear drug delivery, resulting in an attenuation of hearing loss in animal models. We expect the further development of such drug-delivery systems to help translate the findings of experimental studies to clinical applications. PMID:22822510

Nakagawa, Takayuki; Ito, Juichi

2011-06-01

186

Immediate topical drug delivery by natural submicron injectors.  

PubMed

Transdermal delivery is an attractive but challenging solution for delivery of drugs. The sea anemone possesses a sophisticated injection system, which utilizes built-in high osmotic pressures. The system is folded within microcapsules and upon activation it injects a long, needle-like tubule of submicron diameter that penetrates the target in a fraction of a second. Here we show that this natural injection system can be adapted for active topical drug delivery once it is isolated from the cells, formulated into a topical gel, and uploaded with the desired drug. The formulated injectors retained their physical characteristics and were capable of penetrating the skin, achieving immediate delivery of a hydrophilic compound. We demonstrate quantitative rapid delivery of lidocaine hydrochloride as a function of microcapsular and drug concentrations. The adaptation of natural injectors for drug delivery combines the benefits of short topical application with rapid delivery of physical devices, thereby presenting a promising alternative for transdermal drug delivery. PMID:21839819

Ayalon, Ari; Shichor, Iris; Tal, Yossi; Lotan, Tamar

2011-08-03

187

A biodegradable filament for controlled drug delivery.  

PubMed

Biodegradable filaments (diameters of 250-300 microm) for the controlled delivery of dexamethasone or levofloxacin are described. Filaments are prepared by wet-spinning solutions of poly(lactide-co-glycolide) (PLGA) and drug dissolved in dimethyl sulfoxide (DMSO) into a coagulation bath of water. Compositional analyses of the filaments by independent measurements of drug, DMSO, water, and polymer give drug loadings up to 40% of filament mass and drug retention (drug in filament per drug in solution) greater than 40%. Drug release kinetics, and thermal and mechanical properties, of the filaments are reported. Three filaments with levofloxacin contents of 46+/-2, 85+/-4, and 36+/-2 microg/cm (denoted 506-L1, 506-L2, and 506-L3, respectively) are implanted in the conjunctiva of New Zealand white rabbits. The time dependent, in-vivo tear concentrations of levofloxacin from filament implants in New Zealand white rabbit eyes are in general agreement with the results from the in-vitro release profiles, with one of the filaments (506-L1) showing effective levels of levofloxacin in the tears for 6 days. The filaments are generally well tolerated by the rabbits. Filament failure occurs at 6-8 days within the rabbit eyes, essentially the same time to failure observed from in-vitro mechanical properties testing results. PMID:19567255

Mack, Brendan C; Wright, Kenneth W; Davis, Mark E

2009-06-28

188

Application of Sterylglucoside-Containing Particles for Drug Delivery  

Microsoft Academic Search

Recent advances in biotechnology have promoted biomolecular targeting of drugs, peptides and genes in the treatment and management of major diseases and infections. Therapeutic development of drugs and delivery systems may have various objectives: Systemic drugs require optimal delivery and uptake at target sites; peptide drugs require alternative routes of administration, such as nasal or intestinal absorption; gene medicines need

Yoshie Maitani; Koji Nakamura; Kumi Kawano

189

Macrophage specific drug delivery in experimental leishmaniasis.  

PubMed

Macrophage-specific delivery systems are the subject of much interest nowadays, because of the fact that macrophages act as host cells for many parasites and bacteria, which give rise to outbreak of so many deadly diseases(eg. leishmaniasis, tuberculosis etc.) in humans. To combat these deadly diseases initially macrophage specific liposomal delivery system were thought of and tested in vivo against experimental leishmaniasis in hamsters using a series of indigenous or synthetic antileishmanial compounds and the results were critically discussed. In vitro testing was also done against macrophages infected with Leishmania donovani, the causative agent for visceral leishmaniasis. The common problem of liposome therapy being their larger size, stability and storage, non-ionic surfactant vesicles, niosomes were prepared, for their different drug distribution and release characteristics compared to liposomes. When tested in vivo, the retention capacity of niosomes was found to be higher than that of liposomes due to the absence of lipid molecules and their smaller size. Thus the therapeutic efficacy of certain antileishmanial compounds was found to be better than that in the liposomal form. The niosomes, being cheaper, less toxic, biodegradable and non-immunogenic, were considered for sometime as suitable alternatives to liposomes as drug carriers. Besides the advent of other classical drugs carriers(e.g. neoglycoproteins), the biggest challenge came from polymeric delivery vehicles, specially the polymeric nanoparticles which were made of cost effective biodegradable polymers and different natural polymers. Because of very small size and highly stable nature, use of nanoparticles as effective drug carriers has been explored in experimental leishmaniasis using a series of antileishmanial compounds, both of indigenous and synthetic origin. The feasibility of application in vivo, when tested for biological as well as for other physicochemical parameters, the polymeric nanoparticles have turned out to be the best and thus may be projected for effective use in the clinics. PMID:15357216

Basu, Mukul Kumar; Lala, Sanchaita

2004-09-01

190

Advances in the Use of Tocols as Drug Delivery Vehicles  

Microsoft Academic Search

There has been increasing interest in recent years in the drug delivery applications of tocols and their derivatives. Their\\u000a biocompatibility and potential to deliver both poorly soluble and water-soluble drugs make tocols attractive as drug delivery\\u000a vehicles. This review article will focus primarily on topical, oral, and parenteral drug administration using tocols, although\\u000a other routes of delivery such as pulmonary

Panayiotis P. Constantinides; Jihong Han; Stanley S. Davis

2006-01-01

191

Drug accumulation by means of noninvasive magnetic drug delivery system  

NASA Astrophysics Data System (ADS)

The medication is one of the most general treatment methods, but drugs diffuse in the normal tissues other than the target part by the blood circulation. Therefore, side effect in the medication, particularly for a drug with strong effect such as anti-cancer drug, are a serious issue. Drug Delivery System (DDS) which accumulates the drug locally in the human body is one of the techniques to solve the side-effects. Magnetic Drug Delivery System (MDDS) is one of the active DDSs, which uses the magnetic force. The objective of this study is to accumulate the ferromagnetic drugs noninvasively in the deep part of the body by using MDDS. It is necessary to generate high magnetic field and magnetic gradient at the target part to reduce the side-effects to the tissues with no diseases. The biomimetic model was composed, which consists of multiple model organs connected with diverged blood vessel model. The arrangement of magnetic field was examined to accumulate ferromagnetic drug particles in the target model organ by using a superconducting bulk magnet which can generate high magnetic fields. The arrangement of magnet was designed to generate high and stable magnetic field at the target model organ. The accumulation experiment of ferromagnetic particles has been conducted. In this study, rotating HTS bulk magnet around the axis of blood vessels by centering on the target part was suggested, and the model experiment for magnet rotation was conducted. As a result, the accumulation of the ferromagnetic particles to the target model organ in the deep part was confirmed.

Chuzawa, M.; Mishima, F.; Akiyama, Y.; Nishijima, S.

2011-11-01

192

Ultrasonically Activated Chemotherapeutic Drug Delivery in a Rat Model1  

Microsoft Academic Search

Systemic delivery of anticancer agents is accompanied by many un- wanted side effects that can be mitigated by encapsulation of antineoplas- tic agents. However, encapsulation necessitates a technique for controlled delivery to the cancerous tissue. We have developed a novel drug delivery system that releases drug from stabilized micelles upon application of low-frequency ultrasound and that demonstrates efficacy using doxoru-

Jared L. Nelson; Beverly L. Roeder; John C. Carmen; Friederike Roloff; William G. Pitt

193

Microneedles: A Valuable Physical Enhancer to Increase Transdermal Drug Delivery  

Microsoft Academic Search

Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Recently, the use of micron-scale needles in increasing skin permeability has been proposed and shown to dramatically increase transdermal delivery. Microneedles have been fabricated with

José Juan Escobar-Chávez; Dalia Bonilla-Martínez; Martha Angélica Villegas-González; Eva Molina-Trinidad; Norma Casas-Alancaster; Alma Luisa Revilla-Vázquez

2011-01-01

194

Transdermal patch drug delivery interactions with exercise.  

PubMed

Transdermal drug delivery systems, such as the transdermal patch, continue to be a popular and convenient way to administer medications. There are currently several medications that use a transdermal patch drug delivery system. This article describes the potential untoward side effects of increased drug absorption through the use of a transdermal patch in individuals who exercise or participate in sporting events. Four studies have been reported that demonstrate a significant increase in the plasma concentration of nitroglycerin when individuals exercise compared with rest. Likewise, several case reports and two studies have been conducted that demonstrate nicotine toxicity and increased plasma nicotine while wearing a nicotine patch in individuals who exercise or participate in sporting events compared with rest. Healthcare providers, trainers and coaches should be aware of proper transdermal patch use, especially while exercising, in order to provide needed information to their respective patients and athletes to avoid potential untoward side effects. Particular caution should be given to individuals who participate in an extreme sporting event of long duration. Further research that includes more medications is needed in this area. PMID:21395361

Lenz, Thomas L; Gillespie, Nicole

2011-03-01

195

In situ forming polymeric drug delivery systems.  

PubMed

In situ forming polymeric formulations are drug delivery systems that are in sol form before administration in the body, but once administered, undergo gelation in situ, to form a gel. The formation of gels depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner. Various polymers that are used for the formulation of in situ gels include gellan gum, alginic acid, xyloglucan, pectin, chitosan, poly(DL-lactic acid), poly(DL-lactide-co-glycolide) and poly-caprolactone. The choice of solvents like water, dimethylsulphoxide, N-methyl pyrrolidone, triacetin and 2-pyrrolidone for these formulations depends on the solubility of polymer used. Mainly in situ gels are administered by oral, ocular, rectal, vaginal, injectable and intraperitoneal routes. The in situ gel forming polymeric formulations offer several advantages like sustained and prolonged action in comparison to conventional drug delivery systems. The article presents a detailed review of these types of polymeric systems, their evaluation, advancements and their commercial formulations. From a manufacturing point of view, the production of such devices is less complex and thus lowers the investment and manufacturing cost. PMID:20490289

Madan, M; Bajaj, A; Lewis, S; Udupa, N; Baig, J A

2009-05-01

196

Biopolymers as transdermal drug delivery systems in dermatology therapy.  

PubMed

The skin is considered a complex organ for drug delivery because of its structure. Drug delivery systems are designed for the controlled release of drugs through the skin into the systemic circulation, maintaining consistent efficacy and reducing the dose of the drugs and their related side effects. Transdermal drug delivery represents one of the most rapidly advancing areas of novel drug delivery. The excellent impervious nature of the skin is the greatest challenge that must be overcome for successful drug delivery. Today, polymers have been proven to be successful for long-term drug delivery applications as no single polymer can satisfy all of the requirements. Biopolymers in the field of dermal application are rare and the mechanisms that affect skin absorption are almost unknown. Biopolymers are widely used as drug delivery systems, but as such the use of biopolymers as drug delivery systems in dermatologic therapy is still in progress. Commonly used biopolymers include hydrocolloids, alginates, hydrogels, polyurethane, collagen, poly(lactic-co-glycolic acid), chitosan, proteins and peptides, pectin, siRNAs, and hyaluronic acid. These new and exciting methods for drug delivery are already increasing the number and quality of dermal and transdermal therapies. This article reviews current research on biopolymers and focuses on their potential as drug carriers, particularly in relation to the dermatologic aspects of their use. PMID:20499487

Basavaraj, K H; Johnsy, George; Navya, M A; Rashmi, R; Siddaramaiah

2010-01-01

197

Effect of menthol on ocular drug delivery  

Microsoft Academic Search

Background  To assess how safe and effective it is to use menthol as a permeability enhancer in ophthalmic drug delivery systems.\\u000a \\u000a \\u000a \\u000a Methods  In this study, the effect of menthol on permeability of dexamethasone disodium phosphate in the cornea and sclera was investigated\\u000a in vitro. Application of topical drops and subconjunctival injection of dexamethasone disodium phosphate with or without 0.1%\\u000a menthol was administered

Xiaolin Xu; Nannan Yu; Zhengzhong Bai; Yanbin Xun; Di Jin; Zhijian Li; Hao Cui

198

Polyurethane-based drug delivery systems.  

PubMed

Polyurethanes (PUs) are formed by a reaction between isocyanates and diols to yield polymers with urethane bonds (-NH-COO-) in their main chain. A great variety of building blocks is commercially available that allows the chemical and physical properties of PUs to be tailored to their target applications, particularly for the biomedical and pharmaceutical fields. This article reviews the synthesis and characterization of PUs and PU-copolymers, as well as their in vitro and in vivo biodegradability and biocompatibility. Particular emphasis is placed on the use of PUs for the controlled release of drugs and for the (targeted) delivery of biotherapeutics. PMID:23632262

Cherng, Jong Yuh; Hou, Ting Yi; Shih, Mei Fen; Talsma, Herre; Hennink, Wim E

2013-04-28

199

Importance of novel drug delivery systems in herbal medicines  

PubMed Central

Novel drug delivery system is a novel approach to drug delivery that addresses the limitations of the traditional drug delivery systems. Our country has a vast knowledge base of Ayurveda whose potential is only being realized in the recent years. However, the drug delivery system used for administering the herbal medicine to the patient is traditional and out-of-date, resulting in reduced efficacy of the drug. If the novel drug delivery technology is applied in herbal medicine, it may help in increasing the efficacy and reducing the side effects of various herbal compounds and herbs. This is the basic idea behind incorporating novel method of drug delivery in herbal medicines. Thus it is important to integrate novel drug delivery system and Indian Ayurvedic medicines to combat more serious diseases. For a long time herbal medicines were not considered for development as novel formulations owing to lack of scientific justification and processing difficulties, such as standardization, extraction and identification of individual drug components in complex polyherbal systems. However, modern phytopharmaceutical research can solve the scientific needs (such as determination of pharmacokinetics, mechanism of action, site of action, accurate dose required etc.) of herbal medicines to be incorporated in novel drug delivery system, such as nanoparticles, microemulsions, matrix systems, solid dispersions, liposomes, solid lipid nanoparticles and so on. This article summarizes various drug delivery technologies, which can be used for herbal actives together with some examples.

Devi, V. Kusum; Jain, Nimisha; Valli, Kusum S.

2010-01-01

200

Intelligent biomaterials for drug delivery: combining molecular recognition with drug delivery  

Microsoft Academic Search

In the medical field, a need exists for self-contained implantable sensors for the rapid detection of disease and the rapid release of therapeutic agents. The expanding field of molecular imprinting (MIP) technology has an enormous potential to create intelligent, analyte-sensitive polymers that are capable of controlled drug delivery of therapeutic molecules in response to a biological event. MIP systems are

Nicole M Bergmann; E Hunter Lauten; Nicholas A Peppas

2004-01-01

201

Biodegradable injectable in situ forming drug delivery systems  

Microsoft Academic Search

The ability to inject a drug incorporated into a polymer to a localized site and have the polymer form a semi-solid drug depot has a number of advantages. Among these advantages is ease of application and localized, prolonged drug delivery. For these reasons a large number of in situ setting polymeric delivery systems have been developed and investigated for use

A Hatefi; B Amsden

2002-01-01

202

Bioadhesive Microdevices for Drug Delivery: A Feasibility Study  

Microsoft Academic Search

A variety of delivery systems have been devised to improve the oral bioavailability of drugs including enterically coated tablets, capsules, particles, liposomes, and others. Microfabrication technology, however, may offer some potential advantages over conventional drug delivery technologies. This technology, combined with appropriate surface chemistry, may permit the highly localized and unidirectional release of drugs, permeation enhancers, and\\/or promoters. In this

Aamer Ahmed; Chris Bonner; Tejal A. Desai

2001-01-01

203

Pressure-sensitive adhesives for transdermal drug delivery systems  

Microsoft Academic Search

Adhesives are a critical component in transdermal drug delivery (TDD) devices. In addition to the usual requirements of functional adhesive properties, adhesives for TDD applications must have good biocompatibility with the skin, chemical compatibility with the drug, various components of the formulation, and provide consistent, effective delivery of the drug. This review discusses the three most commonly used adhesives (polyisobutylenes,

Hock S Tan; William R Pfister

1999-01-01

204

Development of an implantable drug delivery catheter.  

PubMed

A microtextured, pillared drug delivery system has been designed and tested in rabbits. This model has allowed for the calculation of the mass transport rate indicating after a 4 week time period a pillar device's mass transport rate K1 [min-1] is K1p 1.54 x 10(-2) in contrast to the smooth control which is K1C .043 x 10(-2) and K1im IM which is 0.136 x 10(-2). As a result of these experiments, it is apparent a micropillared drug delivery system is an order magnitude faster than an intramuscular injection and is 30 times faster than the smooth control device. The etiology for this difference is related to close blood vessel proximity and minimal to no fibrous capsule formation with the micropillared implant. Finally, even after a 6-month implantation time, the pillared device has greater reproducibility regarding curve profile and there is no loss in magnitude or rate of mass transport, in contrast the smooth control devices in many instances resulted in complete occlusion with total loss of mass transport capabilities. PMID:1751157

Lewandowski, J J; Picha, G J; Nguyen, A J; Bressen, D

205

Antibody Drug Conjugate bioinformatics: drug delivery through the letterbox.  

PubMed

Antibodies appear to be the first line of defence in the adaptive immune response of vertebrates and thereby are involved in a multitude of biochemical mechanisms, such as regulation of infection, autoimmunity, and cancer. It goes without saying that a full understanding of antibody function is required for the development of novel antibody-interacting drugs. These drugs are the Antibody Drug Conjugates (ADCs), which are a new type of targeted therapy, used for example for cancer. They consist of an antibody (or antibody fragment such as a single-chain variable fragment [scFv]) linked to a payload drug (often cytotoxic). Because of the targeting, the side effects should be lower and give a wider therapeutic window. Overall, the underlying principle of ADCs is to discern the delivery of a drug that is cytotoxic to a target that is cancerous, hoping to increase the antitumoural potency of the original drug by reducing adverse effects and side effects, such as toxicity of the cancer target. This is a pioneering field that employs state-of-the-art computational and molecular biology methods in the fight against cancer using ADCs. PMID:23853668

Vlachakis, Dimitrios; Kossida, Sophia

2013-06-19

206

Design of a Smart Transdermal Insulin Drug Delivery System  

Microsoft Academic Search

In this paper, a micro-needle array combined with transdermal delivery, as well as the detection of micro-sensors intelligent transdermal insulin delivery systems was designed with characteristics of pain-free, smart, timing, positioning, quantitative drug delivery. Transdermal delivery of the requirements for the design of the transdermal delivery of the microneedle array structure, and UV-LIGA process for the production of polymer micro-needle

Zhenqing Hou; Chenghong Lin; Qiqing Zhang

2010-01-01

207

Infrared free electron laser enhanced transdermal drug delivery  

Microsoft Academic Search

It is necessary to control enhancement of transdermal drug delivery with non-invasive. The present study was investigated to assess the effectivity of enhancing the drug delivery by irradiating 6-mum region mid infrared free electron laser (MIR-FEL). The enhancement of transdermal drug (lidocaine) delivery of the samples (hairless mouse skin) irradiated with lasers was examined for flux (mug\\/cm2\\/h) and total penetration

Kunio Awazu; Takeyuki Uchizono; Sachiko Suzuki; Kazushi Yoshikawa

2005-01-01

208

[Research on intelligent controlled drug delivery with polymer].  

PubMed

The intelligent controlled drug delivery systems are a series of the preparations including microcapsules or nanocapsules composed of intelligent polymers and medication. The properties of preparations can change with the external stimuli such as pH value, temperature, chemical substance, light, electricity and magnetism. According to this properties, the drug delivery can be intelligently controlled. This paper has reviewed research on syntheses and applications of intelligent controlled drug delivery systems with polymers. PMID:16532842

Zhang, Zhibin; Tang, Changwei; Chen, Huiqing; Shan, Lianhai; Wan, Changxiu

2006-02-01

209

Recent advances in nanotechnology based drug delivery to the brain  

Microsoft Academic Search

Drug delivery into the brain was difficult due to the existence of blood brain barrier, which only permits some molecules\\u000a to pass through freely. In past decades, nanotechnology has enabled many technical advances including drug delivery into the\\u000a brain with high efficiency and accuracy. In the present paper, we summarize recent important advances in employing nanotechnology\\u000a for drug delivery to

Li-Na Lin; Qun Liu; Lei Song; Fang-Fang Liu; Jin-Xiu Sha

2010-01-01

210

Polymeric carriers: role of geometry in drug delivery  

PubMed Central

The unique properties of synthetic nanostructures promise a diverse set of applications as carriers for drug delivery, which are advantageous in terms of biocompatibility, pharmacokinetics, targeting and controlled drug release. Historically, more traditional drug delivery systems have focused on spherical carriers. However, there is a growing interest in pursuing non-spherical carriers, such as elongated or filamentous morphologies, now available due to novel formulation strategies. Unique physiochemical properties of these supramolecular structures offer distinct advantages as drug delivery systems. In particular, results of recent studies in cell cultures and lab animals indicate that rational design of carriers of a given geometry (size and shape) offers an unprecedented control of their longevity in circulation and targeting to selected cellular and subcellular locations. This article reviews drug delivery aspects of non-spherical drug delivery systems, including material selection and formulation, drug loading and release, biocompatibility, circulation behavior, targeting and subcellular addressing.

Simone, Eric A; Dziubla, Thomas D; Muzykantov, Vladimir R

2009-01-01

211

Extended Release Drug Delivery Strategies in Psychiatry  

PubMed Central

Objective: An overview of the emerging field of long-term delivery strategies for improved convenience and adherence with psychiatric medications is provided. This review is motivated by the hypothesis that adherence to treatment is an important determinant of clinical outcomes in a wide range of settings and is particularly important in psychiatry practice where patients require treatment for months or years and premature discontinuation can have serious consequences for patient health and quality of life. Design: The author reviews the relevant literature and highlights several approaches to providing improved access to continuous medication through new and innovative delivery strategies ranging from days to annual intervals. Benefits and Disadvantages: Several solutions to the problem of discontinuous access to pharmacotherapy are being developed in the form of new, long-acting drug-delivery systems, which gradually release medication over a period of several days or weeks with a single application. Long-acting formulations of psychiatric medications offer a number of potential benefits in comparison with conventional immediate-release agents, including improved safety and effectiveness. Potential limitations to using long-acting formulations may include pain and discomfort at the injection site, perceived inconvenience of a new treatment method, preference for oral medications, and length of time to titrate down to the lowest effective dose. Conclusions: The introduction of new, long-acting drug formulations could provide significant improvements in clinical outcomes and patient satisfaction for many patients, including those with affective disorders, schizophrenia, and alcohol dependence. Switching from oral administration to these new agents requires careful monitoring to reach the optimal dose, and patient concerns regarding the use of new delivery methods must be addressed. Long-acting formulations are not intended to be a sole form of treatment, and the use of psychotherapy as an adjunct form of treatment is still required. Controlled clinical trials of these new formulations have only recently been completed, offering clinicians a new option in their treatment regimens; however, as technologies improve, several new formulations are likely to enter clinical trials during the next few years. Psychiatrists will need to become acquainted with these technologies and educate their patients about them so they may work together to determine the most effective treatment option.

2005-01-01

212

Microencapsulation: A promising technique for controlled drug delivery  

PubMed Central

Microparticles offer various significant advantages as drug delivery systems, including: (i) an effective protection of the encapsulated active agent against (e.g. enzymatic) degradation, (ii) the possibility to accurately control the release rate of the incorporated drug over periods of hours to months, (iii) an easy administration (compared to alternative parenteral controlled release dosage forms, such as macro-sized implants), and (iv) Desired, pre-programmed drug release profiles can be provided which match the therapeutic needs of the patient. This article gives an overview on the general aspects and recent advances in drug-loaded microparticles to improve the efficiency of various medical treatments. An appropriately designed controlled release drug delivery system can be a foot ahead towards solving problems concerning to the targeting of drug to a specific organ or tissue, and controlling the rate of drug delivery to the target site. The development of oral controlled release systems has been a challenge to formulation scientist due to their inability to restrain and localize the system at targeted areas of gastrointestinal tract. Microparticulate drug delivery systems are an interesting and promising option when developing an oral controlled release system. The objective of this paper is to take a closer look at microparticles as drug delivery devices for increasing efficiency of drug delivery, improving the release profile and drug targeting. In order to appreciate the application possibilities of microcapsules in drug delivery, some fundamental aspects are briefly reviewed.

Singh, M.N.; Hemant, K.S.Y.; Ram, M.; Shivakumar, H.G.

2010-01-01

213

Liposomal gels for vaginal drug delivery.  

PubMed

The aim of our study was to develop a liposomal drug carrier system, able to provide sustained and controlled release of appropriate drug for local vaginal therapy. To optimise the preparation of liposomes with regards to size and entrapment efficiency, liposomes containing calcein were prepared by five different methods. Two optimal liposomal preparations (proliposomes and polyol dilution liposomes) were tested for their in vitro stability in media that simulate human vaginal conditions (buffer, pH 4.5). To be closer to in vivo application of liposomes and to achieve further improvement of their stability, liposomes were incorporated in vehicles suitable for vaginal self-administration. Gels of polyacrylate were chosen as vehicles for liposomal preparations. Due to their hydrophilic nature and bioadhesive properties, it was possible to achieve an adequate pH value corresponding to physiological conditions as well as desirable viscosity. In vitro release studies of liposomes incorporated in these gels (Carbopol 974P NF or Carbopol 980 NF) confirmed their applicability as a novel drug carrier system in vaginal delivery. Regardless of the gel used, even 24 h after the incubation of liposomal gel in the buffer pH 4.5 more than 80% of the originally entrapped substance was still retained. PMID:11337174

Paveli?, Z; Skalko-Basnet, N; Schubert, R

2001-05-21

214

Advances in Lymphatic Imaging and Drug Delivery  

SciTech Connect

Cancer remains the second leading cause of death after heart disease in the US. While metastasized cancers such as breast, prostate, and colon are incurable, before their distant spread, these diseases will have invaded the lymphatic system as a first step in their progression. Hence, proper evaluation of the disease state of the lymphatics which drain a tumor site is crucial to staging and the formation of a treatment plan. Current lymphatic imaging modalities with visible dyes and radionucleotide tracers offer limited sensitivity and poor resolution; however, newer tools using nanocarriers, quantum dots, and magnetic resonance imaging promise to vastly improve the staging of lymphatic spread without needless biopsies. Concurrent with the improvement of lymphatic imaging agents, has been the development of drug carriers that can localize chemotherapy to the lymphatic system, thus improving the treatment of localized disease while minimizing the exposure of healthy organs to cytotoxic drugs. This review will focus on polymeric systems that have been developed for imaging and drug delivery to the lymph system, how these new devices improve upon current technologies, and where further improvement is needed.

Nune, Satish K.; Gunda, Padmaja; Majeti, Bharat K.; Thallapally, Praveen K.; Laird, Forrest M.

2011-09-10

215

Advanced techniques for penetration enhancement in transdermal drug delivery system.  

PubMed

Transdermal route has been recognized as a promising drug delivery system for systemic delivery of drugs and provides the advantage of avoidance of first-pass effect, ease of use, better patient compliance, maintaining constant blood level for longer period of time and decrease side effects. The major pitfalls of this route lie with difficulty in permeation of drugs through the skin. Several literatures have been published for enhancing the permeation of drugs by chemical approaches. However the present review highlighted about the advanced physical techniques used for enhancing delivery of drugs such as structure-based, electrically based, velocity based and several other miscellaneous physical techniques for enhancing the permeation of drugs. In addition to these, the present review also gives an exhaustive account on clinical data about these techniques and regulatory considerations for new drugs as well as generic product approval in transdermal drug delivery. PMID:21453254

Swain, Suryakanta; Beg, Sarwar; Singh, Astha; Patro, Ch Niranjan; Rao, M E Bhanoji

2011-07-01

216

Drug delivery by organ-specific immunoliposomes  

SciTech Connect

Monoclonal antibodies highly specific to the mouse pulmonary endothelial cells were conjugated to liposomes. The resulting immunoliposomes showed high levels of lung accumulation when injected intravenously into mice. Optimal target binding and retention were achieved if the lipid composition included ganglioside GM{sub 1} to reduce the uptake of immunoliposomes by the reticuloendothelial system. Details of the construction and optimization of these organ-specific immunoliposomes are reviewed. The drug delivery potential of this novel liposome system was demonstrated in an experimental pulmonary metastasis model. Immunoliposomes containing a lipophilic prodrug of deoxyfluorouridine effectively prolonged the survival time of the tumor-bearing mice. This and other therapeutic applications of the immunoliposomes are discussed. 25 refs., 5 figs.

Maruyama, Kazuo; Mori, Atsuhide; Hunag, Leaf (Tennessee Univ., Knoxville, TN (USA). Dept. of Biochemistry); Kennel, S.J. (Oak Ridge National Lab., TN (USA))

1990-01-01

217

Issues in drug delivery: concepts and practice.  

PubMed

Understanding the transport and deposition of inhaled aerosols is of fundamental importance to inhalation therapy. Herein we address issues that affect drug delivery from experimental and theoretical perspectives. Accordingly, we shall limit our comments to a focused review of laboratory work (ie, an in vitro perspective) and the development of a computer-based 3-dimensional (3D) oral morphology with related computational fluid dynamics (CFD) and particle deposition studies (ie, an "in silico" perspective). To describe the oral region, morphometric data from the literature were employed. With Maya Unlimited, a third-party animation software package, coronal images were used to create initial spline curves, which served as the foundation of a nonuniform rational B-spline surface, representing a 3D morphology. To the best of our knowledge, this study is the first medical application of Maya Unlimited. We have demonstrated that the code can be employed to construct 3D biological structures and perform 3D CFD simulations of aerosols from dry powder inhalers and metered-dose inhalers. A study was also conducted using Fluent, a commercially available software package that has been used extensively in our laboratory for 3D CFD computations. The Maya Unlimited software can generate physiologically realistic oral structures; it has great potential for use in the medical arena, because it requires neither advance technical training nor substantial peripheral ( eg, hardware) support, it allows for the introduction of medical devices ( eg, dry powder inhalers) into simulations, and it predicts 3D CFDpatterns consistent with experimental observations and results of more rigorous software ( Fluent). In the in vitro perspective we considered numerous salient topics, including the performances of dry powder inhalers and metered-dose inhalers, their respective operating characteristics, and relevance to in vivo data. We advocate that 3D CFD software be employed in a complementary manner, in real time, with aerosol therapy protocols in the medical arena, to promote the targeted delivery of inhaled drugs and thereby enhance their efficacies. PMID:16163810

Martonen, Ted B; Smyth, Hugh D; Isaacs, Kristin K; Burton, Ray T

2005-09-01

218

Liposomes and skin: From drug delivery to model membranes  

Microsoft Academic Search

The early eighties saw the introduction of liposomes as skin drug delivery systems, initially promoted primarily for localised effects with minimal systemic delivery. Subsequently, a novel ultradeformable vesicular system (termed “Transfersomes” by the inventors) was reported for transdermal delivery with an efficiency similar to subcutaneous injection. Further research illustrated that the mechanisms of liposome action depended on the application regime

G. M. El Maghraby; B. W. Barry; A. C. Williams

2008-01-01

219

Production of protein nanoparticles for food and drug delivery system  

Microsoft Academic Search

Proteins nanoparticles are one of the new methods for food delivery systems. The protein nanoparticles which represent promising carriers for delivery are fabricated based on different methods. Synthetic protein nanostructure acts as surrogate mimics such as viruses and plasmid for food and drug delivery system. The benefits of protein nanoparticles include non-toxicity, stability for long duration, nonantigenicity and biodegradability. The

M. Rahimnejad; N. Mokhtarian; M. Ghasemi

2009-01-01

220

Microemulsions as transdermal drug delivery vehicles.  

PubMed

Microemulsions are clear, stable, isotropic mixtures of oil, water, and surfactant, frequently in combination with a cosurfactant. Microemulsions have been intensively studied during the last decades by many scientists and technologists because of their great potential in many food and pharmaceutical applications. The use of microemulsions is advantageous not only due to the facile and low cost preparation, but also because of the improved bioavailability. The increased absorption of drugs in topical applications is attributed to enhancement of penetration through the skin by the carrier. Saturated and unsaturated fatty acids serving as an oil phase are frequently used as penetration enhancers. The most popular enhancer is oleic acid. Other permeation enhancers commonly used in transdermal formulations are isopropyl myristate, isopropyl palmitate, triacetin, isostearylic isostearate, R(+)-limonene and medium chain triglycerides. The most popular among the enhancing permeability surfactants are phospholipids that have been shown to enhance drug permeation in a different mode. l-alpha-phosphatidylcholine from egg yolk, l-alpha-phosphatidylcholine 60%, from soybean and dioleylphosphatidyl ethanolamine which are in a fluid state may diffuse into the stratum corneum and enhance dermal and transdermal drug penetration, while distearoylphosphatidyl choline which is in a gel-state has no such capability. Other very commonly used surfactants are Tween 20, Tween 80, Span 20, Azone, Plurol Isostearique and Plurol Oleique. As cosurfactants commonly serve short-chain alkanols such as ethanol and propylene glycol. Long-chain alcohols, especially 1-butanol, are known for their enhancing activity as well. Decanol was found to be an optimum enhancer among other saturated fatty alcohols that were examined (from octanol to myristyl alcohol). Many enhancers are concentration-dependent; therefore, optimal concentration for effective promotion should be determined. The delivery rate is dependent on the type of the drug, the structure and ingredients of the carrier, and on the character of the membrane in use. Each formulation should be examined very carefully, because every membrane alters the mechanism of penetration and can turn an enhancer to a retarder. Various potential mechanisms to enhance drug penetration through the skin include directly affecting the skin and modifying the formulation so the partition, diffusion, or solubility is altered. The combination of several enhancement techniques such as the use of iontophoresis with fatty acids leads to synergetic drug penetration and to decrease in skin toxicity. Selected studies of various microemulsions containing certain drugs including retinoic acid, 5-fluorouracil, triptolide, ascorbic acid, diclofenac, lidocaine, and prilocaine hydrochloride in transdermal formulations are presented in this review. In conclusion, microemulsions were found as an effective vehicle of the solubilization of certain drugs and as protecting medium for the entrapped of drugs from degradation, hydrolysis, and oxidation. It can also provide prolonged release of the drug and prevent irritation despite the toxicity of the drug. Yet, in spite of all the advantages the present formulations lack several key important characteristics such as cosmetic-permitted surfactants, free dilution in water capabilities, stability in the digestive tracts and sufficient solubilization capacity. PMID:16843424

Kogan, Anna; Garti, Nissim

2006-07-14

221

Nasal and buccal drug delivery: management forum conference.  

PubMed

The scope of the conference (Nasal and Buccal Drug Delivery Conference, Management Forum; Chairs Franz Merkus and Julie Suman) was to consider innovations in drug delivery via the nose and oral cavity, notably for the delivery of vaccines, antimalarials and rapidly acting sedatives. Presentations from experts from academia, government agencies and commercial organisations were made over the 2 days. The advantages of both routes were ease of application, patient acceptability and no requirement to produce sterile products. These routes worked best for drugs that are water soluble--but with some lipophilicity--only require low doses, are acceptable to the patient and have low irritancy (particulary for the nasal route). Challenges relate to the effectiveness of deposition from the delivery systems and the efficient clearance mechanisms. It was concluded that for many drugs, buccal and nasal delivery could become the route of choice for their application; vaccines, in particular, appear to show promise for nasal delivery. PMID:22900464

Smart, John D

2012-07-01

222

In situ forming parenteral drug delivery systems: an overview  

Microsoft Academic Search

Biodegradable injectable in situ forming drug delivery systems represent an attractive alternative to microspheres and implants as parenteral depot systems. Their importance will grow as numerous proteins will lose their patent protection in the near future. These devices may offer attractive opportunities for protein delivery and could possibly extend the patent life of protein drugs. The controlled release of bioactive

C. B Packhaeuser; J Schnieders; C. G Oster; T Kissel

2004-01-01

223

Microemulsion-based media as novel drug delivery systems  

Microsoft Academic Search

Microemulsions are clear, stable, isotropic mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. These systems are currently of interest to the pharmaceutical scientist because of their considerable potential to act as drug delivery vehicles by incorporating a wide range of drug molecules. In order to appreciate the potential of microemulsions as delivery vehicles, this review gives

M. Jayne Lawrence; Gareth D. Rees

2000-01-01

224

Polymeric Micelles - The Future of Oral Drug Delivery  

Microsoft Academic Search

This work examines current advancements in polymeric micelles as a method for oral delivery of poorly water-soluble drugs. The oral route presents several barriers to drug delivery that the chosen vesicle must overcome. Polymeric micelles have several physical properties, including molecular weight and copolymer block composition, which can be tailored to alter the vesicle structure and overcome these barriers. Examination

Isaac Godfroy

225

Nano- and microfabrication for overcoming drug delivery challenges  

PubMed Central

This highlight article describes current nano- and microfabrication techniques for creating drug delivery devices. We first review the main physiological barriers to delivering therapeutic agents. Then, we describe how novel fabrication methods can be utilized to combine many features into a single physiologically relevant device to overcome drug delivery challenges.

Kam, Kimberly R.

2013-01-01

226

Surface modification of polyethylene balloon catheters for local drug delivery  

Microsoft Academic Search

Local drug delivery is an attractive approach to the associated problems of percutaneous transluminal coronary angioplasty (PTCA), including arterial injury. The objective of the present research was to deliver a high concentration of a potent anti-thrombin agent, argatroban (ARG), to the vessel wall in order to reduce arterial injury. Local delivery was accomplished by the ionic attachment of drug particles

T Richey; H Iwata; H Oowaki; E Uchida; S Matsuda; Y Ikada

2000-01-01

227

Small-scale systems for in vivo drug delivery  

Microsoft Academic Search

Recent developments in the application of micro- and nanosystems for drug administration include a diverse range of new materials and methods. New approaches include the on-demand activation of molecular interactions, novel diffusion-controlled delivery devices, nanostructured 'smart' surfaces and materials, and prospects for coupling drug delivery to sensors and implants. Micro- and nanotechnologies are enabling the design of novel methods such

David A LaVan; Terry McGuire; Robert Langer

2003-01-01

228

Colon targeted drug delivery systems--an overview.  

PubMed

In the last two decades colon targeted drug delivery has gained increased importance not just for the deliver drugs for the treatment of various colonic diseases but also for its potential for delivery of proteins and therapeutic peptides. In the past various traditional approaches used for colon targeted delivery like prodrugs, pH, time dependent, and microflora activated systems, have achieved limited success. For successful colon targeted drug delivery, the drug needs to be protected from absorption and/or the environment of the upper gastrointestinal tract and then be abruptly released into the colon. Hence continuous efforts have been made on designing colon targeted drug delivery systems with improved site specificity and versatile drug release kinetics to fulfill different therapeutic needs. In last couple of years few new systems have been developed for colon targeted drug delivery such as pressure dependent systems, CODES technology, microsponges, pectin and galactomannan coating, microbially triggered osmotic systems, lectins and neoglyconjugated etc. which are reported to have better in-vivo site specificity and design rationale than the earlier approaches. This review article gives an overview of various approaches for colonic targeted drug delivery with emphasis on newer systems, their merits and demerits, in vitro/ in-vivo evaluation and market status of such delivery systems. PMID:18673262

Kumar, P; Mishra, B

2008-07-01

229

Current status and future potential of transdermal drug delivery  

Microsoft Academic Search

The past twenty five years have seen an explosion in the creation and discovery of new medicinal agents. Related innovations in drug delivery systems have not only enabled the successful implementation of many of these novel pharmaceuticals, but have also permitted the development of new medical treatments with existing drugs. The creation of transdermal delivery systems has been one of

Mark R. Prausnitz; Samir Mitragotri; Robert Langer

2004-01-01

230

AC electrokinetic platform for iontophoretic transdermal drug delivery  

Microsoft Academic Search

Iontophoretic and electroporation transdermal delivery modes of ionic drugs have been utilized in a number of clinical and biomedical devices. However, applications of these methods have been found challenging for the delivery of many non polar and high molecular weight clinically important drugs. The main goal of the present study is to investigate whether transdermal transport of non polar macromolecular

Vadim F. Lvovich; Ellen Matthews; Alan T. Riga; Lakshmi Kaza

2010-01-01

231

Transdermal drug delivery: an assessment of skin impedance models  

Microsoft Academic Search

The variability found in skin impedance can significantly influence the effectiveness of Transdermal Drug Delivery. In order to optimize drug delivery, skin impedance frequency response must be considered. Several electrical models for skin impedance are presented in an attempt to understand the \\

Anthony F. Coston; J. K.-J. Li

2003-01-01

232

Microneedles array with biodegradable tips for transdermal drug delivery  

Microsoft Academic Search

The paper presented an enhancement solution for transdermal drug delivery using microneedles array with biodegradable tips. The microneedles array was fabricated by using deep reactive ion etching (DRIE) and the biodegradable tips were made to be porous by electrochemical etching process. The porous silicon microneedle tips can greatly enhance the transdermal drug delivery in a minimum invasion, painless, and convenient

Ciprian Iliescu; Bangtao Chen; Jiashen Wei; Francis E. H. Tay

2008-01-01

233

A practical assessment of transdermal drug delivery by skin electroporation  

Microsoft Academic Search

Transdermal drug delivery has many potential advantages, but the skin's poorly-permeable stratum corneum blocks delivery of most drugs at therapeutic levels. Short high-voltage pulses have been used to electroporate the skin's lipid bilayer barriers and thereby deliver compounds at rates increased by as much as four orders of magnitude. Evidence that the observed flux enhancement is due to physical alteration

Mark R Prausnitz

1999-01-01

234

Functionalized mesoporous silica particles for application in drug delivery system.  

PubMed

In these years, ordered mesoporous silica materials have shown promising applications in drug delivery system as drug carriers. These carriers with stable mesoporous structure, large surface area, good biocompatibility and tailored size of mesopores exhibit significant property of higher drug loading. However, silica-based mesoporous materials cannot control the release of the loaded drug without modifications. In this paper, we review the recent research work discussing functionalization of mesoporous materials by various components and methods for application in drug delivery systems. All the examples show that these functionalized mesoporous silica-based systems have great potential for a variety of drug delivery applications, specifically in the fields of the drug targeted and controlled delivery systems. PMID:22512562

Pang, J; Luan, Y; Yang, X; Jiang, Y; Zhao, L; Zong, Y; Li, Z

2012-07-01

235

The vesosome-- a multicompartment drug delivery vehicle.  

PubMed

Assembling structures to divide space controllably and spontaneously into subunits at the nanometer scale is a significant challenge, although one that biology has solved in two distinct ways: prokaryotes and eukaryotes. Prokaryotes have a single compartment delimited by one or more lipid-protein membranes. Eukaryotes have nested-membrane structures that provide internal compartments--such as the cell nucleus and cell organelles in which specialized functions are carried out. We have developed a simple method of creating nested bilayer compartments in vitro via the "interdigitated" bilayer phase formed by adding ethanol to a variety of saturated phospholipids. At temperatures below the gel-liquid crystalline transition, T(m), the interdigitated lipid-ethanol sheets are rigid and flat; when the temperature is raised above T(m), the sheets become flexible and close on themselves and the surrounding solution to form closed compartments. During this closure, the sheets can entrap other vesicles, biological macromolecules, or colloidal particles. The result is efficient and spontaneous encapsulation without disruption of even fragile materials to form biomimetic nano-environments for possible use in drug delivery, colloidal stabilization, or as microreactors. The vesosome structure can take full advantage of the 40 years of progress in liposome development including steric stabilization, pH loading of drugs, and intrinsic biocompatibility. However, the multiple compartments of the vesosome give better protection to the interior contents in serum, leading to extended release of model compounds in comparison to unilamellar liposomes. PMID:14754417

Kisak, E T; Coldren, B; Evans, C A; Boyer, C; Zasadzinski, J A

2004-01-01

236

Recent advances in liposomal drug-delivery systems  

Microsoft Academic Search

Liposomal drug-delivery systems have come of age in recent years, with several liposomal drugs currently in advanced clinical trials or already on the market. It is clear from numerous pre-clinical and clinical studies that drugs, such as antitumor drugs, packaged in liposomes exhibit reduced toxicities, while retaining, or gaining enhanced, efficacy. This results, in part, from altered pharmacokinetics, which lead

Arcadio Chonn; Pieter R Cullis

1995-01-01

237

Use of clays as drug delivery systems: Possibilities and limitations  

Microsoft Academic Search

The need for safe, therapeutically effective and patient-compliant drug delivery systems continuously leads researchers to design novel tools and strategies. Clay minerals are widely used materials in drug products both as excipients and active agents. When administered simultaneously, drug–clay interactions have been observed and studied, but until recently were not considered as a possible mechanism to modify drug release. In

C. Aguzzi; P. Cerezo; C. Viseras; C. Caramella

2007-01-01

238

Subcellular targeting strategies for drug design and delivery  

Microsoft Academic Search

Many drug targets are localized to particular subcellular compartments, yet current drug design strategies are focused on bioavailability and tissue targeting and rarely address drug delivery to specific intracellular compartments. Insights into how the cell traffics its constituents to these different cellular locations could improve drug design. In this Review, we explore the fundamentals of membrane trafficking and subcellular organization,

Lawrence Rajendran; Hans-Joachim Knölker; Kai Simons

2010-01-01

239

Synergistic Effect of Enhancers for Transdermal Drug Delivery  

Microsoft Academic Search

Transdermal drug delivery offers a non-invasive route of drug administration, although its applications are limited by low skin permeability. Various enhancers including iontophoresis, chemicals, ultrasound, and electroporation have been shown to enhance transdermal drug transport. Although all these meth- ods have been individually shown to enhance transdermal drug transport, their combinations have often been found to enhance transdermal transport more

Samir Mitragotri

2000-01-01

240

Synergistic Effect of Enhancers for Transdermal Drug Delivery  

Microsoft Academic Search

Transdermal drug delivery offers a non-invasive route of drug administration, although its applications are limited by low skin permeability. Various enhancers including iontophoresis, chemicals, ultrasound, and electroporation have been shown to enhance transdermal drug transport. Although all these methods have been individually shown to enhance transdermal drug transport, their combinations have often been found to enhance transdermal transport more effectively

Samir Mitragotri

2000-01-01

241

Enhancing intestinal drug solubilisation using lipid-based delivery systems  

Microsoft Academic Search

Lipid-based delivery systems are finding increasing application in the oral delivery of poorly water-soluble, lipophilic drugs. Whilst lipidic dose forms may improve oral bioavailability via several mechanisms, enhancement of gastrointestinal solubilisation remains argueably the most important method of absorption enhancement. This review firstly describes the mechanistic rationale which underpins the use of lipid-based delivery systems to enhance drug solubilisation and

Christopher J. H. Porter; Colin W. Pouton; Jean F. Cuine; William N. Charman

2008-01-01

242

Development of a Microfluidics-Based Intracochlear Drug Delivery Device  

Microsoft Academic Search

Background: Direct delivery of drugs and other agents into the inner ear will be important for many emerging therapies, including the treatment of degenerative disorders and guiding regeneration. Methods: We have taken a microfluidics\\/MEMS (MicroElectroMechanical Systems) technology approach to develop a fully implantable reciprocating inner-ear drug-delivery system capable of timed and sequenced delivery of agents directly into perilymph of the

William F. Sewell; Jeffrey T. Borenstein; Zhiqiang Chen; Jason Fiering; Ophir Handzel; Maria Holmboe; Ernest S. Kim; Sharon G. Kujawa; Michael J. McKenna; Mark M. Mescher; Brian Murphy; Erin E. Leary Swan; Marcello Peppi; Sarah Tao

2009-01-01

243

Pharmacosomes: An Emerging Novel Vesicular Drug Delivery System for Poorly Soluble Synthetic and Herbal Drugs  

PubMed Central

In the arena of solubility enhancement, several problems are encountered. A novel approach based on lipid drug delivery system has evolved, pharmacosomes. Pharmacosomes are colloidal, nanometric size micelles, vesicles or may be in the form of hexagonal assembly of colloidal drug dispersions attached covalently to the phospholipid. They act as befitting carrier for delivery of drugs quite precisely owing to their unique properties like small size, amphiphilicity, active drug loading, high entrapment efficiency, and stability. They help in controlled release of drug at the site of action as well as in reduction in cost of therapy, drug leakage and toxicity, increased bioavailability of poorly soluble drugs, and restorative effects. There has been advancement in the scope of this delivery system for a number of drugs used for inflammation, heart diseases, cancer, and protein delivery along with a large number of herbal drugs. Hence, pharmacosomes open new challenges and opportunities for improved novel vesicular drug delivery system.

2013-01-01

244

Cavitation-enhanced extravasation for drug delivery.  

PubMed

A flow-through tissue-mimicking phantom composed of a biocompatible hydro-gel with embedded tumour cells was used to assess and optimize the role of ultrasound-induced cavitation on the extravasation of a macromolecular compound from a channel mimicking vessel in the gel, namely a non-replicating luciferase-expressing adenovirus (Ad-Luc). Using a 500 KHz therapeutic ultrasound transducer confocally aligned with a focussed passive cavitation detector, different exposure conditions and burst mode timings were selected by performing time and frequency domain analysis of passively recorded acoustic emissions, in the absence and in the presence of ultrasound contrast agents acting as cavitation nuclei. In the presence of Sonovue, maximum ultraharmonic emissions were detected for peak rarefactional pressures of 360 kPa, and maximum broadband emissions occurred at 1250 kPa. The energy of the recorded acoustic emissions was used to optimise the pulse repetition frequency and duty cycle in order to maximize either ultraharmonic or broadband emissions while keeping the acoustic energy delivered to the focus constant. Cell viability measurements indicated that none of the insonation conditions investigated induces cell death in the absence of a therapeutic agent (i.e. virus). Phase contrast images of the tissue-mimicking phantom showed that short range vessel disruption can occur when ultra-harmonic emissions (nf0/2) are maximised whereas formation of a micro-channel perpendicular to the flow can be obtained in the presence of broadband acoustic emissions. Following Ad-Luc delivery, luciferase expression measurements showed that a 60-fold increase in its bioavailability can be achieved when broadband noise emissions are present during insonation, even for modest contrast agent concentrations. The findings of the present study suggest that drug delivery systems based on acoustic cavitation may help enhance the extravasation of anticancer agents, thus increasing their penetration distance to hypoxic regions and poorly vascularised tumour regions. PMID:21963037

Arvanitis, Costas D; Bazan-Peregrino, Miriam; Rifai, Bassel; Seymour, Leonard W; Coussios, Constantin C

2011-10-02

245

Microemulsion: New Insights into the Ocular Drug Delivery  

PubMed Central

Delivery of drugs into eyes using conventional drug delivery systems, such as solutions, is a considerable challenge to the treatment of ocular diseases. Drug loss from the ocular surface by lachrymal fluid secretion, lachrymal fluid-eye barriers, and blood-ocular barriers are main obstacles. A number of ophthalmic drug delivery carriers have been made to improve the bioavailability and to prolong the residence time of drugs applied topically onto the eye. The potential use of microemulsions as an ocular drug delivery carrier offers several favorable pharmaceutical and biopharmaceutical properties such as their excellent thermodynamic stability, phase transition to liquid-crystal state, very low surface tension, and small droplet size, which may result in improved ocular drug retention, extended duration of action, high ocular absorption, and permeation of loaded drugs. Further, both lipophilic and hydrophilic characteristics are present in microemulsions, so that the loaded drugs can diffuse passively as well get significantly partitioned in the variable lipophilic-hydrophilic corneal barrier. This review will provide an insight into previous studies on microemulsions for ocular delivery of drugs using various nonionic surfactants, cosurfactants, and associated irritation potential on the ocular surface. The reported in vivo experiments have shown a delayed effect of drug incorporated in microemulsion and an increase in the corneal permeation of the drug.

Hegde, Rahul Rama; Verma, Anurag; Ghosh, Amitava

2013-01-01

246

Microemulsion: new insights into the ocular drug delivery.  

PubMed

Delivery of drugs into eyes using conventional drug delivery systems, such as solutions, is a considerable challenge to the treatment of ocular diseases. Drug loss from the ocular surface by lachrymal fluid secretion, lachrymal fluid-eye barriers, and blood-ocular barriers are main obstacles. A number of ophthalmic drug delivery carriers have been made to improve the bioavailability and to prolong the residence time of drugs applied topically onto the eye. The potential use of microemulsions as an ocular drug delivery carrier offers several favorable pharmaceutical and biopharmaceutical properties such as their excellent thermodynamic stability, phase transition to liquid-crystal state, very low surface tension, and small droplet size, which may result in improved ocular drug retention, extended duration of action, high ocular absorption, and permeation of loaded drugs. Further, both lipophilic and hydrophilic characteristics are present in microemulsions, so that the loaded drugs can diffuse passively as well get significantly partitioned in the variable lipophilic-hydrophilic corneal barrier. This review will provide an insight into previous studies on microemulsions for ocular delivery of drugs using various nonionic surfactants, cosurfactants, and associated irritation potential on the ocular surface. The reported in vivo experiments have shown a delayed effect of drug incorporated in microemulsion and an increase in the corneal permeation of the drug. PMID:23936681

Hegde, Rahul Rama; Verma, Anurag; Ghosh, Amitava

2013-06-27

247

Multipulse drug delivery from a resorbable polymeric microchip device  

Microsoft Academic Search

Controlled-release drug delivery systems have many applications, including treatments for hormone deficiencies and chronic pain. A biodegradable device that could provide multi-dose drug delivery would be advantageous for long-term treatment of conditions requiring pulsatile drug release. In this work, biodegradable polymeric microchips were fabricated that released four pulses of radiolabelled dextran, human growth hormone or heparin in vitro. Heparin that

Amy C. Richards Grayson; Insung S. Choi; Betty M. Tyler; Paul P. Wang; Henry Brem; Michael J. Cima; Robert Langer

2003-01-01

248

Intraperiodontal pocket: An ideal route for local antimicrobial drug delivery  

PubMed Central

Periodontal pockets act as a natural reservoir filled with gingival crevicular fluid for the controlled release delivery of antimicrobials directly. This article reflects the present status of nonsurgical controlled local intrapocket delivery of antimicrobials in the treatment of periodontitis. These sites have specialty in terms of anatomy, permeability, and their ability to retain a delivery system for a desired length of time. A number of antimicrobial products and the composition of the delivery systems, its use, clinical results, and their release are summarized. The goal in using an intrapocket device for the delivery of an antimicrobial agent is the achievement and maintenance of therapeutic drug concentration for the desired period of time. Novel controlled drug delivery system are capable of improving patient compliance as well as therapeutic efficacy with precise control of the rate by which a particular drug dosage is released from a delivery system without the need for frequent administration. These are considered superior drug delivery system because of low cost, greater stability, non-toxicity, biocompatibility, non-immunogenicity, and are biodegradable in nature. This review also focus on the importance and ideal features of periodontal pockets as a drug delivery platform for designing a suitable dosage form along with its potential advantage and limitations. The microbes in the periodontal pocket could destroy periodontal tissues, and a complete knowledge of these as well as an ideal treatment strategy could be helpful in treating this disease.

Nair, Sreeja C.; Anoop, K. R.

2012-01-01

249

Recent trends in oral drug delivery: a review.  

PubMed

There are many ways to deliver drugs into the body, viz oral (through swallowing), sub mucosal (through buccal and sublingual mucosa), parenteral (through injection), transdermal (through skin), pulmonary (through inhalation) etc. Among these deliveries oral delivery (by swallowing) is widely accepted. In oral drug delivery, many scientific challenges and breakthrough technologies are required to generate novel dosage forms raising drug delivery to higher level. Some are self emulsifying systems, solid self nanoemulsion, polymeric micelles, spray freezing, pH controlled systems, time delayed system, osmotic pumps, prodrugs etc. This paper reviews recent patents, technologies and products with their importance, manufacturing and novel approaches implemented till date to overcome the challenges in oral drug delivery systems. PMID:19519576

Gupta, Himanshu; Bhandari, Dinesh; Sharma, Aarti

2009-06-01

250

Polymer nanogels: a versatile nanoscopic drug delivery platform  

PubMed Central

In this review we put the spotlight on crosslinked polymer nanogels, a promising platform that has the characteristics of an “ideal” drug delivery vehicle. Some of the key aspects of drug delivery vehicle design like stability, response to biologically relevant stimuli, passive targeting, active targeting, toxicity and ease of synthesis are discussed. We discuss several delivery systems in this light and highlight some examples of systems, which satisfy some or all of these design requirements. In particular, we point to the advantages that crosslinked polymeric systems bring to drug delivery. We review some of the synthetic methods of nanogel synthesis and conclude with the diverse applications in drug delivery where nanogels have been fruitfully employed.

Chacko, Reuben T.; Ventura, Judy; Zhuang, Jiaming; Thayumanavan, S.

2012-01-01

251

Microneedle technologies for (trans)dermal drug and vaccine delivery.  

PubMed

Microneedles have been used for the dermal and transdermal delivery of a broad range of drugs, such as small molecular weight drugs, oligonucleotides, DNA, peptides, proteins and inactivated viruses. However, until now there are no microneedle-based (trans)dermal drug delivery systems on the market. In the past decade various types of microneedles have been developed by a number of production processes. Numerous geometries of microneedles have been designed from various materials. These microneedles have been used for different approaches of microneedle-based (trans)dermal drug delivery. Following a brief introduction about dermal and transdermal drug delivery, this review describes different production methods for solid and hollow microneedles as well as conditions that influence skin penetration. Besides, the four microneedle-based (trans)dermal drug delivery approaches are discussed: "poke and flow", "poke and patch", "poke and release", and "coat and poke". A separate section of this review is devoted to the use of microneedles for the delivery of therapeutic proteins and vaccines. Finally, we give our view on research and development that is needed to render microneedle-based (trans)dermal drug delivery technologies clinically useful in the near future. PMID:22342643

van der Maaden, Koen; Jiskoot, Wim; Bouwstra, Joke

2012-02-04

252

Chronopharmaceutics: as a clinically relevant drug delivery system.  

PubMed

Current research in the field of drug delivery devices, by which pulsatile release is achieved, has been intensified. In this article, an attempt has been made to discuss several types of drug delivery systems that show pulsatile drug delivery characteristics. As found frequently in the living body, many vital functions are regulated by pulsed or transient release of bioactive substances at a specific site and time. Thus it is important to develop new drug delivery devices to achieve pulsed delivery of a certain amount of drugs in order to mimic the function of the living systems, while minimizing undesired side-effects. Pulsatile delivery, which is meant as the liberation of drugs following programmed lag phases, has drawn increasing interest, especially in view of emerging chronotherapeutic approaches. This review article is an attempt to discuss various design strategies, chiefly including reservoir, capsular, and osmotic formulations, and drug delivery systems which cause the pulsed or triggered release of bioactive compounds induced due to certain stimuli like thermal, electrical, and magnetic. PMID:21138394

Gandhi, B R; Mundada, A S; Gandhi, P P

2011-01-01

253

Advances in chitosan-based drug delivery vehicles  

NASA Astrophysics Data System (ADS)

Within the past few years, chitosan-based drug delivery vehicles have become some of the most attractive to be studied. In contrast to all other polysaccharides, chitosan has demonstrated its unique characteristics for drug delivery platforms, including its active primary amino groups for chemical modification, simple and mild preparation methods for the encapsulation of biomolecules or drugs, mucoadhesion to facilitate transport across mucosal barriers and so on. In this review, an overview of the various types of chitosan-based drug delivery systems is provided, with special focus on polymeric drug conjugates and drug nanocarriers. The first part of the review is concerned with the development and applications of polymeric chitosan-drug conjugates. Then the chitosan-based nanocarrier systems as well as their preparation methods and applications are further discussed.

Hu, Liming; Sun, Yun; Wu, Yan

2013-03-01

254

Recent expansions in an emergent novel drug delivery technology: Emulgel.  

PubMed

Emulgel is an emerging topical drug delivery system to which if more effort is paid towards its formulation & development with more number of topically effective drugs it will prove a boon for derma care & cosmetology. Emulgels are either emulsion of oil in water or water in oil type, which is gelled by mixing it with gelling agent. Incorporation of emulsion into gel increases its stability & makes it a dual control release system. Due to lack of excess oily bases & insoluble excipients, it shows better drug release as compared to other topical drug delivery system. Presence of gel phase makes it a non greasy & favors good patient compliance. These reviews give knowledge about Emulgel including its properties, advantages, formulation considerations, and its recent advances in research field. All factors such as selection of gelling agent, oil agent, emulsifiers influencing the stability and efficacy of Emulgel are discussed. All justifications are described in accordance with the research work carried out by various scientists. These brief reviews on formulation method have been included. Current research works that carried out on Emulgel are also discussed and highlighted the wide utility of Emulgel in topical drug delivery system. After the vast study, it can be concluded that the Emulgels appear better & effective drug delivery system as compared to other topical drug delivery system. The comprehensive analysis of rheological and release properties will provide an insight into the potential usage of Emulgel formulation as drug delivery system. PMID:23831051

Ajazuddin; Alexander, Amit; Khichariya, Ajita; Gupta, Saurabh; Patel, Ravish J; Giri, Tapan Kumar; Tripathi, Dulal Krishna

2013-07-02

255

Recent advances in gastric floating drug delivery technology: a review.  

PubMed

Gastric floating drug delivery systems have been an avenue of considerable interest in terms of their immense potential for better pharmacotherapeutic interventions along with site-specific absorption. These buoyant systems significantly enhance the bioavailability and controlled delivery of several drug molecules. Scientific investigators have also carried out substantial research endeavours worldwide in order to design a more systematic and intellectual floating systems. The present manuscript is an attempt to highlight numerous recent advancements in the design of gastric floating drug delivery systems along with various available commercial preparations. Salient applications, characterization aspects and future perspectives of these multifarious systems have also been addressed. PMID:23808593

Pahwa, Rakesh; Bisht, Seema; Kumar, Vipin; Kohli, Kanchan

2013-06-01

256

Inorganic Nanoporous Membranes for Immunoisolated Cell-Based Drug Delivery  

Microsoft Academic Search

\\u000a \\u000a Materials advances enabled by nanotechnology have brought about promising approaches to improve the encapsulation mechanism\\u000a for immunoisolated cell-based drug delivery. Cell-based drug delivery is a promising treatment for many diseases but has thus\\u000a far achieved only limited clinical success. Treatment of insulin dependent diabetes mellitus (IDDM) by transplantation of\\u000a pancreatic ?-cells represents the most anticipated application of cell-based drug delivery

Adam Mendelsohn; Tejal Desai

257

Branched biodegradable polyesters for parenteral drug delivery systems  

Microsoft Academic Search

Continuous, ‘infusion-like’ drug release profiles from biodegradable parenteral delivery systems are difficult to achieve for proteins and other hydrophilic macromolecular drugs with commonly used linear polyesters from lactic acid (PLA) and its random copolymers with glycolic acid (PLG). Drug release rates can be modified either by increasing the hydrophilicity of polyesters or by manipulating the polymer architecture to adjust polymer

Armin Breitenbach; You Xin Li; Thomas Kissel

2000-01-01

258

Development of colon targeted drug delivery systems for mebendazole  

Microsoft Academic Search

The objective of the present study is to develop colon targeted drug delivery systems for mebendazole using guar gum as a carrier. Matrix tablets containing various proportions of guar gum were prepared by wet granulation technique using starch paste as a binder. The tablets were evaluated for drug content uniformity, and were subjected to in vitro drug release studies. The

Y. S. R Krishnaiah; P Veer Raju; B Dinesh Kumar; P Bhaskar; V Satyanarayana

2001-01-01

259

Chapter 7.1 Microdialysis in clinical drug delivery studies  

Microsoft Academic Search

Appropriate methods to directly measure drug concentrations at their actual sites of action within tissues and organs have not been available in clinical drug delivery studies for many years. Consequently, pharmacokinetic research was long restricted to drug concentration measurements from biological specimens that are relatively easy to obtain, such as tissue biopsies, urine, saliva, or skin blister fluid, or to

Martin Brunner; Markus Müller

2006-01-01

260

Innovations in Transdermal Drug Delivery: Formulations and Techniques  

Microsoft Academic Search

The transdermal route of drug delivery has attracted researchers due to many biomedical advantages associated with it. However, excellent impervious nature of skin is the greatest challenge that has to be overcome for successfully delivering drug molecules to the systemic circulation by this route. Various formulation approaches used to systemically deliver drug molecules include use of prodrugs\\/lipo philic analogs, permeation

Ashok K. Tiwary; Bharti Sapra; Subheet Jain

2007-01-01

261

A Controlled Drug-Delivery Experiment Using Alginate Beads  

ERIC Educational Resources Information Center

|This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

Farrell, Stephanie; Vernengo, Jennifer

2012-01-01

262

PATHWAYS FOR OPTIMIZATION-BASED DRUG DELIVERY SYSTEMS AND DEVICES  

Microsoft Academic Search

Drug synthesis and discovery represents today one of the most rapidly evolving scientific areas. This is primarily due to the interdisciplinary collaboration between chemists, pharmacologists, molecular biologists, and biochemists. A direct implication of the developments in drug discovery is the need for novel drug delivery systems and devices. Considering the advances in engineering disciplines and micro\\/nano technology the potential for

Leonidas Bleris; Panagiotis Vouzis; Mark V. Arnold; Mayuresh V. Kothare

263

Smart drug delivery injector microsystem based on pyrotechnic  

Microsoft Academic Search

A smart drug delivery injector microsystem is presented based on small pyrotechnics to impulse drugs to be injected to a human being. The proposal refers to a feasibility demonstration of the technology for pharmaceutical chips. These chips would be around some cm2 in section and will be able to inject a drug into de subject skin responding to an electrical

Manel Puig-Vidal; Jaime Lopez; Pere Miribel; Josep Samitier-Marti; Carole Rossi; Axel Berthold

2003-01-01

264

Smart-drug delivery system employing molecular motors  

Microsoft Academic Search

A drug delivery system has been envisioned employing actinmyosin molecular motors, liposomes, microcantilevers and a specific track formed by microfilaments. Molecular motors can pull on giant liposomes enclosing the drug to be delivered at the target site. An array of microcantilevers whose deflection in nanometers would cause the opening of the valves responsible for delivering the drug, would be implanted

S. K. Vashist; R. Tewari; I. Kaur; R. P. Bajpai; L. M. Bharadwaj

2005-01-01

265

Formulation aspects in the development of osmotically controlled oral drug delivery systems  

Microsoft Academic Search

Osmotically controlled oral drug delivery systems utilize osmotic pressure for controlled delivery of active agent(s). Drug delivery from these systems, to a large extent, is independent of the physiological factors of the gastrointestinal tract and these systems can be utilized for systemic as well as targeted delivery of drugs. The release of drug(s) from osmotic systems is governed by various

Rajan K Verma; Divi Murali Krishna; Sanjay Garg

2002-01-01

266

A thermally responsive biopolymer for intra-articular drug delivery.  

PubMed

Intra-articular drug delivery is the preferred standard for targeting pharmacologic treatment directly to joints to reduce undesirable side effects associated with systemic drug delivery. In this study, a biologically based drug delivery vehicle was designed for intra-articular drug delivery using elastin-like polypeptides (ELPs), a biopolymer composed of repeating pentapeptides that undergo a phase transition to form aggregates above their transition temperature. The ELP drug delivery vehicle was designed to aggregate upon intra-articular injection at 37 degrees C, and form a drug 'depot' that could slowly disaggregate and be cleared from the joint space over time. We evaluated the in vivo biodistribution and joint half-life of radiolabeled ELPs, with and without the ability to aggregate, at physiological temperatures encountered after intra-articular injection in a rat knee. Biodistribution studies revealed that the aggregating ELP had a 25-fold longer half-life in the injected joint than a similar molecular weight protein that remained soluble and did not aggregate. These results suggest that the intra-articular joint delivery of ELP-based fusion proteins may be a viable strategy for the prolonged release of disease-modifying protein drugs for osteoarthritis and other arthritides. PMID:16959360

Betre, Helawe; Liu, Wenge; Zalutsky, Michael R; Chilkoti, Ashutosh; Kraus, Virginia B; Setton, Lori A

2006-07-26

267

Self-nanoemulsifying drug delivery systems (SNEDDS) for oral delivery of protein drugs: I. Formulation development.  

PubMed

The global aim of this research project was to develop a self-nanoemulsifying drug delivery system (SNEDDS) for non-invasive delivery of protein drugs. The specific aim of this study was to develop SNEDDS formulations. An experimental design was adopted to develop SNEDDS. Fluorescent labeled beta-lactamase (FITC-BLM), a model protein, was loaded into SNEDDS through solid dispersion technique. The experimental design provided 720 compositions of different oil, surfactant, and co-surfactant at various ratios, of which 33 SNEDDS prototypes were obtained. Solid dispersion of FITC-BLM in SoyPC prepared was able to dissolve in 16 SNEDDS prototypes (approximately 2200 mU BLM in 1g SNEDDS). SNEDDS NE-12-7 (composition: Lauroglycol FCC, Cremophor EL and Transcutol; ratio: 5:4:3) formed O/W nanoemulsion with mean droplet size in the range of 22-50 nm when diluted with various pH media and different dilution factor with PBS (pH 7.4). The phase diagram of NE-12-7 indicated a broad region of nanoemulsion. BLM-loaded SNEDDS (NE-12-7) stored at 4 degrees C for 12 weeks indicated 10% loss of BLM activity. A SNEDDS was developed to load FITC-BLM into the oil phase which can spontaneously form O/W nanoemulsion upon the addition of water. PMID:18650038

Rao, Sripriya Venkata Ramana; Shao, Jun

2008-05-27

268

Recent Applications of Mesoscale Modeling to Nanotechnology and Drug Delivery.  

National Technical Information Service (NTIS)

Mesoscale simulations have traditionally been used to investigate structural morphology of polymer in solution, melts and blends. Recently we have been pushing such modeling methods to important areas of Nanotechnology and Drug delivery that are well out ...

A. Maiti J. Wescott P. Kung G. Goldbeck-Wood

2005-01-01

269

Sonophoresis for Rapid Assessment of Interstitial Fluid and Drug Delivery.  

National Technical Information Service (NTIS)

The general objective of the proposed studies was to develop sonophoresis as a platform technology for assessing interstitial fluid from the skin and perform transdermal drug delivery. In this method, a short application of low-frequency ultrasound is use...

S. Mitragotri

2007-01-01

270

Electrically-Assisted Transdermal Drug Delivery  

Microsoft Academic Search

Electrically-assisted transdermal delivery (EATDD) is the facilitated transport of compounds across the skin using an electromotive force. It has been extensively explored as a potential means for delivering peptides and other hydrophilic, acid-labile or orally unstable products of biotechnology. The predominant mechanism for delivery is iontophoresis, although electroosmosis and electroporation have also been investigated. The focus of this review is

Jim E. Riviere; Mark C. Heit

1997-01-01

271

The core-inversible micelles for hydrophilic drug delivery.  

PubMed

A unique core-inversible micelle (CIM) was formed via PEG(5k)CA8 for hydrophilic drug delivery. An amyloid-fibril-inhibiting water-soluble molecule, congo red (CR), has been loaded into the hydrophilic core of CIMs. The targeting folate-CIMs significantly enhanced the intracellular delivery of hydrophilic CR in a folate receptor-expressing cell line. PMID:23775217

Huang, Wenzhe; Shi, Changying; Shao, Yu; Lam, Kit S; Luo, Juntao

2013-07-28

272

Transdermal delivery of drugs for the treatment of bone diseases  

Microsoft Academic Search

The current status of transdermal drug delivery for the treatment of bone diseases is described in this review. The structure, physiology and function of skin and their importance in determining delivery into and across skin are discussed. Special emphasis has been devoted to a description of the major pathways of transport across the skin and the quite continuing controversy over

Chandrasekharan Ramachandran; David Fleisher

2000-01-01

273

Usefulness verification of biocompatible microneedle patch for transdermal drug delivery  

Microsoft Academic Search

The key issues in the development of a microneedle patch as a tool for transdermal drug delivery are safety and delivery performance in addition to economical production. In this paper, a novel fabrication method for an inexpensive microneedle patch made of biocompatible polymer is reported, along with verifications for the fabricated microneedle patch. For microneedle patch fabrication, we combined the

Chun Yan Jin; Man Hee Han; S. S. Lee; Yo Han Choi

2009-01-01

274

Mesoporous SBA15 HPLC evaluation for controlled gentamicin drug delivery  

Microsoft Academic Search

Mesoporous silica SBA-15 was prepared to evaluate its application as gentamicin drug delivery system. Two procedures were used to evaluate the delivery: calcined powder and disk conformed. The samples were charged with gentamicin sulphate and the experiments were carried out in vitro. No significant difference between powder and disk was observed in the tests. The release profiles exhibited a pronounced

A. L. Doadrio; E. M. B. Sousa; J. C. Doadrio; J. Pérez Pariente; I. Izquierdo-Barba; M. Vallet-Reg??

2004-01-01

275

Micelles and Nanoparticles for Ultrasonic Drug and Gene Delivery  

PubMed Central

Drug delivery research employing micelles and nanoparticles has expanded in recent years. Of particular interest is the use of these nanovehicles that deliver high concentrations of cytotoxic drugs to diseased tissues selectively, thus reducing the agent’s side effects on the rest of the body. Ultrasound, traditionally used in diagnostic medicine, is finding a place in drug delivery in connection with these nanoparticles. In addition to their non-invasive nature and the fact that they can be focused on targeted tissues, acoustic waves have been credited with releasing pharmacological agents from nanocarriers, as well as rendering cell membranes more permeable. In this article, we summarize new technologies that combine the use of nanoparticles with acoustic power both in drug and gene delivery. Ultrasonic drug delivery from micelles usually employs polyether block copolymers, and has been found effective in vivo for treating tumors. Ultrasound releases drug from micelles, most probably via shear stress and shock waves from collapse of cavitation bubbles. Liquid emulsions and solid nanoparticles are used with ultrasound to deliver genes in vitro and in vivo. The small packaging allows nanoparticles to extravasate into tumor tissues. Ultrasonic drug and gene delivery from nano-carriers has tremendous potential because of the wide variety of drugs and genes that could be delivered to targeted tissues by fairly non-invasive means.

Husseini, Ghaleb A.; Pitt, William G.

2008-01-01

276

Pharmaceutical Aerosol Sprays for Drug Delivery to the Lungs  

Microsoft Academic Search

\\u000a Respiratory illnesses are commonly treated with drugs delivered to the lungs as an inhaled aerosol. The inhaled aerosol route\\u000a sometimes offers advantages over other routes such as injection or oral delivery. These advantages include rapid and predictable\\u000a onset of action of drug, decreased adverse reactions, as well as safe and convenient delivery. However, the design of a device\\u000a and formulation

W. H. Finlay

277

NMR characterisation and transdermal drug delivery potential of microemulsion systems  

Microsoft Academic Search

The purpose of this study was to investigate the influence of structure and composition of microemulsions (Labrasol\\/Plurol Isostearique\\/isostearylic isostearate\\/water) on their transdermal delivery potential of a lipophilic (lidocaine) and a hydrophilic model drug (prilocaine hydrochloride), and to compare the drug delivery potential of microemulsions to conventional vehicles. Self-diffusion coefficients determined by pulsed-gradient spin-echo NMR spectroscopy and T1 relaxation times were

Mads Kreilgaard; Erik J Pedersen; Jerzy W Jaroszewski

2000-01-01

278

Targeted Drug Delivery to the Eye Enabled by Microneedles  

Microsoft Academic Search

\\u000a Drug delivery targeted to specific tissues within the eye represents an important advance over conventional methods of topical\\u000a and injectable delivery that have poor specificity for particular ocular tissues requiring therapy. This level of intraocular\\u000a targeting can be achieved using microneedles, which are solid and ­hollow needles of micron dimensions. Microneedles can selectively\\u000a target intraocular tissues by delivering drug formulations

Samirkumar R. Patel; Henry F. Edelhauser; Mark R. Prausnitz

279

Brain Tumors: Convection-Enhanced Delivery of Drugs (Method)  

Microsoft Academic Search

\\u000a Delivery of therapeutic agents into the brain has been an ongoing challenge for many years. The poor prognosis for patient\\u000a with primary malignant brain tumors treated with conventional techniques (surgery, radiotherapy and chemotherapy) has motivated\\u000a the development of new strategies to deliver drugs into the brain. Local intracranial delivery of antineoplastic agents has\\u000a appeared to be the most effective drug

Anne-Laure Laine; Emilie Allard; Philippe Menei; Catherine Passirani

280

Retro-Convection Enhanced Drug Delivery: A Computational Study  

Microsoft Academic Search

Retro-convection enhanced delivery (R-CED) is an emerging drug delivery method to overcome the blood brain barrier (BBB).\\u000a We have developed a mathematical model to understand the fluid flow and mass transfer in the interstitium of brain tissue\\u000a in R-CED therapy. The model was used to predict pressure distributions, fluid flow patterns, and drug concentration profiles.\\u000a Some numerical results were obtained

Peng Wang; William L. Olbricht

2010-01-01

281

Transferosomes - A vesicular transdermal delivery system for enhanced drug permeation  

PubMed Central

Transdermal administration of drugs is generally limited by the barrier function of the skin. Vesicular systems are one of the most controversial methods for transdermal delivery of active substances. The interest in designing transdermal delivery systems was relaunched after the discovery of elastic vesicles like transferosomes, ethosomes, cubosomes, phytosomes, etc. This paper presents the composition, mechanisms of penetration, manufacturing and characterization methods of transferosomes as transdermal delivery systems of active substances. For a drug to be absorbed and distributed into organs and tissues and eliminated from the body, it must pass through one or more biological membranes/barriers at various locations. Such a movement of drug across the membrane is called as drug transport. For the drugs to be delivered to the body, they should cross the membranous barrier. The concept of these delivery systems was designed in an attempt to concentrate the drug in the tissues of interest, while reducing the amount of drug in the remaining tissues. Hence, surrounding tissues are not affected by the drug. In addition, loss of drug does not happen due to localization of drug, leading to get maximum efficacy of the medication. Therefore, the phospholipid based carrier systems are of considerable interest in this era.

Rajan, Reshmy; Jose, Shoma; Mukund, V. P. Biju; Vasudevan, Deepa T.

2011-01-01

282

Stimuli sensitive hydrogels for ophthalmic drug delivery: A review  

PubMed Central

Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery.

Kushwaha, Swatantra KS; Saxena, Prachi; Rai, AK

2012-01-01

283

Stimuli sensitive hydrogels for ophthalmic drug delivery: A review.  

PubMed

Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist for past 10-20 years. As an isolated organ, eye is very difficult to study from a drug delivery point of view. Despite this limitation, improvements have been made with the objective of maintaining the drug in the biophase for an extended period. A major problem in ocular therapeutics is the attainment of an optimal drug concentration at the site of action. To achieve effective ophthalmic therapy, an adequate amount of active ingredient must be delivered and maintained within the eye. The most frequently used dosage forms, i.e., eye solution, eye ointments, eye gels, and eye suspensions are compromised in their effectiveness by several limitations leading to poor ocular bioavailability. Ophthalmic use of viscosity-enhancing agents, penetration enhancers, cyclodextrins, prodrug approaches, and ocular inserts, and the ready existing drug carrier systems along with their application to ophthalmic drug delivery are common to improve ocular bioavailability. Amongst these hydrogel (stimuli sensitive) systems are important, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, enzyme substrate) or other external (electric current, light) stimuli. They help to increase in precorneal residence time of drug to a sufficient extent that an ocularly delivered drug can exhibit its maximum biological action. The concept of this innovative ophthalmic delivery approach is to decrease the systemic side effects and to create a more pronounced effect with lower doses of the drug. The present article describes the advantages and use stimuli sensitive of hydrogel systems in ophthalmic drug delivery. PMID:23119233

Kushwaha, Swatantra Ks; Saxena, Prachi; Rai, Ak

2012-04-01

284

Iontophoresis: A Potential Emergence of a Transdermal Drug Delivery System  

PubMed Central

The delivery of drugs into systemic circulation via skin has generated much attention during the last decade. Transdermal therapeutic systems propound controlled release of active ingredients through the skin and into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. However, the excellent impervious nature of the skin offers the greatest challenge for successful delivery of drug molecules by utilizing the concepts of iontophoresis. The present review deals with the principles and the recent innovations in the field of iontophoretic drug delivery system together with factors affecting the system. This delivery system utilizes electric current as a driving force for permeation of ionic and non-ionic medications. The rationale behind using this technique is to reversibly alter the barrier properties of skin, which could possibly improve the penetration of drugs such as proteins, peptides and other macromolecules to increase the systemic delivery of high molecular weight compounds with controlled input kinetics and minimum inter-subject variability. Although iontophoresis seems to be an ideal candidate to overcome the limitations associated with the delivery of ionic drugs, further extrapolation of this technique is imperative for translational utility and mass human application.

Dhote, Vinod; Bhatnagar, Punit; Mishra, Pradyumna K.; Mahajan, Suresh C.; Mishra, Dinesh K.

2012-01-01

285

Drug delivery to the posterior segment of the eye.  

PubMed

Delivery of drugs to the posterior eye is challenging, owing to anatomical and physiological constrains of the eye. There is an increasing need for managing rapidly progressing posterior eye diseases, such as age-related macular degeneration, diabetic retinopathy and retinitis pigmentosa. Drug delivery to the posterior segment of the eye is therefore compounded by the increasing number of new therapeutic entities (e.g. oligonucleotides, aptamers and antibodies) and the need for chronic therapy. Currently, the intravitreal route is widely used to deliver therapeutic entities to the retina. However, frequent administration of drugs via this route can lead to retinal detachment, endophthalmitis and increased intraocular pressure. Various controlled delivery systems, such as biodegradable and non-biodegradable implants, liposomes and nanoparticles, have been developed to overcome such adverse effects, with some success. The periocular route is a promising alternative, owing to the large surface area and the relatively high permeability of the sclera. Yet, the blood-retinal barrier and efflux transporters hamper the transport of therapeutic entities to the retina. As such, the efficient delivery of drugs to the posterior eye remains a major challenge facing the pharmaceutical scientist. In this review, we discuss the barriers of the posterior eye drug delivery and the various drug-delivery strategies used to overcome these barriers. PMID:21167306

Thrimawithana, Thilini Rasika; Young, Simon; Bunt, Craig Robert; Green, Colin; Alany, Raid Ghassan

2010-12-15

286

Electroporation as an efficient physical enhancer for skin drug delivery.  

PubMed

Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Application of high-voltage pulses to the skin increases its permeability (electroporation) and enables the delivery of various substances into and through the skin. The application of electroporation to the skin has been shown to increase transdermal drug delivery. Moreover, electroporation, used alone or in combination with other enhancement methods, expands the range of drugs (small to macromolecules, lipophilic or hydrophilic, charged or neutral molecules) that can be delivered transdermally. The efficacy of transport depends on the electrical parameters and the physicochemical properties of drugs. The in vivo application of high-voltage pulses is well tolerated, but muscle contractions are usually induced. The electrode and patch design is an important issue to reduce the discomfort of the electrical treatment in humans. This review presents the main findings in the field of electroporation-namely, transdermal drug delivery. Particular attention is paid to proposed enhancement mechanisms and trends in the field of topical and transdermal delivery. PMID:19717723

Escobar-Chávez, José Juan; Bonilla-Martínez, Dalia; Villegas-González, Martha Angélica; Revilla-Vázquez, Alma Luisa

2009-08-28

287

Critical Assessment of Implantable Drug Delivery Devices in Glaucoma Management  

PubMed Central

Glaucoma is a group of heterogeneous disorders involving progressive optic neuropathy that can culminate into visual impairment and irreversible blindness. Effective therapeutic interventions must address underlying vulnerability of retinal ganglion cells (RGCs) to degeneration in conjunction with correcting other associated risk factors (such as elevated intraocular pressure). However, realization of therapeutic outcomes is heavily dependent on suitable delivery system that can overcome myriads of anatomical and physiological barriers to intraocular drug delivery. Development of clinically viable sustained release systems in glaucoma is a widely recognized unmet need. In this regard, implantable delivery systems may relieve the burden of chronic drug administration while potentially ensuring high intraocular drug bioavailability. Presently there are no FDA-approved implantable drug delivery devices for glaucoma even though there are several ongoing clinical studies. The paper critically assessed the prospects of polymeric implantable delivery systems in glaucoma while identifying factors that can dictate (a) patient tolerability and acceptance, (b) drug stability and drug release profiles, (c) therapeutic efficacy, and (d) toxicity and biocompatibility. The information gathered could be useful in future research and development efforts on implantable delivery systems in glaucoma.

Manickavasagam, Dharani; Oyewumi, Moses O.

2013-01-01

288

Multiparticulate formulation approach to colon specific drug delivery: current perspectives.  

PubMed

Colon specific drug delivery has gained increased importance not just for the delivery of drugs for the treatment of local diseases associated with the colon but also as potential site for the systemic delivery of therapeutic peptide and proteins. To achieve successful colon targeted drug delivery, a drug needs to be protected from degradation, release and/or absorption in the upper portion of the GI tract and then ensure abrupt or controlled release in the proximal colon. Drug modifications through covalent linkages with carrier or prodrug approach and formulation based approaches can be used for colonic delivery. Report suggests that drug carrier systems larger than 200 mm possess very low gastric transit time due to physiological condition of the bowel in colitis. And for this reason and considering the selective uptake of micron or sub-micron particles by cancerous and inflamed cells/ tissues a multiparticulate approach based on pellets, granules, microsphere or nanoparticle type formulation is expected to have better pharmacological effect in the colon. The review is aimed at understanding recent advancements made in multiparticulate formulation approach for colon specific delivery of medicaments. PMID:17207416

Asghar, Laila Fatima Ali; Chandran, Sajeev

2006-01-01

289

Electrohydrodynamics: A facile technique to fabricate drug delivery systems  

PubMed Central

Electrospinning and electrospraying are facile electrohydrodynamic fabrication methods that can generate drug delivery systems (DDS) through a one-step process. The nano-structured fiber and particle morphologies produced by these techniques offer tunable release kinetics applicable to diverse biomedical applications. Coaxial-electrospinning/electrospraying, a relatively new technique of fabricating core-shell fibers/particles have added to the versatility of these DDS by affording a near zero-order drug release kinetics, dampening of burst release, and applicability to a wider range of bioactive agents. Controllable electrospinning/spraying of fibers and particles and subsequent drug release from these chiefly polymeric vehicles depends on well-defined solution and process parameters. The additional drug delivery capability from electrospun fibers can further enhance the material’s functionality in tissue engineering applications. This review discusses the state-of-the-art of using electrohydrodynamic technique to generate nano-fiber/particles as drug delivery devices.

Chakraborty, Syandan; Liao, I-Chien; Adler, Andrew; Leong, Kam W.

2009-01-01

290

Electrohydrodynamics: A facile technique to fabricate drug delivery systems.  

PubMed

Electrospinning and electrospraying are facile electrohydrodynamic fabrication methods that can generate drug delivery systems (DDS) through a one-step process. The nanostructured fiber and particle morphologies produced by these techniques offer tunable release kinetics applicable to diverse biomedical applications. Coaxial electrospinning/electrospraying, a relatively new technique of fabricating core-shell fibers/particles have added to the versatility of these DDS by affording a near zero-order drug release kinetics, dampening of burst release, and applicability to a wider range of bioactive agents. Controllable electrospinning/spraying of fibers and particles and subsequent drug release from these chiefly polymeric vehicles depends on well-defined solution and process parameters. The additional drug delivery capability from electrospun fibers can further enhance the material's functionality in tissue engineering applications. This review discusses the state-of-the-art of using electrohydrodynamic technique to generate nanofiber/particles as drug delivery devices. PMID:19651167

Chakraborty, Syandan; Liao, I-Chien; Adler, Andrew; Leong, Kam W

2009-08-03

291

A Review on Composite Liposomal Technologies for Specialized Drug Delivery  

PubMed Central

The combination of liposomes with polymeric scaffolds could revolutionize the current state of drug delivery technology. Although liposomes have been extensively studied as a promising drug delivery model for bioactive compounds, there still remain major drawbacks for widespread pharmaceutical application. Two approaches for overcoming the factors related to the suboptimal efficacy of liposomes in drug delivery have been suggested. The first entails modifying the liposome surface with functional moieties, while the second involves integration of pre-encapsulated drug-loaded liposomes within depot polymeric scaffolds. This attempts to provide ingenious solutions to the limitations of conventional liposomes such as short plasma half-lives, toxicity, stability, and poor control of drug release over prolonged periods. This review delineates the key advances in composite technologies that merge the concepts of depot polymeric scaffolds with liposome technology to overcome the limitations of conventional liposomes for pharmaceutical applications.

Mufamadi, Maluta S.; Pillay, Viness; Choonara, Yahya E.; Du Toit, Lisa C.; Modi, Girish; Naidoo, Dinesh; Ndesendo, Valence M. K.

2011-01-01

292

Drug delivery with carbon nanotubes for in vivo cancer treatment.  

PubMed

Chemically functionalized single-walled carbon nanotubes (SWNT) have shown promise in tumor-targeted accumulation in mice and exhibit biocompatibility, excretion, and little toxicity. Here, we show in vivo SWNT drug delivery for tumor suppression in mice. We conjugate paclitaxel (PTX), a widely used cancer chemotherapy drug, to branched polyethylene glycol chains on SWNTs via a cleavable ester bond to obtain a water-soluble SWNT-PTX conjugate. SWNT-PTX affords higher efficacy in suppressing tumor growth than clinical Taxol in a murine 4T1 breast cancer model, owing to prolonged blood circulation and 10-fold higher tumor PTX uptake by SWNT delivery likely through enhanced permeability and retention. Drug molecules carried into the reticuloendothelial system are released from SWNTs and excreted via biliary pathway without causing obvious toxic effects to normal organs. Thus, nanotube drug delivery is promising for high treatment efficacy and minimum side effects for future cancer therapy with low drug doses. PMID:18701489

Liu, Zhuang; Chen, Kai; Davis, Corrine; Sherlock, Sarah; Cao, Qizhen; Chen, Xiaoyuan; Dai, Hongjie

2008-08-15

293

Lipid carrier systems for targeted drug and gene delivery.  

PubMed

For effective chemotherapy, it is necessary to deliver therapeutic agents selectively to their target sites, since most drugs are associated with both beneficial effects and side effects. The use of lipid dispersion carrier systems, such as lipid emulsions and liposomes, as carriers of lipophilic drugs has attracted particular interest. A drug delivery system can be defined as a methodology for manipulating drug distribution in the body. Since drug distribution depends on the carrier, administration route, particle size of the carrier, lipid composition of the carrier, electric charge of the carrier and ligand density of the targeting carrier, these factors must be optimized. Recently, the lipid carrier system has also been applied to gene delivery systems for gene therapy. However, in both drug and gene medicine cases, a lack of cell-selectivity limits the wide application of this kind of drug and/or gene therapy. Therefore, lipid carrier systems for targeted drug and gene delivery must be developed for the rational therapy. In this review, we shall focus on the progress of research into lipid carrier systems for drug and gene delivery following systemic or local injection. PMID:16079512

Hashida, Mitsuru; Kawakami, Shigeru; Yamashita, Fumiyoshi

2005-08-01

294

[Research progress of polyamidoamine dendrimer in targeting drug delivery system].  

PubMed

Targeting drug delivery system (TDDS) is one of the most concerned research fields in cancer treatment because it can bind selectively and react with the target diseased sites at the cellular or sub-cellular level, making distribution and release of drugs in a controlled manner, thus enhance therapeutic effects and reduce toxic and side-effects on normal cells. Polyamidoamine dendrimer (PAMAMD) is a kind of newly developed polymer in nanometer degree. Hyper-branched, monodispersity, three-dimensional structure and host-guest entrapment ability make it used as drug carrier, gene delivery system and imaging agent. Various targeting ligands, which have high affinity to specific organs, tissues or cells in human body, can be linked to surface functional groups of PAMAMD. And drugs and theoretical gene are carried by encapsulation or chemical conjugation. Finally, PAMAMD targeting drug delivery system can carry drugs and theoretical gene to diseased sites and then release them for targeted therapy. The PAMAMD-based conjugates have small size, ligh permeability and retention effect (EPR), low toxicity and so on. The research progress of PAMAMD modified by different ligands in targeting drug delivery system is reviewed, and research direction of the PAMAMD targeting delivery system in the future is also suggested. PMID:21800534

Ding, Rong-min; He, Hua; Li, Juan

2011-05-01

295

Paliperidone Loaded Self Emulsifying Drug Delivery Systems (SEDDS) for Improved Oral Delivery  

Microsoft Academic Search

The present research is aimed to improve the oral delivery of paliperidone by loading into self emulsifying drug delivery systems (SEDDS). Oleic acid, tween 80 and capmul MCM L8 were selected as oil, surfactant and co-surfactant respectively and phase diagram was constructed and the region was identified for the formation of SEDDS. The stable formulations were analyzed for globule size,

Swetha Kanuganti; Raju Jukanti; Prabhakar R. Veerareddy; Suresh Bandari

2011-01-01

296

Ultrasonic Concentration of Drug Delivery Capsules.  

National Technical Information Service (NTIS)

Methods, compositions and apparatus for localized delivery of compounds are provided. In certain embodiments, radiation force is used to direct carriers to a target site, and additional radiation is used to fragment the localized carriers, releasing assoc...

D. Dayton K. W. Ferrara M. Shortencarier S. Bloch

2004-01-01

297

Biomedical materials, devices and drug delivery systems by radiation techniques  

NASA Astrophysics Data System (ADS)

The study of radiation polymerization in a super-cooled state started in 1966 and has been applied to the immobilization of biofunctional materials since 1973. In the last twenty years, application has been concentrated to the immobilization of drugs and hormones for the purpose of drug delivery systems. Very recently, the author has proposed a concept of environmental signal responsive chemical delivery system, as a new generation of controlled release and delivery systems. The study and development of materials, devices and systems is described. The signal responsive delivery system consists of a sensor part and a controlled delivery part. Therefore, the use of immobilization techniques for the biochip sensor and the hydrogel actuator has been investigated. As a future goal, systems for the brain research are to be designed and studied.

Kaetsu, Isao

1996-03-01

298

NMR techniques in drug delivery: application to zein protein complexes.  

PubMed

Zein is a protein containing a large amount of nonpolar amino acids, which has shown the ability to form aggregates and entrap solutes, such as drugs and amino acids. NMR techniques were used to detect binding interactions and measure affinity between zein and three different drugs: tetracycline, amoxicillin and indomethacin. The release study of zein microparticle formulations containing any of these drugs was confronted with the affinity results, showing a remarkable correlation. The feasible methodology employed, focused in the functionality of the protein-drug interaction, can be very promising for the rational design of appropriate drug vehicles for drug delivery. PMID:23041651

Sousa, F F O; Luzardo-Álvarez, Asteria; Blanco-Méndez, José; Martín-Pastor, Manuel

2012-10-05

299

Recent Applications of Liposomes in Ophthalmic Drug Delivery  

PubMed Central

Liposomal formulations were significantly explored over the last decade for the ophthalmic drug delivery applications. These formulations are mainly composed of phosphatidylcholine (PC) and other constituents such as cholesterol and lipid-conjugated hydrophilic polymers. Liposomes are biodegradable and biocompatible in nature. Current approaches for topical delivery of liposomes are focused on improving the corneal adhesion and permeation by incorporating various bioadhesive and penetration enhancing polymers. In the case of posterior segment disorders improvement in intravitreal half life and targeted drug delivery to the retina is achieved by liposomes. In this paper we have attempted to summarize the applications of liposomes in the field of ophthalmic drug delivery by citing numerous investigators over the last decade.

Mishra, Gyan P.; Bagui, Mahuya; Tamboli, Viral; Mitra, Ashim K.

2011-01-01

300

Transdermal Drug Delivery: Penetration Enhancement Techniques  

Microsoft Academic Search

There is considerable interest in the skin as a site of drug application both for local and systemic effect. However, the skin, in particular the stratum corneum, poses a formidable barrier to drug penetration thereby limiting topical and transdermal bioavailability. Skin penetration enhancement techniques have been developed to improve bioavailability and increase the range of drugs for which topical and

Heather A. E. Benson

2005-01-01

301

Mobile Drug-Delivery for Ambient Assisted Living: Implantable and Extracorporeal Devices  

Microsoft Academic Search

Miniaturized smart drug delivery devices pave the way for a personalized treatment of many diseases by un- skilled persons outside the hospital. Many therapies require a repetitive delivery of a defined amount of drug in well defined time slots. Innovative drug delivery systems constitute an important prerequisite for ambient as- sisted living: The reliable delivery of drugs, in time and

S. Haeberle; R. Gronmaier; T. Goettsche; M Vosseler; A. Kain; M. Reiterer; D. Hradetzky; C. Mueller; S. Messner; R. Zengerle

302

Parameters influencing the stealthiness of colloidal drug delivery systems  

Microsoft Academic Search

Over the last few decades, colloidal drug delivery systems (CDDS) such as nano-structures have been developed in order to improve the efficiency and the specificity of drug action. Their small size permits them to be injected intravenously in order to reach target tissues. However, it is known that they can be rapidly removed from blood circulation by the immune system.

Arnaud Vonarbourg; Catherine Passirani; Patrick Saulnier; Jean-Pierre Benoit

2006-01-01

303

New biodegradable polymers for injectable drug delivery systems  

Microsoft Academic Search

Many biodegradable polymers were used for drug delivery and some are successful for human application. There remains fabrication problems, such as difficult processability and limited organic solvent and irreproducible drug release kinetics. New star-shaped block copolymers, of which the typical molecular architecture is presented, results from their distinct solution properties, thermal properties and morphology. Their unique physical properties are due

B. Jeong; Y. K. Choi; Y. H. Bae; G. Zentner; S. W. Kim

1999-01-01

304

Iontophoresis - an approach for controlled drug delivery: a review.  

PubMed

The recent approval of lidocaine hydrochloride and epinephrine combined iontophoretic patch (Lidosite Vysteris Inc.) for localized pain treatment by FDA has invigorated the gaining interest in iontophoretic drug delivery systems for the transdermal delivery of drugs. This technique of facilitated movement of ions across a membrane under the influence of an externally applied electric potential difference, is one of the most promising physical skin penetration enhancing method. The rationale behind using this technique is the capability of this method to increase the systemic delivery of high molecular weight compounds with controlled input kinetics and minimum inter-subject variability, which is otherwise achieved only when parentral route of administration is used. Recently, good permeation of larger peptides like insulin has been achieved through this technique in combination with chemical enhancers. This review briefly describes the factors which affect iontophoretic drug delivery and summarizes the studies conducted recently using this technique in order to achieve higher systemic absorption of the drugs having low passive diffusion otherwise. The effect of permeation enhancers (chemical enhancers) on iontophoretic flux of drugs has also been described. Present review also provides an insight into reverse iontophoresis. Various parameters which affect the transdermal absorption of drugs through iontophoresis like drug concentration, polarity of drugs, pH of donor solution, presence of co-ions, ionic strength, electrode polarity etc. have also been reviewed in detail. PMID:17269912

Dixit, Nitin; Bali, Vikas; Baboota, Sanjula; Ahuja, Alka; Ali, Javed

2007-01-01

305

Transdermal Absorption of Nitroglycerin from Microseal Drug Delivery (MDD) System  

Microsoft Academic Search

A recent important advance in biopharmaceutics has been the utilization of controlled delivery of drugs to the systemic circulation through the intact skin. With the conventional tablet and capsule dosage forms, the amount of drug absorbed through the gastrointestinal (GI) tract varies depending on the quan tity and types of food in the stomach, on the GI motility and transit

Aziz Karim

1983-01-01

306

Self assembled materials: design strategies and drug delivery perspectives.  

PubMed

Self assembly of small molecules in complex supramolecular structures provides a new avenue in the development of materials for drug delivery applications. Owing to the low aqueous solubility of various drugs, an effective delivery system is often required to reach sufficient drug bioavailability and/or to facilitate clinical use. Micelles, amphiphilic gels, vesicles (liposomes), nanodisks, cubosomes, colloidosomes, tubules, microemulsions, lipid particles, polyelectrolyte capsules etc. are some of the intriguing structures formed via self assembly. As well as enabling improved solubilization, such materials can be tuned to offer a range of other advantages, including controlled or stimuli sensitive drug release, protection from drug hydrolysis and chemical or enzymatic degradation, a reduction in toxicity, improvement of drug availability, prevention of RES uptake or selective targeting to organelles etc. Such multiple functionalities can be brought together by self assembly of different functional molecules. This route offers a cost effective means of developing drug delivery carriers tailored to specific needs. Our current understanding of the microstructure evolution of self assembled materials will go a long way towards designing/selecting molecules to create well defined structures. We believe that most of the potential resources mentioned above are untapped and that there is a need to further strengthen research in this area to fully exploit their potential. Selective cross linking of core or shell, stimuli sensitive amphiphiles, prodrug amphiphiles, antibody coupled amphiphiles etc. are only some of the new approaches for the development of effective drug delivery systems via self assembly. PMID:23907560

Verma, Gunjan; Hassan, P A

2013-09-25

307

Formulation of self-emulsifying drug delivery systems  

Microsoft Academic Search

Self-emulsifying drug delivery systems (SEDDS) are mixtures of oils and surfactants, ideally isotropic, sometimes including cosolvents, which emulsify under conditions of gentle agitation, similar to those which would be encountered in the gastro-intestinal tract. Hydrophobic drugs can often be dissolved in SEDDS allowing them to be encapsulated as unit dosage forms for peroral administration. When such a formulation is released

Colin W. Pouton

1997-01-01

308

Mathematical models describing polymer dissolution: consequences for drug delivery  

Microsoft Academic Search

Polymer dissolution is an important phenomenon in polymer science and engineering that has found applications in areas like microlithography, controlled drug delivery, and plastics recycling. This review focuses on the modeling efforts to understand the physics of the drug release process from dissolving polymers. A brief review of the experimentally observed dissolution behavior is presented, thus motivating the modeling of

Balaji Narasimhan

2001-01-01

309

Polymorphism of 17-? estradiol in a transdermal drug delivery system  

Microsoft Academic Search

The inclusions in a typical transdermal drug delivery system (TDS) containing estradiol drug were characterized using microscopic, spectroscopic and thermal analytical techniques. Optical and scanning electron microcscopy were used to determine the locations and morphologies of the crystals in the matrix. Two different types of crystals randomly distributed laterally inside the patch were observed. Solid aggregates were found surrounding needle-like

N. E. Variankaval; K. I. Jacob; S. M. Dinh

2002-01-01

310

Is transdermal drug delivery research still important today?  

Microsoft Academic Search

When measured by the number of medicines consumed or prescriptions written, the topical and transdermal routes of drug delivery pale into insignificance compared with oral therapy. Industrial colleagues, therefore, occasionally adopt a somewhat utilitarian stance and question the value of academic research into skin treatment and drug permeation, with the rather parochial argument that it is of limited use to

Brian W Barry

2001-01-01

311

A method for intracochlear drug delivery in the mouse  

Microsoft Academic Search

The confluence of two rapidly emerging research arenas – development of mouse models of human deafness and inner ear drug therapy for treatment and prevention of hearing loss – provides an opportunity for unprecedented approaches to study and treat deafness. Toward such goals, we have developed a method for intracochlear drug delivery in the mouse. The bulla was exposed using

Zhiqiang Chen; Anthony A. Mikulec; Michael J. McKenna; William F. Sewell; Sharon G. Kujawa

2006-01-01

312

Modeling of transdermal drug delivery with a microneedle array  

Microsoft Academic Search

Transdermal drug delivery is generally limited by the extraordinary barrier properties of the stratum corneum, the outer 10–15 m layer of skin. A conventional needle inserted across this barrier and into deeper tissues could effectively deliver drugs. However, it would lead to infection and cause pain, thereby reducing patient compliance. In order to administer a frequent injection of insulin and

Y-G Lv; J Liu; Y-H Gao; B Xu

2006-01-01

313

A parametric study of iontophoretic transdermal drug-delivery systems  

Microsoft Academic Search

A mathematical model of iontophoretic transdermal drug delivery was applied to study the effects of physical parameters on the cumulative amount of amitriptyline HCl collected. A graphical method, based on an analytical solution of the system, was first used to estimate the drug diffusion coefficient in the membrane and its surface concentration in the absence of an electric potential difference.

Laurent Simon; Alison Nickol Weltner; Yiping Wang; Bozena Michniak

2006-01-01

314

Generation of Multiphase Pulsed Voltages for Transdermal Drug Delivery  

Microsoft Academic Search

This paper first reviews the mechanism of transdermal drug delivery (TDD) and then presents the method for generating multiphase pulsed voltages (MPPVs) for TDD applications. In TDD applications, it offers many potential advantages over conventional methods, such as oral and injection treatments, and it avoids drug degradation through the gastrointestinal tract and liver. Due to the energy stored in an

Sheng-Yu Tseng; Tsai-Fu Wu; Shu-Yuan Fan

2008-01-01

315

Modeling of transdermal drug delivery with a microneedle array  

Microsoft Academic Search

Transdermal drug delivery is generally limited by the extraordinary barrier properties of the stratum corneum, the outer 10-15 µm layer of skin. A conventional needle inserted across this barrier and into deeper tissues could effectively deliver drugs. However, it would lead to infection and cause pain, thereby reducing patient compliance. In order to administer a frequent injection of insulin and

Y.-G. Lv; J. Liu; Y.-H. Gao; B. Xu

2006-01-01

316

Electrically responsive smart hydrogels in drug delivery: a review.  

PubMed

Recently, much of the research activity has been focused on the development of stimuli-responsive hydrogels. Such hydrogels can show a response to the external or internal stimuli in the form of rapid changes in the physical nature of the polymeric network. This hydrogel property can be utilized for drug delivery applications. A literature search suggests that current research related to stimuli responsive drug delivery systems deals with temperature sensitive, pH sensitive, glucose sensitive and bio-molecule sensitive hydrogels. Electrically responsive hydrogels have also been recently developed in the form of gel matrices, implants and membranes for drug delivery. Control over the release of drugs such as quantity and timing, is essential to optimize drug therapy. Reports say that the electrically controlled in vitro and in vivo drug release studies have been carried out on polyelectrolyte hydrogels. A pulsatile pattern of drug release was achieved with the alternative application and removal of the electrical stimulus. This article gives an overview of the latest developments in the formulation of drug delivery systems using electrically responsive hydrogels. PMID:20799182

Kulkarni, R V; Biswanath, Sa

317

Nanotechnology: A Focus on Nanoparticles as a Drug Delivery System  

Microsoft Academic Search

This review will provide an in-depth discussion on the previous development of nanoparticle-based drug delivery systems (DDS) and discuss original research data that includes the therapeutic enhancement of antiretroviral therapy. The use of nanoparticle DDS will allow practitioners to use drugs to target specific areas of the body. In the treatment of malignancies, the use of nanoparticles as a DDS

Jeffrey D. Kingsley; Huanyu Dou; Justin Morehead; Barrett Rabinow; Howard E. Gendelman; Christopher J. Destache

2006-01-01

318

Mathematical modeling and simulation of drug release from microspheres: Implications to drug delivery systems  

Microsoft Academic Search

This article aims to provide a comprehensive review of existing mathematical models and simulations of drug release from polymeric microspheres and of drug transport in adjacent tissues. In drug delivery systems, mathematical modeling plays an important role in elucidating the important drug release mechanisms, thus facilitating the development of new pharmaceutical products by a systematic, rather than trial-and-error, approach. The

Davis Yohanes Arifin; Lai Yeng Lee; Chi-Hwa Wang

2006-01-01

319

Chronopharmaceutics based modern colon specific drug delivery systems.  

PubMed

Colon-targeted delivery of bioactives has recently gained importance in addressing specific needs in the therapy of colon based diseases. Many approaches have been attempted for the development of colon-specific delivery systems, with not much success in the past. With the advancement in the field of chronobiology, modern drug delivery approaches have elevated to a new concept of chronopharmacology i.e. the ability to deliver the therapeutic agent to a patient in a staggered profile. The increasing research interest surrounding this delivery system has widened the areas of pharmaceutics in particular with many more sub-disciplines expected to coexist in the near future. Chronopharmaceutics based technology has eliminated the drawbacks associated with the conventional colon specific delivery systems. This review on chronopharmaceutics based delivery lays emphasis on the existing technologies and future development. PMID:22564168

Tiwari, Akanksha; Shukla, Raj Kumar; Tiwari, Suresh; Naazneen, Surti

2012-12-01

320

Novel mechanisms and devices to enable successful transdermal drug delivery.  

PubMed

Optimisation of drug delivery through human skin is important in modern therapy. This review considers drug-vehicle interactions (drug or prodrug selection, chemical potential control, ion pairs, coacervates and eutectic systems) and the role of vesicles and particles (liposomes, transfersomes, ethosomes, niosomes). We can modify the stratum corneum by hydration and chemical enhancers, or bypass or remove this tissue via microneedles, ablation and follicular delivery. Electrically assisted methods (ultrasound, iontophoresis, electroporation, magnetophoresis, photomechanical waves) show considerable promise. Of particular interest is the synergy between chemical enhancers, ultrasound, iontophoresis and electroporation. PMID:11500256

Barry, B W

2001-09-01

321

The use of shear stress for targeted drug delivery.  

PubMed

Stenosed segments of arteries significantly alter the blood flow known from healthy vessels. In particular, the wall shear stress at critically stenosed arteries is at least an order of magnitude higher than in healthy situations. This alteration represents a change in physical force and might be used as a trigger signal for drug delivery. Mechano-sensitive drug delivery systems that preferentially release their payload under increased shear stress are discussed. Therefore, besides biological or chemical markers, physical triggers are a further principle approach for targeted drug delivery. We hypothesize that such a physical trigger is much more powerful to release drugs for vasodilation, plaque stabilization, or clot lysis at stenosed arteries than any known biological or chemical ones. PMID:23645574

Saxer, Till; Zumbuehl, Andreas; Müller, Bert

2013-05-02

322

Hydrogel-Forming Microneedle Arrays for Enhanced Transdermal Drug Delivery  

PubMed Central

Unique microneedle arrays prepared from crosslinked polymers, which contain no drug themselves, are described. They rapidly take up skin interstitial fluid upon skin insertion to form continuous, unblockable, hydrogel conduits from attached patch-type drug reservoirs to the dermal microcirculation. Importantly, such microneedles, which can be fabricated in a wide range of patch sizes and microneedle geometries, can be easily sterilized, resist hole closure while in place, and are removed completely intact from the skin. Delivery of macromolecules is no longer limited to what can be loaded into the microneedles themselves and transdermal drug delivery is now controlled by the crosslink density of the hydrogel system rather than the stratum corneum, while electrically modulated delivery is also a unique feature. This technology has the potential to overcome the limitations of conventional microneedle designs and greatly increase the range of the type of drug that is deliverable transdermally, with ensuing benefits for industry, healthcare providers and, ultimately, patients.

Donnelly, Ryan F; Singh, Thakur Raghu Raj; Garland, Martin J; Migalska, Katarzyna; Majithiya, Rita; McCrudden, Cian M; Kole, Prashant Laxman; Mahmood, Tuan Mazlelaa Tuan; McCarthy, Helen O; Woolfson, A David

2012-01-01

323

Use of microwave in processing of drug delivery systems.  

PubMed

Microwave has received a widespread application in pharmaceuticals and food processing, microbial sterilization, biomedical therapy, scientific and biomedical analysis, as well as, drug synthesis. This paper reviews the basis of application of microwave to prepare pharmaceutical dosage forms such as agglomerates, gel beads, microspheres, nanomatrix, solid dispersion, tablets and film coat. The microwave could induce drying, polymeric crosslinkages as well as drug-polymer interaction, and modify the structure of drug crystallites via its effects of heating and/or electromagnetic field on the dosage forms. The use of microwave opens a new approach to control the physicochemical properties and drug delivery profiles of pharmaceutical dosage forms without the need for excessive heat, lengthy process or toxic reactants. Alternatively, the microwave can be utilized to process excipients prior to their use in the formulation of drug delivery systems. The intended release characteristics of drugs in dosage forms can be met through modifying the physicochemical properties of excipients using the microwave. PMID:18393808

Wong, T W

2008-04-01

324

A new probe for targeting drug delivery system.  

PubMed

Recently, TDDS (Targeting drug delivery system) plays an important role in enhancing the bioavailability and targeting of anti-tumor drugs. How to transport drugs quickly and precisely to their target sites of action has not been solved fundamentally. A large number of researches have identified artemisinin and its analogs have the merit of precisely targeting to cancer cell, and low side effects to healthy tissue. Thus, if these compounds could be attached to established anti-tumor drugs with probe, a novel targeting anti-tumor drugs will be put into practice in the future. The novel drugs delivery system will be a powerful weapon against cancer disease for their unique targeting. PMID:18829175

Yu, Zhengwen; Wang, Bochu; Sui, Jing; Feng, Yingzhu; Zheng, Chao

2008-09-30

325

Development of a Microfluidics-Based Intracochlear Drug Delivery Device  

PubMed Central

Background Direct delivery of drugs and other agents into the inner ear will be important for many emerging therapies, including the treatment of degenerative disorders and guiding regeneration. Methods We have taken a microfluidics/MEMS (MicroElectroMechanical Systems) technology approach to develop a fully implantable reciprocating inner-ear drug-delivery system capable of timed and sequenced delivery of agents directly into perilymph of the cochlea. Iterations of the device were tested in guinea pigs to determine the flow characteristics required for safe and effective delivery. For these tests, we used the glutamate receptor blocker DNQX, which alters auditory nerve responses but not cochlear distortion product otoacoustic emissions. Results We have demonstrated safe and effective delivery of agents into the scala tympani. Equilibration of the drug in the basal turn occurs rapidly (within tens of minutes) and is dependent on reciprocating flow parameters. Conclusion We have described a prototype system for the direct delivery of drugs to the inner ear that has the potential to be a fully implantable means for safe and effective treatment of hearing loss and other diseases.

Sewell, William F.; Borenstein, Jeffrey T.; Chen, Zhiqiang; Fiering, Jason; Handzel, Ophir; Holmboe, Maria; Kim, Ernest S.; Kujawa, Sharon G.; McKenna, Michael J.; Mescher, Mark M.; Murphy, Brian; Leary Swan, Erin E.; Peppi, Marcello; Tao, Sarah

2009-01-01

326

Drug Delivery to the Posterior Eye Using Etched Microneedles  

Microsoft Academic Search

Sight-threatening diseases, such as age-related macular degeneration (AMD), affect the tissues of the posterior segment of the eye. Though modern classes of biomolecular based drugs are therapeutically useful, drug targeting for prolonged bioavailability to pathological sites within the eye is challenging. Current delivery approaches are invasive and lack control over drug release rates and tissue-specific localization. In this thesis, a

Geetha Mahadevan

2011-01-01

327

Controlled-release drug delivery systems in cardiovascular medicine  

Microsoft Academic Search

Controlled-release drug delivery technology has had a significant effect on the pharmacotherapy of cardiovascular diseases. Oral and transcutaneous controlled-release systems allow relatively short-acting drugs to be administered once or twice daily with comparable therapeutic efficacy and fewer adverse reactions compared with standard formulations. They can provide decreased fluctuations in drug concentrations in plasma while possibly reducing the total amount of

Baruch Katz; Andrew Rosenberg; William H. Frishman

1995-01-01

328

Gastroretentive floating drug-delivery systems: a critical review.  

PubMed

The oral delivery of drugs with a narrow absorption window in the gastrointestinal tract (GIT) is often limited by poor bioavailability with conventional dosage forms due to incomplete drug release and short residence time at the site of absorption. To overcome this drawback and to maximize the oral absorption of these drugs, gastroretentive systems such as mucoadhesive, high-density, expandable, and floating systems have been developed. These systems provide controlled delivery of drugs with prolonged gastric residence time. However, in humans, differences in various physiological and biological factors can affect the gastric residence time and drug-delivery behavior from gastroretentive systems. Some floating drug-delivery systems (FDDS) have shown the capability to accommodate these variations without affecting drug release. This review mainly focuses on various physiological considerations for development of FDDS, and highlights recent technological developments including new dosage forms and their production techniques (e.g., holt-melt extrusion, melt pelletization, and pulsed plasma-irradiation processes). Alternatives to the existing in vitro compendial methods for evaluating floating dosage forms will be discussed, and a critical analysis of the existing literature on FDDS, identifying the potential areas for future research, is provided. PMID:21395515

Kotreka, Udaya K; Adeyeye, Moji Christianah

2011-01-01

329

The Role of Cavitation in Acoustically Activated Drug Delivery  

PubMed Central

Pluronic P105 micelles are potential candidates as chemotherapy drug delivery vehicles using ultrasonic stimulation as a release trigger. Acoustic power has been previously shown to release two anthracycline agents from these polymeric carriers. In this study, an ultrasonic exposure chamber with fluorescence detection was used to examine the mechanism of doxorubicin release from P105 micelles. Acoustic spectra were collected and analyzed, at the same spatial position as fluorescence data, to probe the role of cavitation in drug release. Our study showed a strong correlation between percent drug release and subharmonic acoustic emissions, and we attribute the drug release to collapse cavitation that perturbs the structure of the micelle and releases drug.

Husseini, Ghaleb A.; Diaz de la Rosa, Mario A.; Richardson, Eric S.; Christensen, Douglas A.; Pitt, William G.

2006-01-01

330

Pocketed Microneedles for Drug Delivery to the Skin  

PubMed Central

Drug delivery to the skin is limited by the strong barrier properties of skin’s outer layer of stratum corneum. Micron-scale needles have been developed to deliver drugs across this barrier layer and into the skin in a minimally invasive manner. One method of delivery involves coating these microneedles with a drug that rapidly dissolves off within the skin. As a variation on this approach, this study examines microneedles with holes cut through their shafts to form “pockets” that can be filled with drug formulations using a dip-coating method. Our results (i) demonstrated the filling of microneedle pockets having a variety of different sizes and shapes, (ii) quantified the amount of drug that can be filled into pockets and coated onto microneedle surfaces, (iii) developed composite microneedle structures that sequester one model drug within the microneedle pocket and coat another model drug on the microneedle surface and (iv) showed that pocketed microneedles can deliver a model drug to a targeted depth within the skin. We conclude that pocketed microneedles offer unique capabilities for controlled drug delivery to the skin.

Gill, Harvinder S.; Prausnitz, Mark R.

2010-01-01

331

Principles of local drug delivery to the inner ear.  

PubMed

As more and more substances have been shown in preclinical studies to be capable of preventing damage to the inner ear from exposure to noise, ototoxic drugs, ischemia, infection, inflammation, mechanical trauma and other insults, it is becoming very important to develop feasible and safe methods for the targeted delivery of drugs to specific regions in the inner ear. Recently developed methods for sampling perilymph from the cochlea have overcome major technical problems that have distorted previous pharmacokinetic studies of the ear. These measurements show that drug distribution in perilymph is dominated by passive diffusion, resulting in large gradients along the cochlea when drugs are applied intratympanically. Therefore, in order to direct drugs to specific regions of the ear, a variety of delivery strategies are required. To target drugs to the basal cochlear turn and vestibular system while minimizing exposure of the apical cochlear turns, single one-shot intratympanic applications are effective. To increase the amount of drug reaching the apical cochlear turns, repeated intratympanic injections or controlled-release drug delivery systems, such as biodegradable biopolymers or catheters and pumps, are more effective. However, if the applied substance does not easily pass through the round window membrane, or if a more widespread distribution of drug in the ear is required, then intralabyrinthine injections of the substance may be required. Intralabyrinthine injection procedures, which are currently in development in animals, have not yet been proven safe enough for human use. PMID:19923805

Salt, Alec N; Plontke, Stefan K

2009-11-16

332

A look at emerging delivery systems for topical drug products.  

PubMed

The introduction of new topical drugs based on new chemical entities has become a rare event. Instead, pharmaceutical companies have been focused on reformulating existing drugs resulting in an ever-growing number of topical drug products for every approved drug substance. In light of this trend, soon reformulations may not be as rewarding to their sponsors as they are today unless they offer a substantial improvement over other formulations of the same drug substance and the same indication, namely improved efficacy over existing drugs, reduced side effects, unique drug combinations, or applicability for new indications. This article reviews and compares topical drug delivery systems currently under active research that are designed to offer such advantages in the coming years. The reviewed delivery systems are: liposomes, niosomes, transferosomes, ethosomes, solid lipid nanoparticles, nanostructured lipid carriers, cyclodextrin, and sol-gel microcapsules. Among all the topical drug delivery systems currently undergoing active research, only the sol-gel microencapsulation is at clinical stages. PMID:22353154

Fireman, Sharon; Toledano, Ofer; Neimann, Karine; Loboda, Natalia; Dayan, Nava

333

Targeted Cellular Drug Delivery using Tailored Dendritic Nanostructures  

NASA Astrophysics Data System (ADS)

Dendrimers and hyperbranched polymers possess highly branched architectures, with a large number of controllable, tailorble, ‘peripheral’ functionalities. Since the surface chemistry of these materials can be modified with relative ease, these materials have tremendous potential in targeted drug and gene delivery. The large number of end groups can also be tailored to create special affinity to targeted cells, and can also encapsulate drugs and deliver them in a controlled manner. We are developing tailor-modified dendritic systems for drug delivery. Synthesis, in-vitro drug loading, in-vitro drug delivery, and the targeting efficiency to the cell are being studied systematically using a wide variety of experimental tools. Polyamidoamine and Polyol dendrimers, with different generations and end-groups are studied, with drugs such as Ibuprofen and Methotrexate. Our results indicate that a large number of drug molecules can be encapsulated/attached to the dendrimers, depending on the end groups. The drug-encapsulated dendrimer is able to enter the cells rapidly and deliver the drug. Targeting strategies being explored

Kannan, Rangaramanujam; Kolhe, Parag; Kannan, Sujatha; Lieh-Lai, Mary

2002-03-01

334

Development of a Gas Empowered Drug Delivery system for peptide delivery in the small intestine  

Microsoft Academic Search

The aim of this investigation was to design a novel Gas Empowered Drug Delivery (GEDD) system for CO2 forced transport of peptide drugs together with mucoadhesive polymers to the surface of the small intestine. The GEDD effect of the core tablet was achieved using CO2 gas to push insulin together with the mucoadhesive excipients poly(ethyleneoxide) (PEO) and the permeation enhancer

A. M. M. Sadeghi; M. R. Avadi; Sh. Ejtemaimehr; Sh. Abashzadeh; A. Partoazar; F. Dorkoosh; M. Faghihi; M. Rafiee-Tehrani; H. E. Junginger

2009-01-01

335

EMERGING MICROTECHNOLOGIES FOR THE DEVELOPMENT OF ORAL DRUG DELIVERY DEVICES  

PubMed Central

The development of oral drug delivery platforms for administering therapeutics in a safe and effective manner across the gastrointestinal epithelium is of much importance. A variety of delivery systems such as enterically coated tablets, capsules, particles, and liposomes have been developed to improve oral bioavailability of drugs. However, orally administered drugs suffer from poor localization and therapeutic efficacy due to various physiological conditions such as low pH, and high shear intestinal fluid flow. Novel platforms combining controlled release, improved adhesion, tissue penetration, and selective intestinal targeting may overcome these issues and potentially diminish the toxicity and high frequency of administration associated with conventional oral delivery. Microfabrication along with appropriate surface chemistry, provide a means to fabricate these platforms en masse with flexibility in tailoring the shape, size, reservoir volume, and surface characteristics of microdevices. Moreover, the same technology can be used to include integrated circuit technology and sensors for designing sophisticated autonomous drug delivery devices that promise to significantly improve point of care diagnostic and therapeutic medical applications. This review sheds light on some of the fabrication techniques and addresses a few of the microfabricated devices that can be effectively used for controlled oral drug delivery applications.

Chirra, Hariharasudhan D.; Desai, Tejal A.

2012-01-01

336

Liposomal drug delivery systems: from concept to clinical applications.  

PubMed

The first closed bilayer phospholipid systems, called liposomes, were described in 1965 and soon were proposed as drug delivery systems. The pioneering work of countless liposome researchers over almost 5 decades led to the development of important technical advances such as remote drug loading, extrusion for homogeneous size, long-circulating (PEGylated) liposomes, triggered release liposomes, liposomes containing nucleic acid polymers, ligand-targeted liposomes and liposomes containing combinations of drugs. These advances have led to numerous clinical trials in such diverse areas as the delivery of anti-cancer, anti-fungal and antibiotic drugs, the delivery of gene medicines, and the delivery of anesthetics and anti-inflammatory drugs. A number of liposomes (lipidic nanoparticles) are on the market, and many more are in the pipeline. Lipidic nanoparticles are the first nanomedicine delivery system to make the transition from concept to clinical application, and they are now an established technology platform with considerable clinical acceptance. We can look forward to many more clinical products in the future. PMID:23036225

Allen, Theresa M; Cullis, Pieter R

2012-10-01

337

Drug delivery through soft contact lenses  

Microsoft Academic Search

Clinical studies were conducted on 466 patients waiting for senile cataract surgery and receiving chloromycetin, gentamicin, or carbenicillin subconjunctivally and through New Sauflon 70 and New Sauflon 85 lenses. The aqueous drug levels were biologically estimated at various time intervals. Soft contact lenses provided significantly higher drug penetration than subconjunctival therapy. Both modes of treatment provided therapeutically effective levels against

M. R. Jain

1988-01-01

338

Nanocrystal technology, drug delivery and clinical applications  

PubMed Central

Nanotechnology will affect our lives tremendously over the next decade in very different fields, including medicine and pharmacy. Transfer of materials into the nanodimension changes their physical properties which were used in pharmaceutics to develop a new innovative formulation principle for poorly soluble drugs: the drug nanocrystals. The drug nanocrystals do not belong to the future; the first products are already on the market. The industrially relevant production technologies, pearl milling and high pressure homogenization, are reviewed. The physics behind the drug nanocrystals and changes of their physical properties are discussed. The marketed products are presented and the special physical effects of nanocrystals explained which are utilized in each market product. Examples of products in the development pipelines (clinical phases) are presented and the benefits for in vivo administration of drug nanocrystals are summarized in an overview.

Junghanns, Jens-Uwe A H; Muller, Rainer H

2008-01-01

339

Enhancing Tumor Drug Delivery by Laser-Activated Vascular Barrier Disruption.  

National Technical Information Service (NTIS)

An obstacle for successful drug therapy for cancer is the existence of drug delivery barriers, which causes insufficient drug delivery to the tumor tissue. Because of inadequate drug delivery to the tumor tissue, the drug dose has to be increased, which l...

B. Chen C. He

2006-01-01

340

Enhancing Tumor Drug Delivery by Laser-Activated Vascular Barrier Disruption.  

National Technical Information Service (NTIS)

An obstacle to successful cancer drug therapy is the existence of drug delivery barriers, which causes insufficient drug delivery to the tumor tissue. Because of the inadequate drug delivery, the drug dose has to be increased, which leads to normal tissue...

B. Chen

2009-01-01

341

Enhancing Tumor Drug Delivery by Laser-Activated Vascular Barrier Disruption.  

National Technical Information Service (NTIS)

An obstacle to successful cancer drug therapy is the existence of drug delivery barriers, which causes insufficient drug delivery to the tumor tissue. Because of the inadequate drug delivery, the drug dose has to be increased, which leads to normal tissue...

B. Chen C. He

2008-01-01

342

Enhancing Tumor Drug Delivery by Laser-Activated Vascular Barrier Disruption.  

National Technical Information Service (NTIS)

An obstacle for successful drug therapy for cancer is the existence of drug delivery barriers, which causes insufficient drug delivery to the tumor tissue. Because of inadequate drug delivery to the tumor tissue, the drug dose has to be increased, which l...

B. Chen C. He

2007-01-01

343

Biologically inspired approaches to drug delivery for nerve regeneration.  

PubMed

As the biological processes governing nerve regeneration have become elucidated over the past decades, interest has developed in manipulating these processes to improve nerve regeneration. Drug delivery to the regenerating nerve has the potential for major clinical applications in neurodegenerative diseases, spinal cord injury and peripheral nerve injury or sacrifice. This article reviews the evolution of the field of drug delivery to the regenerating nerve, from simple local applications of neurotrophic agents in solution and osmotic pump delivery, to the existing approaches involving novel biomaterials and genetically manipulated cell populations. A discussion of the various known nerve growth-promoting agents, and the chemical considerations involved in their delivery, is included. A perspective on the role of tissue engineering approaches for nerve regeneration in the future is offered. PMID:17049009

Hadlock, Tessa; Sundback, Cathryn

2006-11-01

344

Biologically erodable microspheres as potential oral drug delivery systems  

Microsoft Academic Search

Biologically adhesive delivery systems offer important advantages1-5 over conventional drug delivery systems6. Here we show that engineered polymer microspheres made of biologically erodable polymers, which display strong adhesive interactions with gastrointestinal mucus and cellular linings, can traverse both the mucosal absorptive epithelium and the follicle-associated epithelium covering the lymphoid tissue of Peyer's patches. The polymers maintain contact with intestinal epithelium

Edith Mathiowitz; Jules S. Jacob; Yong S. Jong; Gerardo P. Carino; Donald E. Chickering; Pravin Chaturvedi; Camilla A. Santos; Kavita Vijayaraghavan; Sean Montgomery; Michael Bassett; Craig Morrell

1997-01-01

345

Piezoelectric control of needle-free transdermal drug delivery  

Microsoft Academic Search

Transdermal drug delivery occurs primarily through hypodermic needle injections, which cause pain, require a trained administrator, and may contribute to the spread of disease. With the growing number of pharmaceutical therapies requiring transdermal delivery, an effective, safe, and simple needle-free alternative is needed. We present and characterize a needle-free jet injector that employs a piezoelectric actuator to accelerate a micron-scale

Jeanne C. Stachowiak; Marcio G. von Muhlen; Thomas H. Li; Laleh Jalilian; Sapun H. Parekh; Daniel A. Fletcher

2007-01-01

346

Thiomers for oral delivery of hydrophilic macromolecular drugs.  

PubMed

In recent years thiolated polymers (thiomers) have appeared as a promising new tool in oral drug delivery. Thiomers are obtained by the immobilisation of thio-bearing ligands to mucoadhesive polymeric excipients. By the formation of disulfide bonds with mucus glycoproteins, the mucoadhesive properties of thiomers are up to 130-fold improved compared with the corresponding unmodified polymers. Owing to the formation of inter- and intramolecular disulfide bonds within the thiomer itself, matrix tablets and particulate delivery systems show strong cohesive properties, resulting in comparatively higher stability, prolonged disintegration times and a more controlled drug release. The permeation of hydrophilic macromolecular drugs through the gastrointestinal (GI) mucosa can be improved by the use of thiomers. Furthermore, some thiomers exhibit improved inhibitory properties towards GI peptidases. The efficacy of thiomers in oral drug delivery has been demonstrated by various in vivo studies. A pharmacological efficacy of 1%, for example, was achieved in rats by oral administration of calcitonin tablets comprising a thiomer. Furthermore, tablets comprising a thiomer and pegylated insulin resulted in a pharmacological efficacy of 7% after oral application to diabetic mice. Low-molecular-weight heparin embedded in thiolated polycarbophil led to an absolute bioavailability of > or = 20% after oral administration to rats. In these studies, formulations comprising the corresponding unmodified polymer had only a marginal or no effect. These results indicate drug carrier systems based on thiomers appear to be a promising tool for oral delivery of hydrophilic macromolecular drugs. PMID:16296722

Bernkop-Schnürch, Andreas; Hoffer, Martin H; Kafedjiiski, Krum

2004-11-01

347

Liposomes in drug delivery: a patent review (2007 - present).  

PubMed

Introduction: Drug therapy is frequently limited by the widespread biodistribution of the active agents and the little specificity for non-healthy cells. Therefore, inadequate drug concentrations result into the site of action, and severe toxicity may also arise. To address the problem, liposome-based medicines have tried to improve pharmacotherapy. Areas covered: The review provides an updated revision of the lately published patents covering recent advances in liposome-based drug delivery. They are principally related to the control of drug biodistribution by using stealth, stimuli-sensitive and/or liposomal structures surface modified for ligand-mediated delivery. The contribution further highlights liposome-based theranosis. Expert opinion: Liposomes have received great attention given their biocompatibility, biodegradability and targetability. From 2007 to present date, patent publications related to their use in drug delivery have shown the move towards more stable structures with optimized drug delivery capabilities, further combining passive and active targeting concepts to gain control of the in vivo fate. However, the introduction of all these liposomal structures in the disease arena is still a challenge. Two key aspects are the difficulty of identifying easy and economic synthesis conditions which can be scaled up in the pharmaceutical industry, and the need for complementary investigations illustrating risks of toxicity/immunogenicity. PMID:23957267

Arias, José L

2013-08-19

348

Oral Delivery of Nucleic Acid Drugs  

Microsoft Academic Search

Nucleic acid molecules have emerged as versatile tools with promising utility in a variety of biochemical, diagnostic, and\\u000a therapeutic applications. A parenteral administration of a nucleic acid is inconvenient because of pain, fear, and risks being\\u000a associated with this type of application. The intestinal epithelium is considered to be an attractive site for oral delivery\\u000a of therapeutic genes.\\u000a \\u000a The successful

Ronny Martien

349

Drug-inorganic-polymer nanohybrid for transdermal delivery.  

PubMed

For transdermal drug delivery, we prepared a drug-inorganic nanohybrid (FB-LDH) by intercalating a transdermal model drug, flurbiprofen (FB), into the layered double hydroxides (LDHs) via coprecipitation reaction. The X-ray diffraction patterns and FT-IR spectra of the FB-LDH indicated that the FB molecules were successfully intercalated via electrostatic interaction within the LDH lattices. The in vitro drug release revealed that the Eudragit(®) S-100 in release media could facilitate the drug out-diffusion by effectively replacing the intercalated drug and also enlarging the lattice spacing of the FB-LDH. In this work, a hydrophobic gel suspension of the FB-LDH was suggested as a transdermal controlled delivery formulation, where the suspensions were mixed with varying amounts of Eudragit(®) S-100 aqueous solution. The Frantz diffusion cell experiments using mouse full-skins showed that a lag time and steady-state flux of the drug could be controlled from 12.8h and 3.28?gcm(-2)h(-1) to less than 1h and 14.57?gcm(-2)h(-1), respectively, by increasing the mass fraction of Eudragit(®) S-100 solution in gel suspensions from 0% to 20% (w/w), respectively. Therefore, we conclude gel formulation of the FB-LDH have a potential for transdermal controlled drug delivery. PMID:23357253

Kim, Myung Hun; Park, Dae-Hwan; Yang, Jae-Hun; Choy, Young Bin; Choy, Jin-Ho

2013-01-26

350

Microneedles for intradermal and transdermal drug delivery.  

PubMed

The formidable barrier properties of the uppermost layer of the skin, the stratum corneum, impose significant limitations for successful systemic delivery of broad range of therapeutic molecules particularly macromolecules and genetic material. Microneedle (MN) has been proposed as a strategy to breach the stratum corneum barrier function in order to facilitate effective transport of molecules across the skin. This strategy involves use of micron sized needles fabricated of different materials and geometries to create transient aqueous conduits across the skin. MN, alone or with other enhancing strategies, has been demonstrated to dramatically enhance the skin permeability of numerous therapeutic molecules including biopharmaceuticals either in vitro, ex vivo or in vivo experiments. This suggested the promising use of MN technology for various possible clinical applications such as insulin delivery, transcutaneous immunisations and cutaneous gene delivery. MN has been proved as minimally invasive and painless in human subjects. This review article focuses on recent and future developments for MN technology including the latest type of MN design, challenges and strategies in MNs development as well as potential safety aspects based on comprehensive literature review pertaining to MN studies to date. PMID:23680534

Tuan-Mahmood, Tuan-Mazlelaa; McCrudden, Maelíosa T C; Torrisi, Barbara M; McAlister, Emma; Garland, Martin J; Singh, Thakur Raghu Raj; Donnelly, Ryan F

2013-05-13

351

Controlled Release of Simvastatin from Biomimetic ?-TCP Drug Delivery System  

PubMed Central

Simvastatin have been shown to induce bone formation and there is currently a urgent need to develop an appropriate delivery system to sustain the release of the drug to increase therapeutic efficacy whilst reducing side effects. In this study, a novel drug delivery system for simvastatin by means of hydrothermally converting marine exoskeletons to biocompatible beta-tricalcium phosphate was investigated. Furthermore, the release of simvastatin was controlled by the addition of an outer apatite coating layer. The samples were characterized by x-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and mass spectroscopy confirming the conversion process. The in-vitro dissolution of key chemical compositional elements and the release of simvastatin were measured in simulated body fluid solution showing controlled release with reduction of approximately 25% compared with un-coated samples. This study shows the potential applications of marine structures as a drug delivery system for simvastatin.

Chou, Joshua; Ito, Tomoko; Bishop, David; Otsuka, Makoto; Ben-Nissan, Besim; Milthorpe, Bruce

2013-01-01

352

Macromolecular drug delivery: basic principles and therapeutic applications.  

PubMed

Macromolecular drugs hold great promise as novel therapeutics of several major disorders, such as cancer and cardiovascular disease. However, their use is limited by lack of efficient, safe, and specific delivery strategies. Successful development of such strategies requires interdisciplinary collaborations involving researchers with expertise on e.g., polymer chemistry, cell biology, nano technology, systems biology, advanced imaging methods, and clinical medicine. This poses obvious challenges to the scientific community, but also provides opportunities for the unexpected at the interface between different disciplines. This review summarizes recent studies of macromolecular delivery that should be of interest to researchers involved in macromolecular drug synthesis as well as in vitro and in vivo drug delivery studies. PMID:19475521

Belting, Mattias; Wittrup, Anders

2009-05-28

353

Improved treatment of nicotine addiction and emerging pulmonary drug delivery.  

PubMed

Nicotine addiction remains the leading cause of death and disease in developed and developing nations and a major cause of mortality around the world. Currently, nicotine replacement therapies (NRTs), bupropion, and varenicline are approved by the regulatory agencies as first-line treatments for nicotine addiction. Emerging evidence indicates that varenicline and bupropion have some therapeutic limitations for treating nicotine addiction with oral route of administration. Thus, continued investigation of innovative drug delivery for nicotine addiction remains a critical priority. This review will discuss some novel strategies and future directions for pulmonary drug delivery, an emerging route of administration for smoking cessation. It is anticipated that the advancement of knowledge on pulmonary drug delivery will provide better management for nicotine addiction and other addictive disorders. PMID:22890202

Islam, Nazrul; Rahman, Shafiqur

2012-06-01

354

Constructing tunable nanopores and their application in drug delivery.  

PubMed

Inspired by biological cell membranes, various "smart" and efficient gating nanoporous devices have been proposed to imitate and to understand life processes. Nanodevices under development with enhanced gating efficiency could play pivotal roles in biosensing and drug delivery. In this Perspective, we highlight an important development by Willner and colleagues that is detailed in this issue of ACS Nano. They designed a new "smart" nanodevice with both "sense" and "release" functionalities for drug delivery based on a nanoporous material, mesoporous silica nanoparticles. We outline recent progress in designing intelligently gated nanoporous devices in material science and nanotechnology. We also summarize new strategies designed for drug delivery based on mesoporous materials. With continuing efforts, we expect more powerful nanodevices to be developed and used in clinical and other real-word applications. PMID:24143925

Duan, Ruixue; Xia, Fan; Jiang, Lei

2013-10-22

355

Chronopharmaceutical Drug Delivery Systems: Hurdles, Hype or Hope??  

PubMed Central

The current advances in chronobiology and the knowledge gained from chronotherapy of selected diseases strongly suggest that “the one size fits all at all times” approach to drug delivery is no longer substantiated, at least for selected bioactive agents and disease therapy or prevention. Thus, there is a critical and urgent need for chronopharmaceutical research (e.g., design and evaluation of robust, spatially and temporally controlled drug delivery systems that would be clinically intended for chronotherapy by different routes of administration). This review provides a brief overview of current delivery system intended for chronotherapy. In theory, such an ideal “magic pill” preferably with affordable cost, would improve the safety, efficacy and patient compliance of old and new drugs. However, currently, there are three major hurdles for the successful transition of such system from laboratory to patient bedside. These include the challenges to identify adequate (i) rhythmic biomaterials and systems, (ii) rhythm engineering modeling, perhaps using system biology and (iii) regulatory guidance.

Youan, Bi-Botti C.

2010-01-01

356

Connecting drug delivery reality to smart materials design.  

PubMed

Inflated claims to both design and mechanistic novelty in drug delivery and imaging systems, including most nanotechnologies, are not supported by the generally poor translation of these systems to clinical efficacy. The "form begets function" design paradigm is seductive but perhaps over-simplistic in translation to pharmaceutical efficacy. Most innovations show few clinically important distinctions in their therapeutic benefits in relevant preclinical disease and delivery models, despite frequent claims to the contrary. Long-standing challenges in drug delivery issues must enlist more realistic, back-to-basics approaches to address fundamental materials properties in complex biological systems, preclinical test beds, and analytical methods to more reliably determine fundamental pharmaceutical figures of merit, including drug carrier purity and batch-batch variability, agent biodistribution, therapeutic index (safety), and efficacy. PMID:23624177

Grainger, David W

2013-04-24

357

LDH nanocontainers as bio-reservoirs and drug delivery carriers.  

PubMed

This review outlines research and patents relating to the use of inorganic nanomaterial, layered double hydroxide, as nanocontainers for drug delivery and gene reservoirs. Various intercalative synthetic routes including coprecipitation, ion exchange, reconstruction and exfoliation-reassembly have been explored to incorporate drug or gene molecules. Its unique two-dimensional structure allows layered double hydroxide to act as a nanospace for the stabilization, targeted delivery or controlled release of gene or drug molecules. Intercalative hybrid nanomaterials have uses such as pharmaceutically active ingredients, in oral- or cellular delivery systems, cosmetic ingredients, molecular coding units and etc. Toxicological studies have found layered double hydroxides to be biocompatible compared with widely used nanoparticles such as iron oxide, silica, and single-walled carbon nanotubes. Due to their versatile functionality and biocompatibility, layered double hydroxides have been widely studied and their applicability can be expanded to other nanoparticle based bio-medical applications. PMID:22747720

Oh, Jae-Min; Park, Dae-Hwan; Choi, Soo-Jin; Choy, Jin-Ho

2012-11-01

358

Microbubbles in Ultrasound-Triggered Drug and Gene Delivery  

PubMed Central

Ultrasound contrast agents, in the form of gas-filled microbubbles, are becoming popular in perfusion monitoring; they are employed as molecular imaging agents. Microbubbles are manufactured from biocompatible materials, they can be injected intravenously, and some are approved for clinical use. Microbubbles can be destroyed by ultrasound irradiation. This destruction phenomenon can be applied to targeted drug delivery and enhancement of drug action. The ultrasonic field can be focused at the target tissues and organs; thus, selectivity of the treatment can be improved, reducing undesirable side effects. Microbubbles enhance ultrasound energy deposition in the tissues and serve as cavitation nuclei, increasing intracellular drug delivery. DNA delivery and successful tissue transfection is observed in the areas of the body where ultrasound is applied after intravascular administration of microbubbles and plasmid DNA. Accelerated blood clot dissolution in the areas of insonation by cooperative action of thrombolytic agents and microbubbles is demonstrated in several clinical trials.

Hernot, Sophie; Klibanov, Alexander L.

2008-01-01

359

Ocular Drug Delivery; Impact of in vitro Cell Culture Models  

PubMed Central

Normal vision depends on the optimal function of ocular barriers and intact membranes that selectively regulate the environment of ocular tissues. Novel pharmacotherapeutic modalities have aimed to overcome such biological barriers which impede efficient ocular drug delivery. To determine the impact of ocular barriers on research related to ophthalmic drug delivery and targeting, herein we provide a review of the literature on isolated primary or immortalized cell culture models which can be used for evaluation of ocular barriers. In vitro cell cultures are valuable tools which serve investigations on ocular barriers such as corneal and conjunctival epithelium, retinal pigment epithelium and retinal capillary endothelium, and can provide platforms for further investigations. Ocular barrier-based cell culture systems can be simply set up and used for drug delivery and targeting purposes as well as for pathological and toxicological research.

Barar, Jaleh; Asadi, Masoud; Mortazavi-Tabatabaei, Seyed Abdolreza; Omidi, Yadollah

2009-01-01

360

Controlled release of simvastatin from biomimetic ?-TCP drug delivery system.  

PubMed

Simvastatin have been shown to induce bone formation and there is currently a urgent need to develop an appropriate delivery system to sustain the release of the drug to increase therapeutic efficacy whilst reducing side effects. In this study, a novel drug delivery system for simvastatin by means of hydrothermally converting marine exoskeletons to biocompatible beta-tricalcium phosphate was investigated. Furthermore, the release of simvastatin was controlled by the addition of an outer apatite coating layer. The samples were characterized by x-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and mass spectroscopy confirming the conversion process. The in-vitro dissolution of key chemical compositional elements and the release of simvastatin were measured in simulated body fluid solution showing controlled release with reduction of approximately 25% compared with un-coated samples. This study shows the potential applications of marine structures as a drug delivery system for simvastatin. PMID:23349949

Chou, Joshua; Ito, Tomoko; Bishop, David; Otsuka, Makoto; Ben-Nissan, Besim; Milthorpe, Bruce

2013-01-18

361

Pressure Waves in Medicine: From Tissue Injury to Drug Delivery  

NASA Astrophysics Data System (ADS)

Pressure waves have the potential to cause injury to cells and tissue or enable novel therapeutic modalities, such as fragmentation of kidney stones and drug delivery. Research on the biological effects of pressure waves have shown that the biological response on depends the pressure-wave characteristics. One of the most prominent effects induced by pressure waves is the permeabilization of a number of barrier structures (cell plasma membrane, skin and microbial biofilms) and facilitate the delivery of macromolecules. The permeabilization of the barrier structure is transient and the barrier function recovers. Thus, pressure waves can induce delivery of molecular species that would not normally cross the barrier structure.

Doukas, Apostolos G.

2004-07-01

362

Pulmonary Drug Delivery: Medicines for Inhalation  

Microsoft Academic Search

\\u000a Mankind has inhaled substances for medical and other reasons for thousands of years, notably resulting in the cultural manifestations\\u000a of tobacco and opium smoking. Over the course of time concepts of pulmonary application, including inhalation devices and\\u000a drug formulations, have been and still are being continuously developed. State of the art instruments even allow for individualized\\u000a drug application by adaption

Andreas Henning; Stephanie Hein; Marc Schneider; Michael Bur; Claus-Michael Lehr

363

Nanostructured lipid carriers (NLCs) for drug delivery and targeting.  

PubMed

Nanostructured lipid carriers (NLCs) are drug-delivery systems composed of both solid and liquid lipids as a core matrix. It was shown that NLCs reveal some advantages for drug therapy over conventional carriers, including increased solubility, the ability to enhance storage stability, improved permeability and bioavailability, reduced adverse effect, prolonged half-life, and tissue-targeted delivery. NLCs have attracted increasing attention in recent years. This review describes recent developments in drug delivery using NLCs strategies. The structures, preparation techniques, and physicochemical characterization of NLCs are systematically elucidated in this review. The potential of NLCs to be used for different administration routes is highlighted. Special attention is paid to parenteral injection and topical delivery since these are the most common routes for investigating NLCs. Relevant issues for the introduction of NLCs to market, including pharmaceutical and cosmetic applications, are discussed. The related patents of NLCs for drug delivery are also reviewed. Finally, the future development and current obstacles needing to be resolved are elucidated. PMID:22946628

Fang, Chia-Lang; Al-Suwayeh, Saleh A; Fang, Jia-You

2013-01-01

364

Hollow copper sulfide nanoparticle-mediated transdermal drug delivery.  

PubMed

A photothermal ablation-enhanced transdermal drug delivery methodology is developed based on hollow copper sulfide nanoparticles (HCuSNPs) with intense photothermal coupling effects. Application of nanosecond-pulsed near-infrared laser allows rapid heating of the nanoparticles and instantaneous heat conduction. This provides very short periods of time but extremely high temperatures in local regions, with focused thermal ablation of the stratum corneum. The depth of skin perforations can be controlled by adjusting the laser power. Skin disruption by HCuSNP-mediated photothermal ablation significantly increases the permeability of human growth hormone. This technique offers compelling opportunities for macromolecular drug and vaccine delivery. PMID:22829400

Ramadan, Samy; Guo, Liangran; Li, Yajuan; Yan, Bingfang; Lu, Wei

2012-07-25

365

Pulmonary drug delivery. Part II: The role of inhalant delivery devices and drug formulations in therapeutic effectiveness of aerosolized medications  

PubMed Central

Research in the area of pulmonary drug delivery has gathered momentum in the last several years, with increased interest in using the lung as a means of delivering drugs systemically. Advances in device technology have led to the development of more efficient delivery systems capable of delivering larger doses and finer particles into the lung. As more efficient pulmonary delivery devices and sophisticated formulations become available, physicians and health professionals will have a choice of a wide variety of device and formulation combinations that will target specific cells or regions of the lung, avoid the lung's clearance mechanisms and be retained within the lung for longer periods. It is now recognized that it is not enough just to have inhalation therapy available for prescribing; physicians and other healthcare providers need a basic understanding of aerosol science, inhaled formulations, delivery devices, and bioequivalence of products to prescribe these therapies optimally.

Labiris, N R; Dolovich, M B

2003-01-01

366

Intravesical drug delivery: Challenges, current status, opportunities and novel strategies.  

PubMed

The urinary bladder has certain unique anatomical features which enable it to form an effective barrier to toxic substances diffusing from the urine into the blood. The barrier function is due to the epithelial surface of the urinary bladder, the urothelium, which has characteristic umbrella cells, joined by tight junctions and covered by impenetrable plaques, as well as an anti-adherent mucin layer. Diseases of the urinary bladder, such as bladder carcinomas and interstitial cystitis, cause acute damage to the bladder wall and cannot be effectively treated by systemic administration of drugs. Such conditions may benefit from intravesical drug delivery (IDD), which involves direct instillation of drug into the bladder via a catheter, to attain high local concentrations of the drug with minimal systemic effects. IDD however has its limitations, since the permeability of the urothelial layer is very low and instilled drug solutions become diluted with urine and get washed out of the bladder during voiding, necessitating repeated infusions of the drug. Permeation enhancers serve to overcome these problems to some extent by using electromotive force to enhance diffusion of the drug into the bladder wall or chemical molecules, such as chitosan, dimethylsulphoxide, to temporarily disrupt the tight packing of the urothelium. Nanotechnology can be integrated with IDD to devise drug-encapsulated nanoparticles that can greatly improve chemical interactions with the urothelium and enhance penetration of drugs into the bladder wall. Nanocarriers such as liposomes, gelatin nanoparticles, polymeric nanoparticles and magnetic particles, have been found to enhance local drug concentrations in the bladder as well as target diseased cells. Intravesical drug carriers can be further improved by using mucoadhesive biomaterials which are strongly adhered to the urothelial cell lining, thus preventing the carrier from being washed away during urine voiding. This increases the residence time of the drug at the target site and enables sustained delivery of the drug over a prolonged time span. Polymeric hydrogels, such as the temperature sensitive PEG-PLGA-PEG polymer, have been used to develop in situ gelling systems to deliver drugs into the bladder cavity. Recent advances and future prospects of biodegradable nanocarriers and in situ gels as drug delivery agents for intravesical drug delivery are reviewed in this paper. PMID:20831887

GuhaSarkar, Shruti; Banerjee, R

2010-09-08

367

Local inner-ear drug delivery and pharmacokinetics.  

PubMed

Several drugs that are applied directly to the inner ear are in widespread clinical use for the treatment of inner-ear disorders. Many new substances and drug delivery systems specific to the inner ear are under development and in some cases are being evaluated in animal experiments and in clinical studies. However, the pharmacokinetics of drugs in the inner ear is not well defined and the field is plagued by technical problems in obtaining pure samples of the inner-ear fluids for analysis. Nevertheless, a basic understanding of the mechanisms of drug dispersal in the inner ear has emerged, which facilitates the design and interpretation of future pharmacokinetic studies. PMID:16214674

Salt, Alec N; Plontke, Stefan K R

2005-10-01

368

Drug trapping and delivery for Alzheimer's diagnosis.  

PubMed

In this investigation, a new design based on a PANDA ring resonator as an optical trapping tool for tangle protein, molecular motor storage, and delivery is proposed. The optical vortices are generated and the trapping mechanism is controlled in the same way as the conventional optical tweezers. The trapping force is produced by a combination of the gradient field and scattering photons. The required molecular volume is trapped and moved dynamically within the molecular network. The tangle protein and molecular motor can be transported and delivered to the required destinations for Alzheimer's diagnosis by molecular buffer and bus network. PMID:22384850

Jalil, M A; Kamoldilok, Surachart; Saktioto, T; Ong, C T; Yupapin, Preecha P

2012-03-02

369

Targeted drug delivery to treat pain and cerebral hypoxia.  

PubMed

Limited drug penetration is an obstacle that is often encountered in treatment of central nervous system (CNS) diseases including pain and cerebral hypoxia. Over the past several years, biochemical characteristics of the brain (i.e., tight junction protein complexes at brain barrier sites, expression of influx and efflux transporters) have been shown to be directly involved in determining CNS permeation of therapeutic agents; however, the vast majority of these studies have focused on understanding those mechanisms that prevent drugs from entering the CNS. Recently, this paradigm has shifted toward identifying and characterizing brain targets that facilitate CNS drug delivery. Such targets include the organic anion-transporting polypeptides (OATPs in humans; Oatps in rodents), a family of sodium-independent transporters that are endogenously expressed in the brain and are involved in drug uptake. OATP/Oatp substrates include drugs that are efficacious in treatment of pain and/or cerebral hypoxia (i.e., opioid analgesic peptides, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors). This clearly suggests that OATP/Oatp isoforms are viable transporter targets that can be exploited for optimization of drug delivery to the brain and, therefore, improved treatment of CNS diseases. This review summarizes recent knowledge in this area and emphasizes the potential that therapeutic targeting of OATP/Oatp isoforms may have in facilitating CNS drug delivery and distribution. Additionally, information presented in this review will point to novel strategies that can be used for treatment of pain and cerebral hypoxia. PMID:23343976

Ronaldson, Patrick T; Davis, Thomas P

2013-01-23

370

Ex vivo investigation of magnetically targeted drug delivery system  

NASA Astrophysics Data System (ADS)

In conventional systemic drug delivery the drug is administered by intravenous injection; it then travels to the heart from where it is pumped to all regions of the body. When the drug is aimed at a small target region, this method is extremely inefficient and leads to require much larger doses than those being necessary. In order to overcome this problem a number of targeted drug delivery methods are developed. One of these, magnetically targeted drug delivery system (MT-DDS) will be a promising way, which involves binding a drug to small biocompatible magnetic particles, injecting these into the blood stream and using a high gradient magnetic field to pull them out of suspension in the target region. In the present paper, we describe an ex vivo experimental work. It is also reported that navigation and accumulation test of the magnetic particles in the Y-shaped glass tube was performed in order to examine the threshold of the magnetic force for accumulation. It is found that accumulation of the magnetic particles was succeeded in the blood vessel when a permanent magnet was placed at the vicinity of the blood vessel. This result indicates the feasibility of the magnetically drug targeting in the blood vessel.

Yoshida, Y.; Fukui, S.; Fujimoto, S.; Mishima, F.; Takeda, S.; Izumi, Y.; Ohtani, S.; Fujitani, Y.; Nishijima, S.

2007-03-01

371

Revival of the abandoned therapeutic wortmannin by nanoparticle drug delivery  

PubMed Central

One of the promises of nanoparticle (NP) carriers is the reformulation of promising therapeutics that have failed clinical development due to pharmacologic challenges. However, current nanomedicine research has been focused on the delivery of established and novel therapeutics. Here we demonstrate proof of the principle of using NPs to revive the clinical potential of abandoned compounds using wortmannin (Wtmn) as a model drug. Wtmn is a potent inhibitor of phosphatidylinositol 3? kinase-related kinases but failed clinical translation due to drug-delivery challenges. We engineered a NP formulation of Wtmn and demonstrated that NP Wtmn has higher solubility and lower toxicity compared with Wtmn. To establish the clinical translation potential of NP Wtmn, we evaluated the therapeutic as a radiosensitizer in vitro and in vivo. NP Wtmn was found to be a potent radiosensitizer and was significantly more effective than the commonly used radiosensitizer cisplatin in vitro in three cancer cell lines. The mechanism of action of NP Wtmn radiosensitization was found to be through the inhibition of DNA-dependent protein kinase phosphorylation. Finally, NP Wtmn was shown to be an effective radiosensitizer in vivo using two murine xenograft models of cancer. Our results demonstrate that NP drug-delivery systems can promote the readoption of abandoned drugs such as Wtmn by overcoming drug-delivery challenges.

Karve, Shrirang; Werner, Michael E.; Sukumar, Rohit; Cummings, Natalie D.; Copp, Jonathan A.; Li, Chenxi; Sethi, Manish; Chen, Ronald C.; Pacold, Michael E.; Wang, Andrew Z.

2012-01-01

372

Chitosan electrodeposition for microrobotic drug delivery.  

PubMed

A method to functionalize steerable magnetic microdevices through the co-electrodeposition of drug loaded chitosan hydrogels is presented. The characteristics of the polymer matrix have been investigated in terms of fabrication, morphology, drug release and response to different environmental conditions. Modifications of the matrix behavior could be achieved by simple chemical post processing. The system is able to load and deliver 40-80 ?g cm(-2) of a model drug (Brilliant Green) in a sustained manner with different profiles. Chitosan allows a pH responsive behavior with faster and more efficient release under slightly acidic conditions as can be present in tumor or inflamed tissue. A prototype of a microrobot functionalized with the hydrogel is presented and proposed for the treatment of posterior eye diseases. PMID:23355508

Fusco, Stefano; Chatzipirpiridis, George; Sivaraman, Kartik M; Ergeneman, Olgaç; Nelson, Bradley J; Pané, Salvador

2013-01-25

373

Paliperidone-Loaded Self-Emulsifying Drug Delivery Systems (SEDDS) for Improved Oral Delivery  

Microsoft Academic Search

The present research is aimed to improve the oral delivery of paliperidone by loading into self-emulsifying drug delivery systems (SEDDS). Oleic acid, Tween 80, and capmul MCM L8 were selected as oil, surfactant, and co-surfactant, respectively and phase diagram was constructed and the region was identified for the formation of SEDDS. The stable formulations were analyzed for globule size, robustness

Swetha Kanuganti; Raju Jukanti; Prabhakar R. Veerareddy; Suresh Bandari

2012-01-01

374

Drug discovery and delivery in the 21st century.  

PubMed

Drug discovery in the late 20th century has increasingly focused on the definition and characterization of the macromolecular substrates that serve as targets for drug design. The advent of genomics and the molecular biology revolution has permitted both the definition of new targets and the characterization of the genetic basis of disease states. The introduction of powerful new technologies should greatly accelerate the pace of new drug discovery. Although genomics, both human and nonhuman, should in principle increase the number of potential drug targets and provide a greater understanding of cellular events contributing to the pathology of disease this has yet to occur in practice, primarily because of the underlying complexity of cellular signaling processes. The emerging discipline of systems biology is attempting to bring both order and understanding to these signaling processes. Genomics has, however, impacted on drug discovery in ways that are important beyond a mere increase in potential drug target numbers. Genomics has provided the tools of contemporary drug discovery, the pharmacogenomic pathways to personalized medicine, and has greatly influenced the nature of synthetic organic chemistry, a discipline that is still the cornerstone of contemporary drug discovery. In the future, genomics and the tools of molecular biology will have a corresponding impact on drug delivery processes and mechanisms through introduction of drug delivery machines capable of both synthesis and activation by disease-specific signals. Such machines will be based on a synthetic genome, using an expanded genetic code, and designed for specific drug synthesis and delivery and activation by a pathological signal. This essay is based upon a lecture of the same title presented at the Faculty of Medicine, Kuwait University during a visit in the spring of 2005. It is intended, as was the lecture, to be a broad, descriptive and speculative overview rather than a comprehensive and detailed review. PMID:17159357

Triggle, David J

2007-01-01

375

Endogenous lectins as targets for drug delivery  

Microsoft Academic Search

To minimize side effects of drugs it would be ideal to target them exclusively to those cell types which require treatment. As a means to this end prototypical cellular recognition systems pique our interest to devise biomimetic strategies. Since oligosaccharides of glycoconjugates outmatch other information-carrying biomolecules (proteins, nucleic acids) in theoretical storage capacity by far, work on the sugar code

N. Yamazaki; S. Kojima; N. V. Bovin; S. André; S. Gabius; H.-J. Gabius

2000-01-01

376

Strategy for effective brain drug delivery  

Microsoft Academic Search

Blood–brain barrier (BBB) together with enzymes restricts the entry of substances for maintaining the internal milieu of the brain. Because of the presence of multiple endogenous transporters, BBB allows a selective entry of nutrients and minerals across it and limits the entry of foreign substances like drugs as well as neuropharmaceutical agents. This makes the CNS treatment ineffective. The conventional

M. Intakhab Alam; Sarwar Beg; Abdus Samad; Sanjula Baboota; Kanchan Kohli; Javed Ali; Alka Ahuja; M. Akbar

2010-01-01

377

Nuclear Drug Delivery for Breast Cancer Chemotherapy.  

National Technical Information Service (NTIS)

Chemo-resistant breast cancer cells overexpress not only membrane- associated but also many cytosolic drug-resistance mechanisms to limit the access of DNA-toxins to the nucleus, causing low chemotherapeutic efficacy. The project aims to synthesize and ev...

W. J. Murdoch Y. Shen

2008-01-01

378

Dendritic polymer-based nanodevices for targeted drug delivery applications  

NASA Astrophysics Data System (ADS)

Dendrimers and hyperbranched polymers are unimolecular micellar nanostructures, characterized by globular shape ( ˜ 20 nm) and large density of functional groups at periphery. The tailorable end groups make them ideal for conjugation with drugs, ligands, and imagining agents, making them an attractive molecular nanodevices for drug delivery. Compared to linear polymers and nanoparticles, these nanodevices enter cells rapidly, carrying drugs and delivering them inside cells. Performance of nanodevices prepared for asthma and cancer drug delivery will be discussed. Our conjugation procedure produced very high drug payloads. Dendritic polymer-drug conjugates were very effective in transporting methotrexate (a chemotherapy drug) into both sensitive (CCRF-CEM cell line) and resistant cell line (CEM-MTX). The conjugate nanodevice was 3 times more effective than free drug in the sensitive line, and 9 times more effective in the resistant cell line (based on IC50). The physics of cell entry and drug release from these nanodevices are being investigated. The conjugates appear to enter cells through endocytosis, with the rate of entry dependent on end-group, molecular weight, the pH of the medium, and the cancerous nature of the cells.

Kannan, R. M.; Kolhe, Parag; Gurdag, Sezen; Khandare, Jayant; Lieh-Lai, Mary

2004-03-01

379

"Nanotheranostics" for tumor imaging and targeted drug delivery  

NASA Astrophysics Data System (ADS)

The magnetic resonance imaging (MRI) technique is a promising tool that improves cancer detection, facilitates diagnosis and monitors therapeutic effects. Superparamagnetic iron oxide nanoparticles (SPIOs) have emerged as MRI contrast agents for tumor imaging and as potential vectors for targeted anti-cancer drug delivery; nevertheless, the application of SPIOs has been hampered due to a lack of specificity to tumor tissues and premature drug release. This project aims at developing multifunctional SPIOs for both cancer imaging and targeted drug delivery via conjugation of tumor specific antibodies with SPIOs. The application of anti-TAG-72 antibodies as tumor targeting modalities was evaluated in cultured colorectal cancer cells and in xenograft models by using fluorescent imaging and positron emission tomography (PET) imaging. It was demonstrated that antibody-labeled SPIOs were superior imaging agents and drug carriers for increased tumor specificity. The regulation and kinetics of intracellular drug release from SPIOs were explored by means of fluorescence imaging. In vitro and in vivo fluorescence resonance energy transfer (FRET) imaging was employed to investigate the mechanisms of premature drug release from nanocarriers. The large volume and high hydrophobicity of cell membranes were found to play an important role in premature drug release. The encapsulation of SPIOs into nanocarriers decreased drug release in a dose-dependent mode. This study provided future opportunities to improve the efficiency of nanocarriers by exploring the mechanism of drug release and disassembly of SPIO-loaded polymeric nanoparticles.

Zou, Peng

380

System-based approach for an advanced drug delivery platform  

NASA Astrophysics Data System (ADS)

Present study is looking at the problem of integrating drug delivery microcapsule, a bio-sensor, and a control mechanism into a biomedical drug delivery system. A wide range of medical practices from cancer therapy to gastroenterological treatments can benefit from such novel bio-system. Drug release in our drug delivery system is achieved by electrochemically actuating an array of polymeric valves on a set of drug reservoirs. The valves are bi-layer structures, made in the shape of a flap hinged on one side to a valve seat, and consisting of thin films of evaporated gold and electrochemically deposited polypyrrole (PPy). These thin PPy(DBS) bi-layer flaps cover access holes of underlying chambers micromachined in a silicon substrate. Chromium and polyimide layers are applied to implement "differential adhesion" to obtain a voltage induced deflection of the bilayer away from the drug reservoir. The Cr is an adhesion-promoting layer, which is used to strongly bind the gold layer down to the substrate, whereas the gold adheres weakly to polyimide. Drug actives (dry or wet) were pre-stored in the chambers and their release is achieved upon the application of a small bias (~ 1V). Negative voltage causes cation adsorption and volume change in PPy film. This translates into the bending of the PPy/Au bi-layer actuator and release of the drug from reservoirs. This design of the drug delivery module is miniaturized to the dimensions of 200?m valve diameter. Galvanostatic and potentiostatic PPy deposition methods were compared, and potentiostatic deposition method yields film of more uniform thickness. PPy deposition experiments with various pyrrole and NaDBS concentrations were also performed. Glucose biosensor based on glucose oxidase (GOx) embedded in the PPy matrix during elechtrochemical deposition was manufactured and successfully tested. Multiple-drug pulsatile release and continuous linear release patterns can be implemented by controlling the operation of an array of valves. Varying amounts of drugs, together with more complex controlling strategies would allow creation of more complex drug delivery patterns.

Kulinsky, Lawrence; Xu, Han; Tsai, Han-Kuan A.; Madou, Marc

2006-04-01

381

Iontophoretic transdermal drug delivery system using a conducting polymeric membrane  

Microsoft Academic Search

This work investigated the application of a porous polyaniline (PANi) membrane as a conducting polymeric membrane as well as an electrode in an iontophoretic transdermal drug delivery (TDD) system. Model drugs studied were: caffeine (MW: 194.2), lidocaine HCl (MW: 270.8) and doxycycline HCl (MW: 480.1). The PANi membrane was first tested as a simple membrane between the donor and receptor

Qiuxi Fan; Kamalesh K. Sirkar; Bozena Michniak

2008-01-01

382

Application of fused deposition modelling in controlled drug delivery devices  

Microsoft Academic Search

Purpose – This paper seeks to present an investigation on building controlled drug delivery device (DDD) matrix using fused deposition modelling (FDM) rapid prototyping (RP) process. The focus of the study is on the effect of FDM fabricated macro-features of reservoir-matrix DDD models on the drug release rates through the diffusion process. Design\\/methodology\\/approach – Using various parameters involved with FDM,

S. H. Masood

2007-01-01

383

Design of microencapsulated chitosan microspheres for colonic drug delivery  

Microsoft Academic Search

Among the different approaches to achieve colon-selective drug delivery, the use of polymers, specifically biodegraded by colonic bacteria, holds great promise. In this work a new system which combines specific biodegradability and pH-dependent release is presented. The system consists of chitosan (CS) microcores entrapped within acrylic microspheres. Sodium diclofenac (SD), used as a model drug, was efficiently entrapped within CS

M. L Lorenzo-Lamosa; C Remuñán-López; J. L Vila-Jato; M. J Alonso

1998-01-01

384

Proniosomes as a drug carrier for transdermal delivery of ketorolac  

Microsoft Academic Search

Niosomes are nonionic surfactant vesicles that have potential applications in the delivery of hydrophobic and hydrophilic drugs. Permeation of a potent nonsteroidal anti-inflammatory, ketorolac, across excised rabbit skin from various proniosome gel formulations was investigated using Franz diffusion cells. Each of the prepared proniosomes significantly improved drug permeation and reduced the lag time (P<0.05). Proniosomes prepared with Span 60 provided

Ibrahim A. Alsarra; A. A. Bosela; S. M. Ahmed; G. M. Mahrous

2005-01-01

385

Nanomedicines for ocular NSAIDs: safety on drug delivery  

Microsoft Academic Search

The eyes are among the most readily accessible organs in terms of location in the body, yet drug delivery to eye tissues is particularly problematic. Poor bioavailability of drugs from ocular dosage forms is mainly due to precorneal loss factors (e.g., tear dynamics, nonproductive absorption, transient residence time in the cul-de-sac, and relative impermeability of the corneal epithelial membrane). There

Joana Araújo; Elisabet Gonzalez; Maria Antonia Egea; Marisa Luisa Garcia; Eliana B. Souto

2009-01-01

386

The use of microbubbles to target drug delivery  

Microsoft Academic Search

Ultrasound-mediated microbubbles destruction has been proposed as an innovative method for noninvasive delivering of drugs and genes to different tissues. Microbubbles are used to carry a drug or gene until a specific area of interest is reached, and then ultrasound is used to burst the microbubbles, causing site-specific delivery of the bioactive materials. Furthermore, the ability of albumin-coated microbubbles to

Jeane M Tsutsui; Feng Xie; Richard Thomas Porter

2004-01-01

387

Biodegradable nanoparticles for sustained occular drug delivery  

NASA Astrophysics Data System (ADS)

Apoptosis (programmed cell-death) is a common final pathway through which cells die in retinal degenerative diseases. The purpose of this project was to develop biodegradable nanoparticles that quickly deliver XIAP, an inhibitor of apoptosis, to retinal cells following acute insults. In vitro protein release profiles from different formulations were established, and two cell types were incubated with nanoparticles to assess cellular uptake. Subretinal injections were carried out in rats to assess in vivo localization and possible toxicity. In vitro studies showed an initial burst of protein followed by sustained release, with overall low levels of protein release. Cell culture experiments suggest that particles are mostly membrane-bound, and some may be internalized. In vivo experiments revealed no signs of toxicity, and protein localized within the photoreceptor layer. In conclusion, nanoparticles may provide a good delivery system for XIAP; however higher levels of protein release are needed for neuroprotection, warranting further investigation.

Cleroux, Carolyne

388

Packaged Au-PPy valves for drug delivery systems  

NASA Astrophysics Data System (ADS)

The most common methods for the drug delivery are swallowing pills or receiving injections. However, formulations that control the rate and period of medicine (i.e., time-release medications) are still problematic. The proposed implantable devices which include batteries, sensors, telemetry, valves, and drug storage reservoirs provide an alternative method for the responsive drug delivery system [1]. Using this device, drug concentration can be precisely controlled which enhances drug efficiency and decreases the side effects. In order to achieve responsive drug delivery, a reliable release valve has to be developed. Biocompatibility, low energy consumption, and minimized leakage are the main requirements for such release method. A bilayer structure composed of Au/PPy film is fabricated as a flap to control the release valve. Optimized potentiostatic control to synthesize polypyrrole (PPy) is presented. The release of miniaturize valve is tested and showed in this paper. A novel idea to simultaneously fabricate the device reservoirs as well as protective packaging is proposed in this paper. The solution of PDMS permeability problem is also mentioned in this article.

Tsai, Han-Kuan A.; Ma, Kuo-Sheng; Zoval, Jim; Kulinsky, Lawrence; Madou, Marc

2006-04-01

389

Silica-based mesoporous nanoparticles for controlled drug delivery  

PubMed Central

Drug molecules with lack of specificity and solubility lead patients to take high doses of the drug to achieve sufficient therapeutic effects. This is a leading cause of adverse drug reactions, particularly for drugs with narrow therapeutic window or cytotoxic chemotherapeutics. To address these problems, there are various functional biocompatible drug carriers available in the market, which can deliver therapeutic agents to the target site in a controlled manner. Among the carriers developed thus far, mesoporous materials emerged as a promising candidate that can deliver a variety of drug molecules in a controllable and sustainable manner. In particular, mesoporous silica nanoparticles are widely used as a delivery reagent because silica possesses favourable chemical properties, thermal stability and biocompatibility. Currently, sol-gel-derived mesoporous silica nanoparticles in soft conditions are of main interest due to simplicity in production and modification and the capacity to maintain function of bioactive agents. The unique mesoporous structure of silica facilitates effective loading of drugs and their subsequent controlled release. The properties of mesopores, including pore size and porosity as well as the surface properties, can be altered depending on additives used to fabricate mesoporous silica nanoparticles. Active surface enables functionalisation to modify surface properties and link therapeutic molecules. The tuneable mesopore structure and modifiable surface of mesoporous silica nanoparticle allow incorporation of various classes of drug molecules and controlled delivery to the target sites. This review aims to present the state of knowledge of currently available drug delivery system and identify properties of an ideal drug carrier for specific application, focusing on mesoporous silica nanoparticles.

Kwon, Sooyeon; Singh, Rajendra K; Perez, Roman A; Abou Neel, Ensanya A

2013-01-01

390

Drug delivery to the inner ear  

NASA Astrophysics Data System (ADS)

Bionic devices electrically activate neural populations to partially restore lost function. Of fundamental importance is the functional integrity of the targeted neurons. However, in many conditions the ongoing pathology can lead to continued neural degeneration and death that may compromise the effectiveness of the device and limit future strategies to improve performance. The use of drugs that can prevent nerve cell degeneration and promote their regeneration may improve clinical outcomes. In this paper we focus on strategies of delivering neuroprotective drugs to the auditory system in a way that is safe and clinically relevant for use in combination with a cochlear implant. The aim of this approach is to prevent neural degeneration and promote nerve regrowth in order to improve outcomes for cochlear implant recipients using techniques that can be translated to the clinic.

Wise, Andrew K.; Gillespie, Lisa N.

2012-12-01

391

POROUS NANOPARTICLES IN DRUG DELIVERY SYSTEMS  

Microsoft Academic Search

This article concentrates mainly on fabrication of porous nanoparticles, its characterisation and its use for controlled release of drug. It also encompasses the strategies that have been used to translate and fabricate a wide range of particulate carriers e.g., nanospheres, liposomes, micelles, oil-in-water emulsions, with prolonged circulation and\\/or target specificity. Sol-gel technique is one of the most widely used techniques

Murray RK; Granner DK; Rodwell VW

392

Protein Drug Delivery and Formulation Development  

Microsoft Academic Search

\\u000a Several therapeutic agents including low and high molecular weight drugs intended for treating back of the eye disorders are\\u000a routinely administered as intravitreal injections. Intravitreal injection of Lucentis®, a therapeutic protein, was approved in 2006 for treating the wet form of age-related macular degeneration. This chapter\\u000a summarizes the challenges and opportunities in delivering therapeutic proteins to the eye. Specifically, barriers

Rinku Baid; Puneet Tyagi; Shelley A. Durazo; Uday B. Kompella

393

Targeted Therapeutics and Nanodevices for Vascular Drug Delivery: Quo Vadis?  

PubMed Central

Summary This issue of the journal is dedicated to targeted delivery of therapeutics in the vasculature, an approach that holds promise to optimize treatment of diverse pathological conditions ranging from ischemia and tumor growth to metabolic and genetic diseases. From the standpoint of drug delivery, circulation system represents the natural route to the targets, whereas its components (blood and vascular cells) represent targets, carriers or barriers for drug delivery. Diverse nanodevices and targeted therapeutic agents that are designed and tested in animal and early clinical studies to achieve optimal and precise spatiotemporal control of the pharmacokinetics, destination, metabolism and effect of pharmacological agents will be discussed in this introductory essay and subsequent critical reviews in this series.

Muzykantov, Vladimir R.

2012-01-01

394

Polymeric Nanoparticles for Drug Delivery to the Central Nervous System  

PubMed Central

The central nervous system (CNS) poses a unique challenge for drug delivery. The blood-brain barrier significantly hinders the passage of systemically-delivered therapeutics and the brain extracellular matrix limits the distribution and longevity of locally-delivered agents. Polymeric nanoparticles represent a promising solution to these problems. Over the past 40 years, substantial research efforts have demonstrated that polymeric nanoparticles can be engineered for effective systemic and local delivery of therapeutics to the CNS. Moreover, many of the polymers used in nanoparticle fabrication are both biodegradable and biocompatible, thereby increasing the clinical utility of this strategy. Here, we review the major advances in the development of polymeric nanoparticles for drug delivery to the CNS.

Patel, Toral; Zhou, Jiangbing; Piepmeier, Joseph M.; Saltzman, W. Mark

2012-01-01

395

Chitosan-based hydrogels for controlled, localized drug delivery.  

PubMed

Hydrogels are high-water content materials prepared from cross-linked polymers that are able to provide sustained, local delivery of a variety of therapeutic agents. Use of the natural polymer, chitosan, as the scaffold material in hydrogels has been highly pursued thanks to the polymer's biocompatibility, low toxicity, and biodegradability. The advanced development of chitosan hydrogels has led to new drug delivery systems that release their payloads under varying environmental stimuli. In addition, thermosensitive hydrogel variants have been developed to form a chitosan hydrogel in situ, precluding the need for surgical implantation. The development of these intelligent drug delivery devices requires a foundation in the chemical and physical characteristics of chitosan-based hydrogels, as well as the therapeutics to be delivered. In this review, we investigate the newest developments in chitosan hydrogel preparation and define the design parameters in the development of physically and chemically cross-linked hydrogels. PMID:19799949

Bhattarai, Narayan; Gunn, Jonathan; Zhang, Miqin

2009-09-30

396

Buccal drug delivery of pravastatin sodium.  

PubMed

The purpose of this study was to develop and optimize formulations of mucoadhesive bilayered buccal tablets of pravastatin sodium using carrageenan gum as the base matrix. The tablets were prepared by direct compression method. Polyvinyl pyrrolidone (PVP) K 30, Pluronic(R) F 127, and magnesium oxide were used to improve tablet properties. Magnesium stearate, talc, and lactose were used to aid the compression of tablets. The tablets were found to have good appearance, uniform thickness, diameter, weight, pH, and drug content. A 2(3) full factorial design was employed to study the effect of independent variables viz. levels of carrageenan gum, Pluronic F 127 and PVP K30, which significantly influenced characteristics like in vitro mucoadhesive strength, in vitro drug release, swelling index, and in vitro residence time. The tablet was coated with an impermeable backing layer of ethyl cellulose to ensure unidirectional drug release. Different penetration enhancers were tried to improve the permeation of pravastatin sodium through buccal mucosa. Formulation containing 1% sodium lauryl sulfate showed good permeation of pravastatin sodium through mucosa. Histopathological studies revealed no buccal mucosal damage. It can be concluded that buccal route can be one of the alternatives available for the administration of pravastatin sodium. PMID:20300898

Shidhaye, Supriya S; Thakkar, Pritesh V; Dand, Neha M; Kadam, Vilasrao J

2010-03-19

397

Impact of emulsion-based drug delivery systems on intestinal permeability and drug release kinetics  

Microsoft Academic Search

Lipid based drug delivery systems, and in particular self-emulsifying drug delivery systems (SEDDS), show great potential for enhancing oral bioavailability but have not been broadly applied, largely due to lack of general formulation guidance. To help understand how formulation design influences physicochemical emulsion properties and associated function in the gastrointestinal environment, a range of twenty-seven representative self-emulsifying formulations were investigated.

Fulden Buyukozturk; James C. Benneyan; Rebecca L. Carrier

2010-01-01

398

Polysaccharides-based nanoparticles as drug delivery systems  

Microsoft Academic Search

Natural polysaccharides, due to their outstanding merits, have received more and more attention in the field of drug delivery systems. In particular, polysaccharides seem to be the most promising materials in the preparation of nanometeric carriers. This review relates to the newest developments in the preparation of polysaccharides-based nanoparticles. In this review, four mechanisms are introduced to prepare polysaccharides-based nanoparticles,

Zonghua Liu; Yanpeng Jiao; Yifei Wang; Changren Zhou; Ziyong Zhang

2008-01-01

399

Self-tuning controller for drug delivery systems  

Microsoft Academic Search

A new adaptive control algorithm, the Control Advance Moving Average Controller (CAMAC), was implemented in a drug delivery system to control mean arterial pressure by the infusion of sodium nitroprusside. The CAMAC, which is designed to control non-minimum-phase systems with unknown or varying dead times, is presented here. The control law minimizes a cost function at a time advance which

G. I. Voss; H. J. CHIZECK; P. G. KATONA

1988-01-01

400

Smart and genetically engineered biomaterials and drug delivery systems  

Microsoft Academic Search

The design, synthesis, and properties of novel stimuli-sensitive and genetically engineered biomaterials and drug delivery systems are reviewed. Two approaches to their engineering are presented. One approach is to improve the traditional methods of synthesis, as demonstrated by the example of controlled copolymerization of ?-amino acid N-carboxyanhydrides. The other approach, discussed in more detail, uses genetic engineering methods. The design

Jind?ich Kope?ek

2003-01-01

401

Targeted Cellular Drug Delivery using Tailored Dendritic Nanostructures  

Microsoft Academic Search

Dendrimers and hyperbranched polymers possess highly branched architectures, with a large number of controllable, tailorble, `peripheral' functionalities. Since the surface chemistry of these materials can be modified with relative ease, these materials have tremendous potential in targeted drug and gene delivery. The large number of end groups can also be tailored to create special affinity to targeted cells, and can

Rangaramanujam Kannan; Parag Kolhe; Sujatha Kannan; Mary Lieh-Lai

2002-01-01

402

Molecularly imprinted materials as advanced excipients for drug delivery systems  

Microsoft Academic Search

The application of the molecular imprinting technology in the design of new drug delivery systems (DDS) and devices useful in closely related fields, such as diagnostic sensors or biological traps, is receiving increasing attention. Molecular imprinting technology can provide polymeric materials with the ability to recognize specific bioactive molecules and with a sorption\\/release behaviour that can be made sensitive to

Carmen Alvarez-Lorenzo; Angel Concheiro

2006-01-01

403

Transdermal microconduits by microscission for drug delivery and sample acquisition  

Microsoft Academic Search

BACKGROUND: Painless, rapid, controlled, minimally invasive molecular transport across human skin for drug delivery and analyte acquisition is of widespread interest. Creation of microconduits through the stratum corneum and epidermis is achieved by stochastic scissioning events localized to typically 250 ?m diameter areas of human skin in vivo. METHODS: Microscissioning is achieved by a limited flux of accelerated gas: 25

Terry O Herndon; Salvador Gonzalez; TR Gowrishankar; R Rox Anderson; James C Weaver

2004-01-01

404

Adhesion Dynamics of Functional Nanoparticles for Targeted Drug Delivery  

Microsoft Academic Search

Adhesion of micro and nanoparticles onto cardiovascular walls is a critical process in applications such as targeted drug delivery, biomedical imaging, and cancer treatment. This paper intends to develop an understanding of the dynamic interaction between particle and vessel wall through computational modeling. The ligand-receptor binding dynamics is coupled with Immersed Finite Element Method to study the adhesion process of

Yaling Liu; Samar Shah; Wenchuang Hu; Jinming Gao

405

Electroporation of prostate cancer cells for drug delivery  

Microsoft Academic Search

Electroporation has been shown to be a powerful method to temporarily disrupt biological barriers and thereby enhance drug delivery. However, incomplete understanding of electroporation mechanisms and dependence on electrical parameters has limited quantitative predictions of molecular uptake and cell viability. To provide a rational basis for designing electroporation protocols we used flow cytometry to quantify uptake and viability for more

P. J. Canatella; M. M. Black; C. McKenna; J. K. Karr; J. A. Petros; M. R. Prausnitz

1999-01-01

406

Carbopol\\/pluronic phase change solutions for ophthalmic drug delivery  

Microsoft Academic Search

The major purpose of this study is to develop and characterize a series of carbopol- and pluronic-based solutions as the in situ gelling vehicles for ophthalmic drug delivery. The rheological properties, in vitro release as well as in vivo pharmacological response of various polymer solutions, including carbopol, pluronic and carbopol\\/pluronic solution, were evaluated. It was found that the optimum concentration

Hong-Ru Lin; K. C Sung

2000-01-01

407

Interfacial kinetics effects on transdermal drug delivery: a computer modeling  

Microsoft Academic Search

Background\\/purpose: Percutaneous permeation is a fre- quently used approach in drug delivery, but the detailed physics process in the patch - stratum corneum (SC) - viable epidermis system remains unclear: the influence of the interphases in the multilayered structure has been little studied. Methods: This paper applied the finite-element method to develop a contact algorithm with an interphase element to

Malcolm M. Q. Xing; Ning Pan; Wen Zhong; Xiaoyin Hui; Howard I. Maibach

2007-01-01

408

Biodegradable polymer microneedles: fabrication, mechanics and transdermal drug delivery  

Microsoft Academic Search

To overcome skin's barrier properties that block transdermal delivery of most drugs, we and others have microfabricated arrays of microscopic needles, primarily out of silicon or metal. This study addresses microneedles made of biocompatible and biodegradable polymers, which are expected to improve safety and manufacturability. To make biodegradable polymer microneedles with sharp tips, we adapted microelectromechanical masking and etching to

Jung-Hwan Park; Mark G. Allen; Mark R. Prausnitz

2004-01-01

409

Electrochemically controlled drug delivery based on intrinsically conducting polymers  

Microsoft Academic Search

This paper reviews the application of intrinsically conducting polymers (ICPs) in drug delivery. ICPs are organic polymers with electrical, magnetic and optical properties usually associated with metals, whilst retaining the advantageous mechanical properties and ease of processing usually associated with polymers. Due to the inherent properties of these unique materials, electrical stimulation can be used to alter the redox state

Darren Svirskis; Jadranka Travas-Sejdic; Anthony Rodgers; Sanjay Garg

2010-01-01

410

Dendrimers as versatile platform in drug delivery applications  

Microsoft Academic Search

About forty percent of newly developed drugs are rejected by the pharmaceutical industry and will never benefit a patient because of poor bioavailability due to low water solubility and\\/or cell membrane permeability. New delivery technologies could help to overcome this challenge. Nanostructures with uniform and well-defined particle size and shape are of eminent interest in biomedical applications because of their

Sonke Svenson

2009-01-01

411

Mathematical modeling of bioerodible, polymeric drug delivery systems  

Microsoft Academic Search

The aim of this article is to give an introduction into mathematical modeling approaches of bioerodible controlled drug delivery systems and to present the most important erosion theories reported in the literature. First, important parameters such as degradation and erosion are defined and physicochemical methods for their investigation are briefly presented. Then, phenomenological empirical models as well as models based

J. Siepmann; A. Göpferich

2001-01-01

412

Targeted drug delivery and enhanced intracellular release using functionalized liposomes  

Microsoft Academic Search

The ability to target cancer cells using an appropriate drug delivery system can significantly reduce the associated side effects from cancer therapies and can help in improving the overall quality of life, post cancer survival. Integrin alpha5beta1 is expressed on several types of cancer cells, including colon cancer and plays an important role in tumor growth and metastasis. Thus, the

Ashish Garg

2009-01-01

413

Applications of novel drug delivery system for herbal formulations  

Microsoft Academic Search

Over the past several years, great advances have been made on development of novel drug delivery systems (NDDS) for plant actives and extracts. The variety of novel herbal formulations like polymeric nanoparticles, nanocapsules, liposomes, phytosomes, nanoemulsions, microsphere, transferosomes, and ethosomes has been reported using bioactive and plant extracts. The novel formulations are reported to have remarkable advantages over conventional formulations

Ajazuddin; S. Saraf

2010-01-01

414

Drug Design, Development, and Delivery: An Interdisciplinary Course on Pharmaceuticals  

ERIC Educational Resources Information Center

|We developed a new interdisciplinary course on pharmaceuticals to address needs of undergraduate and graduate students in chemical engineering and other departments. This course introduces drug design, development, and delivery in an integrated fashion that provides scientific depth in context with broader impacts in business, policy, and ethics.…

Prausnitz, Mark R.; Bommarius, Andreas S.

2011-01-01

415

Enhancing effect of electret on transdermal drug delivery  

Microsoft Academic Search

The present work was undertaken to study the enhancing effect of electret on in vitro transdermal drug delivery. The experiment was conducted using the improved Franz diffusion cells, with the skin of rat mounted between the two half cells and the electret film covered on the model compound in the donor cell. The receiver solution was withdrawn at a predetermined

Lili Cui; Jian Jiang; Li Zhang; Chenrong Song; Weiquan Zhao; Jinmin Lin

2001-01-01

416

Sugar Micro Needles as Transdermic Drug Delivery System  

Microsoft Academic Search

We designed and fabricated an array of sugar micro needles of the length ranging from 150 ? m to 2 mm for transdermic delivery of drugs. Micro needles were molded out of maltose mixed with pharmaceutical material, being expected bio-degradable in the human skin. To test basic tolerance to the healthy human skin, a clinical experiment was carried out for

Takaya Miyano; Yoshikazu Tobinaga; Takahiro Kanno; Yasushi Matsuzaki; Hitoshi Takeda; Makoto Wakui; Katsumi Hanada

2005-01-01

417

Quasiresonant flyback converter for transdermal drug delivery applications  

Microsoft Academic Search

This paper explores a new application field of power electronics. A soft-switching quasiresonant flyback converter is designed for transdermal drug delivery (TDD) applications with the processes of electroporation and phonophoresis. The converter can generate a constant DC voltage output for a pulsed generator in electroporation processing and can generate a variable DC voltage to drive a radial type of piezoelectric

S.-Y. Tseng; Y.-M. Chen; Y.-K. Huang; H.-T. Hsieh; T.-F. Wu

2004-01-01

418

Biodegradable polymer microneedles: Fabrication, mechanics and transdermal drug delivery  

Microsoft Academic Search

To overcome the skin's barrier properties that block transdermal delivery of most drugs, arrays of microscopic needles have been microfabricated primarily out of silicon or metal. This study addresses microneedles made of biocompatible and biodegradable polymers, which are expected to improve safety and manufacturability. To make biodegradable polymer microneedles with sharp tips, micro-electromechanical masking and etching were adapted to produce

Jung-Hwan Park; Mark G. Allen; Mark R. Prausnitz

2005-01-01

419

Fundamentals of electroporative delivery of drugs and genes  

Microsoft Academic Search

Electrooptical and conductometrical relaxation methods have given a new insight in the molecular mechanisms of the electroporative delivery of drug-like dyes and genes (DNA) to cells and tissues. Key findings are: (1) Membrane electroporation (ME) and hence the electroporative transmembrane transport of macromolecules are facilitated by a higher curvature of the membrane as well as by a gradient of the

Eberhard Neumann; Sergej Kakorin; Katja Tœnsing

1999-01-01

420

Synthetic biodegradable polymers for tissue engineering and drug delivery  

Microsoft Academic Search

Advances in tissue engineering and drug delivery are often enabled by the development of new biomaterials, designed specifically for such purposes. Advances in synthetic degradable biomaterials that permit in situ transformations from liquid precursors to solid final forms that enable the biomaterial to be directly recognized by the biochemical features of the cells and that make use of novel approaches

Jeffrey A Hubbell

1998-01-01

421

Carrier-mediated transport to enhance drug delivery to brain  

Microsoft Academic Search

Drug delivery to brain can be improved through the design of novel therapeutic agents that are rapidly and selectively shuttled into the nervous system across the blood–brain barrier (BBB) by the facilitated influx transporters of brain capillaries. Messenger RNA analysis has demonstrated high expression of >20 influx transporters at the BBB, including carriers for glucose (GLUT1), monocarboxylic acids (MCT1), large

Quentin R. Smith

2005-01-01

422

Brain drug delivery technologies: novel approaches for transporting therapeutics  

Microsoft Academic Search

The blood–brain barrier (BBB) denies many therapeutic agents access to brain tumours and other diseases of the central nervous system (CNS). Despite remarkable advances in our understanding of the mechanisms involved in the development of the brain diseases and the actions of neuroactive agents, drug delivery to the brain remains a challenge. For more than 20 years, extensive efforts have

Jamal Temsamani; Jean-Michel Scherrmann; Anthony R Rees; Michel Kaczorek

2000-01-01

423

Therapeutic Ultrasound Enhancement of Drug Delivery to Soft Tissues  

Microsoft Academic Search

Effects of exposure to 1.58 MHz focused ultrasound on transport of Evans Blue Dye (EBD) in soft tissues are investigated when an external pressure gradient is applied to induce convective flow through the tissue. The magnitude of the external pressure gradient is chosen to simulate conditions in brain parenchyma during convection-enhanced drug delivery (CED) to the brain. EBD uptake and

George Lewis; William Olbricht

2009-01-01

424

Nanotechnologies for drug delivery: Application to cancer and autoimmune diseases  

Microsoft Academic Search

Polymer-based nanotechnologies are now proposed as an alternative to classical formulations for drug administration, delivery and targeting. Therapeutic applications of the first generation of nanotechnologies include the treatment of cancer liver diseases. Avoiding the recognition by the liver is also possible by developing long circulating polymeric colloidal carriers (“stealth” systems) able to avoid the opsonization process and the recognition by

P. Couvreur; R. Gref; K. Andrieux; C. Malvy

2006-01-01

425

PEG-based degradable networks for drug delivery applications  

Microsoft Academic Search

The controlled delivery of therapeutic agents by biodegradable hydrogels has become a popular mechanism for drug administration in recent years. Hydrogels are three-dimensional networks of polymer chains held together by crosslinks. Although the changes which the hydrogel undergoes in solution are important to a wide range of experimental studies, they have not been investigated systematically and the factors which influence

Jamie L. Ostroha

2006-01-01

426

Liposomes for intravitreal drug delivery: a state of the art.  

PubMed

Intravitreal administration of drugs has raised a large interest during the last two decades improving the treatment of infectious diseases of the posterior segment of the eye or edematous maculopathies. This route of administration allows achieving high drug concentrations in the vitreous and avoiding adverse effects resulting from systemic administration. However, many drugs are rapidly cleared from the vitreous humor; therefore, to reach and to maintain effective therapy, repeated administrations are necessary. Unfortunately, frequent intravitreal injections increase the risk of endophthalmitis, damage to lens, retinal detachment. Moreover, some drugs provoke a local toxicity at their effective dose inducing side-effects and possible retinal lesions. This is the reason why new drug delivery systems, among which liposomes, have been developed to improve the intravitreal administration of drugs. Liposomes can reduce the toxicity and increase the residence time of several active molecules in the eye. In vivo, they can protect poorly-stable drugs such as peptides and nucleic acids from degradation. Successful reports have shown their potential for improving the treatment of retinitis induced by cytomegalovirus in human and more recently for the treatment of uveitis in rats. Moreover, recent preliminary studies about the trafficking of liposomes in ocular tissues and fluids following intravitreal injection attempted to elucidate their fate. All the data discussed in this review support the large interest raised by these colloidal carriers for intravitreal drug delivery. PMID:22289436

Bochot, Amélie; Fattal, Elias

2012-01-25

427

Pulmonary drug delivery systems for antimicrobial agents: facts and myths.  

PubMed

Inhaled antimicrobial agents are used for the treatment of respiratory tract infections due to Gram-negative bacteria, mainly Pseudomonas aeruginosa. The effectiveness of the inhaled antimicrobial therapy is believed to correlate with the delivery system used. The objective of this review was to search for data supporting differentiation in clinical effectiveness between systems used for pulmonary delivery of antibiotics, including delivery using disposable nebulisers and oxygen flow. Published studies in peer-reviewed journals comparing the effectiveness of pulmonary drug delivery systems for antimicrobial agents were retrieved. The studies found were either in vitro or Phase I and Phase II clinical studies. Differences in in vitro parameters may affect the in vivo efficacy of the devices, and in vivo differences may imply differences in clinical effectiveness. The main difference between newer and older devices is the time needed for antibiotic delivery. Interpretation and association with clinical effectiveness is difficult. In conclusion, Phase III clinical trials comparing the clinical effectiveness of delivery systems, including delivery using a hospital's oxygen flow and disposable nebulisers, do not exist. Cost is an important parameter, which may be counterbalanced in cystic fibrosis patients by a better quality of life and a greater adherence to treatment. PMID:19939637

Falagas, Matthew E; Michalopoulos, Argyris; Metaxas, Eugenios I

2009-11-24

428

Elastic vesicles as topical/transdermal drug delivery systems.  

PubMed

Skin acts a major target as well as a principle barrier for topical/transdermal drug delivery. Despite the many advantages of this system, the major obstacle is the low diffusion rate of drugs across the stratum corneum. Several methods have been assessed to increase the permeation rate of drugs temporarily. One simple and convenient approach is application of drugs in formulation with elastic vesicles or skin enhancers. Elastic vesicles are classified with phospholipid (Transfersomes((R)) and ethosomes) and detergent-based types. Elastic vesicles were more efficient at delivering a low and high molecular weight drug to the skin in terms of quantity and depth. Their effectiveness strongly depends on their physicochemical properties: composition, duration and application volume, and entrapment efficiency and application methods. This review focuses on the effect of elastic liposomes for enhancing the drug penetration and defines the action mechanism of penetration into deeper skin. PMID:18492190

Choi, M J; Maibach, H I

2005-08-01

429

Residual Drug in Transdermal and Related Drug Delivery ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... the formulation and system design, as ... Most important, the justification for applications of ... containing liquid reservoir systems— should demonstrate ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

430

The effect of carbon nanotubes on drug delivery in an electro-sensitive transdermal drug delivery system  

Microsoft Academic Search

An electro-sensitive transdermal drug delivery system was prepared by the electrospinning method to control drug release. A semi-interpenetrating polymer network was prepared as the matrix with polyethylene oxide and pentaerythritol triacrylate polymers. Multi-walled carbon nanotubes were used as an additive to increase the electrical sensitivity. The release experiment was carried out under different electric voltage conditions. Carbon nanotubes were observed

Ji S. Im; Byong Ch. Bai; Young-Seak Lee

2010-01-01

431

Development of magnetically targeted drug delivery system using superconducting magnet  

NASA Astrophysics Data System (ADS)

Development of a novel drug delivery system was made to accumulate/navigate magnetic drugs with the help of a superconducting magnet in order to control the drugs in blood vessels located deep inside the body. In the present paper, we tested the feasibility of a novel navigation system, made by applying a strong external (magnetic) field through SmBaCuO and YBaCuO bulk superconductors in order to realize the practice of using externally applied magnetic fields for targeting the magnetic particles to a circumscribed body region.

Takeda, Shin-Ichi; Mishima, Fumihito; Fujimoto, Suketaka; Izumi, Yoshinobu; Nishijima, Shigehiro

2007-04-01

432

A laser based reusable microjet injector for transdermal drug delivery  

NASA Astrophysics Data System (ADS)

A laser based needle-free liquid drug injection device has been developed. A laser beam is focused inside the liquid contained in the rubber chamber of microscale. The focused laser beam causes explosive bubble growth, and the sudden volume increase in a sealed chamber drives a microjet of liquid drug through the micronozzle. The exit diameter of a nozzle is 125 ?m and the injected microjet reaches an average velocity of 264 m/s. This device adds the time-varying feature of microjet to the current state of liquid injection for drug delivery.

Han, Tae-Hee; Yoh, Jack J.

2010-05-01

433

Photoswitchable Nanoparticles for Triggered Tissue Penetration and Drug Delivery  

PubMed Central

We report a novel nanoparticulate drug delivery system that undergoes reversible volume change from 150 to 40 nm upon phototriggering with UV light. The volume change of these monodisperse nanoparticles comprising spiropyran, which undergoes reversible photoisomerization, and PEGylated lipid enables repetitive dosing from a single administration and enhances tissue penetration. The photoswitching allows particles to fluoresce and release drugs inside cells when illuminated with UV light. The mechanism of the light-induced size switching and triggered-release is studied. These particles provide spatiotemporal control of drug release and enhanced tissue penetration, useful properties in many disease states including cancer.

2012-01-01

434

Imaging and drug delivery using theranostic nanoparticles?  

PubMed Central

Nanoparticle technologies are significantly impacting the development of both therapeutic and diagnostic agents. At the intersection between treatment and diagnosis, interest has grown in combining both paradigms into clinically effective formulations. This concept, recently coined as theranostics, is highly relevant to agents that target molecular biomarkers of disease and is expected to contribute to personalized medicine. Here we review state-of-the-art nanoparticles from a therapeutic and a diagnostic perspective and discuss challenges in bringing these fields together. Major classes of nanoparticles include, drug conjugates and complexes, dendrimers, vesicles, micelles, core–shell particles, microbubbles, and carbon nanotubes. Most of these formulations have been described as carriers of either drugs or contrast agents. To observe these formulations and their interactions with disease, a variety of contrast agents have been used, including optically active small molecules, metals and metal oxides, ultrasonic contrast agents, and radionuclides. The opportunity to rapidly assess and adjust treatment to the needs of the individual offers potential advantages that will spur the development of theranostic agents.

MacKay, J. Andrew

2013-01-01

435

Substituted amylose matrices for oral drug delivery  

NASA Astrophysics Data System (ADS)

High amylose corn starch was used to obtain substituted amylose (SA) polymers by chemically modifying hydroxyl groups by an etherification process using 1,2-epoxypropanol. Tablets for drug-controlled release were prepared by direct compression and their release properties assessed by an in vitro dissolution test (USP XXIII no 2). The polymer swelling was characterized by measuring gravimetrically the water uptake ability of polymer tablets. SA hydrophilic matrix tablets present sequentially a burst effect, typical of hydrophilic matrices, and a near constant release, typical of reservoir systems. After the burst effect, surface pores disappear progressively by molecular association of amylose chains; this allows the creation of a polymer layer acting as a diffusion barrier and explains the peculiar behaviour of SA polymers. Several formulation parameters such as compression force, drug loading, tablet weight and insoluble diluent concentration were investigated. On the other hand, tablet thickness, scanning electron microscope analysis and mercury intrusion porosimetry showed that the high crushing strength values observed for SA tablets were due to an unusual melting process occurring during tabletting although the tablet external layer went only through densification, deformation and partial melting. In contrast, HPMC tablets did not show any traces of a melting process.

Moghadam, S. H.; Wang, H. W.; Saddar El-Leithy, E.; Chebli, C.; Cartilier, L.

2007-03-01

436

Enhanced drug delivery capabilities from stents coated with absorbable polymer and crystalline drug.  

PubMed

Current drug eluting stent (DES) technology is not optimized with regard to the pharmacokinetics of drug delivery. A novel, absorbable-coating sirolimus-eluting stent (AC-SES) was evaluated for its capacity to deliver drug more evenly within the intimal area rather than concentrating drug around the stent struts and for its ability to match coating erosion with drug release. The coating consisted of absorbable poly-lactide-co-glycolic acid (PLGA) and crystalline sirolimus deposited by a dry-powder electrostatic process. The AC-SES demonstrated enhanced drug stability under simulated use conditions and consistent drug delivery balanced with coating erosion in a porcine coronary implant model. The initial drug burst was eliminated and drug release was sustained after implantation. The coating was absorbed within 90 days. Following implantation into porcine coronary arteries the AC-SES coating is distributed in the surrounding intimal tissue over the course of several weeks. Computational modeling of drug delivery characteristics demonstrates how distributed coating optimizes the load of drug immediately around each stent strut and extends drug delivery between stent struts. The result was a highly efficient arterial uptake of drug with superior performance to a clinical bare metal stent (BMS). Neointimal thickness (0.17±0.07 mm vs. 0.28±0.11 mm) and area percent stenosis (22±9% vs. 35±12%) were significantly reduced (p<0.05) by the AC-SES compared to the BMS 30 days after stent implantation in an overlap configuration in porcine coronary arteries. Inflammation was significantly reduced in the AC-SES compared to the BMS at both 30 and 90 days after implantation. Biocompatible, rapidly absorbable stent coatings enable the matching of drug release with coating erosion and provide for the controlled migration of coating material into tissue to reduce vicissitudes in drug tissue levels, optimizing efficacy and reducing potential toxicity. PMID:22800575

Carlyle, Wenda C; McClain, James B; Tzafriri, Abraham R; Bailey, Lynn; Zani, Brett G; Markham, Peter M; Stanley, James R L; Edelman, Elazer R

2012-07-16

437

pH-responsive Nanoparticles for Drug Delivery  

PubMed Central

First-generation nanoparticles (NPs) have been clinically translated as pharmaceutical drug delivery carriers for their ability to improve on drug tolerability, circulation half-life, and efficacy. Towards the development of the next-generation NPs, researchers have designed novel multifunctional platforms for sustained release, molecular targeting, and environmental responsiveness. This review focuses on environmentally-responsive mechanisms used in NP designs, and highlights the use of pH-responsive NPs in drug delivery. Different organs, tissues, and subcellular compartments – as well as their pathophysiological states – can be characterized by their pH levels and gradients. When exposed to these pH stimuli, pH-responsive NPs respond with physicochemical changes to their material structure and surface characteristics. These include swelling, dissociating or surface charge switching, in a manner that favors drug release at the target site over surrounding tissues. The novel developments described here may revise the classical outlook that NPs are passive delivery vehicles, in favor of responsive, sensing vehicles that use environmental cues to achieve maximal drug potency.

Gao, Weiwei; Chan, Juliana; Farokhzad, Omid C.

2010-01-01

438

Imaging Drug Delivery to Skin with Stimulated Raman Scattering Microscopy  

PubMed Central

Efficient drug delivery to the skin is essential for the treatment of major dermatologic diseases, such as eczema, psoriasis and acne. However, many compounds penetrate the skin barrier poorly and require optimized formulations to ensure their bioavailability. Here, stimulated Raman scattering (SRS) microscopy, a recently-developed, label-free chemical imaging tool, is used to acquire high resolution images of multiple chemical components of a topical formulation as it penetrates into mammalian skin. This technique uniquely provides label-free, non-destructive, three-dimensional images with high spatiotemporal resolution. It reveals novel features of (trans)dermal drug delivery in the tissue environment: different rates of drug penetration via hair follicles as compared to the intercellular pathway across the stratum corneum are directly observed, and the precipitation of drug crystals on the skin surface is visualized after the percutaneous penetration of the co-solvent excipient in the formulation. The high speed three-dimensional imaging capability of SRS thus reveals features that cannot be seen with other techniques, providing both kinetic information and mechanistic insight into the (trans)dermal drug delivery process.

Saar, Brian G.; Contreras-Rojas, L. Rodrigo; Xie, X. Sunney; Guy, Richard H.

2011-01-01

439

Drug delivery with carbon nanotubes for in vivo cancer treatment  

PubMed Central

Chemically functionalized single-walled carbon nanotubes (SWNTs) have shown promise in tumor targeted accumulation in mice and exhibit biocompatibility, excretion and little toxicity. Here, we demonstrate in-vivo SWNT drug delivery for tumor suppression in mice. We conjugate paclitaxel (PTX), a widely used cancer chemotherapy drug to branched polyethylene-glycol (PEG) chains on SWNTs via a cleavable ester bond to obtain a water soluble SWNT-paclitaxel conjugate (SWNT-PTX). SWNT-PTX affords higher efficacy in suppressing tumor growth than clinical Taxol® in a murine 4T1 breast-cancer model, owing to prolonged blood circulation and 10-fold higher tumor PTX uptake by SWNT delivery likely through enhanced permeability and retention (EPR). Drug molecules carried into the reticuloendothelial system are released from SWNTs and excreted via biliary pathway without causing obvious toxic effects to normal organs. Thus, nanotube drug delivery is promising for high treatment efficacy and minimum side effects for future cancer therapy with low drug doses.

Liu, Zhuang; Chen, Kai; Davis, Corrine; Sherlock, Sarah; Cao, Qizhen; Chen, Xiaoyuan; Dai, Hongjie

2008-01-01

440

Imaging drug delivery to skin with stimulated Raman scattering microscopy.  

PubMed

Efficient drug delivery to the skin is essential for the treatment of major dermatologic diseases, such as eczema, psoriasis and acne. However, many compounds penetrate the skin barrier poorly and require optimized formulations to ensure their bioavailability. Here, stimulated Raman scattering (SRS) microscopy, a recently developed, label-free chemical imaging tool, is used to acquire high resolution images of multiple chemical components of a topical formulation as it penetrates into mammalian skin. This technique uniquely provides label-free, nondestructive, three-dimensional images with high spatiotemporal resolution. It reveals novel features of (trans)dermal drug delivery in the tissue environment: different rates of drug penetration via hair follicles as compared to the intercellular pathway across the stratum corneum are directly observed, and the precipitation of drug crystals on the skin surface is visualized after the percutaneous penetration of the cosolvent excipient in the formulation. The high speed three-dimensional imaging capability of SRS thus reveals features that cannot be seen with other techniques, providing both kinetic information and mechanistic insight into the (trans)dermal drug delivery process. PMID:21548600

Saar, Brian G; Contreras-Rojas, L Rodrigo; Xie, X Sunney; Guy, Richard H

2011-05-17

441

Microsponges: A novel strategy for drug delivery system  

PubMed Central

Microsponges are polymeric delivery systems composed of porous microspheres. They are tiny sponge-like spherical particles with a large porous surface. Moreover, they may enhance stability, reduce side effects and modify drug release favorably. Microsponge technology has many favorable characteristics, which make it a versatile drug delivery vehicle. Microsponge Systems are based on microscopic, polymer-based microspheres that can suspend or entrap a wide variety of substances, and can then be incorporated into a formulated product such as a gel, cream, liquid or powder. The outer surface is typically porous, allowing a sustained flow of substances out of the sphere. Microsponges are porous, polymeric microspheres that are used mostly for topical use and have recently been used for oral administration. Microsponges are designed to deliver a pharmaceutical active ingredient efficiently at the minimum dose and also to enhance stability, reduce side effects, and modify drug release.

Kaity, Santanu; Maiti, Sabyasachi; Ghosh, Ashoke Kumar; Pal, Dilipkumar; Ghosh, Animesh; Banerjee, Subham

2010-01-01

442

Microsponges: A novel strategy for drug delivery system.  

PubMed

Microsponges are polymeric delivery systems composed of porous microspheres. They are tiny sponge-like spherical particles with a large porous surface. Moreover, they may enhance stability, reduce side effects and modify drug release favorably. Microsponge technology has many favorable characteristics, which make it a versatile drug delivery vehicle. Microsponge Systems are based on microscopic, polymer-based microspheres that can suspend or entrap a wide variety of substances, and can then be incorporated into a formulated product such as a gel, cream, liquid or powder. The outer surface is typically porous, allowing a sustained flow of substances out of the sphere. Microsponges are porous, polymeric microspheres that are used mostly for topical use and have recently been used for oral administration. Microsponges are designed to deliver a pharmaceutical active ingredient efficiently at the minimum dose and also to enhance stability, reduce side effects, and modify drug release. PMID:22247859

Kaity, Santanu; Maiti, Sabyasachi; Ghosh, Ashoke Kumar; Pal, Dilipkumar; Ghosh, Animesh; Banerjee, Subham

2010-07-01

443

New Technologies for Drug Delivery across the Blood Brain Barrier  

PubMed Central

The blood-brain barrier (BBB) efficiently restricts penetration of therapeutic agents to the brain from the periphery. Therefore, discovery of new modalities allowing for effective delivery of drugs and biomacromolecules to the central nervous system (CNS) is of great need and importance for treatment of neurodegenerative disorders. This manuscript focuses on three relatively new strategies. The first strategy involves inhibition of the drug efflux transporters expressed in BBB by Pluronic® block copolymers, which allows for the increased transport of the substrates of these transporters to the brain. The second strategy involves the design of nanoparticles conjugated with specific ligands that can target receptors in the brain microvasculature and carry the drugs to the brain through the receptor mediated transcytosis. The third strategy involves artificial hydrophobization of peptides and proteins that facilitates the delivery of these peptides and proteins across BBB. This review discusses the current state, advantages and limitations of each of the three technologies and outlines their future prospects.

Kabanov, A.V.; Batrakova, E.V.

2009-01-01

444

Functionalized mesoporous silica materials for controlled drug delivery.  

PubMed

In the past decade, non-invasive and biocompatible mesoporous silica materials as efficient drug delivery systems have attracted special attention. Great progress in structure control and functionalization (magnetism and luminescence) design has been achieved for biotechnological and biomedical applications. This review highlights the most recent research progress on silica-based controlled drug delivery systems, including: (i) pure mesoporous silica sustained-release systems, (ii) magnetism and/or luminescence functionalized mesoporous silica systems which integrate targeting and tracking abilities of drug molecules, and (iii) stimuli-responsive controlled release systems which are able to respond to environmental changes, such as pH, redox potential, temperature, photoirradiation, and biomolecules. Although encouraging and potential developments have been achieved, design and mass production of novel multifunctional carriers, some practical biological application, such as biodistribution, the acute and chronic toxicities, long-term stability, circulation properties and targeting efficacy in vivo are still challenging. PMID:22441299

Yang, Piaoping; Gai, Shili; Lin, Jun

2012-03-22

445

Porous silicon in drug delivery devices and materials?  

PubMed Central

Porous Si exhibits a number of properties that make it an attractive material for controlled drug delivery applications: The electrochemical synthesis allows construction of tailored pore sizes and volumes that are controllable from the scale of microns to nanometers; a number of convenient chemistries exist for the modification of porous Si surfaces that can be used to control the amount, identity, and in vivo release rate of drug payloads and the resorption rate of the porous host matrix; the material can be used as a template for organic and biopolymers, to prepare composites with a designed nanostructure; and finally, the optical properties of photonic structures prepared from this material provide a self-reporting feature that can be monitored in vivo. This paper reviews the preparation, chemistry, and properties of electrochemically prepared porous Si or SiO2 hosts relevant to drug delivery applications.

Anglin, Emily J.; Cheng, Lingyun; Freeman, William R.; Sailor, Michael J.

2009-01-01

446

[Recent trend of transdermal drug delivery system development].  

PubMed

The potential of transdermal drug delivery systems has been demonstrated in recent years with the approval of several medicines for use by patients who are unable to use conventional dosage routes, like oral administration or injection. To enhance the TDDS (Transdermal Drug Delivery System) potential to include other drug candidates, many researchers have been exploring enhancement approaches to increase the permeability of various drugs through the skin. Recently, physical enhancement systems are being reported as having big potential by many researchers. In particular, iontophoresis is a very attractive way of delivering ionized drugs by the application of an electric field to the skin. This has been marketed with some topical and systemic drugs (lidocaine and fentanyl). Sonophoresis is also an attractive method to deliver a drug through the skin using ultrasound. Besides these technologies, various physical approaches are under study. Such technologies can be expected to deliver not only small MW compounds but also macromolecules like peptides. In this article, after looking back through the history of TDDS development, I would like to summarize with new physical and chemical approaches and outline of the new trend of TDDS development with those enhancement system. PMID:17409694

Higo, Naruhito

2007-04-01

447

Oral drug delivery systems using chemical conjugates or physical complexes.  

PubMed

Oral delivery of therapeutics is extremely challenging. The digestive system is designed in a way that naturally allows the degradation of proteins or peptides into small molecules prior to absorption. For systemic absorption, the intact drug molecules must traverse the impending harsh gastrointestinal environment. Technologies, such as enteric coating, with oral dosage formulation strategies have successfully provided the protection of non-peptide based therapeutics against the harsh, acidic condition of the stomach. However, these technologies showed limited success on the protection of therapeutic proteins and peptides. Importantly, inherent permeability coefficient of the therapeutics is still a major problem that has remained unresolved for decades. Addressing this issue in the context, we summarize the strategies that are developed in enhancing the intestinal permeability of a drug molecule either by modifying the intestinal epithelium or by modifying the drug itself. These modifications have been pursued by using a group of molecules that can be conjugated to the drug molecule to alter the cell permeability of the drug or mixed with the drug molecule to alter the epithelial barrier function, in order to achieve the effective drug permeation. This article will address the current trends and future perspectives of the oral delivery strategies. PMID:23220326

Al-Hilal, Taslim A; Alam, Farzana; Byun, Youngro

2012-12-07

448

Doxorubicin and paclitaxel loaded microbubbles for ultrasound triggered drug delivery  

PubMed Central

A polymer ultrasound contrast agent (UCA) developed in our lab has been shown to greatly reduce in size when exposed to ultrasound, resulting in nanoparticles less than 400 nm in diameter capable of escaping the leaky vasculature of a tumor to provide a sustained release of drug. Previous studies with the hydrophilic drug doxorubicin (DOX) demonstrated enhanced drug delivery to tumors when triggered with ultrasound. However the therapeutic potential has been limited due to the relatively low payload of DOX. This study compares