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Sample records for 2d6-mediated dextromethorphan o-demethylation

  1. Dextromethorphan

    MedlinePlus

    Children's Robitussin Cough Long-Acting® ... Vicks DayQuil Cough® ... Vicks Formula 44 Custom Care Dry Cough® ... Zicam Cough MAX® ... Dextromethorphan is used to temporarily relieve cough caused by the common cold, the flu, or other conditions. Dextromethorphan will relieve a cough but will not treat the cause of ...

  2. Dextromethorphan

    MedlinePlus

    ... for your symptoms. Check nonprescription cough and cold product labels carefully before using 2 or more products at ... adults to children.Before you give a dextromethorphan product to a child, check the package label to find out how much medication the child ...

  3. Dextromethorphan overdose

    MedlinePlus

    DXM overdose; Robo overdose; Orange crush overdose; Red devils overdose; Triple C's overdose ... under the names: Orange crush Triple Cs Red Devils Skittles Dex Other products may also contain dextromethorphan.

  4. Inhibition of dextromethorphan metabolism by moclobemide.

    PubMed

    Härtter, S; Dingemanse, J; Baier, D; Ziegler, G; Hiemke, C

    1998-01-01

    This pilot study was conducted to evaluate the potential of the new antidepressant moclobemide to inhibit the cytochrome enzyme P4502D6 (CYP2D6) using the cough suppressant dextromethorphan as a substrate in four extensive metabolizers (EM) of debrisoquine. The subjects received seven oral doses of 20 mg dextromethorphan at 4-h intervals over 2 days (1 and 2) and subsequently moclobemide (300 mg b.i.d.) for 9 days. On days 10 and 11, they received seven doses of 20 mg dextromethorphan in addition to moclobemide. During monotreatment and combined treatment, blood was collected on days 2 and 11, respectively, for determination of dextromethorphan and its demethylated metabolites using automated high-performance liquid chromatography with column switching. Concurrent administration of moclobemide markedly reduced the O-demethylation of dextromethorphan, whereas the N-demethylation of dextrorphan to hydroxymorphinan was not affected. The findings indicate that moclobemide can affect the pharmacokinetics of drugs that are mainly metabolized by CYP2D6. PMID:9489930

  5. Anaerobic O-demethylation of phenylmethylethers

    SciTech Connect

    Frazer, A.C.; Young, L.Y.

    1990-01-01

    Anaerobic O-demethylation (AOD) of phenylmethylethers is a process of both basic and applied significance. The aryl-O-methyl ethers are abundant in natural products, particularly as components of lignin. They are present as methoxylated lignin monomers in anaerobic environments and can be completely degraded there by mixed microbial populations. AOD is an essential early step in this process, and it is also a key reaction in the utilization of the O-methyl substituent as a C-one substrate by acetogens. An understanding of the AOD reaction mechanism might suggest new ways in which chemicals could be derived from lignocellulosic materials. The biochemical mechanism for the anaerobic cleavage of the aryl-O-methyl ether bond is an intriguing, but relatively unexplored process. In contrast to aerobic O-demethylating enzymes, AOD appears to involve methyl group transfer. Thus, novel biochemical information on an important biotransformation reaction will be gained from the research proposed. Recently, we have shown that AOD activity is inducible and have developed an assay for detecting AOD activity in cell-free extracts of Acetobacterium woodii. AOD activity is stimulated in vitro by the addition of ATP (1mM) and pyruvate (30 mM), the K{sub M} for vanillate being 0.4 mM. In collaboration with protein purification experts, we proposed to purify the AOD enzyme and characterize the protein(s) and the enzymatic reaction involved. 8 figs., 5 tabs.

  6. Understanding the determinants of selectivity in drug metabolism through modeling of dextromethorphan oxidation by cytochrome P450

    PubMed Central

    Oláh, Julianna; Mulholland, Adrian J.; Harvey, Jeremy N.

    2011-01-01

    Cytochrome P450 enzymes play key roles in the metabolism of the majority of drugs. Improved models for prediction of likely metabolites will contribute to drug development. In this work, two possible metabolic routes (aromatic carbon oxidation and O-demethylation) of dextromethorphan are compared using molecular dynamics (MD) simulations and density functional theory (DFT). The DFT results on a small active site model suggest that both reactions might occur competitively. Docking and MD studies of dextromethorphan in the active site of P450 2D6 show that the dextromethorphan is located close to heme oxygen in a geometry apparently consistent with competitive metabolism. In contrast, calculations of the reaction path in a large protein model [using a hybrid quantum mechanical–molecular mechanics (QM/MM) method] show a very strong preference for O-demethylation, in accordance with experimental results. The aromatic carbon oxidation reaction is predicted to have a high activation energy, due to the active site preventing formation of a favorable transition-state structure. Hence, the QM/MM calculations demonstrate a crucial role of many active site residues in determining reactivity of dextromethorphan in P450 2D6. Beyond substrate binding orientation and reactivity of Compound I, successful metabolite predictions must take into account the detailed mechanism of oxidation in the protein. These results demonstrate the potential of QM/MM methods to investigate specificity in drug metabolism. PMID:21444768

  7. Dextromethorphan Abuse in Adolescence

    PubMed Central

    Bryner, Jodi K.; Wang, Uerica K.; Hui, Jenny W.; Bedodo, Merilin; MacDougall, Conan; Anderson, Ilene B.

    2008-01-01

    Objectives To analyze the trend of dextromethorphan abuse in California and to compare these findings with national trends. Design A 6-year retrospective review. Setting California Poison Control System (CPCS), American Association of Poison Control Centers (AAPCC), and Drug Abuse Warning Network (DAWN) databases from January 1, 1999, to December 31, 2004. Participants All dextromethorphan abuse cases reported to the CPCS, AAPCC, and DAWN. The main exposures of dextromethorphan abuse cases included date of exposure, age, acute vs long-term use, coingestants, product formulation, and clinical outcome. Main Outcome Measure The annual proportion of dextromethorphan abuse cases among all exposures reported to the CPCS, AAPCC, and DAWN databases. Results A total of 1382 CPCS cases were included in the study. A 10-fold increase in CPCS dextromethorphan abuse cases from 1999 (0.23 cases per 1000 calls) to 2004 (2.15 cases per 1000 calls) (odds ratio, 1.48; 95% confidence interval, 1.43–1.54) was identified. Of all CPCS dextromethorphan abuse cases, 74.5% were aged 9 to 17 years; the frequency of cases among this age group increased more than 15-fold during the study (from 0.11 to 1.68 cases per 1000 calls). Similar trends were seen in the AAPCC and DAWN databases. The highest frequency of dextromethorphan abuse occurred among adolescents aged 15 and 16 years. The most commonly abused product was Coricidin HBP Cough & Cold Tablets. Conclusions Our study revealed an increasing trend of dextromethorphan abuse cases reported to the CPCS that is paralleled nationally as reported to the AAPCC and DAWN. This increase was most evident in the adolescent population. PMID:17146018

  8. Biochemistry and Occurrence of O-Demethylation in Plant Metabolism

    PubMed Central

    Hagel, Jillian M.; Facchini, Peter J.

    2010-01-01

    Demethylases play a pivitol role in numerous biological processes from covalent histone modification and DNA repair to specialized metabolism in plants and microorganisms. Enzymes that catalyze O- and N-demethylation include 2-oxoglutarate (2OG)/Fe(II)-dependent dioxygenases, cytochromes P450, Rieske-domain proteins and flavin adenine dinucleotide (FAD)-dependent oxidases. Proposed mechanisms for demethylation by 2OG/Fe(II)-dependent enzymes involve hydroxylation at the O- or N-linked methyl group followed by formaldehyde elimination. Members of this enzyme family catalyze a wide variety of reactions in diverse plant metabolic pathways. Recently, we showed that 2OG/Fe(II)-dependent dioxygenases catalyze the unique O-demethylation steps of morphine biosynthesis in opium poppy, which provides a rational basis for the widespread occurrence of demethylases in benzylisoquinoline alkaloid metabolism. PMID:21423357

  9. Sulfation of o-demethyl apixaban: enzyme identification and species comparison.

    PubMed

    Wang, Lifei; Raghavan, Nirmala; He, Kan; Luettgen, Joseph M; Humphreys, W Griffith; Knabb, Robert M; Pinto, Donald J; Zhang, Donglu

    2009-04-01

    Apixaban, a potent and highly selective factor Xa inhibitor, is currently under development for treatment of arterial and venous thrombotic diseases. The O-demethyl apixaban sulfate is a major circulating metabolite in humans but circulates at lower concentrations relative to parent in animals. The aim of this study was to identify the sulfotransferases (SULTs) responsible for the sulfation reaction. Apixaban undergoes O-demethylation catalyzed by cytochrome P450 enzymes to O-demethyl apixaban, and then is conjugated by SULTs to form O-demethyl apixaban sulfate. Of the five human cDNA-expressed SULTs tested, SULT1A1 and SULT1A2 exhibited significant levels of catalytic activity for formation of O-demethyl apixaban sulfate, and SULT1A3, SULT1E1, and SULT2A1 showed much lower catalytic activities. In human liver S9, quercetin, a highly selective inhibitor of SULT1A1 and SULT1E1, inhibited O-demethyl apixaban sulfate formation by 99%; 2,6-dichloro-4-nitrophenol, another inhibitor of SULT1A1, also inhibited this reaction by >90%; estrone, a competitive inhibitor for SULT1E1, had no effect on this reaction. The comparable K(m) values for formation of O-demethyl apixaban sulfate were 41.4 microM (human liver S9), 36.8 microM (SULT1A1), and 70.8 microM (SULT1A2). Because of the high level of expression of SULT1A1 in liver and its higher level of catalytic activity for formation of O-demethyl apixaban sulfate, SULT1A1 might play a major role in humans for formation of O-demethyl apixaban sulfate. O-Demethyl apixaban was also investigated in liver S9 of mice, rats, rabbits, dogs, monkeys, and humans. The results indicated that liver S9 samples from dogs, monkeys, and humans had higher activities for formation of O-demethyl apixaban sulfate than those of mice, rats, and rabbits. PMID:19131519

  10. Inhalant Abuse and Dextromethorphan.

    PubMed

    Storck, Michael; Black, Laura; Liddell, Morgan

    2016-07-01

    Inhalant abuse is the intentional inhalation of a volatile substance for the purpose of achieving an altered mental state. As an important, yet underrecognized form of substance abuse, inhalant abuse crosses all demographic, ethnic, and socioeconomic boundaries, causing significant morbidity and mortality in school-aged and older children. This review presents current perspectives on epidemiology, detection, and clinical challenges of inhalant abuse and offers advice regarding the medical and mental health providers' roles in the prevention and management of this substance abuse problem. Also discussed is the misuse of a specific "over-the-counter" dissociative, dextromethorphan. PMID:27338970

  11. Anaerobic O-demethylation of phenylmethylethers. [und Acetobacterium woodii :a3

    SciTech Connect

    Frazer, A.C.; Young, L.Y.

    1991-08-01

    Assay of O-demethylation in cell-free extracts of Acetobacterium woodii: we have shown that THF and ATP are necessary for enzyme activity and thus are probably reactants; apparent Km values were 0.65 mM for the methoxylated substrate, 0.27 mM for ATP, and 0.17 mM for DL-THF. The enzyme activity is present in the cytosol, rather than being membrane bound, and is sensitive to oxygen. There is evidence to suggest that the enzyme system involves more than one protein component. Studies using suspensions of whole cells, suggest that there are several inducible AOD systems with distinguishable substrate specificities in A. woodii. A similar phenomenon has previously been suggested for the related acetogen, Eubacterium limosum. We have developed a system for obtaining mutants that are deficient in O-demethylation (AOD{sup {minus}}) in E. limosum, by using transposon mutagenesis with Tn916. In an ancillary study, A. woodii and E. limosum, were compared with respect to their capacity to O-demethylate guaiacol and chloroguaiacols. 8 refs., 1 fig., 1 tab.

  12. Importance of tetrahydrofolate and ATP in the anaerobic O-demethylation reaction for phenylmethylethers.

    PubMed

    Berman, M H; Frazer, A C

    1992-03-01

    DL-Tetrahydrofolate (THF) and ATP were necessary for the anaerobic O-demethylation of phenylmethylethers in cell extracts of the type strain (ATCC 29683) of the homoacetogen Acetobacterium woodii. The reactants for this enzymatic activity have not been previously demonstrated in any system, nor has the mediating enzyme been studied. An assay using reaction mixtures containing 1 mM THF, 2 mM ATP, and 2 mM hydroferulate (i.e., 4-hydroxy,3-methoxyphenylpropionate) was developed and was performed under stringent anaerobic conditions. Pyridine nucleotides and several other possible cofactors were tested but had no effect on the activity. After centrifugation of disrupted cells at 27,000 x g, the activity was found primarily in the supernatant, which had a specific activity of 14.2 +/- 0.5 nmol/min/mg of protein. At saturating levels of each of the other two substrates, apparent Km values for the variable substrate were 0.65 mM hydroferulate, 0.27 mM ATP, and 0.17 mM THF. Activity was significantly decreased when extract was preincubated at 60 degrees C and was completely lost after preincubation in air for 30 min. Thus, the soluble anaerobic O-demethylating enzyme system of A. woodii is oxygen sensitive. The THF- and ATP-dependent activity measurable in the soluble fraction of cell extracts constituted about 34% of the activity seen with intact cells. PMID:1575495

  13. Importance of tetrahydrofolate and ATP in the anaerobic O-demethylation reaction for phenylmethylethers

    SciTech Connect

    Berman, M.H.; Frazer, A.C. )

    1992-03-01

    DL-Tetrahydrofolate (THF) and ATP were necessary for the anaerobic O-demethylation of phenylmethylethers in cell extracts of the type strain (ATCC 29683) of the homoacetogen Acetobacterium woodii. The reactants for this enzymatic activity have not been previously demonstrated in any system, nor has the mediating enzyme been studied. An assay using reaction mixtures containing 1 mM THF, 2 mM ATP, and 2 mM hydroferulate (i.e., 4-hydroxy,3-methoxyphenylpropionate) was developed and was performed under stringent anaerobic conditions. Pyridine nucleotides and several other possible cofactors were tested but had no effect on the activity. After centrifugation of disrupted cells at 27,000 x g, the activity was found primarily in the supernatant, which had a specific activity of 14.2 {plus minus} 0.5 nmol/min/mg of protein. At saturating levels of each of the other two substrates, apparent K{sub m} values for the variable substrate were 0.65 mM hydroferulate, 0.27 mM ATP, and 0.17 mM THF. Activity was significantly decreased when extract was preincubated at 60C and was completely lost after preincubation in air for 30 min. Thus, the soluble anaerobic O-demethylating enzyme system of A. woodii is oxygen sensitive. The THF- and ATP-dependent activity measurable in the soluble fraction of cell extracts constituted about 34% of the activity seen with intact cells.

  14. Human Enteric Microsomal CYP4F Enzymes O-Demethylate the Antiparasitic Prodrug Pafuramidine

    PubMed Central

    Wang, Michael Zhuo; Wu, Judy Qiju; Bridges, Arlene S.; Zeldin, Darryl C.; Kornbluth, Sally; Tidwell, Richard R.; Hall, James Edwin; Paine, Mary F.

    2008-01-01

    CYP4F enzymes, including CYP4F2 and CYP4F3B, were recently shown to be the major enzymes catalyzing the initial oxidative O-demethylation of the antiparasitic prodrug pafuramidine (DB289) by human liver microsomes. As suggested by a low oral bioavailability, DB289 could undergo first-pass biotransformation in the intestine, as well as in the liver. Using human intestinal microsomes (HIM), we characterized the enteric enzymes that catalyze the initial O-demethylation of DB289 to the intermediate metabolite, M1. M1 formation in HIM was catalyzed by cytochrome P450 (P450) enzymes, as evidenced by potent inhibition by 1-aminoben-zotriazole and the requirement for NADPH. Apparent Km and Vmax values ranged from 0.6 to 2.4 μM and from 0.02 to 0.89 nmol/min/mg protein, respectively (n = 9). Of the P450 chemical inhibitors evaluated, ketoconazole was the most potent, inhibiting M1 formation by 66%. Two inhibitors of P450-mediated arachidonic acid metabolism, HET0016 (N-hydroxy-N′-(4-n-butyl-2-methylphenyl)formamidine) and 17-octadecynoic acid, inhibited M1 formation in a concentration-dependent manner (up to 95%). Immunoinhibition with an antibody raised against CYP4F2 showed concentration-dependent inhibition of M1 formation (up to 92%), whereas antibodies against CYP3A4/5 and CYP2J2 had negligible to modest effects. M1 formation rates correlated strongly with arachidonic acid ω-hydroxylation rates (r2 = 0.94, P < 0.0001, n = 12) in a panel of HIM that lacked detectable CYP4A11 protein expression. Quantitative Western blot analysis revealed appreciable CYP4F expression in these HIM, with a mean (range) of 7 (3–18) pmol/mg protein. We conclude that enteric CYP4F enzymes could play a role in the first-pass biotransformation of DB289 and other xenobiotics. PMID:17709372

  15. O-Demethylation and Successive Oxidative Dechlorination of Methoxychlor by Bradyrhizobium sp. Strain 17-4, Isolated from River Sediment

    PubMed Central

    Masuda, Minoru; Sato, Kiyoshi

    2012-01-01

    O-Demethylation of insecticide methoxychlor is well known as a phase I metabolic reaction in various eukaryotic organisms. Regarding prokaryotic organisms, however, no individual species involved in such reaction have been specified and characterized so far. Here we successfully isolated a bacterium that mediates oxidative transformation of methoxychlor, including O-demethylation and dechlorination, from river sediment. The isolate was found to be closely related to Bradyrhizobium elkanii at the 16S rRNA gene sequence level (100% identical). However, based on some differences in the physiological properties of this bacterium, we determined that it was actually a different species, Bradyrhizobium sp. strain 17-4. The isolate mediated O-demethylation of methoxychlor to yield a monophenolic derivative [Mono-OH; 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane] as the primary degradation product. The chiral high-performance liquid chromatography (HPLC) analysis revealed that the isolate possesses high enantioselectivity favoring the formation of (S)-Mono-OH (nearly 100%). Accompanied by the sequential O-demethylation to form the bis-phenolic derivative Bis-OH [1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane], oxidative dechlorination of the side chain proceeded, and monophenolic carboxylic acid accumulated, followed by the formation of multiple unidentified polar degradation products. The breakdown proceeded more rapidly when reductively dechlorinated (dichloro-form) methoxychlor was applied as the initial substrate. The resultant carboxylic acids and polar degradation products are likely further biodegraded by ubiquitous bacteria. The isolate possibly plays an important role for complete degradation (mineralization) of methoxychlor by providing the readily biodegradable substrates. PMID:22635993

  16. H2-CO2-Dependent Anaerobic O-Demethylation Activity in Subsurface Sediments and by an Isolated Bacterium

    PubMed Central

    Liu, Shi; Suflita, Joseph M.

    1993-01-01

    The ability of microorganisms in sediments from the Atlantic Coastal Plain to biodegrade methoxylated aromatic compounds was examined. O-demethylation activity was detected in deep (121- and 406-m) sediments, as well as in the surface soil. A syringate-demethylating consortium, containing at least three types of bacteria, was enriched from a deep-sediment sample in a medium containing syringate as the sole organic carbon source and with a N2-CO2 atmosphere. An isolate which demethylated syringate was obtained from the enrichment on an agar medium incubated under a H2-CO2 but not a N2-CO2 or N2 atmosphere. O demethylation of syringate of this isolate was dependent on the presence of both H2 and CO2 in the gas phase. The metabolism of syringate occurred in a sequential manner: methylgallate accumulated transiently before it was converted to gallate. Mass balance analysis suggests that the stoichiometry of the reaction in this isolate proceeds in accordance with the following generalized equation: C7H3O3(OCH3)n- + nHCO3- + nH2 → C7H3O3(OH)n- + nCH3COO- + nH2O. Images PMID:16348928

  17. The Roles of a Flavone-6-Hydroxylase and 7-O-Demethylation in the Flavone Biosynthetic Network of Sweet Basil*

    PubMed Central

    Berim, Anna; Gang, David R.

    2013-01-01

    Lipophilic flavonoids found in the Lamiaceae exhibit unusual 6- and 8-hydroxylations whose enzymatic basis is unknown. We show that crude protein extracts from peltate trichomes of sweet basil (Ocimum basilicum L.) cultivars readily hydroxylate position 6 of 7-O-methylated apigenin but not apigenin itself. The responsible protein was identified as a P450 monooxygenase from the CYP82 family, a family not previously reported to be involved in flavonoid metabolism. This enzyme prefers flavones but also accepts flavanones in vitro and requires a 5-hydroxyl in addition to a 7-methoxyl residue on the substrate. A peppermint (Mentha × piperita L.) homolog displayed identical substrate requirements, suggesting that early 7-O-methylation of flavones might be common in the Lamiaceae. This hypothesis is further substantiated by the pioneering discovery of 2-oxoglutarate-dependent flavone demethylase activity in basil, which explains the accumulation of 7-O-demethylated flavone nevadensin. PMID:23184958

  18. Dioxygenases Catalyze O-Demethylation and O,O-Demethylenation with Widespread Roles in Benzylisoquinoline Alkaloid Metabolism in Opium Poppy*

    PubMed Central

    Farrow, Scott C.; Facchini, Peter J.

    2013-01-01

    In opium poppy, the antepenultimate and final steps in morphine biosynthesis are catalyzed by the 2-oxoglutarate/Fe(II)-dependent dioxygenases, thebaine 6-O-demethylase (T6ODM) and codeine O-demethylase (CODM). Further investigation into the biochemical functions of CODM and T6ODM revealed extensive and unexpected roles for such enzymes in the metabolism of protopine, benzo[c]phenanthridine, and rhoeadine alkaloids. When assayed with a wide range of benzylisoquinoline alkaloids, CODM, T6ODM, and the functionally unassigned paralog DIOX2, renamed protopine O-dealkylase, showed novel and efficient dealkylation activities, including regio- and substrate-specific O-demethylation and O,O-demethylenation. Enzymes catalyzing O,O-demethylenation, which cleave a methylenedioxy bridge leaving two hydroxyl groups, have previously not been reported in plants. Similar cleavage of methylenedioxy bridges on substituted amphetamines is catalyzed by heme-dependent cytochromes P450 in mammals. Preferred substrates for O,O-demethylenation by CODM and protopine O-dealkylase were protopine alkaloids that serve as intermediates in the biosynthesis of benzo[c]phenanthridine and rhoeadine derivatives. Virus-induced gene silencing used to suppress the abundance of CODM and/or T6ODM transcripts indicated a direct physiological role for these enzymes in the metabolism of protopine alkaloids, and they revealed their indirect involvement in the formation of the antimicrobial benzo[c]phenanthridine sanguinarine and certain rhoeadine alkaloids in opium poppy. PMID:23928311

  19. Abuse of over-the-counter dextromethorphan by teenagers.

    PubMed

    Murray, S; Brewerton, T

    1993-10-01

    Dextromethorphan, the d-isomer of the opiate agonist levorphanol, has none of the analgesic or sedative effects associated with the opiates and is approved for over-the-counter use as an antitussive. It is available, in various combinations with other medications, in nonprescription cough suppressant and common cold formulations, and its availability in the United States is not controlled. In this paper we have reported two cases of recreational use of dextromethorphan-containing cough syrup by two unrelated teenage boys. Despite the safety of this medication when used at the recommended dosage, there have been cases of "recreational" use of dextromethorphan as well as death by overdose. Although usually thought to be nonaddictive, dextromethorphan produces a substance dependence syndrome, and physicians should be aware of its abuse potential, particularly by youths. PMID:8211334

  20. Objective evaluation of dextromethorphan and glaucine as antitussive agents.

    PubMed Central

    Rühle, K H; Criscuolo, D; Dieterich, H A; Köhler, D; Riedel, G

    1984-01-01

    Twenty-four inpatients affected by chronic cough completed a single-dose double-blind cross-over study of placebo, glaucine 30 mg and dextromethorphan 30 mg. The study was carried out using a balanced incomplete block design, each patient receiving two of the three experimental treatments. Objective evaluation of cough was ensured by means of a writing cough recorder. Coughs after dextromethorphan and glaucine were fewer than coughs after placebo: however only glaucine was significantly different from placebo in reducing coughs. Treatments were well tolerated: clinical results included a reduction in pulse rate after both dextromethorphan and glaucine , and a large number of patients reporting side effects after dextromethorphan administration. PMID:6375709

  1. Objective evaluation of dextromethorphan and glaucine as antitussive agents.

    PubMed

    Rühle, K H; Criscuolo, D; Dieterich, H A; Köhler, D; Riedel, G

    1984-05-01

    Twenty-four inpatients affected by chronic cough completed a single-dose double-blind cross-over study of placebo, glaucine 30 mg and dextromethorphan 30 mg. The study was carried out using a balanced incomplete block design, each patient receiving two of the three experimental treatments. Objective evaluation of cough was ensured by means of a writing cough recorder. Coughs after dextromethorphan and glaucine were fewer than coughs after placebo: however only glaucine was significantly different from placebo in reducing coughs. Treatments were well tolerated: clinical results included a reduction in pulse rate after both dextromethorphan and glaucine , and a large number of patients reporting side effects after dextromethorphan administration. PMID:6375709

  2. Patterns and Perceptions of Dextromethorphan Use in Adult Members of an Online Dextromethorphan Community.

    PubMed

    Pringle, George; McDonald, Michael P; Gabriel, Kara I

    2015-01-01

    Dextromethorphan (DXM) is a widely available antitussive that has, at elevated dose levels, euphoric and dissociative effects. This article presents the reported patterns and preferences of DXM use, and perceptions of DXM use among adult members of an online DXM community. Analyses were conducted of quantitative and qualitative responses from nine female and 43 male individuals, aged 18-63 years old. All respondents reported illegal and DXM drug use, beginning, on average, at 15.7 and 17.1 years of age, respectively. The majority of respondents first heard about DXM online or from a friend, preferred to use DXM alone, ingested substances concurrently with DXM to modify its effects, had not been to an emergency room or arrested because of their DXM use, and used DXM for its dissociative and mind-altering effects. DXM was perceived as safe and in no need of further regulation with only 14% of respondents mentioning DXM's addictive qualities. Findings from this sample of adult DXM users reveal a sophisticated subculture in which users report using DXM specifically to induce changes to their mental state and use a variety of substances to modify or enhance DXM's effects. PMID:26266886

  3. Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical use.

    PubMed

    Taylor, Charles P; Traynelis, Stephen F; Siffert, Joao; Pope, Laura E; Matsumoto, Rae R

    2016-08-01

    Dextromethorphan (DM) has been used for more than 50years as an over-the-counter antitussive. Studies have revealed a complex pharmacology of DM with mechanisms beyond blockade of N-methyl-d-aspartate (NMDA) receptors and inhibition of glutamate excitotoxicity, likely contributing to its pharmacological activity and clinical potential. DM is rapidly metabolized to dextrorphan, which has hampered the exploration of DM therapy separate from its metabolites. Coadministration of DM with a low dose of quinidine inhibits DM metabolism, yields greater bioavailability and enables more specific testing of the therapeutic properties of DM apart from its metabolites. The development of the drug combination DM hydrobromide and quinidine sulfate (DM/Q), with subsequent approval by the US Food and Drug Administration for pseudobulbar affect, led to renewed interest in understanding DM pharmacology. This review summarizes the interactions of DM with brain receptors and transporters and also considers its metabolic and pharmacokinetic properties. To assess the potential clinical relevance of these interactions, we provide an analysis comparing DM activity from in vitro functional assays with the estimated free drug DM concentrations in the brain following oral DM/Q administration. The findings suggest that DM/Q likely inhibits serotonin and norepinephrine reuptake and also blocks NMDA receptors with rapid kinetics. Use of DM/Q may also antagonize nicotinic acetylcholine receptors, particularly those composed of α3β4 subunits, and cause agonist activity at sigma-1 receptors. PMID:27139517

  4. Pharmacokinetics of dextromethorphan after single or multiple dosing in combination with quinidine in extensive and poor metabolizers.

    PubMed

    Pope, Laura E; Khalil, M H; Berg, James E; Stiles, Mark; Yakatan, Gerald J; Sellers, Edward M

    2004-10-01

    Dextromethorphan (DM) pharmacological properties predict that the widely used cough suppressant could be used to treat several neuronal disorders, but it is rapidly metabolized after oral dosing. To find out whether quinidine (Q), a CYP2D6 inhibitor, could elevate and prolong DM plasma profiles, 2 multiple-dose studies identified the lowest oral dose of Q that could be used in a fixed combination with 3 doses of DM. A multiple-dose study in healthy subjects with an extensive or a poor enzyme metabolizer phenotype evaluated the safety and pharmacokinetic profile of a selected fixed-dose combination (AVP-923). Study 1 randomized 46 healthy subjects, who were extensive CYP2D6 metabolizers, to receive 0, 2.5, 10, 25, 50, or 75 mg Q twice daily in combination with 30 mg DM for 7 days. Plasma and urine samples were collected after the first and last doses for the assay of DM, dextrorphan (DX), and Q. Study 2 randomized 65 healthy extensive CYP2D6 metabolizers to 8 groups given twice-daily 45- or 60-mg DM doses combined with 0, 30, 45, or 60 mg Q for 7 days. The effects of increasing Q were not different with doses greater than 25 mg, whereas lower doses showed a dose-related increase in plasma DM concentrations. Urinary ratios of DM/DX showed a Q dose- and time-related increase in the number of subjects converted to the poor metabolizer phenotype that reached 100% on day 3 of dosing with 25 mg Q. Results from both studies indicated that 25 to 30 mg Q is adequate to maximally suppress O-demethylation of DM. Study 3 evaluated 7 extensive metabolizers and 2 poor metabolizers given an oral capsule every 12 hours containing 30 mg Q combined with 30 mg DM. DM plasma AUC values increased in both groups of subjects during the 8-day study. The mean urinary metabolic ratio (DM/DX) increased at least 27-fold in extensive metabolizers by day 8. There was no effect of Q on urinary metabolic ratios in poor metabolizers. Safety evaluations, including electrocardiograms, indicated that

  5. [Dextromethorphan enhances analgesic activity of propacetamol--experimental study].

    PubMed

    Dobrogowski, Jan; Wordliczek, Jerzy; Przewłocka, Barbara

    2005-01-01

    While many pre-clinical and clinical studies have suggested that the addition of N-methyl-d--aspartate (NMDA) receptor antagonists, such as dextromethorphan, to opioid analgesics, such as morphine may enhance the analgesic effects. The aim of the study was to assess the effect of non-competitive NMDA antagonists and paracetamol (propacetamol) on pain threshold and analgesic potency of this drugs and their combinations in formalin model for pain in rats. Intraperitoneal administration of paracetamol only in doses of 100 g/kg or higher resulted in increase of pain threshold in tail flick and paw pressure tests. The results of our study suggest that there was no significant difference in pain threshold between separate administration of dextromethorphan and in combination with paracetamol. In a formalin model for pain we have shown that paracetamol in non-analgesic doses (10 mg/kg) administered in combination with dextrometorphan, ketamine and mamantine was more effective than those drugs given separately but the best analgesic effect was obtained when combination of paracetamol and dextromethorphan was applied. The addition of higher doses of these combined drugs, that is paracetamol and all three NMDA antagonists did not result in enhancement of dose-dependant analgesia. In conclusion it should be stated that NMDA antagonists improve analgesic effect of paracetamol in the formalin model for pain. although only to a limited extend. PMID:17037292

  6. Signs & Symptoms of Dextromethorphan Exposure from YouTube

    PubMed Central

    Chary, Michael; Park, Emily H.; McKenzie, Andrew; Sun, Julia; Manini, Alex F.; Genes, Nicholas

    2014-01-01

    Detailed data on the recreational use of drugs are difficult to obtain through traditional means, especially for substances like Dextromethorphan (DXM) which are available over-the-counter for medicinal purposes. In this study, we show that information provided by commenters on YouTube is useful for uncovering the toxicologic effects of DXM. Using methods of computational linguistics, we were able to recreate many of the clinically described signs and symptoms of DXM ingestion at various doses, using information extracted from YouTube comments. Our study shows how social networks can enhance our understanding of recreational drug effects. PMID:24533044

  7. Dextromethorphan interactions with histaminergic and serotonergic treatments to reduce nicotine self-administration in rats.

    PubMed

    Briggs, Scott A; Hall, Brandon J; Wells, Corinne; Slade, Susan; Jaskowski, Paul; Morrison, Margaret; Rezvani, Amir H; Rose, Jed E; Levin, Edward D

    2016-03-01

    Combining effective treatments with diverse mechanisms of action for smoking cessation may provide better therapy by targeting multiple points of control in the neural circuits underlying addiction. Previous research in a rat model has shown that dextromethorphan, which has α3β4 nicotinic and NMDA glutamatergic antagonist actions, significantly decreases nicotine self-administration. We have found in the rat model that the H1 histamine antagonist pyrilamine and the serotonin 5HT2C agonist lorcaserin also significantly reduce nicotine self-administration. The current studies were conducted to determine the interactive effects of dextromethorphan with pyrilamine and lorcaserin on nicotine self-administration in rats. Young adult female rats were fitted with jugular IV catheters and trained to self-administer a nicotine infusion dose of 0.03-mg/kg/infusion. In an initial dose-effect function study of dextromethorphan, we found a monotonic decrease in nicotine self-administration over a dose range of 1 to 30-mg/kg with the lowest effective dose of 3-mg/kg. Then, with two separate cohorts of rats, dextromethorphan (0, 3.3, and 10-mg/kg) interactions with pyrilamine (0, 4.43, and 13.3-mg/kg) were investigated as well as interactions with lorcaserin (0, 0.3125 and 0.625-mg/kg). In the pyrilamine-dextromethorphan interaction study, an acute dose of pyrilamine (13.3-mg/kg) as well as an acute dose of dextromethorphan caused a significant decrease in nicotine self-administration. There were mutually augmenting effects of these two drugs. The combination of dextromethorphan (10-mg/kg) and pyrilamine (13.3-mg/kg) significantly lowered nicotine self-administration relative to either 10-mg/kg of dextromethorphan alone (p<0.05) or 13.3-mg/kg of pyrilamine alone (p<0.0005). In the lorcaserin-dextromethorphan study, an acute dose of lorcaserin (0.312-mg/kg) as well as an acute dose of dextromethorphan (10-mg/kg) caused a significant decrease in nicotine self

  8. Dextromethorphan, chlorphenamine and serotonin toxicity: case report and systematic literature review

    PubMed Central

    Monte, Andrew A; Chuang, Ryan; Bodmer, Michael

    2010-01-01

    The aim of this review was to describe a patient with serotonin toxicity after an overdose of dextromethorphan and chlorphenamine and to perform a systematic literature review exploring whether dextromethorphan and chlorphenamine may be equally contributory in the development of serotonin toxicity in overdose. A Medline literature review was undertaken to identify cases of serotonin toxicity due to dextromethorphan and/or chlorphenamine. Case reports were included if they included information on the ingested dose or plasma concentrations of dextromethorphan and/or chlorphenamine, information about co-ingestions and detailed clinical information to evaluate for serotonin toxicity. Cases were reviewed by two toxicologists and serotonin toxicity, defined by the Hunter criteria, was diagnosed when appropriate. The literature was then reviewed to evaluate whether chlorphenamine may be a serotonergic agent. One hundred and fifty-five articles of dextromethorphan or chlorphenamine poisoning were identified. There were 23 case reports of dextromethorphan, of which 18 were excluded for lack of serotonin toxicity. No cases were identified in which serotonin toxicity could be solely attributed to chlorphenamine. This left six cases of dextrometorphane and/or chlorphenamine overdose, including our own, in which serotonin toxicity could be diagnosed based on the presented clinical information. In three of the six eligible cases dextromethorphan and chlorphenamine were the only overdosed drugs. There is substantial evidence from the literature that chlorphenamine is a similarly potent serotonin re-uptake inhibitor when compared with dextrometorphan. Chlorphenamine is a serotonergic medication and combinations of chlorphenamine and dextromethorphan may be dangerous in overdose due to an increased risk of serotonin toxicity. PMID:21175434

  9. Dextromethorphan/quinidine: a review of its use in adults with pseudobulbar affect.

    PubMed

    Yang, Lily P H; Deeks, Emma D

    2015-01-01

    Fixed-dose dextromethorphan/quinidine capsules (Nuedexta(®)) utilize quinidine to inhibit the metabolism of dextromethorphan, enabling high plasma dextromethorphan concentrations to be reached without using a larger dose of the drug. The drug combination is the first treatment to be approved for pseudobulbar affect (PBA), a condition of contextually inappropriate/exaggerated emotional expression that often occurs in adults with neurological damage conditions, such as amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), stroke, traumatic brain injury, Alzheimer's disease or Parkinson's disease. Dextromethorphan/quinidine at the recommended dosages of 20/10 or 30/10 mg twice daily reduced the rate of PBA episodes and improved PBA severity in a 12-week, double-blind, placebo-controlled trial in adults with ALS or MS (STAR), with further improvements in the severity of the condition observed in a 12-week open-label extension phase. Dextromethorphan/quinidine 20/10 mg twice daily also improved PBA secondary to dementia in a cohort of a 12-week noncomparative trial (PRISM II). The drug combination was generally well tolerated in these studies, with no particular safety or tolerability concerns. Although longer-term efficacy and tolerability data for dextromethorphan/quinidine 20/10 or 30/10 mg twice daily would be beneficial, current evidence indicates that it is a useful option in the treatment of adults with PBA. PMID:25420446

  10. Efficacy and tolerability of levodropropizine in adult patients with non-productive cough. Comparison with dextromethorphan.

    PubMed

    Catena, E; Daffonchio, L

    1997-01-01

    The results of a double-blind, randomized clinical trial involving 209 adult patients of either sex with moderate non-productive cough are reported. The therapeutic efficacy and the tolerability of levodropropizine syrup (60 mg t.i.d. for 5 days) was evaluated in comparison with dextromethorphan syrup (15 mg t.i.d. for 5 days). Efficacy was assessed by the number of coughing spells in a 6h period, the cough frequency classes, the cough intensity and the night awakenings due to cough. Tolerability was evaluated by laboratory results, vital signs and any adverse event occurred during the clinical trial, including presence or absence of somnolence. Independently from the underlying pathology and from the degree of baseline cough severity, the number of coughing spells was significantly (P < 0.05) reduced by both levodropropizine and dextromethorphan already after the 2nd day of treatment, the effect and its time of onset being similar for both drugs. Cough intensity was significantly (P < 0.01) reduced by both drugs throughout the treatment, at an earlier time with levodropropizine than with dextromethorphan. Concurrently with the relief of cough, the number of night awakenings was decreased remarkably and significantly (P < 0.05), with levodropropizine displaying an improvement significantly higher (P < 0.05) than dextromethorphan. No change in laboratory tests values was considered clinically relevant and vital signs were not clinically affected by the study drugs. The number of patients reporting adverse events was significantly higher (P < 0.05) in the dextromethorphan (12.1%) than in the levodropropizine (3.6%) group. Overall, somnolence was reported for a low percentage of patients with both drugs, with the percentage of patients experiencing this side effect being one half in the group treated with levodropropizine (4.6%) as compared with dextromethorphan (10.4%). These results confirm the antitussive effectiveness of levodropropizine and point out a more

  11. Analgesic effects of dextromethorphan and morphine in patients with chronic pain.

    PubMed

    Heiskanen, Tarja; Härtel, Brita; Dahl, Marja-Liisa; Seppälä, Timo; Kalso, Eija

    2002-04-01

    N-methyl-aspartate (NMDA) receptor antagonists have been shown to improve opioid analgesia in the animal model. The cough suppressant dextromethorphan is a clinically available NMDA-receptor antagonist. In this randomised, double-blind, placebo-controlled study 20 patients with chronic pain of several years duration were given 100 mg of oral dextromethorphan or matching placebo 4 h prior to an intravenous infusion of morphine 15 mg. Pain intensity and adverse effects were assessed at 0, 4, 5 and 7 h. Dextromethorphan had no effect on morphine analgesia: the mean (+/-SEM) visual analogue scores for pain relief (VAS, 0-100 mm) at the end of the morphine infusion were 38 (+/-6) for dextromethorphan+morphine and 38 (+/-7) for placebo+morphine. VAS scores for pain intensity were comparable both at rest and at movement at all time points. The most common adverse effects reported were dizziness, nausea and sedation. There were no significant differences in either the incidence or severity of adverse effects. In conclusion, oral dextromethorphan 100 mg had no effect on pain relief by intravenous morphine 15 mg in patients with chronic pain. PMID:11972998

  12. Dextromethorphan Mediated Bitter Taste Receptor Activation in the Pulmonary Circuit Causes Vasoconstriction

    PubMed Central

    Upadhyaya, Jasbir D.; Chakraborty, Raja; Pydi, Sai P.; Bhullar, Rajinder P.; Dakshinamurti, Shyamala; Chelikani, Prashen

    2014-01-01

    Activation of bitter taste receptors (T2Rs) in human airway smooth muscle cells leads to muscle relaxation and bronchodilation. This finding led to our hypothesis that T2Rs are expressed in human pulmonary artery smooth muscle cells and might be involved in regulating the vascular tone. RT-PCR was performed to reveal the expression of T2Rs in human pulmonary artery smooth muscle cells. Of the 25 T2Rs, 21 were expressed in these cells. Functional characterization was done by calcium imaging after stimulating the cells with different bitter agonists. Increased calcium responses were observed with most of the agonists, the largest increase seen for dextromethorphan. Previously in site-directed mutational studies, we have characterized the response of T2R1 to dextromethorphan, therefore, T2R1 was selected for further analysis in this study. Knockdown with T2R1 specific shRNA decreased mRNA levels, protein levels and dextromethorphan-induced calcium responses in pulmonary artery smooth muscle cells by up to 50%. To analyze if T2Rs are involved in regulating the pulmonary vascular tone, ex vivo studies using pulmonary arterial and airway rings were pursued. Myographic studies using porcine pulmonary arterial and airway rings showed that stimulation with dextromethorphan led to contraction of the pulmonary arterial and relaxation of the airway rings. This study shows that dextromethorphan, acting through T2R1, causes vasoconstrictor responses in the pulmonary circuit and relaxation in the airways. PMID:25340739

  13. Dextromethorphan inhibits activations and functions in dendritic cells.

    PubMed

    Chen, Der-Yuan; Song, Pei-Shan; Hong, Jau-Shyong; Chu, Ching-Liang; Pan, I-Horng; Chen, Yi-Ming; Lin, Ching-Hsiung; Lin, Sheng-Hao; Lin, Chi-Chen

    2013-01-01

    Dendritic cells (DCs) play an important role in connecting innate and adaptive immunity. Thus, DCs have been regarded as a major target for the development of immunomodulators. In this study, we examined the effect of dextromethorphan (DXM), a common cough suppressant with a high safety profile, on the activation and function of DCs. In the presence of DXM, the LPS-induced expression of the costimulatory molecules in murine bone marrow-derived dendritic cells (BMDCs) was significantly suppressed. In addition, DXM treatment reduced the production of reactive oxygen species (ROS), proinflammatory cytokines, and chemokines in maturing BMDCs that were activated by LPS. Therefore, DXM abrogated the ability of LPS-stimulated DCs to induce Ag-specific T-cell activation, as determined by their decreased proliferation and IFN- γ secretion in mixed leukocyte cultures. Moreover, the inhibition of LPS-induced MAPK activation and NF- κ B translocation may contribute to the suppressive effect of DXM on BMDCs. Remarkably, DXM decreased the LPS-induced surface expression of CD80, CD83, and HLA-DR and the secretion of IL-6 and IL-12 in human monocyte-derived dendritic cells (MDDCs). These findings provide a new insight into the impact of DXM treatment on DCs and suggest that DXM has the potential to be used in treating DC-related acute and chronic diseases. PMID:23781253

  14. [Dextromethorphan abuse in adolescents: what can the pharmacists do?].

    PubMed

    Müller, Sandra; Jaffan, Linda; Kloiber, Edith; Läer, Stephanie

    2014-03-01

    In Germany, dextromethorphan (DXM) is used as OTC cough and cold medication. Overdose, however, can cause psychotropic side effects and is therefore abused among adolescents. To better control the drug by the pharmacist, a pilot was undertaken to monitor drug selling of DXM in German retail pharmacies. Over a 6-month period, pharmacies documented the request of DXM preparations. These data were compared to abuse cases of the German regulatory agency, the Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM), an analysis of the 2010 annual sales statistic from the IMS OTC and information about DXM products from drug abuse websites. Especially the young DXM buyers in German retail pharmacies showed characteristics similar to those people from the BfArM abuse data file: They were male and used the DXM product Hustenstiller-ratiopharm. Hustenstiller-ratiopharm has well-directed instructions for DXM abuse in the internet. However, the 2010 annual sales statistic from the IMS OTC report identified Wick MediNait as the product with highest sales numbers whereas Hustenstiller-ratiopharm" was of less importance indicating DXM abuse is limited to a small part of the DXM user population. PMID:24741849

  15. Dextromethorphan Inhibits Activations and Functions in Dendritic Cells

    PubMed Central

    Chen, Der-Yuan; Song, Pei-Shan; Hong, Jau-Shyong; Chu, Ching-Liang; Pan, I-Horng; Chen, Yi-Ming; Lin, Ching-Hsiung; Lin, Sheng-Hao; Lin, Chi-Chen

    2013-01-01

    Dendritic cells (DCs) play an important role in connecting innate and adaptive immunity. Thus, DCs have been regarded as a major target for the development of immunomodulators. In this study, we examined the effect of dextromethorphan (DXM), a common cough suppressant with a high safety profile, on the activation and function of DCs. In the presence of DXM, the LPS-induced expression of the costimulatory molecules in murine bone marrow-derived dendritic cells (BMDCs) was significantly suppressed. In addition, DXM treatment reduced the production of reactive oxygen species (ROS), proinflammatory cytokines, and chemokines in maturing BMDCs that were activated by LPS. Therefore, DXM abrogated the ability of LPS-stimulated DCs to induce Ag-specific T-cell activation, as determined by their decreased proliferation and IFN-γ secretion in mixed leukocyte cultures. Moreover, the inhibition of LPS-induced MAPK activation and NF-κB translocation may contribute to the suppressive effect of DXM on BMDCs. Remarkably, DXM decreased the LPS-induced surface expression of CD80, CD83, and HLA-DR and the secretion of IL-6 and IL-12 in human monocyte-derived dendritic cells (MDDCs). These findings provide a new insight into the impact of DXM treatment on DCs and suggest that DXM has the potential to be used in treating DC-related acute and chronic diseases. PMID:23781253

  16. CYP4F Enzymes Are the Major Enzymes in Human Liver Microsomes That Catalyze the O-Demethylation of the Antiparasitic Prodrug DB289 [2,5-Bis(4-amidinophenyl)furan-bis-O-methylamidoxime

    PubMed Central

    Wang, Michael Zhuo; Saulter, Janelle Y.; Usuki, Etsuko; Cheung, Yen-Ling; Hall, Michael; Bridges, Arlene S.; Loewen, Greg; Parkinson, Oliver T.; Stephens, Chad E.; Allen, James L.; Zeldin, Darryl C.; Boykin, David W.; Tidwell, Richard R.; Parkinson, Andrew; Paine, Mary F.; Hall, James Edwin

    2007-01-01

    DB289 [2,5-bis(4-amidinophenyl)furan-bis-O-methylamidoxime] is biotransformed to the potent antiparasitic diamidine DB75 [2,5-bis(4-amidinophenyl) furan] by sequential oxidative O-demethylation and reductive N-dehydroxylation reactions. Previous work demonstrated that the N-dehydroxylation reactions are catalyzed by cytochrome b5/NADH-cytochrome b5 reductase. Enzymes responsible for catalyzing the DB289 O-demethylation pathway have not been identified. We report an in vitro metabolism study to characterize enzymes in human liver microsomes (HLMs) that catalyze the initial O-demethylation of DB289 (M1 formation). Potent inhibition by 1-aminobenzotriazole confirmed that M1 formation is catalyzed by P450 enzymes. M1 formation by HLMs was NADPH-dependent, with a Km and Vmax of 0.5 μM and 3.8 nmol/min/mg protein, respectively. Initial screening showed that recombinant CYP1A1, CYP1A2, and CYP1B1 were efficient catalysts of M1 formation. However, none of these three enzymes was responsible for M1 formation by HLMs. Further screening showed that recombinant CYP2J2, CYP4F2, and CYP4F3B could also catalyze M1 formation. An antibody against CYP4F2, which inhibited both CYP4F2 and CYP4F3B, inhibited 91% of M1 formation by HLMs. Two inhibitors of P450-mediated arachidonic acid metabolism, HET0016 (N-hydroxy-N′-(4-n-butyl-2-methylphenyl)formamidine) and 17-octadecynoic acid, effectively inhibited M1 formation by HLMs. Inhibition studies with ebastine and antibodies against CYP2J2 suggested that CYP2J2 was not involved in M1 formation by HLMs. Additionally, ketoconazole preferentially inhibited CYP4F2, but not CYP4F3B, and partially inhibited M1 formation by HLMs. We conclude that CYP4F enzymes (e.g., CYP4F2, CYP4F3B) are the major enzymes responsible for M1 formation by HLMs. These findings indicate that, in human liver, members of the CYP4F subfamily biotransform not only endogenous compounds but also xenobiotics. PMID:16997912

  17. Protective effect of dextromethorphan against endotoxic shock in mice.

    PubMed

    Li, Guorong; Liu, Yuxin; Tzeng, Nian-ssheng; Cui, Gang; Block, Michelle L; Wilson, Belinda; Qin, Liya; Wang, Tongguang; Liu, Bin; Liu, Jie; Hong, Jau-Shyong

    2005-01-15

    Dextromethorphan (DM) is a dextrorotatory morphinan and an over-the-counter non-opioid cough suppressant. We have previously shown that DM protects against LPS-induced dopaminergic neurodegeneration through inhibition of microglia activation. Here, we investigated protective effects of DM against endotoxin shock induced by lipopolysaccharide/d-galactosamine (LPS/GalN) in mice and the mechanism underlying its protective effect. Mice were given multiple injections of DM (12.5 mg/kg, s.c.) 30 min before and 2, 4 h after an injection of LPS/GalN (20 microg/700 mg/kg). DM administration decreased LPS/GalN-induced mortality and hepatotoxicity, as evidenced by increased survival rate, decreased serum alanine aminotransferase activity and improved pathology. Furthermore, DM was also effective when it was given 30 min after LPS/GalN injection. The protection was likely associated with reduced serum and liver tumor necrosis factor alpha (TNF-alpha) levels. DM also attenuated production of superoxide and intracellular reactive oxygen species in Kupffer cells and neutrophils. Real-time RT-PCR analysis revealed that DM administration suppressed the expression of a variety of inflammation-related genes such as macrophage inflammatory protein-2, CXC chemokine, thrombospondin-1, intercellular adhesion molecular-1 and interleukin-6. DM also decreased the expression of genes related to cell-death pathways, such as the DNA damage protein genes GADD45 and GADD153. In summary, DM is effective in protecting mice against LPS/GalN-induced hepatotoxicity, and the mechanism is likely through a faster TNF-alpha clearance, and decrease of superoxide production and inflammation and cell-death related components. This study not only extends neuroprotective effect of DM, but also suggests that DM may be a novel compound for the therapeutic intervention for sepsis. PMID:15627475

  18. A Mechanism of O-Demethylation of Aristolochic Acid I by Cytochromes P450 and Their Contributions to This Reaction in Human and Rat Livers: Experimental and Theoretical Approaches

    PubMed Central

    Stiborová, Marie; Bárta, František; Levová, Kateřina; Hodek, Petr; Schmeiser, Heinz H.; Arlt, Volker M.; Martínek, Václav

    2015-01-01

    Aristolochic acid I (AAI) is a plant alkaloid causing aristolochic acid nephropathy, Balkan endemic nephropathy and their associated urothelial malignancies. AAI is detoxified by cytochrome P450 (CYP)-mediated O-demethylation to 8-hydroxyaristolochic acid I (aristolochic acid Ia, AAIa). We previously investigated the efficiencies of human and rat CYPs in the presence of two other components of the mixed-functions-oxidase system, NADPH:CYP oxidoreductase and cytochrome b5, to oxidize AAI. Human and rat CYP1A are the major enzymes oxidizing AAI. Other CYPs such as CYP2C, 3A4, 2D6, 2E1, and 1B1, also form AAIa, but with much lower efficiency than CYP1A. Based on velocities of AAIa formation by examined CYPs and their expression levels in human and rat livers, here we determined the contributions of individual CYPs to AAI oxidation in these organs. Human CYP1A2 followed by CYP2C9, 3A4 and 1A1 were the major enzymes contributing to AAI oxidation in human liver, while CYP2C and 1A were most important in rat liver. We employed flexible in silico docking methods to explain the differences in AAI oxidation in the liver by human CYP1A1, 1A2, 2C9, and 3A4, the enzymes that all O-demethylate AAI, but with different effectiveness. We found that the binding orientations of the methoxy group of AAI in binding centers of the CYP enzymes and the energies of AAI binding to the CYP active sites dictate the efficiency of AAI oxidation. Our results indicate that utilization of experimental and theoretical methods is an appropriate study design to examine the CYP-catalyzed reaction mechanisms of AAI oxidation and contributions of human hepatic CYPs to this metabolism. PMID:26593908

  19. Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations

    NASA Astrophysics Data System (ADS)

    Amin, Alaa S.; El-Sheikh, Ragaa; Zahran, Faten; Gouda, Ayman Abou El-fetouh

    2007-07-01

    A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of pipazethate hydrochloride, dextromethorphan hydrobromide and drotaverine hydrochloride using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of pipazethate HCl and dextromethorphan HBr or into methylene chloride in the case of drotaverine HCl. The ion-associates exhibit absorption maxima at 528, 540 and 532 nm with C2B and at 526, 517 and 522 nm with C2R for pipazethate HCl, dextromethorphan HBr and drotaverine HCl, respectively. The calibration curves resulting from the measurements of absorbance-concentration relations (at the optimum reaction conditions) of the extracted ion-pairs are linear over the concentration range 4.36-52.32 μg mL -1 for pipazethate, 3.7-48.15 μg mL -1 for dextromethorphan and 4.34-60.76 μg mL -1 for drotaverine, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were estimated. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. Statistical treatment of the results reflects that the procedure is precise, accurate and easily applied for the determination of the drugs under investigation in pure form and in their pharmaceutical preparations.

  20. Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations.

    PubMed

    Amin, Alaa S; El-Sheikh, Ragaa; Zahran, Faten; Gouda, Ayman Abou El-fetouh

    2007-07-01

    A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of pipazethate hydrochloride, dextromethorphan hydrobromide and drotaverine hydrochloride using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of pipazethate HCl and dextromethorphan HBr or into methylene chloride in the case of drotaverine HCl. The ion-associates exhibit absorption maxima at 528, 540 and 532 nm with C2B and at 526, 517 and 522 nm with C2R for pipazethate HCl, dextromethorphan HBr and drotaverine HCl, respectively. The calibration curves resulting from the measurements of absorbance-concentration relations (at the optimum reaction conditions) of the extracted ion-pairs are linear over the concentration range 4.36-52.32 microg mL(-1) for pipazethate, 3.7-48.15 microg mL(-1) for dextromethorphan and 4.34-60.76 microg mL(-1) for drotaverine, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were estimated. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. Statistical treatment of the results reflects that the procedure is precise, accurate and easily applied for the determination of the drugs under investigation in pure form and in their pharmaceutical preparations. PMID:17092767

  1. Analysis of Dextromethorphan in Cough Drops and Syrups: A Medicinal Chemistry Laboratory

    ERIC Educational Resources Information Center

    Hamilton, Todd M.; Wiseman, Frank L., Jr.

    2009-01-01

    Fluorescence spectroscopy is used to determine the quantity of dextromethorphan hydrobromide (DM) in over-the-counter (OTC) cough drops and syrups. This experiment is appropriate for an undergraduate medicinal chemistry laboratory course when studying OTC medicines and active ingredients. Students prepare the cough drops and syrups for analysis,…

  2. The Treatment of the Behavioral Sequelae of Autism with Dextromethorphan: A Case Report

    ERIC Educational Resources Information Center

    Woodard, Cooper; Groden, June; Goodwin, Matthew; Shanower, Cori; Bianco, Joanne

    2005-01-01

    Dextromethorphan is the d-isomer of levorphenol, and an ingredient in antitussive preparations. A 10 year-old male diagnosed with Autistic Disorder, Pervasive Developmental Disorder, and Generalized Anxiety Disorder was administered this medication initially to treat a medical condition. This became a quasi-experimental ABAB design (A = baseline,…

  3. The therapeutic effect of adding dextromethorphan to clonidine for reducing symptoms of opioid withdrawal: a randomized clinical trial.

    PubMed

    Malek, Ayyoub; Amiri, Shahrokh; Habibi Asl, Bohlool

    2013-01-01

    Background. Dextromethorphan is a noncompetitive N-methyl D-aspartate receptor antagonist that is clinically feasible for relieving the opioid withdrawal symptoms. This study compares the efficacy of a combination therapy with dextromethorphan and clonidine to treatment with clonidine alone. Methods and Materials. In this double-blind randomized clinical trial, patients were selected from inpatients of detox and rehabilitation ward of Razi Hospital, Tabriz, Iran. They were randomly allocated to two groups receiving either clonidine (0.4-1.2 mg/day) or clonidine and dextromethorphan (300 mg/day). Withdrawal symptoms were evaluated in the first day of admission and again 24, 48, and 72 hours later. Results. Thirty male patients completed the trial in each group. Withdrawal symptoms began to decrease in the second day in patients receiving dextromethorphan and clonidine while patients receiving clonidine experienced the more severe symptoms in 72 hours. Analysis of variance of the symptom severity score revealed a significant group × time interaction (F = 14.25; P < 0.001), so that patients receiving dextromethorphan plus clonidine had milder symptoms during three days in all of the measurements compared to clonidine group. Conclusion. Combination therapy of dextromethorphan and clonidine would result in milder opioid withdrawal symptoms compared to clonidine alone with a reduction beginning at the second day. PMID:23864983

  4. Assessment of antitussive efficacy of dextromethorphan in smoking related cough: objective vs. subjective measures

    PubMed Central

    Ramsay, James; Wright, Caroline; Thompson, Rachel; Hull, David; Morice, Alyn H

    2008-01-01

    AIMS Using an established model of smokers cough we measured the antitussive effects of dextromethorphan compared with placebo. METHODS The study was a randomized, double-blind placebo controlled, crossover comparison of 22 mg 0.8 ml−1 dextromethorphan delivered pregastrically with matched placebo. Objective and subjective measurements of cough were recorded. Subjective measures included a daily diary record of cough symptoms and the Leicester quality of life questionnaire. Cough frequency was recorded using a manual cough counter. The objective measure of cough reflex sensitivity was the citric acid, dose–response cough challenge. RESULTS Dextromethorphan was significantly associated with an increase in the concentration of citric acid eliciting an average of two coughs/inhalation (C2) when compared with placebo, 1 h post dose by 0.49 mM (95% CI 0.05, 0.45, geometric mean 3.09) compared with placebo 0.24 mM (geometric mean 1.74) P < 0.05 and at 2 h 0.57 mM (95% CI 0.01, 0.43, geometric mean 3.75) compared with placebo 0.34 mM (geometric mean 2.19) P < 0.05). There was a highly significant improvement in the subjective data when compared with baseline. However, there was no significant difference between placebo and active treatment. No correlation was seen between cough sensitivity to citric acid and recorded cough counts or symptoms. When both subjective and objective data were compared with screening data there was evidence of a marked ‘placebo’ effect. CONCLUSIONS The objective measure of cough sensitivity demonstrates dextromethorphan effectively diminishes the cough reflex sensitivity. However, subjective measures do not support this. Other studies support these findings, which may represent a profound sensitivity of the cough reflex to higher influences. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Dextromethorphan is widely used as a cough suppressant in over the counter medications. Its efficacy in altering cough reflex sensitivity has been shown in

  5. Dextromethorphan Addiction Mediated Through the NMDA System: Common Pathways With Alcohol?

    PubMed

    Roy, A Kenison; Hsieh, Chenen; Crapanzano, Kathleen

    2015-01-01

    Dextromethorphan, an antitussive (cough suppressant) drug of the morphinan class with sedative and dissociative properties found in cough syrup and other over-the-counter products, is also a substance of abuse, seen primarily in young adults all over the world. A case of dextromethorphan use disorder is presented in a 45-year-old women. Her repeated attempts at abstinence were unsuccessful secondary to continued intense cravings. Treatment with topiramate resulted in complete resolution of her cravings. Topiramate was chosen empirically because of a common action with dextromethorphan in the NMDA system. Genetic testing was obtained and the patient was found to be a carrier of the GRIK1 rs2832407(C:C) allele. The (C:C) allele has been associated with an increased risk of alcohol use disorder and a treatment response of patients with heavy drinking to topiramate. This case provides an opportunity to discuss personalized medicine (treatment options aided by the use of genetic testing) and the possible shared genetic susceptibility for dependence in 2 substances of abuse. PMID:26441400

  6. Dextromethorphan and debrisoquine metabolism and polymorphism of the gene for cytochrome P450 isozyme 2D50 in Thoroughbreds.

    PubMed

    Corado, Carley R; McKemie, Daniel S; Knych, Heather K

    2016-09-01

    OBJECTIVE To characterize polymorphisms of the gene for cytochrome P450 isozyme 2D50 (CYP2D50) and the disposition of 2 CYP2D50 probe drugs, dextromethorphan and debrisoquine, in horses. ANIMALS 23 healthy horses (22 Thoroughbreds and 1 Standardbred). PROCEDURES Single-nucleotide polymorphisms (SNPs) in CYP2D50 were identified. Disposition of dextromethorphan (2 mg/kg) and debrisoquine (0.2 mg/kg) were determined after oral (dextromethorphan) or nasogastric (debrisoquine) administration to the horses. Metabolic ratios of plasma dextromethorphan and total dextrorphan (dextrorphan plus dextrorphan-O-β-glucuronide) and 4-hydroxydebrisoquine concentrations were calculated on the basis of the area under the plasma concentration-versus-time curve extrapolated to infinity for the parent drug divided by that for the corresponding metabolite. Pharmacokinetic data were used to categorize horses into the phenotypic drug-metabolism categories poor, extensive, and ultrarapid. Disposition patterns were compared among categories, and relationships between SNPs and metabolism categories were explored. RESULTS Gene sequencing identified 51 SNPs, including 27 nonsynonymous SNPs. Debrisoquine was minimally detected after oral administration. Disposition of dextromethorphan varied markedly among horses. Metabolic ratios for dextromethorphan ranged from 0.03 to 0.46 (mean, 0.12). On the basis of these data, 1 horse was characterized as a poor metabolizer, 18 were characterized as extensive metabolizers, and 3 were characterized as ultrarapid metabolizers. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that CYP2D50 is polymorphic and that the disposition of the probe drug varies markedly in horses. The polymorphisms may be related to rates of drug metabolism. Additional research involving more horses of various breeds is needed to fully explore the functional implication of polymorphisms in CYP2D50. PMID:27580115

  7. Mania after misuse of dextromethorphan: a case report and brief review of "robotripping".

    PubMed

    Stanciu, Cornel N; Penders, Thomas M

    2015-01-01

    Dextromethorphan (DXM) in combination with antihistamines and/or pseudoephedrine is widely available as an over-the-counter remedy commonly used for relief of colds and cough. In supratherapeutic amounts, DXM can be extremely activating. These cough preparations have been adopted by many young users of recreational drugs for their psychoactive effects. When used in amounts exceeding those recommended, this practice, known as "robotripping," may result in a manic toxidrome of psychomotor agitation, hostility, grandiose behavior, hallucinations, paranoia, and panic. A case illustration of this phenomenon is described and implications of this phenomenon discussed. There are few reports associating DXM use with bipolar symptomatology. PMID:25622122

  8. Dextromethorphan prevents the diethyldithiocarbamate enhancement of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice.

    PubMed

    Vaglini, Francesca; Pardini, Carla; Bonuccelli, Ubaldo; Maggio, Roberto; Corsini, Giovanni U

    2003-05-30

    In this report we show that dextromethorphan, a non-opioid cough suppressant, prevents the neurodegeneration of dopaminergic neurons in the substantia nigra of mice treated with diethyldithiocarbamate (DDC) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). This effect is further substantiated by the assessment of dopamine (DA) content in the striatum of these animals. Dextromethorphan does not attenuate the striatal DA fall induced by MPTP alone but completely prevents DDC-induced enhancement after the combined treatment. Moreover, a study of DA metabolites has confirmed this neuroprotective property. The striatal levels of serotonin, which were studied as a control neuronal marker, did not change with any of the treatments administered. Furthermore, we show that dextromethorphan reduces the toxicity of glutamate against dopamine neurons in mesencephalic cell cultures. In line with previous data suggesting that dextromethorphan can prevent neuronal damage, our observations supply new evidence regarding the possibility of this compound being of therapeutic use in neurodegenerative diseases. PMID:12738074

  9. The Abuse of Dextromethorphan-Based Cough Syrup: A Pilot Study of the Community of Waynesboro, Pennsylvania.

    ERIC Educational Resources Information Center

    Momodou, N. Darboe; And Others

    1996-01-01

    Discusses the emergence of a new type of abused drug, dextromethorphan, which is used in cough syrup. Presents the results of the first phase of a comprehensive investigation of this phenomenon in the Waynesboro, Pa. school district. Survey data indicate abuse of cough syrup has increased over the years and is increasingly perceived as a problem…

  10. The antitussive effect of dextromethorphan in relation to CYP2D6 activity

    PubMed Central

    Abdul Manap, R; Wright, C E; Gregory, A; Rostami-Hodjegan, A; Meller, S T; Kelm, G R; Lennard, M S; Tucker, G T; Morice, A H

    1999-01-01

    Aims To test the hypothesis that inhibition of cytochrome P450 2D6 (CYP2D6) by quinidine increases the antitussive effect of dextromethorphan (DEX) in an induced cough model. Methods Twenty-two healthy extensive metaboliser phenotypes for CYP2D6 were studied according to a double-blind, randomised cross-over design after administration of: (1) Placebo antitussive preceded at 1 h by placebo inhibitor; (2) 30 mg oral DEX preceded at 1 h by placebo inhibitor (DEX30); (3) 60 mg oral DEX preceded at 1 h by placebo inhibitor (DEX60); (4) 30 mg oral DEX preceded at 1 h by 50 mg oral quinidine sulphate (QDEX30). Cough frequency following inhalation of 10% citric acid was measured at baseline and at intervals up to 12 h. Plasma concentrations of DEX and its metabolites were measured up to 96 h by h.p.l.c. Results Inhibition of CYP2D6 by quinidine caused a significant increase in the mean ratio of DEX to dextrorphan (DEX:DOR) plasma AUC(96) (0.04 vs 1.81, P < 0.001). The mean (±s.d.) decrements in cough frequency below baseline over 12 h (AUEC) were: 8% (11), 17% (14.5), 25% (16.2) and 25% (16.9) for placebo, DEX30, DEX60 and QDEX30 treatments, respectively. Statistically significant differences in antitussive effect were detected for the contrasts between DEX60/placebo (P < 0.001; 95% CI of difference +80, +327) and QDEX30/placebo (P < 0.001, +88, +336), but not for DEX30/placebo, DEX30/DEX60 or DEX30/QDEX30 (P = 0.071, −7, +241; P = 0.254, −37, +211; P = 0.187, −29, +219, respectively). Conclusions A significant antitussive effect was demonstrated after 60 mg dextromethorphan and 30 mg dextromethorphan preceded by 50 mg quinidine using an induced cough model. However, although the study was powered to detect a 10% difference in cough response, the observed differences for other contrasts were less than 10%, such that it was possible only to imply a dose effect (30 vs 60 mg) in the antitussive activity of DEX and enhancement of this effect by CYP2D6 inhibition. PMID

  11. Dextromethorphan increases tyrosine hydroxylase mRNA in the mesencephalon of adolescent rats.

    PubMed

    Zhang, T Y; Jahng, J W; Kim, D G

    2001-08-24

    Dextromethorphan (DM), an antitussive widely available in over-the-counter, has been abused mostly in teenage groups at high doses. To examine effects of DM on the reward pathway, we injected a high dose of DM (40 mg/kg; intraperitoneally) into the adolescent rat and measured tyrosine hydroxylase (TH) mRNA by in situ hybridization in the ventral tegmental area (VTA) and the substantia nigra (SN). Remarkable increases in the level of TH mRNA were observed in the VTA and SN 2 h after DM injection. Stereotyped behavior and ataxia increased, and rearing decreased by DM administration. These results suggest that DM-induced increase in TH mRNA expression in mesencephalon contribute to the reinforcing property and the behavioral effects of DM. PMID:11502351

  12. Dextromethorphan: An update on its utility for neurological and neuropsychiatric disorders.

    PubMed

    Nguyen, Linda; Thomas, Kelan L; Lucke-Wold, Brandon P; Cavendish, John Z; Crowe, Molly S; Matsumoto, Rae R

    2016-03-01

    Dextromethorphan (DM) is a commonly used antitussive and is currently the only FDA-approved pharmaceutical treatment for pseudobulbar affect. Its safety profile and diverse pharmacologic actions in the central nervous system have stimulated new interest for repurposing it. Numerous preclinical investigations and many open-label or blinded clinical studies have demonstrated its beneficial effects across a variety of neurological and psychiatric disorders. However, the optimal dose and safety of chronic dosing are not fully known. This review summarizes the preclinical and clinical effects of DM and its putative mechanisms of action, focusing on depression, stroke, traumatic brain injury, seizure, pain, methotrexate neurotoxicity, Parkinson's disease and autism. Moreover, we offer suggestions for future research with DM to advance the treatment for these and other neurological and psychiatric disorders. PMID:26826604

  13. The effect of the NMDA receptor blocker, dextromethorphan, on cribbing in horses.

    PubMed

    Rendon, R A; Shuster, L; Dodman, N H

    2001-01-01

    Stereotypic cribbing in horses is thought to involve excess dopaminergic activity within the striatum. Various models of stress-induced stereotypies including cribbing in horses postulate that stress stimulates the release of endorphins, triggering the release of striatal dopamine. Dopamine in turn activates basal ganglia motor programs, reinforcing behavior via a reward mechanism. Furthermore, the release of dopamine by endorphins has been shown to depend on activation of NMDA receptors. In the present study, horses identified as cribbers and volunteered by their owners were treated with the NMDA receptor antagonist dextromethorphan (DM). When DM was administered via jugular injection (1 mg/kg), eight of nine horses responded with reductions in cribbing rate (CR) compared to baseline, and cribbing was suppressed completely for a period of time in almost half of the horses tested. PMID:11274707

  14. The Effects of Dextromethorphan on Driving Performance and the Standardized Field Sobriety Test.

    PubMed

    Perry, Paul J; Fredriksen, Kristian; Chew, Stephanie; Ip, Eric J; Lopes, Ingrid; Doroudgar, Shadi; Thomas, Kelan

    2015-09-01

    Dextromethorphan (DXM) is abused most commonly among adolescents as a recreational drug to generate a dissociative experience. The objective of the study was to assess driving with and without DXM ingestion. The effects of one-time maximum daily doses of DXM 120 mg versus a guaifenesin 400 mg dose were compared among 40 healthy subjects using a crossover design. Subjects' ability to drive was assessed by their performance in a driving simulator (STISIM® Drive driving simulator software) and by conducting a standardized field sobriety test (SFST) administered 1-h postdrug administration. The one-time dose of DXM 120 mg did not demonstrate driving impairment on the STISIM® Drive driving simulator or increase SFST failures compared to guaifenesin 400 mg. Doses greater than the currently recommended maximum daily dose of 120 mg are necessary to perturb driving behavior. PMID:26294136

  15. Simultaneous high-pressure liquid chromatographic determination of acetaminophen, guaifenesin, and dextromethorphan hydrobromide in cough syrup.

    PubMed

    McSharry, W O; Savage, I V

    1980-02-01

    Acetaminophen (I), guaifenesin (II), and dextromethorphan hydrobromide (III) were separated and quantitated simultaneously in cough syrup by high-pressure liquid chromatography. A chemically bonded octadecylsilane stationary phase was used with a mobile phase of 48% (v/v) aqueous methanol. The mobile phase pH was stabilized to 4.2 by adding formic acid--ammonium formate buffer (approximately 0.4%). The internal standard was o-dinitrobenzene. Retention volumes were 4 ml for I, 6 ml for II, 11 ml for the internal standard, and 20 ml for III. Inactive syrup components did not interfere, permitting direct diluted sample injection. Results on active ingredients were essentially 100% of the claim, with standard deviations of +/- 1.5, 1.2, and 2.1% for I, II, and III, respectively. PMID:7359328

  16. High-affinity dextromethorphan binding sites in guinea pig brain. II. Competition experiments.

    PubMed

    Craviso, G L; Musacchio, J M

    1983-05-01

    Binding of dextromethorphan (DM) to guinea pig brain is stereoselective, since levomethorphan is 20 times weaker than DM in competing for DM sites. In general, opiate agonists and antagonists as well as their corresponding dextrorotatory isomers are weak competitors for tritiated dextromethorphan ([3H]DM) binding sites and display IC50 values in the micromolar range. In contrast, several non-narcotic, centrally acting antitussives are inhibitory in the nanomolar range (IC50 values for caramiphen, carbetapentane, dimethoxanate, and pipazethate are 25 nM, 9 nM, 41 nM, and 190 nM, respectively). Other antitussives, such as levopropoxyphene, chlophedianol, and fominoben, have poor affinity for DM sites whereas the antitussive noscapine enhances DM binding by increasing the affinity of DM for its central binding sites. Additional competition studies indicate that there is no correlation of DM binding with any of the known or putative neurotransmitters in the central nervous system. DM binding is also not related to tricyclic antidepressant binding sites or biogenic amine uptake sites. However, certain phenothiazine neuroleptics and typical and atypical antidepressants inhibit binding with IC50 values in the nanomolar range. Moreover, the anticonvulsant drug diphenylhydantoin enhances DM binding in a manner similar to that of noscapine. Preliminary experiments utilizing acid extracts of brain have not demonstrated the presence of an endogenous ligand for DM sites. The binding characteristics of DM sites studied in rat and mouse brain indicate that the relative potencies of several antitussives to inhibit specific DM binding vary according to species. High-affinity, saturable, and stereoselective [3H]DM binding sites are present in liver homogenates, but several differences have been found for these peripheral binding sites and those described for brain. Although the nature of central DM binding sites is not known, the potent interaction of several classes of centrally

  17. Quantization of Dextromethorphan and Levocetirizine in Combined Dosage form Using a Novel Validated RP-HPLC Method

    PubMed Central

    Joshi, Shalini; Bhatia, C.; Bal, C. S.; Rawat, M. S. M.

    2012-01-01

    The present study reveals a simple isocratic RP-HPLC method for the simultaneous determination of dextromethorphan hydrobromide and levocetirizine dihydrochloride in a cough syrup. The separation of these compounds was achieved within 10 min on a Phenomenex (USA) C18 analytical column, 250×4.0 mm i.d., using an isocratic mobile phase consisting of potassium dihydrogen phosphate buffer (pH 2.5) - acetonitrile- tetrahydrofuran (70:25:5, v/v/v). The analysis was performed at a flow rate of 1.2 ml/min and at a detection wavelength of 232 nm. Percentage recovery and RSD were 100.36% and 0.05% for levocetirizine dihydrochloride, 100.35% and 0.27% for dextromethorphan hydrobromide respectively. Quantification of the components in syrup formulation was calculated against the peak areas of freshly prepared standard solutions. The method was validated as per ICH guidelines. PMID:23204629

  18. Quantization of Dextromethorphan and Levocetirizine in Combined Dosage form Using a Novel Validated RP-HPLC Method.

    PubMed

    Joshi, Shalini; Bhatia, C; Bal, C S; Rawat, M S M

    2012-01-01

    The present study reveals a simple isocratic RP-HPLC method for the simultaneous determination of dextromethorphan hydrobromide and levocetirizine dihydrochloride in a cough syrup. The separation of these compounds was achieved within 10 min on a Phenomenex (USA) C(18) analytical column, 250×4.0 mm i.d., using an isocratic mobile phase consisting of potassium dihydrogen phosphate buffer (pH 2.5) - acetonitrile- tetrahydrofuran (70:25:5, v/v/v). The analysis was performed at a flow rate of 1.2 ml/min and at a detection wavelength of 232 nm. Percentage recovery and RSD were 100.36% and 0.05% for levocetirizine dihydrochloride, 100.35% and 0.27% for dextromethorphan hydrobromide respectively. Quantification of the components in syrup formulation was calculated against the peak areas of freshly prepared standard solutions. The method was validated as per ICH guidelines. PMID:23204629

  19. Dextromethorphan overdose

    MedlinePlus

    DXM overdose; Robo overdose; Orange crush overdose; Red devils overdose; Triple C's overdose ... streets under the names: Orange crush Triple Cs Red Devils Skittles Dex Other products may also contain ...

  20. A randomized placebo controlled trial to evaluate the effects of butamirate and dextromethorphan on capsaicin induced cough in healthy volunteers

    PubMed Central

    Faruqi, Shoaib; Wright, Caroline; Thompson, Rachel; Morice, Alyn H

    2014-01-01

    Aims The examination of cough reflex sensitivity through inhalational challenge can be utilized to demonstrate pharmacological end points. Here we compare the effect of butamirate, dextromethorphan and placebo on capsaicin-induced cough in healthy volunteers. Methods In this randomized, placebo-controlled, six way crossover study the effect of dextromethrophan 30 mg, four doses of butamirate and placebo was evaluated on incremental capsaicin challenges performed at baseline and 2, 4, 6, 8, 12 and 24 h following dosing. The primary end point was the area under the curve (AUC(0,12h)) of log10 C5 from pre-dose to 12 h after dosing. Plasma butamirate metabolites were analyzed to evaluate pharmacokinetic and pharmacodynamic relationships. Results Thirty-four subjects (13 males, median age 25 years) completed the study. Cough sensitivity decreased from baseline in all arms of the study. Dextromethorphan was superior to placebo (P = 0.01) but butamirate failed to show significant activity with maximum attenuation at the 45 mg dose. There was no apparent relationship between pharmacokinetic and pharmacodynamic parameters for butamirate. Conclusions We have demonstrated for the first time that dextromethorphan attenuates capsaicin challenge confirming its broad activity on the cough reflex. The lack of efficacy of butamirate could be due to formulation issues at higher doses. PMID:24995954

  1. Clinical assessment of CYP2D6-mediated herb-drug interactions in humans: effects of milk thistle, black cohosh, goldenseal, kava kava, St. John's wort, and Echinacea.

    PubMed

    Gurley, Bill J; Swain, Ashley; Hubbard, Martha A; Williams, D Keith; Barone, Gary; Hartsfield, Faith; Tong, Yudong; Carrier, Danielle J; Cheboyina, Shreekar; Battu, Sunil K

    2008-07-01

    Cytochrome P450 2D6 (CYP2D6), an important CYP isoform with regard to drug-drug interactions, accounts for the metabolism of approximately 30% of all medications. To date, few studies have assessed the effects of botanical supplementation on human CYP2D6 activity in vivo. Six botanical extracts were evaluated in three separate studies (two extracts per study), each incorporating 16 healthy volunteers (eight females). Subjects were randomized to receive a standardized botanical extract for 14 days on separate occasions. A 30-day washout period was interposed between each supplementation phase. In study 1, subjects received milk thistle (Silybum marianum) and black cohosh (Cimicifuga racemosa). In study 2, kava kava (Piper methysticum) and goldenseal (Hydrastis canadensis) extracts were administered, and in study 3 subjects received St. John's wort (Hypericum perforatum) and Echinacea (Echinacea purpurea). The CYP2D6 substrate, debrisoquine (5 mg), was administered before and at the end of supplementation. Pre- and post-supplementation phenotypic trait measurements were determined for CYP2D6 using 8-h debrisoquine urinary recovery ratios (DURR). Comparisons of pre- and post-supplementation DURR revealed significant inhibition (approximately 50%) of CYP2D6 activity for goldenseal, but not for the other extracts. Accordingly, adverse herb-drug interactions may result with concomitant ingestion of goldenseal supplements and drugs that are CYP2D6 substrates. PMID:18214849

  2. Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate

    PubMed Central

    Gouda, Ayman Abou El-Fetouh; El-Sheikh, Ragaa; El Shafey, Zeineb.; Hossny, Nagda.; El-Azzazy, Rham

    2008-01-01

    Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer’s law is obeyed in the concentration range of 2.0-16 and 2.0-15 μg mL-1 for PiCl and DEX, respectively with correlation coefficient (n=6) ≥ 0.9993. The apparent molar absorptivity and sandell sensitivity values are in the range 1.062-1.484 × 104, 3.35-4.51 × 104 L mol-1 cm-1 and 29.36-41.03, 8.21-11.06 ng cm-2 for PiCl and DEX, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods. PMID:23675101

  3. Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate.

    PubMed

    Gouda, Ayman Abou El-Fetouh; El-Sheikh, Ragaa; El Shafey, Zeineb; Hossny, Nagda; El-Azzazy, Rham

    2008-12-01

    Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 2.0-16 and 2.0-15 μg mL(-1) for PiCl and DEX, respectively with correlation coefficient (n=6) ≥ 0.9993. The apparent molar absorptivity and sandell sensitivity values are in the range 1.062-1.484 × 10(4), 3.35-4.51 × 10(4) L mol(-1) cm(-1) and 29.36-41.03, 8.21-11.06 ng cm(-2) for PiCl and DEX, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods. PMID:23675101

  4. Determination of Dextromethorphan in Oral Fluid by LC-MS-MS.

    PubMed

    Amaratunga, Piyadarsha; Clothier, Morgan; Lorenz Lemberg, Bridget; Lemberg, Dave

    2016-06-01

    Dextromethorphan (DXM) is an antitussive drug found in commonly used nonprescription cold and cough medications. At low doses, DXM is a safe drug that does not produce adverse reactions. However, abuse of DXM has been reported among adolescents and young adults using the drug at higher doses. DXM is not a scheduled drug in the USA, and the primary reason for its abuse is the ease of availability. DXM is available to purchase in the form of over-the-counter cough medications, such as Robitussin(®) and Coricidin(®), or it can be purchased over the Internet in the form of a powder. In this research work, we developed an LC-MS-MS method that can quantify DXM and dextrorphan (DXO) in oral fluid in a high-throughput toxicology laboratory setting. The developed method was validated according to the Scientific Working Group for Forensic Toxicology guidelines. The linear dynamic range was 5-100 ng/mL with a lowest limit of quantitation (LLOQ) of 5.0 ng/mL for DXM and DXO. Overall, the results of the accuracy and the precision values were within the acceptance criteria for both drugs. In addition, selectivity, matrix effect and recovery were calculated for the LC-MS-MS method. Authentic samples (n = 59) were tested to evaluate the applicability of the method. Thirty samples were found to be positive for DXM and DXO and two samples were found to be positive for DXM only. PMID:27185818

  5. Ovariectomy ameliorates dextromethorphan--induced memory impairment in young female rats.

    PubMed

    Jahng, Jeong Won; Cho, Hee Jeong; Kim, Jae Goo; Kim, Nam Youl; Lee, Seoul; Lee, Yil Seob

    2006-01-01

    We have previously found that dextromethorphan (DM), over-the-counter cough suppressant, impairs memory retention in water maze task, when it is repeatedly administrated to adolescent female rats at high doses. In this study we examined first if ovariectomy ameliorates the DM-induced memory impairment in female rats, and then whether or not the DM effect is revived by estrogen replacement in ovariectomized female rats. Female rat pups received bilateral ovariectomy or sham operation on postnatal day (PND) 21, and then intraperitoneal DM (40 mg/kg) daily during PND 28-37. Rats were subjected to the Morris water maze task from PND 38, approximately 24 h after the last DM injection. In probe trial, goal quadrant dwell time was significantly reduced by DM in the sham operated group, however, the reduction by DM did not occur in the ovariectomy group. When 17beta-estradiol was supplied to ovariectomized females during DM treatment, the goal quadrant dwell time was significantly decreased, compared to the vehicle control group. Furthermore, a major effect of estrogen replacement was found in the escape latency during the last 3 days of initial learning trials. These results suggest that ovariectomy may ameliorate the adverse effect of DM treatment on memory retention in young female rats, and that estrogen replacement may revive it, i.e. estrogen may take a major role in DM-induced memory impairment in female rats. PMID:16563229

  6. Evaluation of a [13C]-Dextromethorphan Breath Test to Assess CYP2D6 Phenotype

    PubMed Central

    Leeder, J. Steven; Pearce, Robin E.; Gaedigk, Andrea; Modak, Anil; Rosen, David I.

    2016-01-01

    A [13C]-dextromethorphan ([13C]-DM) breath test was evaluated to assess its feasibility as a rapid, phenotyping assay for CYP2D6 activity. [13C]-DM (0.5 mg/kg) was administered orally with water or potassium bicarbonate-sodium bicarbonate to 30 adult Caucasian volunteers (n = 1 each): CYP2D6 poor metabolizers (2 null alleles; PM-0) and extensive metabolizers with 1 (EM-1) or 2 functional alleles (EM-2). CYP2D6 phenotype was determined by 13CO2 enrichment measured by infrared spectrometry (delta-over-baseline [DOB] value) in expired breath samples collected before and up to 240 minutes after [13C]-DM ingestion and by 4-hour urinary metabolite ratio. The PM-0 group was readily distinguishable from either EM group by both the breath test and urinary metabolite ratio. Using a single point determination of phenotype at 40 minutes and defining PMs as subjects with a DOB ≤ 0.5, the sensitivity of the method was 100%; specificity was 95% with 95% accuracy and resulted in the misclassification of 1 EM-1 individual as a PM. Modification of the initial protocol (timing of potassium bicarbonate-sodium bicarbonate administration relative to dose) yielded comparable results, but there was a tendency toward increased DOB values. Although further development is required, these studies suggest that the [13C]-DM breath test offers promise as a rapid, minimally invasive phenotyping assay for CYP2D6 activity. PMID:18728242

  7. Therapeutic use of dextromethorphan: key learnings from treatment of pseudobulbar affect.

    PubMed

    Miller, Ariel; Panitch, Hillel

    2007-08-15

    A variety of neurological conditions and disease states are accompanied by pseudobulbar affect (PBA), an emotional disorder characterized by uncontrollable outbursts of laughing and crying. The causes of PBA are unclear but may involve lesions in neural circuits regulating the motor output of emotional expression. Several agents used in treating other psychiatric disorders have been applied in the treatment of PBA with some success but data are limited and these agents are associated with unpleasant side effects due to nonspecific activity in diffuse neural networks. Dextromethorphan (DM), a widely used cough suppressant, acts at receptors in the brainstem and cerebellum, brain regions implicated in the regulation of emotional output. The combination of DM and quinidine (Q), an enzyme inhibitor that blocks DM metabolism, has recently been tested in phase III clinical trials in patients with multiple sclerosis and amyotrophic lateral sclerosis and was both safe and effective in palliating PBA symptoms. In addition, clinical studies pertaining to the safety and efficacy of DM/Q in a variety of neurological disease states are ongoing. PMID:17433820

  8. Effect of dextromethorphan on reference memory assessed in rats by a three-panel runway task.

    PubMed

    Göçmez, Semil Selcen; Erden, Bekir Faruk; Ulak, Güner; Utkan, Tijen; Yildiz, Füruzan; Gacar, Nejat; Mutlu, Oguz

    2006-01-01

    The effects of dextromethorphan (DM, CAS 6700-34-1), a common over-the-counter cough suppressant, on the reference memory have been investigated by a three-panel runway setup in rats. This study was designed by using a repeated acquisition procedure such as a radialarm maze task or a water maze task. DM (20-40 mg/kg i.p.) produced a significant decrease in the number of errors (pushes made on the two incorrect panels of the three panel gates at four choice points) and latency. Systemically administered scopolamine (CAS 114-49-8) (1 mg/kg i.p.) impaired the performance on both parameters. DM (40 mg/kg i.p.) was effective in reversing the reference memory deficit induced by administration of scopolamine. DM acts as a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptors. Our results suggest that inhibition of NMDA receptors by DM supports its potential positive properties. This finding might present an oppurtunity for the evaluation of this old antitussive drug. PMID:16724513

  9. Involvement of AMPA receptors in the antidepressant-like effects of dextromethorphan in mice.

    PubMed

    Nguyen, Linda; Matsumoto, Rae R

    2015-12-15

    Dextromethorphan (DM) is an antitussive with rapid acting antidepressant potential based on pharmacodynamic similarities to ketamine. Building upon our previous finding that DM produces antidepressant-like effects in the mouse forced swim test (FST), the present study aimed to establish the antidepressant-like actions of DM in the tail suspension test (TST), another well-established model predictive of antidepressant efficacy. Additionally, using the TST and FST, we investigated the role of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors in the antidepressant-like properties of DM because accumulating evidence suggests that AMPA receptors play an important role in the pathophysiology of depression and may contribute to the efficacy of antidepressant medications, including that of ketamine. We found that DM displays antidepressant-like effects in the TST similar to the conventional and fast acting antidepressants characterized by imipramine and ketamine, respectively. Moreover, decreasing the first-pass metabolism of DM by concomitant administration of quinidine (CYP2D6 inhibitor) potentiated antidepressant-like actions, implying DM itself has antidepressant efficacy. Finally, in both the TST and FST, pretreatment with the AMPA receptor antagonist NBQX (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide) significantly attenuated the antidepressant-like behavior elicited by DM. Together, the data show that DM exerts antidepressant-like actions through AMPA receptors, further suggesting DM may act as a safe and effective fast acting antidepressant drug. PMID:25804358

  10. Acute cognitive effects of high doses of dextromethorphan relative to triazolam in humans

    PubMed Central

    Carter, Lawrence P.; Reissig, Chad J.; Johnson, Matthew W.; Klinedinst, Margaret A.; Griffiths, Roland R.

    2012-01-01

    BACKGROUND Although concerns surrounding high-dose dextromethorphan (DXM) abuse have recently increased, few studies have examined the acute cognitive effects of high doses of DXM. The aim of this study was to compare the cognitive effects of DXM with those of triazolam and placebo. METHODS Single, acute, oral doses of DXM (100, 200, 300, 400, 500, 600, 700, 800 mg/70 kg), triazolam (0.25, 0.5 mg /70 kg), and placebo were administered p.o. to twelve healthy volunteers with histories of hallucinogen use, under double-blind conditions, using an ascending dose run-up design. Effects on cognitive performance were examined at baseline and after drug administration for up to 6 hours. RESULTS Both triazolam and DXM produced acute impairments in attention, working memory, episodic memory, and metacognition. Impairments observed following doses of 100-300 mg/70 kg DXM were generally smaller in magnitude than those observed after 0.5 mg/70 kg triazolam. Doses of DXM that impaired performance to the same extent as triazolam were in excess of 10-30 times the therapeutic dose of DXM. CONCLUSION The magnitude of the doses required for these effects and the absence of effects on some tasks within the 100-300 mg/70 kg dose range of DXM, speak to the relatively broad therapeutic window of over-the-counter DXM preparations when used appropriately. However, the administration of supratherapeutic doses of DXM resulted in acute cognitive impairments on all tasks that were examined. These findings are likely relevant to cases of high-dose DXM abuse. PMID:22989498

  11. Prevention of Hippocampal Neuronal Damage and Cognitive Function Deficits in Vascular Dementia by Dextromethorphan.

    PubMed

    Xu, Xiaofeng; Zhang, Bin; Lu, Kaili; Deng, Jiangshan; Zhao, Fei; Zhao, Bing-Qiao; Zhao, Yuwu

    2016-07-01

    Dextromethorphan (DM) is a non-competitive antagonist of NMDA receptors and a widely used component of cough medicine. Recently, its indication has been extended experimentally to a wide range of disorders including inflammation-mediated central nervous system disorders such as Parkinson disease (PD) and multiple sclerosis (MS). In this study, we investigate whether DM treatment has protective effects on the hippocampal neuron damage induced by bilateral occlusion of the common carotid arteries (two-vessel occlusion [2VO]), an animal model of vascular dementia (VaD). Sprague-Dawley (SD) (10 weeks of age) rats were subjected to the 2VO, and DM was injected intraperitoneally once per day for 37 days. Neuron death, glial activation, and cognitive function were assessed at 37 days after 2VO (0.2 mg/kg, i.p., "DM-0.2" and 2 mg/kg, i.p., "DM-2"). DM-2 treatment provided protection against neuronal death and glial activation in the hippocampal CA1 subfield and reduced cognitive impairment induced by 2VO in rats. The study also demonstrates that activation of the Nrf2-HO-1 pathway and upregulation of superoxide dismutase (SOD) play important roles in these effects. These results suggest that DM is effective in treating VaD and protecting against oxidative stress, which is strongly implicated in the pathogenesis of VaD. Therefore, the present study suggests that DM treatment may represent a new and promising protective strategy for treating VaD. PMID:26887382

  12. Dextromethorphan and its metabolite dextrorphan block alpha3beta4 neuronal nicotinic receptors.

    PubMed

    Hernandez, S C; Bertolino, M; Xiao, Y; Pringle, K E; Caruso, F S; Kellar, K J

    2000-06-01

    Dextromethorphan (DM), a structural analog of morphine and codeine, has been widely used as a cough suppressant for more than 40 years. DM is not itself a potent analgesic, but it has been reported to enhance analgesia produced by morphine and nonsteroidal anti-inflammatory drugs. Although DM is considered to be nonaddictive, it has been reported to reduce morphine tolerance in rats and to be useful in helping addicted subjects to withdraw from heroin. Here we studied the effects of DM on neuronal nicotinic receptors stably expressed in human embryonic kidney cells. Studies were carried out to examine the effects of DM on nicotine-stimulated whole cell currents and nicotine-stimulated (86)Rb(+) efflux. We found that both DM and its metabolite dextrorphan block nicotinic receptor function in a noncompetitive but reversible manner, suggesting that both drugs block the receptor channel. Consistent with blockade of the receptor channel, neither drug competed for the nicotinic agonist binding sites labeled by [(3)H]epibatidine. Although DM is approximately 9-fold less potent than the widely used noncompetitive nicotinic antagonist mecamylamine in blocking nicotinic receptor function, the block by DM appears to reverse more slowly than that by mecamylamine. These data indicate that DM is a useful antagonist for studying nicotinic receptor function and suggest that it might prove to be a clinically useful neuronal nicotinic receptor antagonist, possibly helpful as an aid for helping people addicted to nicotine to refrain from smoking, as well as in other conditions where blockade of neuronal nicotinic receptors would be helpful. PMID:10869398

  13. Lack of effect of chronic dextromethorphan on experimental pain tolerance in methadone-maintained patients.

    PubMed

    Compton, Peggy A; Ling, Walter; Torrington, Matt A

    2008-09-01

    Good evidence exists to suggest that individuals on opioid maintenance for the treatment of addiction (i.e. methadone) are less tolerant of experimental pain than are matched controls or ex-opioid addicts, a phenomenon theorized to reflect opioid-induced hyperalgesia (OIH). Agonist activity at the excitatory ionotropic N-methyl-D-aspartate (NMDA) receptor on dorsal horn neurons has been implicated in the development of both OIH and its putative expression at the clinical level-opioid tolerance. The aim of this study was to evaluate the potential utility of the NMDA-receptor antagonist, dextromethorphan (DEX), to reverse or treat OIH in methadone-maintenance (MM) patients. Utilizing a clinical trial design and double-blind conditions, changes in pain threshold and tolerance [cold pressor (CP) and electrical stimulation (ES)] following a 5-week trial of DEX (titrated to 480 mg/day) in comparison with placebo was evaluated in a well-characterized sample of MM patients. The sample (n = 40) was 53% male and ethnically diverse (53% Latino, 28% African American, 10% White, 9% other), with a mean age of 48.0 years (SD = 6.97). Based on t-test analyses, no difference was found between groups on CP pain threshold, CP pain tolerance, ES pain threshold or ES pain tolerance, both pre- and postmedication. Notably, DEX-related changes significantly differed by gender, with women tending to show diminished tolerance for pain with DEX therapy. These results support that chronic high-dose NMDA antagonism does not improve tolerance for pain in MM patients, although a gender effect on DEX response is suggested. PMID:18507735

  14. High doses of dextromethorphan, an NMDA antagonist, produce effects similar to classic hallucinogens

    PubMed Central

    Carter, Lawrence P.; Johnson, Matthew W.; Mintzer, Miriam Z.; Klinedinst, Margaret A.; Griffiths, Roland R.

    2013-01-01

    Rationale Although reports of dextromethorphan (DXM) abuse have increased recently, few studies have examined the effects of high doses of DXM. Objective This study in humans evaluated the effects of supratherapeutic doses of DXM and triazolam. Methods Single, acute, oral doses of DXM (100, 200, 300, 400, 500, 600, 700, 800 mg/70 kg), triazolam (0.25, 0.5 mg/70kg), and placebo were administered to twelve healthy volunteers with histories of hallucinogen use, under double-blind conditions, using an ascending dose run-up design. Subjective, behavioral, and physiological effects were assessed repeatedly after drug administration for 6 hours. Results Triazolam produced dose-related increases in subject-rated sedation, observer-rated sedation, and behavioral impairment. DXM produced a profile of dose-related physiological and subjective effects differing from triazolam. DXM effects included increases in blood pressure, heart rate, and emesis, increases in observer-rated effects typical of classic hallucinogens (e.g. distance from reality, visual effects with eyes open and closed, joy, anxiety), and participant ratings of stimulation (e.g. jittery, nervous), somatic effects (e.g. tingling, headache), perceptual changes, end-of-session drug liking, and mystical-type experience. After 400 mg/70kg DXM, 11 of 12 participants indicated on a pharmacological class questionnaire that they thought they had received a classic hallucinogen (e.g. psilocybin). Drug effects resolved without significant adverse effects by the end of the session. In a 1-month follow up volunteers attributed increased spirituality and positive changes in attitudes, moods, and behavior to the session experiences. Conclusions High doses of DXM produced effects distinct from triazolam and had characteristics that were similar to the classic hallucinogen psilocybin. PMID:22526529

  15. The N-methyl-D-aspartate receptor antagonist dextromethorphan selectively reduces temporal summation of second pain in man.

    PubMed

    Price, D D; Mao, J; Frenk, H; Mayer, D J

    1994-11-01

    Oral doses of dextromethorphan (DM), a common cough suppressant and N-methyl-D-aspartate (NMDA) receptor antagonist, and their vehicle control were given on a double-blind basis to normal volunteer human subjects who rated intensities of first and second pain in response to repeated painful electric shocks and repeated 52 degrees C heat pulses. Doses of 30 and 45 mg, but not 15 mg, were effective in attenuating temporal summation of second pain, a psychophysical correlate of temporal summation of C afferent-mediated responses of dorsal horn nociceptive neurons, termed 'wind-up'. By contrast, neither first nor second pain evoked by the first stimulus in a train of stimuli were affected by any of these doses of DM. These results further confirm temporal summation of second pain as a psychophysical correlate of wind-up by providing evidence that DM selectively reduces temporal summation of second pain, as has been shown for wind-up. PMID:7892014

  16. Combination With Low-dose Dextromethorphan Improves the Effect of Amlodipine Monotherapy in Clinical Hypertension

    PubMed Central

    Yin, Wei-Hsian; Chen, Pei; Yeh, Hung-I; Wang, Kuo-Yang; Hung, Yi-Jen; Tseng, Wei-Kung; Wen, Ming-Shien; Wu, Tao-Cheng; Wu, Chau-Chung; Cheng, Shu-Meng; Chen, Jaw-Wen

    2016-01-01

    Abstract The combination of low rather than high dose of dextromethorphan (DXM) with amlodipine (AM) could improve blood pressure (BP) reduction in hypertensive animals. The study aimed to evaluate the feasibility of different doses of DXM combined with standard AM treatment in clinical hypertension. This was a prospective, 14-week, dose-escalation, multicenter study. After 2-week run-in period with AM 5 mg/day, hypertensive patients who got the BP goal of 140/90 mmHg kept receiving AM monotherapy for another 12 weeks. The nonresponders, while kept on AM 5 mg/day, received additional DXM treatment for 3 sequential dose-titrated periods with initially 2.5 mg/day, followed by 7.5 mg/day, and finally 30 mg/day. Each period was for 4 weeks. The patients at BP goal after each treatment period were defined as the responders and kept on the same combination till the end of the study. The responder rate of each treatment period was recorded. The changes of BP and serum antioxidant/endothelial markers between week 14 and week 2 were evaluated. Of the 103 patients initially enrolled, 89 entered the treatment period. In the 78 patients completing the study, 31 (40%) at BP goal after 2-week AM run-in kept on AM monotherapy (DXM0). The addition of 2.5 (DXM2.5) and 7.5 mg/day (DXM7.5) of DXM enabled BP goal achievement in 22 (47%) nonresponders to AM monotherapy including 16 (29%) with DXM2.5 and 6 (18%) with DXM7.5. Only 4 patients (16%) reached BP goal with the combination of DXM 30 mg/day (DXM30). Overall, 73% of the 78 patients reached BP goal at the end of the 14-week study. Mean systolic BP was reduced by 7.9% ± 7.0% with DXM2.5 (P < 0.001) and by 5.4% ± 2.4% with DXM7.5 (P = 0.003) respectively at week 14 from that at week 2, which was unchanged in either DXM0 or DXM30 group. Besides, the effects of combination treatment were particularly significant in the patients with impaired endothelial function suggested by reduced serum NOx level

  17. Liquid chromatography/quadrupole-time-of-flight mass spectrometry with metabolic profiling of human urine as a tool for environmental analysis of dextromethorphan.

    PubMed

    Thurman, E Michael; Ferrer, Imma

    2012-10-12

    We use the combination of liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC/Q-TOF-MS) and urine metabolic profiling to find and identify the metabolites of dextromethorphan, a common over-the-counter (OTC) cough suppressant. Next, we use the combination of ion masses, their MS/MS fragmentation, and retention times to determine dextromethorphan and its metabolites in surface water impacted by wastewater. Prior to this study, neither dextromethorphan nor its metabolites have been reported in surface water; in spite of its common use in over 100 various OTC medications. We found that the concentration of the dextrorphan metabolite in surface water greatly exceeded the parent compound by factors of 5-10 times, which reflects the urine profile, where parent compound is approximately <2% of the total excreted drug based on ion intensities. Urine profiling also indicated that glucuronide metabolites are major phase 2 products (92% of the total) in urine and then are completely hydrolyzed in wastewater to dextrorphan and N-demethyldextrorphan, which are phase 1 metabolites-a "kind of reversal" of human metabolism. PMID:22443892

  18. Repeated, high-dose dextromethorphan treatment decreases neurogenesis and results in depression-like behavior in rats.

    PubMed

    Po, Kai Ting; Siu, Andrew Man-Hong; Lau, Benson Wui-Man; Chan, Jackie Ngai-Man; So, Kwok-Fai; Chan, Chetwyn C H

    2015-07-01

    Abuse of cough mixture is increasingly prevalent worldwide. Clinical studies showed that chronic consumption of cough mixture at high dosages may lead to psychiatric symptoms, especially affective disturbances, with the underlying mechanisms remain elusive. The present study aims at exploring the effect of repeated, high-dose dextromethorphan (DXM, a common active component of cough mixture) treatment on adult hippocampal neurogenesis, which is associated with pathophysiology of mood disturbances. After treatment with a high-dose of DXM (40 mg/kg/day) for 2 weeks, Sprague-Dawley rats showed increased depression-like behavior when compared to the control animals. Neurogenesis in the hippocampus was suppressed by DXM treatment, which was indicated by decreases in number of proliferative cells and doublecortin (an immature neuron marker)-positive new neurons. Furthermore, the dendritic complexity of the immature neurons was suppressed by DXM treatment. These findings suggest that DXM induces depression- and anxiety-like behavior and suppresses neurogenesis in rats. The current experimental paradigm may serve as an animal model for study on affective effect of cough mixture abuse, rehabilitation treatment options for abusers and the related neurological mechanisms. PMID:25939533

  19. Potential transducers based man-tailored biomimetic sensors for selective recognition of dextromethorphan as an antitussive drug.

    PubMed

    El-Naby, Eman H; Kamel, Ayman H

    2015-09-01

    A biomimetic potentiometric sensor for specific recognition of dextromethorphan (DXM), a drug classified according to the Drug Enforcement Administration (DEA) as a "drug of concern", is designed and characterized. A molecularly imprinted polymer (MIP), with special molecular recognition properties of DXM, was prepared by thermal polymerization in which DXM acted as template molecule, methacrylic acid (MAA) and acrylonitrile (AN) acted as functional monomers in the presence of ethylene glycol dimethacrylate (EGDMA) as crosslinker. The sensors showed a high selectivity and a sensitive response to the template in aqueous system. Electrochemical evaluation of these sensors revealed near-Nernstian response with slopes of 49.6±0.5 and 53.4±0.5 mV decade(-1) with a detection limit of 1.9×10(-6), and 1.0×10(-6) mol L(-1) DXM with MIP/MAA and MIP/AN membrane based sensors, respectively. Significantly improved accuracy, precision, response time, stability, selectivity and sensitivity were offered by these simple and cost-effective potentiometric sensors compared with other standard techniques. The method has the requisite accuracy, sensitivity and precision to assay DXM in pharmaceutical products. PMID:26046285

  20. Behavioral and biochemical effects of ketamine and dextromethorphan relative to its antidepressant-like effects in Swiss Webster mice.

    PubMed

    Nguyen, Linda; Lucke-Wold, Brandon P; Logsdon, Aric F; Scandinaro, Anna L; Huber, Jason D; Matsumoto, Rae R

    2016-09-28

    Ketamine has been shown to produce rapid and robust antidepressant effects in depressed individuals; however, its abuse potential and adverse psychotomimetic effects limit its widespread use. Dextromethorphan (DM) may serve as a safer alternative on the basis of pharmacodynamic similarities to ketamine. In this proof-of-concept study, behavioral and biochemical analyses were carried out to evaluate the potential involvement of brain-derived neurotrophic factor (BDNF) in the antidepressant-like effects of DM in mice, with comparisons to ketamine and imipramine. Male Swiss, Webster mice were injected with DM, ketamine, or imipramine and their behaviors were evaluated in the forced-swim test and the open-field test. Western blots were used to measure BDNF and its precursor, pro-BDNF, protein expression in the hippocampus and the frontal cortex of these mice. Our results show that both DM and imipramine reduced immobility time in the forced-swim test without affecting locomotor activity, whereas ketamine reduced immobility time and increased locomotor activity. Ketamine also rapidly (within 40 min) increased pro-BDNF expression in an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-dependent manner in the hippocampus, whereas DM and imipramine did not alter pro-BDNF or BDNF levels in either the hippocampus or the frontal cortex within this timeframe. These data show that DM shares some features with both ketamine and imipramine. Additional studies examining DM may aid in the development of more rapid, safe, and efficacious antidepressant treatments. PMID:27580401

  1. Role of hippocampal and prefrontal cortical signaling pathways in dextromethorphan effect on morphine-induced memory impairment in rats.

    PubMed

    Ghasemzadeh, Zahra; Rezayof, Ameneh

    2016-02-01

    Evidence suggests that dextromethorphan (DM), an NMDA receptor antagonist, induces memory impairment. Considering that DM is widely used in cough-treating medications, and the co-abuse of DM with morphine has recently been reported, the aims of the present study was (1) to investigate whether there is a functional interaction between morphine and DM in passive avoidance learning and (2) to assess the possible role of the hippocampal and prefrontal cortical (PFC) signaling pathways in the effects of the drugs on memory formation. Our findings indicated that post-training or pre-test administration of morphine (2 and 6 mg/kg) or DM (10-30 mg/kg) impaired memory consolidation and retrieval which was associated with the attenuation of the levels of phosphorylated Ca(2+)/calmodulin-dependent protein kinase II (p-CAMKII) and cAMP responsive element-binding protein (p-CREB) in the targeted sites. Moreover, the memory impairment induced by post-training administration of morphine was reversed by pre-test administration of the same dose of morphine or DM (30 mg/kg), indicating state-dependent learning (SDL) and a cross-SDL between the drugs. It is important to note that the levels of p-CAMKII/CAMKII and p-CREB/CREB in the hippocampus and the PFC increased in drugs-induced SDL. In addition, DM administration potentiated morphine-induced SDL which was related to the enhanced levels of hippocampal and PFC CAMKII-CREB signaling pathways. It can be concluded that there is a relationship between the hippocampus and the PFC in the effect of DM and/or morphine on memory retrieval. Moreover, a cross SDL can be induced between the co-administration of DM and morphine. Interestingly, CAMKII-CREB signaling pathways also mediate the drugs-induced SDL. PMID:26708494

  2. Further characterization of a ¹³C-dextromethorphan breath test for CYP2D6 phenotyping in breast cancer patients on tamoxifen therapy.

    PubMed

    Opdam, F L; Modak, A S; Gelderblom, H; Guchelaar, H J

    2015-06-01

    In a previous study, we found that the CYP2D6 phenotype determined by (13)C-dextromethorphan breath test (DM-BT) might be used to predict tamoxifen treatment outcome in breast cancer patients in the adjuvant setting. However, large variation in the delta-over-baseline (DOB) values was observed in the extensive metabolizer predicted phenotype group based on single point measures. In the present work we aimed to analyze the variability of phenotype results and determine reproducibility to further characterize the clinical utility of DM-BT by introducing multiple breath sampling instead of single breath sampling and by administration of a fixed dose of (13)C-DM. PMID:25891764

  3. Therapeutic Approach of a High Functioning Individual With Traumatic Brain Injury and Subsequent Emotional Volatility With Features of Pathological Laughter and Crying With Dextromethorphan/Quinidine.

    PubMed

    Garcia-Baran, Dynela; Johnson, Thomas M; Wagner, Joyce; Shen, Joann; Geers, Michelle

    2016-03-01

    Pathological laughing and crying, or pseudobulbar affect (PBA), has been described in patients with neurological disorders such as multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, stroke, and traumatic brain injury (TBI) since the 19th century (Schiffer 2005). The syndrome is characterized by inappropriate episodes of laughing or crying after minor stimuli. It was first coined a disinhibition of cortical control by Kinnier Wilson in 1924. It was observed in brain disease and seen with mild TBI. It can impair social and occupational function and is largely underrecognized in clinical settings. PBA is usually treated with antidepressants and dopaminergic agents. In this case we treated a military recruit with TBI with Nuedexta-a dextromethorphan/Quinidine derivative with a subsequent decrease in his episodes. PMID:27015166

  4. Dextromethorphan and Quinidine

    MedlinePlus

    ... is in a class of medications called central nervous system agents. The way it works in the brain ... ever had myasthenia gravis (a disorder of the nervous system that causes muscle weakness), a history of street ...

  5. Dextromethorphan and Quinidine

    MedlinePlus

    ... disease; condition in which the nerves that control muscle movement slowly die, causing the muscles to shrink and weaken) or multiple sclerosis (a ... and patients may experience weakness, numbness, loss of muscle coordination and problems with vision, speech, and bladder ...

  6. Analysis of dextromethorphan and dextrorphan in decomposed skeletal tissues by microwave assisted extraction, microplate solid-phase extraction and gas chromatography- mass spectrometry (MAE-MPSPE-GCMS).

    PubMed

    Fraser, Candice D; Cornthwaite, Heather M; Watterson, James H

    2015-08-01

    Analysis of decomposed skeletal tissues for dextromethorphan (DXM) and dextrorphan (DXT) using microwave assisted extraction (MAE), microplate solid-phase extraction (MPSPE) and gas chromatography-mass spectrometry (GC-MS) is described. Rats (n = 3) received 100 mg/kg DXM (i.p.) and were euthanized by CO2 asphyxiation roughly 20 min post-dose. Remains decomposed to skeleton outdoors and vertebral bones were recovered, cleaned, and pulverized. Pulverized bone underwent MAE using methanol as an extraction solvent in a closed microwave system, followed by MPSPE and GC-MS. Analyte stability under MAE conditions was assessed and found to be stable for at least 60 min irradiation time. The majority (>90%) of each analyte was recovered after 15 min. The MPSPE-GCMS method was fit to a quadratic response (R(2)  > 0.99), over the concentration range 10-10 000 ng⋅mL(-1) , with coefficients of variation <20% in triplicate analysis. The MPSPE-GCMS method displayed a limit of detection of 10 ng⋅mL(-1) for both analytes. Following MAE for 60 min (80 °C, 1200 W), MPSPE-GCMS analysis of vertebral bone of DXM-exposed rats detected both analytes in all samples (DXM: 0.9-1.5 µg⋅g(-1) ; DXT: 0.5-1.8 µg⋅g(-1) ). PMID:25487525

  7. A new hydrophilic interaction liquid chromatographic (HILIC) procedure for the simultaneous determination of pseudoephedrine hydrochloride (PSH), diphenhydramine hydrochloride (DPH) and dextromethorphan hydrobromide (DXH) in cough-cold formulations.

    PubMed

    Ali, Mohammed Shahid; Ghori, Mohsin; Rafiuddin, Syed; Khatri, Aamer Roshanali

    2007-01-01

    A new HILIC method has been developed for the simultaneous determination of pseudoephedrine hydrochloride (PSH), diphenhydramine hydrochloride (DPH) and dextromethorphan hydrobromide (DXH) in cough-cold syrup. Mobile phase consists of methanol:water (containing 6.0 g of ammonium acetate and 10 mL of triethylamine per liter, pH adjusted to 5.2 with orthophosphoric acid), 95:5 (v/v). Column containing porous silica particles (Supelcosil LC-Si, 25 cm x 4.6 mm, 5 microm) is used as stationary phase. Detection is carried out using a variable wavelength UV-vis detector at 254 nm for PSH and DPH, and at 280 nm for DXH. Solutions are injected into the chromatograph under isocratic condition at constant flow rate of 1.2 mL/min. Linearity range and percent recoveries for PSH, DPH and DXH were 150-600, 62.5-250, 75-300 microg/mL and 100.7%, 100.1% and 100.8%, respectively. Method is stability indicating and excipients like saccharin sodium, sodium citrate, flavour and sodium benzoate did not interfere in the analysis. Compounds elute in order of increasing ionization degree caused by cation-exchange mechanism in a run time of less than 15 min. Mobile phase pH is manipulated to regulate ionization and ion-exchange interaction and thereby retention of compounds. PMID:16887317

  8. An open-label multicenter study to assess the safety of dextromethorphan/quinidine in patients with pseudobulbar affect associated with a range of underlying neurological conditions

    PubMed Central

    Pattee, Gary L.; Wymer, James P.; Lomen-Hoerth, Catherine; Appel, Stanley H.; Formella, Andrea E.; Pope, Laura E.

    2014-01-01

    Abstract Background: Pseudobulbar affect (PBA) is associated with neurological disorders or injury affecting the brain, and characterized by frequent, uncontrollable episodes of crying and/or laughing that are exaggerated or unrelated to the patient’s emotional state. Clinical trials establishing dextromethorphan and quinidine (DM/Q) as PBA treatment were conducted in patients with amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS). This trial evaluated DM/Q safety in patients with PBA secondary to any neurological condition affecting the brain. Objective: To evaluate the safety and tolerability of DM/Q during long-term administration to patients with PBA associated with multiple neurological conditions. Methods: Fifty-two-week open-label study of DM/Q 30/30 mg twice daily. Safety measures included adverse events (AEs), laboratory tests, electrocardiograms (ECGs), vital signs, and physical examinations. Clinical trial registration: #NCT00056524. Results: A total of 553 PBA patients with >30 different neurological conditions enrolled; 296 (53.5%) completed. The most frequently reported treatment-related AEs (TRAEs) were nausea (11.8%), dizziness (10.5%), headache (9.9%), somnolence (7.2%), fatigue (7.1%), diarrhea (6.5%), and dry mouth (5.1%). TRAEs were mostly mild/moderate, generally transient, and consistent with previous controlled trials. Serious AEs (SAEs) were reported in 126 patients (22.8%), including 47 deaths, mostly due to ALS progression and respiratory failure. No SAEs were deemed related to DM/Q treatment by investigators. ECG results suggested no clinically meaningful effect of DM/Q on myocardial repolarization. Differences in AEs across neurological disease groups appeared consistent with the known morbidity of the primary neurological conditions. Study interpretation is limited by the small size of some disease groups, the lack of a specific efficacy measure and the use of a DM/Q dose higher than the eventually approved dose

  9. Determination of dextromethorphan and its metabolite dextrorphan in human urine using high performance liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry: a study of selectivity of a tandem mass spectrometric assay.

    PubMed

    Constanzer, M L; Chavez-Eng, C M; Fu, I; Woolf, E J; Matuszewski, B K

    2005-02-25

    Analytical method for the simultaneous determination of dextromethorphan (1) and dextrorphan (2) in urine, based on solid-phase extraction of drug from acidified hydrolyzed biological matrix, were developed. The analytes (1 and 2) and the internal standard (levallorphan, 3, IS) were detected by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) in positive ionization mode using a heated nebulizer (HN) probe and monitoring their precursor-->product ion combinations of m/z 272-->215, 258-->201, and 284-->201 for 1, 2, and 3, respectively, in multiple reaction monitoring mode. The analytes and IS were chromatographed on a Keystone Prism reverse phase (50 mm x 2.0 mm) 5 microm column using a mobile phases consisting of a 35/65 or 27/73 mixtures of methanol/water containing 0.1% TFA adjusted to pH 3 with ammonium hydroxide pumped at 0.4 ml/min for 1 and 2, respectively. The limits of reliable quantification of 1 and 2 were 2 and 250 ng/ml, respectively, when 1 ml of urine was processed. The absence of matrix effect was demonstrated by analysis of neat standards and standards spiked into urine extracts originating from five different sources. The linear ranges of the assay were 2-200 and 250-20,000 ng/ml for 1 and 2, respectively. Assay selectivity was evaluated by monitoring the "cross-talk" effects from other metabolites into the MS/MS channels used for monitoring 1, 2, and 3. In addition, an interfering peak originating from an unknown metabolite of 1 into the quantification of dextromethorphan was detected, requiring an effective chromatographic separation of analytes from other metabolites of 1. The need for careful assessment of selectivity of the HPLC-MS/MS assay in the presence of metabolites, and the assessment of matrix effect, are emphasized. PMID:15664362

  10. Development and validation of a sensitive UHPLC-MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics.

    PubMed

    Heneedak, Hala M; Salama, Ismail; Mostafa, Samia; El-Kady, Ehab; El-Sadek, Mohamed

    2015-07-01

    The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O-desmethyltramadol, dsmethyl-chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction method using ethyl acetate-diethyl-ether (1:1). Extracted samples were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil-Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3-9.8 and -1.7-4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide. PMID:25417559

  11. Microbial Transformations of Natural Antitumor Agents: O-Demethylation of Vindoline by Sepedonium chrysospermum

    PubMed Central

    Wu, Geng-Shuen; Nabih, Thomas; Youel, Leisa; Peczynska-Czoch, Wanda; Rosazza, John P.

    1978-01-01

    Vindoline (1a) was transformed to O-demethylvindoline (1b) by Sepedonium chrysospermum ATCC 13378 in 33% yield. Thin-layer and high-pressure liquid chromatographic methods distinguished 1b from previously reported microbial metabolites of vindoline. The structural proof of 1b was based on its mass spectral fragmentation pattern and on its chemical and nuclear magnetic resonance spectral properties. PMID:568911

  12. Combination With Low-dose Dextromethorphan Improves the Effect of Amlodipine Monotherapy in Clinical Hypertension: A First-in-human, Concept-proven, Prospective, Dose-escalation, Multicenter Study.

    PubMed

    Yin, Wei-Hsian; Chen, Pei; Yeh, Hung-I; Wang, Kuo-Yang; Hung, Yi-Jen; Tseng, Wei-Kung; Wen, Ming-Shien; Wu, Tao-Cheng; Wu, Chau-Chung; Cheng, Shu-Meng; Chen, Jaw-Wen

    2016-03-01

    The combination of low rather than high dose of dextromethorphan (DXM) with amlodipine (AM) could improve blood pressure (BP) reduction in hypertensive animals. The study aimed to evaluate the feasibility of different doses of DXM combined with standard AM treatment in clinical hypertension.This was a prospective, 14-week, dose-escalation, multicenter study. After 2-week run-in period with AM 5 mg/day, hypertensive patients who got the BP goal of 140/90 mmHg kept receiving AM monotherapy for another 12 weeks. The nonresponders, while kept on AM 5 mg/day, received additional DXM treatment for 3 sequential dose-titrated periods with initially 2.5 mg/day, followed by 7.5 mg/day, and finally 30 mg/day. Each period was for 4 weeks. The patients at BP goal after each treatment period were defined as the responders and kept on the same combination till the end of the study. The responder rate of each treatment period was recorded. The changes of BP and serum antioxidant/endothelial markers between week 14 and week 2 were evaluated.Of the 103 patients initially enrolled, 89 entered the treatment period. In the 78 patients completing the study, 31 (40%) at BP goal after 2-week AM run-in kept on AM monotherapy (DXM0). The addition of 2.5 (DXM2.5) and 7.5 mg/day (DXM7.5) of DXM enabled BP goal achievement in 22 (47%) nonresponders to AM monotherapy including 16 (29%) with DXM2.5 and 6 (18%) with DXM7.5. Only 4 patients (16%) reached BP goal with the combination of DXM 30 mg/day (DXM30). Overall, 73% of the 78 patients reached BP goal at the end of the 14-week study. Mean systolic BP was reduced by 7.9% ± 7.0% with DXM2.5 (P < 0.001) and by 5.4% ± 2.4% with DXM7.5 (P = 0.003) respectively at week 14 from that at week 2, which was unchanged in either DXM0 or DXM30 group. Besides, the effects of combination treatment were particularly significant in the patients with impaired endothelial function suggested by reduced serum NOx level at baseline

  13. Potential Mechanism of Action of 3'-Demethoxy-6-O-demethyl-isoguaiacin on Methicillin Resistant Staphylococcus aureus.

    PubMed

    Favela-Hernández, Juan Manuel J; Clemente-Soto, Aldo F; Balderas-Rentería, Isaías; Garza-González, Elvira; Camacho-Corona, María del Rayo

    2015-01-01

    Bacterial infections represent one of the main threats to global public health. One of the major causative agents associated with high morbidity and mortality infections in hospitals worldwide is methicillin-resistant Staphylococcus aureus. Therefore, there is a need to develop new antibacterial agents to treat these infections, and natural products are a rich source of them. In previous studies, we reported that lignan 3'-demethoxy-6-O-demethylisoguaiacin, isolated and characterized from Larrea tridentate, showed the best activity towards methicillin-resistant S. aureus. Thus, the aim of this study was to determine the potential molecular mechanism of the antibacterial activity of 3'-demethoxy-6-O-demethylisoguaiacin against methicillin-resistant S. aureus using microarray technology. Results of microarray genome expression were validated by real-time polymerase chain reaction (RT-PCR). The genetic profile expression results showed that lignan 3'-demethoxy-6-O-demethylisoguaiacin had activity on cell membrane affecting proteins of the ATP-binding cassette (ABC) transport system causing bacteria death. This molecular mechanism is not present in any antibacterial commercial drug and could be a new target for the development of novel antibacterial agents. PMID:26184132

  14. Potential mechanism of action of 3'-demethoxy-6-O-demethyl-isoguaiacin on methicillin resistant Staphylococcus aureus.

    PubMed

    Favela-Hernández, Juan Manuel J; Clemente-Soto, Aldo F; Balderas-Rentería, Isaías; Garza-González, Elvira; Camacho-Corona, María Del Rayo

    2015-01-01

    Bacterial infections represent one of the main threats to global public health. One of the major causative agents associated with high morbidity and mortality infections in hospitals worldwide is methicillin-resistant Staphylococcus aureus. Therefore, there is a need to develop new antibacterial agents to treat these infections, and natural products are a rich source of them. In previous studies, we reported that lignan 3'-demethoxy-6-O-demethylisoguaiacin, isolated and characterized from Larrea tridentate, showed the best activity towards methicillin-resistant S. aureus. Thus, the aim of this study was to determine the potential molecular mechanism of the antibacterial activity of 3'-demethoxy-6-O-demethylisoguaiacin against methicillin-resistant S. aureus using microarray technology. Results of microarray genome expression were validated by real-time polymerase chain reaction (RT-PCR). The genetic profile expression results showed that lignan 3'-demethoxy-6-O-demethylisoguaiacin had activity on cell membrane affecting proteins of the ATP-binding cassette (ABC) transport system causing bacteria death. This molecular mechanism is not present in any antibacterial commercial drug and could be a new target for the development of novel antibacterial agents. PMID:26205047

  15. Effect of Garden Cress Seeds Powder and Its Alcoholic Extract on the Metabolic Activity of CYP2D6 and CYP3A4

    PubMed Central

    Al-Jenoobi, Fahad I.; Al-Thukair, Areej A.; Abbas, Fawkeya A.; Al-Mohizea, Abdullah M.; Alkharfy, Khalid M.; Al-Suwayeh, Saleh A.

    2014-01-01

    The powder and alcoholic extract of dried seeds of garden cress were investigated for their effect on metabolic activity of CYP2D6 and CYP3A4 enzymes. In vitro and clinical studies were conducted on human liver microsomes and healthy human subjects, respectively. Dextromethorphan was used as a common marker for measuring metabolic activity of CYP2D6 and CYP3A4 enzymes. In in vitro studies, microsomes were incubated with NADPH in presence and absence of different concentrations of seeds extract. Clinical investigations were performed in two phases. In phase I, six healthy female volunteers were administered a single dose of dextromethorphan and in phase II volunteers were treated with seeds powder for seven days and dextromethorphan was administered with last dose. The O-demethylated and N-demethylated metabolites of dextromethorphan were measured as dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Observations suggested that garden cress inhibits the formation of DOR and 3-MM metabolites. This inhibition of metabolite level was attributed to the inhibition of CYP2D6 and CYP3A4 activity. Garden cress decreases the level of DOR and 3-MM in urine and significantly increases the urinary metabolic ratio of DEX/DOR and DEX/3-MM. The findings suggested that garden cress seeds powder and ethanolic extract have the potential to interact with CYP2D6 and CYP3A4 substrates. PMID:24711855

  16. Development of a V79 cell line expressing human cytochrome P450 2D6 and its application as a metabolic screening tool.

    PubMed

    Rauschenbach, R; Gieschen, H; Salomon, B; Kraus, C; Kühne, G; Hildebrand, M

    1997-02-15

    Expression of human cytochrome P450 (CYP) in heterologous cells is a means of specifically studying the role of these enzymes in drug metabolism. The complete cDNA encoding CYP2D6-VAL(374) was inserted into an expression vector containing the strong mycloproliferative sarcoma virus promotor in combination with the enhancer of the cytomegalovirus and stably expressed in V79 Chinese hamster cells. The presence of genomically integrated CYP2D6 cDNA was confirmed by polymerase chain reaction analysis. The protein expression was shown by Western blotting. Functional expression could be demonstrated by O-demethylation of dextromethorphan to dextrorphan in live cells. The enzymatic activity of 154 ± 16 pmol min(-1) mg(-1) protein was comparable with dextromethorphan-O-demethylation activities of human liver. The metabolism of two dopaminergic ergoline derivatives was investigated in whole recombinant V19 cells. Both lisuride and terguride were monodeethylated; in case of lisuride a correlation to the in vivo situation was demonstrated comparing poor and extensive metabolizers. PMID:21781755

  17. Effects of gestational and overt diabetes on placental cytochromes P450 and glutathione S-transferase.

    PubMed

    Glover; McRobie; Tracy

    1998-07-01

    Objective: Animal and in vivo human studies have observed that diabetes alters the expression of hepatic metabolizing cytochrome P450 (CYP) and glutathione S-transferase (GST) enzymes. The placenta has the ability to metabolize a number of xenobiotic and endogenous compounds by processes similar to those seen in the liver. Our objective was to compare placental xenobiotic metabolizing activity in diabetics to matched non-diabetic controls to determine if the presence of diabetes alters placental xenobiotic metabolizing activity.Methods: The catalytic activities of 7-ethoxyresorufin-O-deethylation [EROD] (CYP1A1), chlorzoxazone 6-hydroxylation (CYP2E1), dextromethorphan N-demethylation (CYP3A4), dextromethorphan O-demethylation (CYP2D6), and 1-chloro-2,4-dinitrobenzene (CDNB) conjugation with glutathione (GST) from placentas of diet controlled (class A1) and insulin-dependent (class A2) gestational diabetics and overt diabetics were compared to matched controls.Results: No differences in EROD activity were observed among overt or gestational diabetics and their respectively matched controls. CYP2E1, 2D6, and 3A4 enzyme activity were not detected in human placentas. In contrast, GST activity was significantly reduced by 30% (P <.05) in overt diabetics as compared to their matched controls and gestational diabetics.Conclusion: Pregnant women with overt diabetes have reduced GST activity in the placenta, which could potentially result in exposure of the fetus to harmful reactive electrophilic metabolites. PMID:10838356

  18. Determination of colchicine and O-demethylated metabolites in decomposed skeletal tissues by microwave assisted extraction, microplate solid phase extraction and ultra-high performance liquid chromatography (MAE-MPSPE-UHPLC).

    PubMed

    Watterson, J H; Imfeld, A B; Cornthwaite, H C

    2014-06-01

    Microwave assisted extraction (MAE) followed by microplate solid phase extraction (MPSPE) coupled with ultra high performance liquid chromatography (UHPLC) for the semi-quantitative determination of colchicine, 3-demethyl colchicine and 2-demethyl colchicine in postmortem rat bone is described. Rats (n=4) received 50mg/kg colchicine (i.p), and euthanized by CO2 asphyxiation. Remains decomposed to skeleton outdoors and vertebral bones were collected cleaned, and ground to a fine powder. Powdered bone underwent MAE using methanol in a closed microwave system, followed by MPSPE and analysis using UHPLC-PDA. MAE analyte stability was assessed and found to be stable for at least 60 min irradiation time. The majority (>95%) of each analyte was recovered after 15 min. The MPSPE-UHPLC method was linear between 10 and 2,000 ng/mL, with coefficients of variation <20% in triplicate analysis, with a limit of detection of 10 ng/mL for each of the three analytes. Following MAE for 30 min (80°C, 1200W), MPSPE-UHPLC analysis of vertebral bone of colchicine-exposed rats detected colchicine (1.8-4.1 μg/g), 3-demethyl colchicine (0.77-1.8 μg/g) and 2-demethyl colchicine (0.43-0.80 μg/g) in all samples assayed. PMID:24799069

  19. Effects of gestational and overt diabetes on human placental cytochromes P450 and glutathione S-transferase.

    PubMed

    McRobie, D J; Glover, D D; Tracy, T S

    1998-04-01

    The placenta possesses the ability to metabolize a number of xenobiotics and endogenous compounds by processes similar to those seen in the liver. Animal and in vivo studies have observed that the presence of diabetes alters the expression of hepatic metabolizing enzymes (cytochrome P450 and glutathione S-transferase); however, it is unknown whether similar alterations occur in the human placenta. To evaluate whether diabetes has any effect of placental xenobiotic metabolizing activity, the catalytic activities of 7-ethoxyresorufin O-deethylation (EROD, CYP1A1), chlorzoxazone 6-hydroxylation (CYP2E1), dextromethorphan N-demethylation (CYP3A4), dextromethorphan O-demethylation (CYP2D6), and 1-chloro-2, 4-dinitrobenzene (CDNB) conjugation with glutathione (glutathione S-transferase, GST) from placentas of diet (class A1) and insulin-dependent (class A2) gestational diabetics and overt diabetics were compared with matched controls. EROD activity (CYP1A1) ranged from 0.29 to 2.67 pmol/min/mg protein. However, no differences were observed among overt or gestational diabetics and their respective matched controls. CDNB conjugation (GST) ranged from 0.275 to 1.65 units/min/mg protein. In contrast to that observed with CYP1A1, a small but statistically significant reduction in GST activity was noted in overt diabetics as compared with their matched controls and gestational diabetics. CYP2E1, 2D6, and 3A4 enzymatic activities were not detected in human placental tissue. GST protein was detectable in all tissues studied, but no CYP protein could be detected in any of the tissues. Thus, it seems that pregnant women with overt diabetes have reduced GST activity in the placenta, which could potentially result in the exposure of the fetus to harmful electrophiles. However, the full clinical significance of this finding remains to be elucidated. PMID:9531526

  20. Metabolism of human cytochrome P450 marker substrates in mouse: a strain and gender comparison.

    PubMed

    Löfgren, S; Hagbjörk, A L; Ekman, S; Fransson-Steen, R; Terelius, Y

    2004-09-01

    The aim was to characterize mouse gender and strain differences in the metabolism of commonly used human cytochrome (CYP) P450 probe substrates. Thirteen human CYP probe substrates (phenacetin, coumarin, 7-ethoxy-4-trifluoromethyl coumarin, amiodarone, paclitaxel, diclofenac, S-mephenytoin, bufuralol, dextromethorphan, chlorzoxazone, p-nitrophenol, testosterone and lauric acid) were used in activity measurements. The metabolism of the probe substrates was compared in liver microsomes from male and female NMRI, CBA, C57bl/6, 129/SvJ and CD1 strains. The expression of proteins identified on Western blots with commonly available antibodies selective for specific human and rat CYP enzymes were compared in the different mouse strains. Males had higher metabolism than corresponding females for phenacetin O-deethylation (human marker for CYP1A2 activity), and a high correlation was found between phenacetin activity and immunoreactivity in Western blots produced with rat CYP1A2 antibodies. Protein detected by antibodies cross-reacting with human CYP2B6 and rat CYP2B1/2 antibodies was female specific except for the 129/SvJ strain, where it was absent in both genders. Females generally had a higher metabolism of bufuralol 1'-hydroxylation and dextromethorphan O-demethylation (human markers for CYP2D activity). Bufuralol 1'-hydroxylation correlated with a female-dominant mouse CYP, which was detected with antibodies against rat CYP2D4. p-Nitrophenol 2-hydroxylation correlated better than chlorzoxazone 6-hydroxylation with the protein detected with antibodies against rat CYP2E1, indicating that p-nitrophenol is a more specific substrate for mouse CYP2E1. PMID:15742976

  1. Mechanism-based inhibition of CYP3A4 and CYP2D6 by Indonesian medicinal plants.

    PubMed

    Subehan; Usia, Tepy; Iwata, Hiroshi; Kadota, Shigetoshi; Tezuka, Yasuhiro

    2006-05-24

    Thirty samples of Indonesian medicinal plants were tested for their mechanism-based inhibition on cytochrome P450 3A4 (CYP3A4) and CYP2D6 via erythromycin N-demethylation and dextromethorphan O-demethylation activities in human liver microsomes. From screening with 0 and 20min preincubation at 0.5mg/ml of methanol extracts, five plants (Cinnamomum burmani bark, Foeniculum vulgare seed, Strychnos ligustrina wood, Tinospora crispa stem, and Zingiber cassumunar rhizome) showed more than 30% increase of CYP3A4 inhibition, while three (Alpinia galanga rhizome, Melaleuca leucadendron leaf, and Piper nigrum fruit) showed more than 30% increase of CYP2D6 inhibition. In these eight plants, Foeniculum vulgare seed, Cinnamomum burmani bark, and Strychnos ligustrina wood showed time-dependent inhibition on CYP3A4 and Piper nigrum fruit and Melaleuca leucadendron leaf on CYP2D6. Among these, four plants other than Melaleuca leucadendron revealed NADPH-dependent inhibition. Thus, Foeniculum vulgare, Cinnamomum burmani, and Strychnos ligustrina should contain mechanism-based inhibitors on CYP3A4 and Piper nigrum contain that on CYP2D6. PMID:16414224

  2. Guanfu base A, an antiarrhythmic alkaloid of Aconitum coreanum, Is a CYP2D6 inhibitor of human, monkey, and dog isoforms.

    PubMed

    Sun, Jianguo; Peng, Ying; Wu, Hui; Zhang, Xueyuan; Zhong, Yunxi; Xiao, Yanan; Zhang, Fengyi; Qi, Huanhuan; Shang, Lili; Zhu, Jianping; Sun, Yue; Liu, Ke; Liu, Jinghan; A, Jiye; Ho, Rodney J Y; Wang, Guangji

    2015-05-01

    Guanfu base A (GFA) is a novel heterocyclic antiarrhythmic drug isolated from Aconitum coreanum (Lèvl.) rapaics and is currently in a phase IV clinical trial in China. However, no study has investigated the influence of GFA on cytochrome P450 (P450) drug metabolism. We characterized the potency and specificity of GFA CYP2D inhibition based on dextromethorphan O-demethylation, a CYP2D6 probe substrate of activity in human, mouse, rat, dog, and monkey liver microsomes. In addition, (+)-bufuralol 1'-hydroxylation was used as a CYP2D6 probe for the recombinant form (rCYP2D6), 2D1 (rCYP2D1), and 2D2 (rCYP2D2) activities. Results show that GFA is a potent noncompetitive inhibitor of CYP2D6, with inhibition constant Ki = 1.20 ± 0.33 μM in human liver microsomes (HLMs) and Ki = 0.37 ± 0.16 μM for the human recombinant form (rCYP2D6). GFA is also a potent competitive inhibitor of CYP2D in monkey (Ki = 0.38 ± 0.12 μM) and dog (Ki = 2.4 ± 1.3 μM) microsomes. However, GFA has no inhibitory activity on mouse or rat CYP2Ds. GFA did not exhibit any inhibition activity on human recombinant CYP1A2, 2A6, 2C8, 2C19, 3A4, or 3A5, but showed slight inhibition of 2B6 and 2E1. Preincubation of HLMs and rCYP2D6 resulted in the inactivation of the enzyme, which was attenuated by GFA or quinidine. Beagle dogs treated intravenously with dextromethorphan (2 mg/ml) after pretreatment with GFA injection showed reduced CYP2D metabolic activity, with the Cmax of dextrorphan being one-third that of the saline-treated group and area under the plasma concentration-time curve half that of the saline-treated group. This study suggests that GFA is a specific CYP2D6 inhibitor that might play a role in CYP2D6 medicated drug-drug interaction. PMID:25681130

  3. Evaluation of CYP2D6 enzyme activity using a Dextromethorphan Breath Test in Women Receiving Adjuvant Tamoxifen

    PubMed Central

    Safgren, Stephanie L.; Suman, Vera J.; Kosel, Matthew L.; Gilbert, Judith A; Buhrow, Sarah A.; Black, John L.; Northfelt, Donald W.; Modak, Anil S.; Rosen, David; Ingle, James N.; Ames, Matthew M.; Reid, Joel M.; Goetz, Matthew P.

    2015-01-01

    Background In tamoxifen-treated patients, breast cancer recurrence differs according to CYP2D6 genotype and endoxifen steady state concentrations (Endx Css). The 13Cdextromethorphan breath test (DM-BT), labeled with 13C at the O-CH3 moiety, measures CYP2D6 enzyme activity. We sought to examine the ability of the DM-BT to identify known CYP2D6 genotypic poor metabolizers and examine the correlation between DMBT and Endx Css. Methods DM-BT and tamoxifen pharmacokinetics were obtained at baseline (b), 3 month (3m) and 6 months (6m) following tamoxifen initiation. Potent CYP2D6 inhibitors were prohibited. The correlation between bDM-BT with CYP2D6 genotype and Endx Css was determined. The association between bDM-BT (where values ≤0.9 is an indicator of poor in vivo CYP2D6 metabolism) and Endx Css (using values ≤ 11.2 known to be associated with poorer recurrence free survival) was explored. Results 91 patients were enrolled and 77 were eligible. CYP2D6 genotype was positively correlated with b, 3m and 6m DMBT (r ranging from 0.457-0. 60 p < 0.001). Both CYP2D6 genotype (r = 0.47; 0.56, p <.0001), and bDM-BT (r=0.60; 0.54; p<.001) were associated with 3m and 6m Endx Css respectively. Seven of 9 patients (78%) with low (≤11.2 nM) 3m Endx Css also had low DM-BT (≤0.9) including 2/2 CYP2D6 PM/PM and 5/5 IM/PM. In contrast, 1 of 48 pts (2%) with a low DM-BT had Endx Css > 11.2 nM. Conclusions In patients not taking potent CYP2D6 inhibitors, DM-BT was associated with CYP2D6 genotype and 3m and 6 m Endx Css but did not provide better discrimination of Endx Css compared to CYP2D6 genotype alone. Further studies are needed to identify additional factors which alter Endx Css. PMID:25714002

  4. Hallucinogens and Dissociative Drugs, Including LSD, PCP, Ketamine, Dextromethorphan. National Institute on Drug Abuse Research Report Series.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHHS/PHS), Rockville, MD.

    Research is developing a clearer picture of the dangers of mind-altering drugs. The goal of this report is to present the latest information to providers to help them strengthen their prevention and treatment efforts. A description is presented of dissociative drugs, and consideration is given as to why people take hallucinogens. The physical…

  5. Abuse of Dextromethorphan-Based Cough Syrup as a Substitute for Licit and Illicit Drugs: A Theoretical Framework.

    ERIC Educational Resources Information Center

    Darboe, Momodou N.

    1996-01-01

    Discusses the emergence of new types of abused drugs in the United States. Notes that young persons often search for substitutes for better-known substances. It is unclear, however, what factors determine the choice of drug or substance for experimentation, considering the wide range of choices. This paper attempts to delineate the factors that…

  6. Inhibitory Activities of Thai Medicinal Plants with Promising Activities Against Malaria and Cholangiocarcinoma on Human Cytochrome P450.

    PubMed

    Sumsakul, Wiriyaporn; Mahavorasirikul, Wiratchanee; Na-Bangchang, Kesara

    2015-12-01

    Malaria and cholangiocarcinoma remain important public health problems in tropical countries including Southeast Asian nations. Newly developed chemotherapeutic and plant-derived drugs are urgently required for the control of both diseases. The aim of the present study was to investigate the propensity to inhibit cytochrome P450-mediated hepatic metabolism (CYP1A2, CYP2C19, CYP2D6 and CYP3A4) of the crude ethanolic extract of eight Thai medicinal plants with promising activities against malaria and cholangiocarcinoma, using human liver microsomes in vitro. Piper chaba Linn. (PC) and Atractylodes lancea (thung.) DC. (AL) exhibited the most potent inhibitory activities on CYP1A2-mediated phenacetin O-deethylation with mean IC50 of 0.04 and 0.36 µg/mL, respectively. Plumbago indica Linn. (PI) and Dioscorea membranacea Pierre. (DM) potently inhibited CYP2C19-mediated omeprazole 5-hydroxylation (mean IC50 4.71 and 6.92 µg/mL, respectively). DM, Dracaena loureiri Gagnep. (DL) and PI showed the highest inhibitory activities on dextromethorphan O-demethylation (mean IC50 2.93-9.57 µg/mL). PC, DM, DL and PI exhibited the most potent inhibitory activities on CYP3A4-mediated nifedipine oxidation (mean IC50 1.54-6.43 µg/mL). Clinical relevance of the inhibitory potential of DM, PC and PI is of concern for the further development of these plants for the treatment of malaria and/or cholangiocarcinoma. PMID:26490449

  7. Doxylamine

    MedlinePlus

    Vicks NyQuil® Cold and Flu Relief (as a combination product containing Acetaminophen, Dextromethorphan, Doxylamine) ... Vicks NyQuil® Cold and Flu Symptom Relief Plus Vitamin C (as a combination product containing Acetaminophen, Dextromethorphan, ...

  8. Butorphanol Injection

    MedlinePlus

    ... following: antidepressants; antihistamines; barbiturates such as butabarbital (Butisol), pentobarbital (Nembutal), phenobarbital, or secobarbital (Seconal); cyclobenzaprine (Amrix); dextromethorphan ( ...

  9. Butorphanol Nasal Spray

    MedlinePlus

    ... following: antidepressants; antihistamines; barbiturates such as butabarbital (Butisol), pentobarbital (Nembutal), phenobarbital, or secobarbital (Seconal); cyclobenzaprine (Amrix); dextromethorphan ( ...

  10. Brompheniramine

    MedlinePlus

    Children's Dimetapp® Cold and Cough (as a combination product containing Brompheniramine, Dextromethorphan, Phenylephrine) ... Trexbrom® (as a combination product containing Brompheniramine, Chlophedianol, Phenylephrine)

  11. The identification of the urinary metabolites of 3-(4-methoxybenzoyl)-1-pentylindole (RCS-4), a novel cannabimimetic, by gas chromatography-mass spectrometry.

    PubMed

    Kavanagh, Pierce; Grigoryev, Andrej; Melnik, Aleksandra; Simonov, Anton

    2012-06-01

    3-(4-Methoxybenzoyl)-1-pentylindole (RCS-4), a synthetic indole-derived cannabimimetic, was first reported to the European Monitoring Centre for Drugs and Drug Addiction via the Early Warning System by Hungarian authorities in 2010 and later identified in head shop test purchases in Ireland. Using gas chromatography-mass spectrometry, we have identified a series of RCS-4 metabolites in urine samples from individuals admitted to hospitals with symptoms of drug intoxication. The metabolites were tentatively identified as products of (i) aromatic monohydroxylation; (ii) dihydroxylation; (iii) aromatic hydroxylation/oxidation of the N-pentyl chain to a ketone; (iv) O-demethylation; (v) O-demethylation/monohydroxylation of N-pentyl chain; (vi) O-demethylation/oxidation of the N-pentyl chain to a ketone; (vii) O-demethylation/aromatic hydroxylation/oxidation of the N-pentyl chain to a ketone; (viii) N-depentylation/aromatic monohydroxylation; and (ix) N and O-dealkylation. The parent compound was not detected. The O-demethylated metabolites were found to be the most useful metabolic markers for the identification of RCS-4 ingestion. PMID:22582265

  12. Use of liquid chromatography coupled to low- and high-resolution linear ion trap mass spectrometry for studying the metabolism of paynantheine, an alkaloid of the herbal drug Kratom in rat and human urine.

    PubMed

    Philipp, Anika A; Wissenbach, Dirk K; Weber, Armin A; Zapp, Josef; Zoerntlein, Siegfried W; Kanogsunthornrat, Jidapha; Maurer, Hans H

    2010-04-01

    The Thai medicinal plant Mitragyna speciosa (Kratom in Thai) is misused as a herbal drug of abuse. During studies on the main Kratom alkaloid mitragynine (MG) in rats and humans, several dehydro analogs could be detected in urine of Kratom users, which were not found in rat urine after administration of pure MG. Questions arose as to whether these compounds are formed from MG only by humans or whether they are metabolites formed from the second abundant Kratom alkaloid paynantheine (PAY), the dehydro analog of MG. Therefore, the aim of the presented study was to identify the phase I and II metabolites of PAY in rat urine after administration of the pure alkaloid. This was first isolated from Kratom leaves. Liquid chromatography-linear ion trap mass spectrometry provided detailed structure information of the metabolites in the MS(n) mode particularly with high resolution. Besides PAY, the following phase I metabolites could be identified: 9-O-demethyl PAY, 16-carboxy PAY, 9-O-demethyl-16-carboxy PAY, 17-O-demethyl PAY, 17-O-demethyl-16,17-dihydro PAY, 9,17-O-bisdemethyl PAY, 9,17-O-bisdemethyl-16,17-dihydro PAY, 17-carboxy-16,17-dihydro PAY, and 9-O-demethyl-17-carboxy-16,17-dihydro PAY. These metabolites indicated that PAY was metabolized via the same pathways as MG. Several metabolites were excreted as glucuronides or sulfates. The metabolism studies in rats showed that PAY and its metabolites corresponded to the MG-related dehydro compounds detected in urine of the Kratom users. In conclusion, PAY and its metabolites may be further markers for a Kratom abuse in addition of MG and its metabolites. PMID:19902190

  13. Codeine

    MedlinePlus

    ... and carisoprodol; and as an ingredient in many cough and cold medications. This monograph only includes information ... the following: cyclobenzaprine (Amrix); dextromethorphan (found in many cough medications; in Nuedexta); lithium (Lithobid); medications for cough, ...

  14. Cough Medicine: Understanding Your OTC Options

    MedlinePlus

    ... The only expectorant available in OTC products is guaifenesin (2 brand names: Mucinex, Robitussin Chest Congestion). How ... fluids also helps keep mucus thin. Dextromethorphan and guaifenesin are sometimes combined with each other (1 brand ...

  15. Guaifenesin

    MedlinePlus

    Little Remedies Little Colds Mucus Relief Expectorant Melt Aways® ... Nature Fusion® (as a combination product containing Dextromethorphan, Guaifenesin) ... best for your symptoms. Check nonprescription cough and cold product labels carefully before using two or more ...

  16. Structure of the cobalamin-binding protein of a putative O-demethylase from Desulfitobacterium hafniense DCB-2

    PubMed Central

    Sjuts, Hanno; Dunstan, Mark S.; Fisher, Karl; Leys, David

    2013-01-01

    This study describes the identification and the structural and spectroscopic analysis of a cobalamin-binding protein (termed CobDH) implicated in O-demethylation by the organo­halide-respiring bacterium Desulfitobacterium hafniense DCB-2. The 1.5 Å resolution crystal structure of CobDH is presented in the cobalamin-bound state and reveals that the protein is composed of an N-terminal helix-bundle domain and a C-­terminal Rossmann-fold domain, with the cobalamin coordinated in the base-off/His-on conformation similar to other cobalamin-binding domains that catalyse methyl-transfer reactions. EPR spectroscopy of CobDH confirms cobalamin binding and reveals the presence of a cob(III)alamin superoxide, indicating binding of oxygen to the fully oxidized cofactor. These data provide the first structural insights into the methyltransferase reactions that occur during O-demethylation by D. hafniense. PMID:23897483

  17. Biotransformations with plant tissue cultures.

    PubMed

    Carew, D P; Bainbridge, T

    1976-01-01

    Suspension cultures of Catharanthus roseus, Apocynum cannabinum and Conium maculatum were examined for their capacity to transform aniline, anisole, acetanilide, benzoic acid and coumarin. None of the cultures transformed acetanilide but each produced acetanilide when fed aniline. All three cultures converted benzoic acid to its para-hydroxy derivative. Coumarin was selectively hydroxylated at the 7-position by Catharanthus and Conium and anisole was O-demethylated only by older Catharanthus tissue. PMID:1084950

  18. Apixaban metabolism and pharmacokinetics after oral administration to humans.

    PubMed

    Raghavan, Nirmala; Frost, Charles E; Yu, Zhigang; He, Kan; Zhang, Haiying; Humphreys, W Griffith; Pinto, Donald; Chen, Shiangyuan; Bonacorsi, Samuel; Wong, Pancras C; Zhang, Donglu

    2009-01-01

    The metabolism and disposition of [(14)C]apixaban, an orally bioavailable, highly selective, and direct acting/reversible factor Xa inhibitor, was investigated in 10 healthy male subjects without (group 1, n=6) and with bile collection (group 2, n=4) after a single 20-mg oral dose. Urine, blood, and feces samples were collected from all subjects. Bile samples were also collected for 3 to 8 h after dosing from group 2 subjects. There were no serious adverse events or discontinuations due to adverse effects. In plasma, apixaban was the major circulating component and O-demethyl apixaban sulfate, a stable and water-soluble metabolite, was the significant metabolite. The exposure of apixaban (C(max) and area under the plasma concentration versus time curve) in subjects with bile collection was generally similar to that in subjects without bile collection. The administered dose was recovered in feces (group 1, 56.0%; group 2, 46.7%) and urine (group 1, 24.5%; group 2, 28.8%), with the parent drug representing approximately half of the recovered dose. Biliary excretion represented a minor elimination pathway (2.44% of the administered dose) from group 2 subjects within the limited collection period. Metabolic pathways identified for apixaban included O-demethylation, hydroxylation, and sulfation of hydroxylated O-demethyl apixaban. Thus, apixaban is an orally bioavailable inhibitor of factor Xa with elimination pathways that include metabolism and renal excretion. PMID:18832478

  19. Application of A. C.-polarography in a study of p-nitroanisole metabolism and its kinetic properties.

    PubMed

    Burgschat, H; Netter, K J

    1977-05-01

    Phase sensitive alternating current polarography was introduced for the simultaneous determination of p-nitroanisole and its metabolites p-nitrophenol and p-nitrocatechol in kinetic studies with rat liver microsomes. The substrate p-nitroanisole disappears rather rapidly while p-nitrophenol is formed. First traces of a second oxidation product, p-nitrocatechol, can be detected only after a few minutes after the initiation of the reaction. This suggest that O-demethylation of p-nitroanisole is the primary reaction which is followed by aromatic ortho hydroxylation of p-nitrophenol. After incubation times longer than 15 minutes, appreciable amounts of p-nitrocatechol are found which shows optical absorption characteristics similar to those of p-nitrophenol (absorption maximum at 440 nm). It is concluded from these kinetic experiments that optical determination of the primary metabolite during the initial reaction phase constitutes a reliable measure of microsomal O-demethylation activity. Phenobarbital induction differentially increases O-demethylation and ring-ortho-hydroxylation activities. From this and respective inhibition studies it is concluded that possibly multiple forms of cytochrome P-450 are involved in the metabolism of either p-nitroanisole or p-nitrophenol. PMID:859107

  20. Structure of the cobalamin-binding protein of a putative O-demethylase from Desulfitobacterium hafniense DCB-2

    SciTech Connect

    Sjuts, Hanno; Dunstan, Mark S.; Fisher, Karl; Leys, David

    2013-08-01

    The first crystal structure of the vitamin B12-binding protein from a three-component O-demethylase enzyme system is reported. During O-demethylation methyl groups are transferred from phenyl methyl ethers to tetrahydrofolate via methyl-B12 intermediates. This study describes the identification and the structural and spectroscopic analysis of a cobalamin-binding protein (termed CobDH) implicated in O-demethylation by the organohalide-respiring bacterium Desulfitobacterium hafniense DCB-2. The 1.5 Å resolution crystal structure of CobDH is presented in the cobalamin-bound state and reveals that the protein is composed of an N-terminal helix-bundle domain and a C-terminal Rossmann-fold domain, with the cobalamin coordinated in the base-off/His-on conformation similar to other cobalamin-binding domains that catalyse methyl-transfer reactions. EPR spectroscopy of CobDH confirms cobalamin binding and reveals the presence of a cob(III)alamin superoxide, indicating binding of oxygen to the fully oxidized cofactor. These data provide the first structural insights into the methyltransferase reactions that occur during O-demethylation by D. hafniense.

  1. Primaquine pharmacology in the context of CYP 2D6 pharmacogenomics: Current state of the art.

    PubMed

    Marcsisin, Sean R; Reichard, Gregory; Pybus, Brandon S

    2016-05-01

    Primaquine is the only antimalarial drug available to clinicians for the treatment of relapsing forms of malaria. Primaquine development and usage dates back to the 1940s and has been administered to millions of individuals to treat and eliminate malaria infections. Primaquine therapy is not without disadvantages, however, as it can cause life threatening hemolysis in humans with glucose-6-phosphate dehydrogenase (G6PD) deficiency. In addition, the efficacy of primaquine against relapsing malaria was recently linked to CYP 2D6 mediated activation to an active metabolite, the structure of which has escaped definitive identification for over 75years. CYP 2D6 is highly polymorphic among various human populations adding further complexity to a comprehensive understanding of primaquine pharmacology. This review aims to discuss primaquine pharmacology in the context of state of the art understanding of CYP 2D6 mediated 8-aminoquinoline metabolic activation, and shed light on the current knowledge gaps of 8-aminoquinoline mechanistic understanding against relapsing malaria. PMID:27016470

  2. Pre-emptive oral dexmethorphan reduces fentanyl-induced cough as well as immediate postoperative adrenocortico-tropic hormone and growth hormone level

    PubMed Central

    Mukherjee, Avik; Kundu, Asim Kumar; Ghosh, Sudipta; Choudhuri, Rajat; Bandopadhyay, Bijoy Kumar; Dasgupta, Sugata

    2011-01-01

    Background: Fentanyl-induced cough is not always benign and brief and can be remarkably troublesome, spasmodic, and explosive. Dextromethorphan, an opioid derivative with an antitussive action, may be effective in reducing the fentanyl-induced cough. Dextromethorphan, a N-methyl D aspartate receptor antagonist, may have some effect on diminishing the stress response to surgery. This study was undertaken to determine whether preoperative dextromethorphan could effectively attenuate its incidence, severity, and effect on postoperative stress hormone levels. Materials and Methods: Three hundred and twenty patients of American society of anesthesiologists I-II, aged 18–60 years, undergoing elective laparoscopic cholecystectomy or appendicectomy were randomly allocated into two groups (Group C, control; Group D, dextromethorphan) consisting of 160 patients each. Patients in Group D received dextromethorphan 40 mg orally and in Group C received placebo tablets 60 minutes before induction of anesthesia. The incidence of cough was recorded for 1 minute after fentanyl injection and graded as none (0), mild (1–2), moderate (3–5), and severe (>5 cough). Blood samples were collected for estimation of stress hormone levels before surgery and again at 1 hour and 24 hours postoperatively and compared. The appearance of adverse reactions was recorded. Results: The incidence of reflex fentanyl cough was lower in dextromethorphan group (3.9%) in comparison to placebo (59.8%). Five patients developed mild and one moderate cough in the dextromethorphan group. In the control group, 31 patients developed mild, 29 moderate, and 32 severe cough. The stress hormones were significantly higher at 1 hour and 24 hours postoperatively in both groups in comparison to its preoperative values. However, at 1 hour postoperatively, adrenocorticotropic hormone, epinephrine, and growth hormone values were significantly low in the dextromethorphan group (61.5 ± 21.1 pg/ ml, 142.1 ± 11.2 pg

  3. Efficacy of cough suppressants in children.

    PubMed

    Taylor, J A; Novack, A H; Almquist, J R; Rogers, J E

    1993-05-01

    To test the hypothesis that codeine and dextromethorphan are effective in alleviating the symptoms of acute cough, we conducted a randomized, controlled trial. Eligible patients were children 18 months to 12 years of age, seen in private pediatric practices, with significant night cough of less than 14 days' duration. Study patients were randomly selected to receive codeine, dextromethorphan, or placebo at bedtime for 3 consecutive nights. Outcomes were assessed by the use of a parent questionnaire rating the severity of symptoms at the initiation of therapy, and after each night of the study. Every patient had a cough score (range 0 to 4) and composite symptom score (range 0 to 9) computed for each day of the study. One hundred forty-one doses of study medication were evaluated in 49 patients, including 13 children receiving placebo, 19 dextromethorphan, and 17 codeine. Mean cough and composite symptom scores decreased in each of the three treatment groups on each day of the study; there were no significant differences. Regression analysis, with reduction in cough score as the outcome of interest, showed that neither dextromethorphan nor codeine was significantly more effective than placebo (p = 0.41 and 0.70, respectively). Reduction in cough score was positively correlated with the severity of cough at the start of treatment (p = 0.007). Our data suggest that, in the doses used, neither codeine nor dextromethorphan is superior to placebo in treating night cough in children. PMID:8496765

  4. Effects of opiates on sodium excretion in the isolated perfused rat kidney.

    PubMed

    Ellis, A G; Adam, W R

    1991-12-01

    1. A rat isolated perfused kidney preparation was utilized to define clearly a renal site of action. The variables measured were perfusate pressure and flow, glomerular filtration rate, urine volume, sodium excretion and potassium excretion. 2. Dextromethorphan (3 nmol/L) and dextrorphan (10 nmol/L) reduced sodium excretion in kidneys from rats on either control or high K+ diet, in the absence of any other measured renal effects. Dextromethorphan (10 nmol/L) produced a decrease in glomerular filtration rate as well as a decrease in sodium excretion. Naloxone (1 mumol/L) inhibited the effect of dextromethorphan on sodium excretion but had no effect when administered alone. 3. The levorotatory opiates levorphanol and levomethorphan, the kappa agonist ketocyclazocine and a range of other opiates had no effect on sodium excretion. 4. The results suggest a renal action specific for dextrorotatory opiates. This renal action is consistent with earlier binding studies suggesting preferential recognition of dextrorotatory opiates. PMID:1797448

  5. Prediction of CYP2D6 drug interactions from in vitro data: evidence for substrate-dependent inhibition.

    PubMed

    VandenBrink, Brooke M; Foti, Robert S; Rock, Dan A; Wienkers, Larry C; Wahlstrom, Jan L

    2012-01-01

    Predicting the magnitude of potential drug-drug interactions is important for underwriting patient safety in the clinical setting. Substrate-dependent inhibition of cytochrome P450 enzymes may confound extrapolation of in vitro results to the in vivo situation. However, the potential for substrate-dependent inhibition with CYP2D6 has not been well characterized. The inhibition profiles of 20 known inhibitors of CYP2D6 were characterized in vitro against four clinically relevant CYP2D6 substrates (desipramine, dextromethorphan, metoprolol, and thioridazine) and bufuralol. Dextromethorphan exhibited the highest sensitivity to in vitro inhibition, whereas metoprolol was the least sensitive. In addition, when metoprolol was the substrate, inhibitors with structurally constrained amino moieties (clozapine, debrisoquine, harmine, quinidine, and yohimbine) exhibited at least a 5-fold decrease in inhibition potency when results were compared with those for dextromethorphan. Atypical inhibition kinetics were observed for these and other inhibitor-substrate pairings. In silico docking studies suggested that interactions with Glu216 and an adjacent hydrophobic binding pocket may influence substrate sensitivity and inhibition potency for CYP2D6. The in vivo sensitivities of the clinically relevant CYP2D6 substrates desipramine, dextromethorphan, and metoprolol were determined on the basis of literature drug-drug interaction (DDI) outcomes. Similar to the in vitro results, dextromethorphan exhibited the highest sensitivity to CYP2D6 inhibition in vivo. Finally, the magnitude of in vivo CYP2D6 DDIs caused by quinidine was predicted using desipramine, dextromethorphan, and metoprolol. Comparisons of the predictions with literature results indicated that the marked decrease in inhibition potency observed for the metoprolol-quinidine interaction in vitro translated to the in vivo situation. PMID:21976621

  6. Antitussives and substance abuse

    PubMed Central

    Burns, Jarrett M; Boyer, Edward W

    2013-01-01

    Abuse of antitussive preparations is a continuing problem in the United States and throughout the world. Illicit, exploratory, or recreational use of dextromethorphan and codeine/promethazine cough syrups is widely described. This review describes the pharmacology, clinical effects, and management of toxicity from commonly abused antitussive formulations. PMID:24648790

  7. 77 FR 16842 - Draft and Revised Draft Guidances for Industry Describing Product-Specific Bioequivalence...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-22

    ... INFORMATION: I. Background In the Federal Register of June 11, 2010 (75 FR 33311), FDA announced the... FR 3777). This notice announces draft product-specific recommendations, either new or revised, that... Clindamycin Phosphate (multiple RLDs), D Dalfampridine, Dexmethylphenidate HCl, Dextromethorphan...

  8. Antitussives and substance abuse.

    PubMed

    Burns, Jarrett M; Boyer, Edward W

    2013-01-01

    Abuse of antitussive preparations is a continuing problem in the United States and throughout the world. Illicit, exploratory, or recreational use of dextromethorphan and codeine/promethazine cough syrups is widely described. This review describes the pharmacology, clinical effects, and management of toxicity from commonly abused antitussive formulations. PMID:24648790

  9. Comparative metabolism of 14C-labeled apixaban in mice, rats, rabbits, dogs, and humans.

    PubMed

    Zhang, Donglu; He, Kan; Raghavan, Nirmala; Wang, Lifei; Mitroka, James; Maxwell, Brad D; Knabb, Robert M; Frost, Charles; Schuster, Alan; Hao, Feng; Gu, Zheming; Humphreys, W Griffith; Grossman, Scott J

    2009-08-01

    The metabolism and disposition of [(14)C]apixaban, a potent, reversible, and direct inhibitor of coagulation factor Xa, were investigated in mice, rats, rabbits, dogs, and humans after a single oral administration and in incubations with hepatocytes. In plasma, the parent compound was the major circulating component in mice, rats, dogs, and humans. O-Demethyl apixaban sulfate (M1) represented approximately 25% of the parent area under the time curve in human plasma. This sulfate metabolite was present, but in lower amounts relative to the parent, in plasma from mice, rats, and dogs. Rabbits showed a plasma metabolite profile distinct from that of other species with apixaban as a minor component and M2 (O-demethyl apixaban) and M14 (O-demethyl apixaban glucuronide) as prominent components. The fecal route was a major elimination pathway, accounting for >54% of the dose in animals and >46% in humans. The urinary route accounted for <15% of the dose in animals and 25 to 28% in humans. Apixaban was the major component in feces of every species and in urine of all species except rabbit. M1 and M2 were common prominent metabolites in urine and feces of all species as well as in bile of rats and humans. In vivo metabolite profiles showed quantitative differences between species and from in vitro metabolite profiles, but all human metabolites were found in animal species. After intravenous administration of [(14)C]apixaban to bile duct-cannulated rats, the significant portion (approximately 22%) of the dose was recovered as parent drug in the feces, suggesting direct excretion of the drug from gastrointestinal tracts of rats. Overall, apixaban was effectively eliminated via multiple elimination pathways in animals and humans, including oxidative metabolism, and direct renal and intestinal excretion. PMID:19420130

  10. (-)-Arctigenin as a lead compound for anticancer agent.

    PubMed

    Chen, Gui-Rong; Li, Hong-Fu; Dou, De-Qiang; Xu, Yu-Bin; Jiang, Hong-Shuai; Li, Fu-Rui; Kang, Ting-Guo

    2013-01-01

    (-)-Arctigenin, an important active constituent of the traditional Chinese herb Fructus Arctii, was found to exhibit various bioactivities, so it can be used as a good lead compound for further structure modification in order to find a safer and more potent medicine. (-)-Arctigenin derivatives 1-5 of (-)-arctingen were obtained by modifying with ammonolysis at the lactone ring and sulphonylation at C (6') and C (6″) and O-demethylation at CH3O-C (3'), CH3O-C (3″) and CH3O-C (4″), and their anticancer bioactivities were examined. PMID:23962054

  11. In vivo metabolism of 5-methoxy-N,N-dimethyltryptamine and N,N-dimethyltryptamine in the rat.

    PubMed

    Sitaram, B R; Lockett, L; Talomsin, R; Blackman, G L; McLeod, W R

    1987-05-01

    Following intraperitoneal administration, 5-methoxy-N,N-dimethyltryptamine and N,N-dimethyltryptamine are subject to both a very rapid uptake into, and clearance from, all tissues examined. The current studies in vivo confirm previous in vitro observations that the routes involved in the metabolism of these compounds include oxidative deamination, N-demethylation, O-demethylation, and N-oxidation. The analysis of metabolic profiles in various tissues led to the identification of the N-oxides as major metabolites. The successful inhibition and redirection of metabolism away from the indole acids towards the parent compounds and their structurally unique metabolites were demonstrated in animals pretreated with iproniazid. PMID:3472526

  12. The pharmacokinetic profile of naproxen suppository in man.

    PubMed

    Guelen, P J; Janssen, T J; Brueren, M M; Vree, T B; Lipperts, G J

    1988-04-01

    After a rectal dose of 500 mg in a suppository, naproxen is 6-O-demethylated (20%) and glucuronidated (40%), the metabolites are subsequently excreted renally. The elimination half-life is 15.2 +/- 2.6 h. Ten out of 22 subjects show biphasic elimination kinetics with half-lives of 7 and 15 h, respectively. There is a wide range in the percentage of the dose that is glucuronidated and demethylated (20-70%). This variation does not deviate from a normal distribution. PMID:3403096

  13. Antimicrobial hasubanalactam alkaloid from Stephania glabra.

    PubMed

    Semwal, Deepak Kumar; Rawat, Usha

    2009-03-01

    A novel hasubanalactam alkaloid, named glabradine, has been isolated from the tubers of Stephania glabra, together with three known quaternary protoberberine alkaloids, palmatine, dehydrocorydalmine and stepharanine. The structure of glabradine was assigned as 7-O-demethyl-N,O-dimethyloxostephinine, by means of rigorous spectroscopic analysis including 2 D NMR measurements. It was evaluated for antimicrobial activity against Staphylococcus aureus, S. mutans, Microsporum gypseum, M. canis and Trichophyton rubrum and displayed potent antimicrobial activity superior to those of novobiocin and erythromycin used as positive controls. PMID:19148860

  14. Mu receptor binding of some commonly used opioids and their metabolites

    SciTech Connect

    Chen, Zhaorong; Irvine, R.J. ); Somogyi, A.A.; Bochner, F. Royal Adelaide Hospital )

    1991-01-01

    The binding affinity to the {mu} receptor of some opioids chemically related to morphine and some of their metabolites was examined in rat brain homogenates with {sup 3}H-DAMGO. The chemical group at position 6 of the molecule had little effect on binding. Decreasing the length of the alkyl group at position 3 decreased the K{sub i} values (morphine < codeine < ethylmorphine < pholcodine). Analgesics with high clinical potency containing a methoxyl group at position 3 had relatively weak receptor binding, while their O-demethylated metabolites had much stronger binding. Many opioids may exert their pharmacological actions predominantly through metabolites.

  15. Black perithecial pigmentation in Fusarium species is due to the accumulation of 5-deoxybostrycoidin-based melanin.

    PubMed

    Frandsen, Rasmus J N; Rasmussen, Silas A; Knudsen, Peter B; Uhlig, Silvio; Petersen, Dirk; Lysøe, Erik; Gotfredsen, Charlotte H; Giese, Henriette; Larsen, Thomas O

    2016-01-01

    Biosynthesis of the black perithecial pigment in the filamentous fungus Fusarium graminearum is dependent on the polyketide synthase PGL1 (oPKS3). A seven-membered PGL1 gene cluster was identified by over-expression of the cluster specific transcription factor pglR. Targeted gene replacement showed that PGL1, pglJ, pglM and pglV were essential for the production of the perithecial pigment. Over-expression of PGL1 resulted in the production of 6-O-demethyl-5-deoxybostrycoidin (1), 5-deoxybostrycoidin (2), and three novel compounds 5-deoxybostrycoidin anthrone (3), 6-O-demethyl-5-deoxybostrycoidin anthrone (4) and purpurfusarin (5). The novel dimeric bostrycoidin purpurfusarin (5) was found to inhibit the growth of Candida albicans with an IC50 of 8.0 +/- 1.9 μM. The results show that Fusarium species with black perithecia have a previously undescribed form of 5-deoxybostrycoidin based melanin in their fruiting bodies. PMID:27193384

  16. Degradation of topoisomerase I induced by topoisomerase I inhibitors is dependent on inhibitor structure but independent of cell death.

    PubMed

    Fu, Q; Kim, S W; Chen, H X; Grill, S; Cheng, Y C

    1999-04-01

    DNA topoisomerase I (top I) is the target of the antitumor drug camptothecin (CPT) and its analogs. CPT induces dose- and time-dependent degradation of top I. Degradation of top I also occurs in a CPT-resistant cell line and, therefore, is not a consequence of cell death. Top I degradation is preceded by the appearance of a high molecular weight ladder of top I immunoreactivity and can be blocked by specific inhibitors of the proteasome. We compared the effects of five top I poisons [CPT, topotecan, 6-N-formylamino-12,13-dihydro-1, 11-dihydroxy-13-(beta-D-glucopyranosyl)-5H-indolo[2,3-a]pyrrolo[3, 4-c]carbazole-5,7(6H)-dione (NB506), camptothecin-(para)-4beta-amino-4'-O-demethyl Epipodophyllotoxin (W1), and camptothecin-(ortho)-4beta-amino-4'-O-demethyl Epipodophyllotoxin (W2)] on cleavable complex formation and top I degradation. Although all five drugs induced cleavable complex formation, two of the drugs, NB506 and W1 did not induce top I degradation. PMID:10101025

  17. Black perithecial pigmentation in Fusarium species is due to the accumulation of 5-deoxybostrycoidin-based melanin

    PubMed Central

    Frandsen, Rasmus J. N.; Rasmussen, Silas A.; Knudsen, Peter B.; Uhlig, Silvio; Petersen, Dirk; Lysøe, Erik; Gotfredsen, Charlotte H.; Giese, Henriette; Larsen, Thomas O.

    2016-01-01

    Biosynthesis of the black perithecial pigment in the filamentous fungus Fusarium graminearum is dependent on the polyketide synthase PGL1 (oPKS3). A seven-membered PGL1 gene cluster was identified by over-expression of the cluster specific transcription factor pglR. Targeted gene replacement showed that PGL1, pglJ, pglM and pglV were essential for the production of the perithecial pigment. Over-expression of PGL1 resulted in the production of 6-O-demethyl-5-deoxybostrycoidin (1), 5-deoxybostrycoidin (2), and three novel compounds 5-deoxybostrycoidin anthrone (3), 6-O-demethyl-5-deoxybostrycoidin anthrone (4) and purpurfusarin (5). The novel dimeric bostrycoidin purpurfusarin (5) was found to inhibit the growth of Candida albicans with an IC50 of 8.0 +/− 1.9 μM. The results show that Fusarium species with black perithecia have a previously undescribed form of 5-deoxybostrycoidin based melanin in their fruiting bodies. PMID:27193384

  18. Metabolism of One-Carbon Compounds by the Ruminal Acetogen Syntrophococcus sucromutans

    PubMed Central

    Doré, J.; Bryant, M. P.

    1990-01-01

    Syntrophococcus sucromutans is the predominant species capable of O demethylation of methoxylated lignin monoaromatic derivatives in the rumen. The enzymatic characterization of this acetogen indicated that it uses the acetyl coenzyme A (Wood) pathway. Cell extracts possess all the enzymes of the tetrahydrofolate pathway, as well as carbon monoxide dehydrogenase, at levels similar to those of other acetogens using this pathway. However, formate dehydrogenase could not be detected in cell extracts, whether formate or a methoxyaromatic was used as electron acceptor for growth of the cells on cellobiose. Labeled bicarbonate, formate, [1-14C] pyruvate, and chemically synthesized O-[methyl-14C]vanillate were used to further investigate the catabolism of one-carbon (C1) compounds by using washed-cell preparations. The results were consistent with little or no contribution of formate dehydrogenase and pointed out some unique features. Conversion of formate to CO2 was detected, but labeled formate predominantly labeled the methyl group of acetate. Labeled CO2 readily exchanged with the carboxyl group of pyruvate but not with formate, and both labeled CO2 and pyruvate predominantly labeled the carboxyl group of acetate. No CO2 was formed from O demethylation of vanillate, and the acetate produced was position labeled in the methyl group. The fermentation pattern and specific activities of products indicated a complete synthesis of acetate from pyruvate and the methoxyl group of vanillate. PMID:16348178

  19. Reactive intermediates produced from the metabolism of the vanilloid ring of capsaicinoids by p450 enzymes.

    PubMed

    Reilly, Christopher A; Henion, Fred; Bugni, Tim S; Ethirajan, Manivannan; Stockmann, Chris; Pramanik, Kartick C; Srivastava, Sanjay K; Yost, Garold S

    2013-01-18

    This study characterized electrophilic and radical products derived from the metabolism of capsaicin by cytochrome P450 and peroxidase enzymes. Multiple glutathione and β-mercaptoethanol conjugates (a.k.a., adducts), derived from the trapping of quinone methide and quinone intermediates of capsaicin, its analogue nonivamide, and O-demethylated and aromatic hydroxylated metabolites thereof, were produced by human liver microsomes and individual recombinant human P450 enzymes. Conjugates derived from concomitant dehydrogenation of the alkyl terminus of capsaicin were also characterized. Modifications to the 4-OH substituent of the vanilloid ring of capsaicinoids largely prevented the formation of electrophilic intermediates, consistent with the proposed structures and mechanisms of formation for the various conjugates. 5,5'-Dicapsaicin, presumably arising from the bimolecular coupling of free radical intermediates was also characterized. Finally, the analysis of hepatic glutathione conjugates and urinary N-acetylcysteine conjugates from mice dosed with capsaicin confirmed the formation of glutathione conjugates of O-demethylated quinone methide and 5-OH-capsaicin in vivo. These data demonstrated that capsaicin and structurally similar analogues are converted to reactive intermediates by certain P450 enzymes, which may partially explain conflicting reports related to the cytotoxic, pro-carcinogenic, and chemoprotective effects of capsaicinoids in different cells and/or organ systems. PMID:23088752

  20. Reactive Intermediates Produced from Metabolism of the Vanilloid Ring of Capsaicinoids by P450 Enzymes

    PubMed Central

    Reilly, Christopher A.; Henion, Fred; Bugni, Tim S.; Ethirajan, Manivannan; Stockmann, Chris; Pramanik, Kartick C.; Srivastava, Sanjay K.; Yost, Garold S.

    2012-01-01

    This study characterized electrophilic and radical products derived from metabolism of capsaicin by cytochrome P450 and peroxidase enzymes. Multiple glutathione and β-mercaptoethanol conjugates (a.k.a., adducts), derived from trapping of quinone methide and quinone intermediates of capsaicin, its analogue nonivamide, and O-demethylated and aromatic hydroxylated metabolites thereof, were produced by human liver microsomes and individual recombinant human P450 enzymes. Conjugates derived from concomitant dehydrogenation of the alkyl terminus of capsaicin, were also characterized. Modifications to the 4-OH substituent of the vanilloid ring of capsaicinoids largely prevented the formation of electrophilic intermediates, consistent with the proposed structures and mechanisms of formation for the various conjugates. 5,5’-Dicapsaicin, presumably arising from bi-molecular coupling of free radical intermediates, was also characterized. Finally, the analysis of hepatic glutathione conjugates and urinary N-acetylcysteine conjugates from mice dosed with capsaicin confirmed the formation of glutathione conjugates of O-demethylated, quinone methide, and 5-OH-capsaicin in vivo. These data demonstrated that capsaicin and structurally similar analogues are converted to reactive intermediates by certain P450 enzymes, which may partially explain conflicting reports related to the cytotoxic, pro-carcinogenic, and chemoprotective effects of capsaicinoids in different cells and/or organ systems. PMID:23088752

  1. Metabolism of the endocrine disruptor pesticide-methoxychlor by human P450s: pathways involving a novel catechol metabolite.

    PubMed

    Hu, Yiding; Kupfer, David

    2002-09-01

    The metabolism of methoxychlor, a proestrogenic pesticide (endocrine disruptor), was investigated with cDNA expressed human cytochrome P450s and liver microsomes (HLM). In addition to 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane (mono-OH-M), 1,1,1-trichloro-2, 2-bis(4-hydroxyphenyl)ethane (bis-OH-M), and 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(3, 4-dihydroxyphenyl)ethane (tris-OH-M), a new metabolite was identified as 1,1,1-trichloro-2-(4-methoxyphenyl)-2-(3, 4-dihydroxyphenyl)ethane (catechol-M; previously assumed to be ring-OH-M) and as a key metabolic intermediate. A novel metabolic route was proposed involving methoxychlor O-demethylation to mono-OH-M, followed by bifurcation of the pathway, both leading to the same final product tris-OH-M: pathway a, mono-OH-M is demethylated to bis-OH-M, followed by ortho-hydroxylation forming tris-OH-M and pathway b, mono-OH-M is ortho-hydroxylated forming catechol-M that is O-demethylated forming tris-OH-M. Among the human cDNA-expressed P450s examined, CYP1A2, 2A6, 2C8, 2C9, 2C19, and 2D6 exhibited mainly O-demethylation, with CYP2C19 being the most catalytically competent. CYP3A4, 3A5, and rat 2B1 catalyzed primarily ortho-hydroxylation of mono-OH-M (CYP3A4 being catalytically the most active) but were weak in O-demethylation. CYP1A1, 1B1, 2E1, and 4A11 demonstrated little or no catalytic activity. CYP2B6 appeared unique, catalyzing effectively both O-demethylation and ortho-hydroxylation. Thus, CYP2B6 demethylated methoxychlor to mono-OH-M and ortho-hydroxylated the mono-OH-M forming catechol-M; however, 2B6 did not appreciably demethylate mono-OH-M or ortho-hydroxylate bis-OH-M, suggesting a narrow substrate specificity. CYP2C19-catalyzed demethylation of methoxychlor, mono-OH-M and catechol-M, demonstrating relatively good substrate affinity (K(m) = 0.23 - 0.41 microM). However, the 3A4 ortho-hydroxylation of mono-OH-M and bis-OH-M exhibited lower affinity, K(m) = 12 and 25 microM, respectively. Thus, a

  2. Population pharmacokinetic modelling to assess the impact of CYP2D6 and CYP3A metabolic phenotypes on the pharmacokinetics of tamoxifen and endoxifen

    PubMed Central

    ter Heine, Rob; Binkhorst, Lisette; de Graan, Anne Joy M; de Bruijn, Peter; Beijnen, Jos H; Mathijssen, Ron H J; Huitema, Alwin D R

    2014-01-01

    Aims Tamoxifen is considered a pro-drug of its active metabolite endoxifen. The major metabolic enzymes involved in endoxifen formation are CYP2D6 and CYP3A. There is considerable evidence that variability in activity of these enzymes influences endoxifen exposure and thereby may influence the clinical outcome of tamoxifen treatment. We aimed to quantify the impact of metabolic phenotype on the pharmacokinetics of tamoxifen and endoxifen. Methods We assessed the CYP2D6 and CYP3A metabolic phenotypes in 40 breast cancer patients on tamoxifen treatment with a single dose of dextromethorphan as a dual phenotypic probe for CYP2D6 and CYP3A. The pharmacokinetics of dextromethorphan, tamoxifen and their relevant metabolites were analyzed using non-linear mixed effects modelling. Results Population pharmacokinetic models were developed for dextromethorphan, tamoxifen and their metabolites. In the final model for tamoxifen, the dextromethorphan derived metabolic phenotypes for CYP2D6 as well as CYP3A significantly (P < 0.0001) explained 54% of the observed variability in endoxifen formation (inter-individual variability reduced from 55% to 25%). Conclusions We have shown that not only CYP2D6, but also CYP3A enzyme activity influences the tamoxifen to endoxifen conversion in breast cancer patients. Our developed model may be used to assess separately the impact of CYP2D6 and CYP3A mediated drug–drug interactions with tamoxifen without the necessity of administering this anti-oestrogenic drug and to support Bayesian guided therapeutic drug monitoring of tamoxifen in routine clinical practice. PMID:24697814

  3. Laser electrospray mass spectrometry of adsorbed molecules at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Brady, John J.; Judge, Elizabeth J.; Simon, Kuriakose; Levis, Robert J.

    2010-02-01

    Atmospheric pressure mass analysis of solid phase biomolecules is performed using laser electrospray mass spectrometry (LEMS). A non-resonant femtosecond duration laser pulse vaporizes native samples at atmospheric pressure for subsequent electrospray ionization and transfer into a mass spectrometer. LEMS was used to detect a complex molecule (irinotecan HCl), a complex mixture (cold medicine formulation with active ingredients: acetaminophen, dextromethorphan HBr and doxylamine succinate), and a biological building block (deoxyguanosine) deposited on steel surfaces without a matrix molecule.

  4. Bullous mastocytosis in an infant associated with the use of a nonprescription cough suppressant.

    PubMed

    Cook, J; Stith, M; Sahn, E E

    1996-01-01

    Bullous mastocytosis is an unusual expression of mastocytosis typically seen in young children, and many causes of the acute mast cell degranulation with bulla formation have been identified. We report a 6-month-old boy with urticaria pigmentosa and an extensive bullous eruption associated with the ingestion of a nonprescription cough suppressant containing dextromethorphan. The pathogenesis of mastocytosis and the care of patients with this disease are discussed. PMID:8893244

  5. Dystonia as acute adverse reaction to cough suppressant in a 3-year-old girl.

    PubMed

    Polizzi, A; Incorpora, G; Ruggieri, M

    2001-01-01

    Cough suppressant preparations containing mixtures of dextromethorphan or codeine with antihistamines, decongestants (sympathomimetic), expectorants and antipyretics with either sedative or anticholinergic activity have been associated with dystonic reactions in children. We report on a 3-year-old girl who presented with episodic stiffness and abnormal posturing with rigidity after arbitrary maternal administration of a mixture of methylcodeine and extract from Hedera plant. PMID:11587381

  6. Non-opioid antitussives and methadone differentially influence hippocampal long-term potentiation in freely moving rats.

    PubMed

    Krug, M; Matthies, R; Wagner, M; Brödemann, R

    1993-02-16

    Long-term potentiation (LTP) of monosynaptically evoked field potentials (MEFP) in the dentate gyrus of freely moving rats following tetanization of the perforant pathway was investigated after peripheral application of substances which have been shown to influence NMDA receptor-mediated effects (dextromethorphan, methadone) as well as structurally related substances with similar antitussive effects (codeine, normethadone). The noncompetitive NMDA receptor antagonist MK 801 was also tested for comparison. Whereas under control conditions the field e.p.s.p. (excitatory postsynaptic potential) and the population spike of the MEFP were largely uninfluenced by these substances, different effects were seen after the induction of LTP. MK 801 (0.2 mg/kg i.p.) suppressed the induction of LTP of both the field e.p.s.p. and the population spike. Dextromethorphan (40 mg/kg i.p.) also prevented the potentiation of the field e.p.s.p. and the population spike, thus resembling MK 801 in its effect. Codeine (20 mg/kg i.p.), the levorotatory structural analogue of dextromethorphan had no effect. Methadone and normethadone did not influence the potentiation of the field e.p.s.p. or interfere with the induction of potentiation of the population spike but depressed its maintenance. The results obtained with MK 801 confirm those reported by others. Comparison of the effects of dextromethorphan with those of MK 801, suggests that there is a direct interaction with the NMDA receptor-ionophore complex. The effects of methadone and normethadone appear not to be linked to an interaction with opioid receptors, since naloxone did not influence the suppression of LTP caused by methadone. The possibility of interference with the NMDA receptor-ionophore complex is discussed. PMID:8449228

  7. Do OTC remedies relieve cough in acute URIs?

    PubMed

    Dealleaume, Lauren; Tweed, Beth; Neher, Jon O

    2009-10-01

    Dextromethorphan (DM) for adults and honey for children provide some relief. DM may modestly decrease cough in adults compared with placebo. The data supporting zinc for the common cold are mixed. Antihistamines, antihistamine-decongestant combinations, and guaifenesin do not provide greater relief than placebo in adults. In children, antihistamines, decongestants, DM, or combinations of them do not relieve cough better than placebo. Honey may modestly decrease frequency and severity of cough compared with DM or no treatment. PMID:19874728

  8. Clinical inhibition of CYP2D6-catalysed metabolism by the antianginal agent perhexiline

    PubMed Central

    Davies, Benjamin J L; Coller, Janet K; James, Heather M; Gillis, David; Somogyi, Andrew A; Horowitz, John D; Morris, Raymond G; Sallustio, Benedetta C

    2004-01-01

    Aims Perhexiline is an antianginal agent that displays both saturable and polymorphic metabolism via CYP2D6. The aim of this study was to determine whether perhexiline produces clinically significant inhibition of CYP2D6-catalysed metabolism in angina patients. Methods The effects of perhexiline on CYP2D6-catalysed metabolism were investigated by comparing urinary total dextrorphan/dextromethorphan metabolic ratios following a single dose of dextromethorphan (16.4 mg) in eight matched control patients not taking perhexiline and 24 patients taking perhexiline. All of the patients taking perhexiline had blood drawn for CYP2D6 genotyping as well as to measure plasma perhexiline and cis-OH-perhexiline concentrations. Results Median (range) dextrorphan/dextromethorphan metabolic ratios were significantly higher (P < 0.0001) in control patients, 271.1 (40.3–686.1), compared with perhexiline-treated patients, 5.0 (0.3–107.9). In the perhexiline-treated group 10/24 patients had metabolic ratios consistent with poor metabolizer phenotypes; however, none was a genotypic poor metabolizer. Interestingly, 89% of patients who had phenocopied to poor metabolizers had only one functional CYP2D6 gene. There was a significant negative linear correlation between the log of the dextrorphan/dextromethorphan metabolic ratio and plasma perhexiline concentrations (r2 = 0.69, P < 0.0001). Compared with patients with at least two functional CYP2D6 genes, those with one functional gene were on similar perhexiline dosage regimens but had significantly higher plasma perhexiline concentrations, 0.73 (0.21–1.00) vs. 0.36 (0.04–0.69) mg l−1 (P = 0.04), lower cis-OH-perhexiline/perhexiline ratios, 2.85 (0.35–6.10) vs. 6.51 (1.84–11.67) (P = 0.03), and lower dextrorphan/dextromethorphan metabolic ratios, 2.51 (0.33–39.56) vs. 11.80 (2.90–36.93) (P = 0.005). Conclusions Perhexiline significantly inhibits CYP2D6-catalysed metabolism in angina patients. The plasma cis

  9. The anticonvulsant actions of σ receptor ligands in the Mg2+-free model of epileptiform activity in rat hippocampal slices

    PubMed Central

    Thurgur, Claire; Church, John

    1998-01-01

    The anticonvulsant potency of a series of structurally-dissimilar compounds which possess nanomolar affinities for high-affinity σ binding sites was examined in the Mg2+-free model of epileptiform activity in rat hippocampal slices. Extracellular field potential recordings in the CA1 region were employed to examine the effects of test compounds on spontaneous epileptiform activity and multiple population spikes evoked by stimulation of the Schaffer collateral-commissural pathway.Applied at σ site-selective (i.e. nanomolar) concentrations, dextromethorphan, ditolylguanidine, caramiphen and opipramol failed to modify Mg2+-free epileptiform activity; neither pro- nor anticonvulsant effects were observed. However, applied at micromolar concentrations, these and additional test compounds reversibly inhibited orthodromically-evoked epileptiform field potentials with a rank order potency (IC50 values in μM): dextrorphan (1.5)>ifenprodil (6.3)>dextromethorphan (10)>ditolylguanidine (15)>loperamide (28)>carbetapentane (38)>caramiphen (46)>opipramol (52). Micromolar concentrations of the same compounds also inhibited spontaneous epileptiform bursts recorded during perfusion with Mg2+-free medium.Co-application of ropizine (10 μM), an allosteric modulator of dextromethorphan binding to high-affinity σ receptors, failed to endow dextromethorphan 10 nM with anticonvulsant properties and did not modify the anticonvulsant potency of 10 μM dextromethorphan.The effects of dextrorphan (10 μM), ifenprodil (20 μM), loperamide (50 μM) and caramiphen (100 μM) were examined in the presence of external Mg2+ on field potential input/output (I/O) relationships and paired-pulse facilitation (PPF) of field excitatory postsynaptic potentials. Only caramiphen elicited effects on these parameters, affecting synaptic transmission at the point of synaptic transfer and depressing PPF ratios to below baseline values. The effects of caramiphen on I/O relationships mimicked

  10. Maduramicin. alpha. : Characterization of sup 14 C-derived residues in turkey excreta

    SciTech Connect

    Stout, S.J.; daCunha, A.R.; Lee, A. ); Jinn Wu; King, K.G. )

    1991-02-01

    Maduramicin {alpha}, a highly potent polyether ionophore antibiotic for preventing coccidiosis in poultry, is passed predominantly in turkey excreta following oral feeding. Following isolation and purification, the turkey excreta metabolites were characterized primarily by liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry. Maduramicin {alpha} and its metabolites generate a characteristic pair of ions corresponding to (M + NH{sub 4}){sup +} and (M + Na){sup +} which assist in differentiating the metabolites from matrix coextractives. These two ions also fragment differently in tandem mass spectrometry, thus providing structural information for characterizing the nature of unknown metabolites. The primary metabolic pathway of maduramicin {alpha} in the turkey is O-demethylation at one or more of the methoxy groups. Hydroxylation and glucuronide conjugation are minor secondary metabolic processes.

  11. Chromogenic nitrophenolate-based substrates for light-driven hybrid P450 BM3 enzyme assay.

    PubMed

    Lam, Quan; Cortez, Alejandro; Nguyen, Thanh Truc; Kato, Mallory; Cheruzel, Lionel

    2016-05-01

    The incorporation of a p-nitrophenoxy moiety in substrates has enabled the development of colorimetric assays to rapidly screen for O-demethylation activity of P450 enzymes. For the light-driven hybrid P450 BM3 enzymes, where a Ru(II) photosensitizer powers the enzyme upon visible light irradiation, we have investigated a family of p-nitrophenoxy derivatives as useful chromogenic substrates compatible with the light-driven approach. The validation of this assay and its adaptability to a 96-well plate format will enable the screening of the next generation of hybrid P450 BM3 enzymes towards C-H bond functionalization of non-natural substrates. PMID:26712653

  12. Biobased Epoxy Nanocomposites Derived from Lignin-Based Monomers.

    PubMed

    Zhao, Shou; Abu-Omar, Mahdi M

    2015-07-13

    Biobased epoxy nanocomposites were synthesized based on 2-methoxy-4-propylphenol (dihydroeugenol, DHE), a molecule that has been obtained from the lignin component of biomass. To increase the content of hydroxyl groups, DHE was o-demethylated using aqueous HBr to yield propylcatechol (DHEO), which was subsequently glycidylated to epoxy monomer. Optimal conditions in terms of yield and epoxy equivalent weight were found to be 60 °C with equal NaOH/phenolic hydroxyl molar ratio. The structural evolution from DHE to cured epoxy was followed by (1)H NMR and Fourier transform infrared spectroscopy. The nano-montmorillonite modified DHEO epoxy exhibited improved storage modulus and thermal stability as determined from dynamic mechanical analysis and thermogravimetric analysis. This study widens the synthesis routes of biobased epoxy thermosets from lignin-based molecules. PMID:26135389

  13. Antifungal dibenzofuran bis(bibenzyl)s from the liverwort Asterella angusta.

    PubMed

    Qu, Jianbo; Xie, Chunfeng; Guo, Huaifang; Yu, Wentao; Lou, Hongxiang

    2007-07-01

    Bioactivity-guided separation of an antifungal extract from the liverwort Asterella angusta afforded four bis(bibenzyl)s, asterelin A (1), asterelin B (2), 11-O-demethyl marchantin I (3), and dihydroptychantol A (4), together with six known ones. Their structures were established by extensive spectroscopic analysis (1D and 2D-NMR, MS), and that of 2 was confirmed by X-ray crystallographic diffraction analysis. Compounds 1 and 2 are the first examples of dibenzofuran bis(bibenzyl)s. The antifungal activity of the isolated bis(bibenzyl)s against the common clinical pathogenic fungus Candida albicans was evaluated using both the thin-layer chromatography bioautographic assay and the broth microdilution method. They showed moderate antifungal activities with minimal inhibitory concentration (MIC) values ranging from 16 microg/ml to 512 microg/ml. PMID:17570447

  14. A small-scale, inexpensive method for detecting formaldehyde or methanol in biochemical reactions containing interfering substances.

    PubMed

    Jiang, Wen Zhi; Adamec, Jiri; Weeks, Donald P

    2013-11-15

    A simple, inexpensive microdistillation device is described for capturing methanol or formaldehyde as end products of biochemical reactions or in environmental samples. We demonstrate that the microdistillation protocol, coupled with the use of alcohol oxidase and the formaldehyde-sensitive reagent Purpald (4-amino-3-hydrazino-5-mercapto-1,2,4-triazole), serves as a quick and inexpensive alternative to chromatographic and mass spectrometer analyses for determining if formaldehyde or methanol is a product of reactions that contain substances that interfere with the Purpald reaction. These techniques were used to affirm formaldehyde as the end product of the dicamba monooxygenase-catalyzed O-demethylation of the herbicide dicamba (2-methoxy-3,6-dichlorobenzoic acid). PMID:23938775

  15. Metabolism of the cinnamon constituent o-methoxycinnamaldehyde in the rat.

    PubMed

    Samuelsen, O B; Brenna, J; Solheim, E; Scheline, R R

    1986-09-01

    The metabolism of o-methoxycinnamaldehyde (1.3 mmol/kg, intragastrically) was studied in rats. Identification of the urinary metabolites by g.l.c.-mass spectrometry and quantification by h.p.l.c. showed that the major metabolic pathway (approx. two-thirds of the dose) was oxidation to the corresponding cinnamic and phenylpropionic acids (C6-C3 acids) which were largely excreted as glycine conjugates. Intermediate amounts (approx. 10% of the dose) of the O-demethylated C6-C3 acids were excreted. Relatively large amounts of the beta-hydroxylated phenylpropionic acid derivative were found, however only traces of the further products of beta-oxidation (2-methoxylated derivatives of benzoic and hippuric acid) were excreted. No evidence was obtained for conjugation of o-methoxycinnamaldehyde with glutathione. Urinary excretion of metabolites was rapid (91% in 24 h and 98% in 48 h). PMID:3765663

  16. Papaverine 7-O-demethylase, a novel 2-oxoglutarate/Fe(2+)-dependent dioxygenase from opium poppy.

    PubMed

    Farrow, Scott C; Facchini, Peter J

    2015-09-14

    Opium poppy (Papaver somniferum) produces several pharmacologically important benzylisoquinoline alkaloids including the vasodilator papaverine. Pacodine and palaudine are tri-O-methylated analogs of papaverine, which contains four O-linked methyl groups. However, the biosynthetic origin of pacodine and palaudine has not been established. Three members of the 2-oxoglutarate/Fe(2+)-dependent dioxygenases (2ODDs) family in opium poppy display widespread O-dealkylation activity on several benzylisoquinoline alkaloids with diverse structural scaffolds, and two are responsible for the antepenultimate and ultimate steps in morphine biosynthesis. We report a novel 2ODD from opium poppy catalyzing the efficient substrate- and regio-specific 7-O-demethylation of papaverine yielding pacodine. The occurrence of papaverine 7-O-demethylase (P7ODM) expands the enzymatic scope of the 2ODD family in opium poppy and suggests an unexpected biosynthetic route to pacodine. PMID:26264169

  17. Total synthesis of Elisabethin A: intramolecular Diels-Alder reaction under biomimetic conditions.

    PubMed

    Heckrodt, Thilo J; Mulzer, Johann

    2003-04-23

    We describe the first total synthesis of the marine diterpenoid elisabethin A. The synthesis uses (S)-hydroxy-2-methyl-propionate as the chiral starting material, which is elaborated into a dienyl-iodide and added to an aryl acetic acid ester via enolate alkylation. The hydroquinoid system is oxidized to the quinone which serves as the dienophile in a highly stereocontrolled intramolecular Diels-Alder addition. This IMDA reaction, which to our knowledge is the first one to employ a terminal (Z)-diene, proceeds under biomimetic conditions (water, ferrichloride as the oxidant, room temperature) with high yield and stereoselectivity. The Diels-Alder adduct is transformed into the natural product via a three-step sequence including selective hydrogenation, base-catalyzed epimerization of the cis- into the trans-decalin system and O-demethylation. PMID:12696865

  18. Metabolic pathways of the psychotropic-carboline alkaloids, harmaline and harmine, by liquid chromatography/mass spectrometry and NMR spectroscopy.

    PubMed

    Zhao, Ting; Zheng, Shan-Song; Zhang, Bin-Feng; Li, Yuan-Yuan; Bligh, S W Annie; Wang, Chang-Hong; Wang, Zheng-Tao

    2012-09-15

    The β-carboline alkaloids, harmaline and harmine, are present in hallucinogenic plants Ayahuasca and Peganum harmala, and in a variety of foods. In order to establish the metabolic pathway and bioactivities of endogenous and xenobiotic bioactive β-carbolines, high-performance liquid chromatography, coupled with mass spectrometry, was used to identify these metabolites in human liver microsomes (HLMs) in vitro and in rat urine and bile samples after oral administration of the alkaloids. Three metabolites of harmaline and two of harmine were found in the HLMs. Nine metabolites for harmaline and seven metabolites for harmine, from the rat urine and bile samples, were identified. Among them, four in vivo metabolites were isolated and fully characterised by NMR analysis. For the first time, harmaline is shown transforming to harmine by oxidative dehydrogenation in rat. Five metabolic pathways were therefore proposed, namely, oxidative dehydrogenation, 7-O-demethylation, hydroxylation, O-glucuronide conjugation and O-sulphate conjugation. PMID:23107733

  19. Use of 13C NMR and ftir for elucidation of degradation pathways during natural litter decomposition and composting I. early stage leaf degradation

    USGS Publications Warehouse

    Wershaw, R. L.; Leenheer, J.A.; Kennedy, K.R.; Noyes, T.I.

    1996-01-01

    Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of plant tissue follows the sequence of O-demethylation, and hydroxylation followed by ring-fission, chain-shortening, and oxidative removal of substituents. Oxidative ring-fission leads to the formation of carboxylic acid groups on the cleaved ends of the rings and, in the process, transforms phenolic groups into aliphatic alcoholic groups. The carbohydrate components are broken down into aliphatic hydroxy acids and aliphatic alcohols.

  20. Metabolism and disposition of N,N-dimethyltryptamine and harmala alkaloids after oral administration of ayahuasca.

    PubMed

    Riba, Jordi; McIlhenny, Ethan H; Valle, Marta; Bouso, José Carlos; Barker, Steven A

    2012-01-01

    Ayahuasca is an Amazonian psychotropic plant tea obtained from Banisteriopsis caapi, which contains β-carboline alkaloids, chiefly harmine, harmaline and tetrahydroharmine. The tea usually incorporates the leaves of Psychotria viridis or Diplopterys cabrerana, which are rich in N,N-dimethyltryptamine (DMT), a psychedelic 5-HT(2A/1A/2C) agonist. The β-carbolines reversibly inhibit monoamine-oxidase (MAO), effectively preventing oxidative deamination of the orally labile DMT and allowing its absorption and access to the central nervous system. Despite increased use of the tea worldwide, the metabolism and excretion of DMT and the β-carbolines has not been studied systematically in humans following ingestion of ayahuasca. In the present work, we used an analytical method involving high performance liquid chromatography (HPLC)/electrospray ionization (ESI)/selected reaction monitoring (SRM)/tandem mass spectrometry(MS/MS) to characterize the metabolism and disposition of ayahuasca alkaloids in humans. Twenty-four-hour urine samples were obtained from 10 healthy male volunteers following administration of an oral dose of encapsulated freeze-dried ayahuasca (1.0 mg DMT/kg body weight). Results showed that less than 1% of the administered DMT dose was excreted unchanged. Around 50% was recovered as indole-3-acetic acid but also as DMT-N-oxide (10%) and other MAO-independent compounds. Recovery of DMT plus metabolites reached 68%. Harmol, harmalol, and tetrahydroharmol conjugates were abundant in urine. However, recoveries of each harmala alkaloid plus its O-demethylated metabolite varied greatly between 9 and 65%. The present results show the existence in humans of alternative metabolic routes for DMT other than biotransformation by MAO. Also that O-demethylation plus conjugation is an important but probably not the only metabolic route for the harmala alkaloids in humans. PMID:22514127

  1. Cytochrome P450 CYP81A12 and CYP81A21 Are Associated with Resistance to Two Acetolactate Synthase Inhibitors in Echinochloa phyllopogon1[W

    PubMed Central

    Iwakami, Satoshi; Endo, Masaki; Saika, Hiroaki; Okuno, Junichi; Nakamura, Naoki; Yokoyama, Masao; Watanabe, Hiroaki; Toki, Seiichi; Uchino, Akira; Inamura, Tatsuya

    2014-01-01

    Previous studies have demonstrated multiple herbicide resistance in California populations of Echinochloa phyllopogon, a noxious weed in rice (Oryza sativa) fields. It was suggested that the resistance to two classes of acetolactate synthase-inhibiting herbicides, bensulfuron-methyl (BSM) and penoxsulam (PX), may be caused by enhanced activities of herbicide-metabolizing cytochrome P450. We investigated BSM metabolism in the resistant (R) and susceptible (S) lines of E. phyllopogon, which were originally collected from different areas in California. R plants metabolized BSM through O-demethylation more rapidly than S plants. Based on available information about BSM tolerance in rice, we isolated and analyzed P450 genes of the CYP81A subfamily in E. phyllopogon. Two genes, CYP81A12 and CYP81A21, were more actively transcribed in R plants compared with S plants. Transgenic Arabidopsis (Arabidopsis thaliana) expressing either of the two genes survived in media containing BSM or PX at levels at which the wild type stopped growing. Segregation of resistances in the F2 generation from crosses of R and S plants suggested that the resistance to BSM and PX were each under the control of a single regulatory element. In F6 recombinant inbred lines, BSM and PX resistances cosegregated with increased transcript levels of CYP81A12 and CYP81A21. Heterologously produced CYP81A12 and CYP81A21 proteins in yeast (Saccharomyces cerevisiae) metabolized BSM through O-demethylation. Our results suggest that overexpression of the two P450 genes confers resistance to two classes of acetolactate synthase inhibitors to E. phyllopogon. The overexpression of the two genes could be regulated simultaneously by a single trans-acting element in the R line of E. phyllopogon. PMID:24760819

  2. Identification of a unique 2-oxoglutarate-dependent flavone 7-O-demethylase completes the elucidation of the lipophilic flavone network in basil.

    PubMed

    Berim, Anna; Kim, Min-Jeong; Gang, David R

    2015-01-01

    Small molecule demethylation is considered unusual in plants. Of the studied instances, the N-demethylation of nicotine is catalyzed by a Cyt P450 monooxygenase, while the O-dealkylation of alkaloids in Papaver somniferum is mediated by 2-oxoglutarate-dependent dioxygenases (2-ODDs). This report describes a 2-ODD regiospecifically catalyzing the 7-O-demethylation of methoxylated flavones in peltate trichomes of sweet basil (Ocimum basilicum L.). Three candidate 2-ODDs were identified in the basil trichome transcriptome database. Only the candidate designated ObF7ODM1 was found to be active with and highly specific for the proposed natural substrates, gardenin B and 8-hydroxysalvigenin. Of the characterized 2-ODDs, ObF7ODM1 is most closely related to O-demethylases from Papaver. The demethylase activity in trichomes from four basil chemotypes matches well with the abundance of ObF7ODM1 peptides and transcripts in the same trichome preparations. Treatment of basil plants with a 2-ODD inhibitor prohexadione-calcium significantly reduced the accumulation of 7-O-demethylated flavone nevadensin, confirming the involvement of a 2-ODD in its formation. Notably, the full-length open reading frame of ObF7ODM1 contains a second in-frame AUG codon 57 nucleotides downstream of the first translation initiation codon. Both AUG codons are recognized by bacterial translation machinery during heterologous gene expression. The N-truncated ObF7ODM1 is nearly inactive. The N-terminus essential for activity is unique to ObF7ODM1 and does not align with the sequences of other 2-ODDs. Further studies will reveal whether alternative translation initiation plays a role in regulating the O-demethylase activity in planta. Molecular identification of the flavone 7-O-demethylase completes the biochemical elucidation of the lipophilic flavone network in basil. PMID:25378691

  3. Studies on the in vivo contribution of human cytochrome P450s to the hepatic metabolism of glaucine, a new drug of abuse.

    PubMed

    Meyer, Golo M J; Meyer, Markus R; Wink, Carina S D; Zapp, Josef; Maurer, Hans H

    2013-11-15

    Glaucine ((S)-5,6,6a,7-tetrahydro-1,2,9,10-tetramethoxy-6-methyl-4H-dibenzo [de,g]quinoline), main isoquinoline alkaloid of Glaucium flavum (Papaveraceae), is used as antitussive, but also as recreational drug of abuse. Glaucine was mainly metabolized by O- and N-demethylation to four isomers in rats. So far, only scarce pharmacokinetic data were available. Therefore, the aim of the presented study was to assess the involvement of the ten most important cytochrome P450 (P450) isoforms in the main metabolic steps and determination of their kinetic parameters using the metabolite formation approach. Reference standards of investigated metabolites were synthesized for quantification. In addition, the impact of isomeric standards was tested for calibration and the use of simple peak area ratios on the kinetic constants and resulting contribution of P450 isoforms on estimated hepatic clearance. Kinetic profiles of all metabolite formations followed classic Michaelis-Menten behavior. Km values were between 25 and 140μM, Vmax between 0.10 and 1.92pmol/min/pmol. Using the relative activity factor approach, the hepatic clearance was calculated to be 27 and 73% for 2-O-demethylation by CYP1A2 and CYP3A4, 82, 3, and 15% for 9-O-demethylation by CYP1A2, CYP2C19, and CYP2D6, and finally <1 and 99% for N-demethylation by CYP2D6 and CYP3A4. These data were confirmed by inhibition tests. The calibration mode for determination of the metabolite concentrations had no relevant impact on the estimation of in vivo hepatic clearance of glaucine. As glaucine was metabolized via three initial steps and different P450 isoforms were involved in the hepatic clearance of glaucine, a clinically relevant interaction with single inhibitors should not be expected. PMID:23988488

  4. Monitoring of kratom or Krypton intake in urine using GC-MS in clinical and forensic toxicology.

    PubMed

    Philipp, Anika A; Meyer, Markus R; Wissenbach, Dirk K; Weber, Armin A; Zoerntlein, Siegfried W; Zweipfenning, Peter G M; Maurer, Hans H

    2011-04-01

    The Thai medicinal plant Mitragyna speciosa (kratom) is misused as a herbal drug. Besides this, a new herbal blend has appeared on the drugs of abuse market, named Krypton, a mixture of O-demethyltramadol (ODT) and kratom. Therefore, urine drug screenings should include ODT and focus on the metabolites of the kratom alkaloids mitragynine (MG), paynantheine (PAY), speciogynine (SG), and speciociliatine (SC). The aim of this study was to develop a full-scan gas chromatography-mass spectrometry procedure for monitoring kratom or Krypton intake in urine after enzymatic cleavage of conjugates, solid-phase extraction, and trimethylsilylation. With use of reconstructed mass chromatography with the ions m/z 271, 286, 329, 344, 470, 526, 528, and 586, the presence of MG, 16-carboxy-MG, 9-O-demethyl-MG, and/or 9-O-demethyl-16-carboxy-MG could be indicated, and in case of Krypton, with m/z 58, 84, 116, 142, 303, 361, 393, and 451, the additional presence of ODT and its nor metabolite could be indicated. Compounds were identified by comparison with their respective reference spectra. Depending on the plant type, dose, administration route, and/or sampling time, further metabolites of MG, PAY, SG, and SC could be detected. The limits of detection (signal-to-noise ratio of 3) were 100 ng/ml for the parent alkaloids and 50 ng/ml for ODT. As mainly metabolites of the kratom alkaloids were detected in urine, the detectability of kratom was tested successfully using rat urine after administration of a common user's dose of MG. As the metabolism in humans was similar, this procedure should be suitable to prove an intake of kratom or Krypton. PMID:21153588

  5. Interindividual and interethnic differences in the demethylation and glucuronidation of codeine.

    PubMed Central

    Yue, Q Y; Svensson, J O; Alm, C; Sjöqvist, F; Säwe, J

    1989-01-01

    1. The 8 h urinary excretion of codeine and seven of its metabolites was compared in 149 healthy Swedish Caucasians and 133 healthy Chinese following a single oral dose of 25 mg codeine phosphate. 2. The total 8 h urinary recovery of drug-related material was 74 +/- 24% in the Caucasians and 60 +/- 14% in the Chinese (P less than 0.001). The excretion of unchanged codeine was significantly higher in the Chinese (7.2%) compared with the Caucasians (4.3%, P less than 0.001). 3. The Caucasians excreted significantly greater proportions of codeine-6-glucuronide (C6G) (62%) than the Chinese (44%) (P less than 0.001). The frequency distribution of the log metabolic ratio (MR) for glucuronidation (codeine/C6G) was shifted towards higher values in the Chinese population. Males in both groups and Chinese smokers had significantly lower glucuronidation MRs than females and non-smokers in the respective populations (P less than 0.001). 4. The frequency distribution of the MR for O-demethylation (codeine/morphine (M) + M-3 and M-6-glucuronide (M3G and M6G) + normorphine (NM) was highly skewed in the Caucasians, suggestive of a bimodal distribution. There was a 160-fold interindividual variation in this MR. A unimodal distribution of the log O-demethylation MR was observed in Chinese. The Caucasians excreted less M and more M6G than did the Chinese (P less than 0.001). 5. Significantly more norcodeine (NC) and less NC-glucuronide (NCG) were excreted in the Chinese compared with the Caucasians (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2611085

  6. Microbial and dietary factors associated with the 8-prenylnaringenin producer phenotype: a dietary intervention trial with fifty healthy post-menopausal Caucasian women.

    PubMed

    Bolca, Selin; Possemiers, Sam; Maervoet, Veerle; Huybrechts, Inge; Heyerick, Arne; Vervarcke, Stefaan; Depypere, Herman; De Keukeleire, Denis; Bracke, Marc; De Henauw, Stefaan; Verstraete, Willy; Van de Wiele, Tom

    2007-11-01

    Hop-derived food supplements and beers contain the prenylflavonoids xanthohumol (X), isoxanthohumol (IX) and the very potent phyto-oestrogen (plant-derived oestrogen mimic) 8-prenylnaringenin (8-PN). The weakly oestrogenic IX can be bioactivated via O-demethylation to 8-PN. Since IX usually predominates over 8-PN, human subjects may be exposed to increased doses of 8-PN. A dietary intervention trial with fifty healthy post-menopausal Caucasian women was undertaken. After a 4 d washout period, participants delivered faeces, blank urine and breath samples. Next, they started a 5 d treatment with hop-based supplements that were administered three times per d and on the last day, a 24 h urine sample was collected. A semi-quantitative FFQ was used to estimate fat, fibre, alcohol, caffeine and theobromine intakes. The recoveries of IX, 8-PN and X in the urine were low and considerable inter-individual variations were observed. A five-fold increase in the dosage of IX without change in 8-PN concentration resulted in a significant lower IX recovery and a higher 8-PN recovery. Classification of the subjects into poor (60%), moderate (25%) and strong (15%) 8-PN producers based on either urinary excretion or microbial bioactivation capacity gave comparable results. Recent antibiotic therapy seemed to affect the 8-PN production negatively. A positive trend between methane excretion and 8-PN production was observed. Strong 8-PN producers consumed less alcohol and had a higher theobromine intake. From this study we conclude that in vivo O-demethylation of IX increases the oestrogenic potency of hop-derived products. PMID:17521469

  7. Studies on the metabolism and toxicological detection of the new psychoactive designer drug 2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe) in human and rat urine using GC-MS, LC-MS(n), and LC-HR-MS/MS.

    PubMed

    Caspar, Achim T; Helfer, Andreas G; Michely, Julian A; Auwärter, Volker; Brandt, Simon D; Meyer, Markus R; Maurer, Hans H

    2015-09-01

    25I-NBOMe, a new psychoactive substance, is a potent 5-HT2A receptor agonist with strong hallucinogenic potential. Recently, it was involved in several fatal and non-fatal intoxication cases. The aim of the present work was to study its phase I and II metabolism and its detectability in urine screening approaches. After application of 25I-NBOMe to male Wistar rats, urine was collected over 24 h. The phase I and II metabolites were identified by LC-HR-MS/MS in urine after suitable workup. For the detectability studies, standard urine screening approaches (SUSA) by GC-MS, LC-MS(n), and LC-HR-MS/MS were applied to rat and also to authentic human urine samples submitted for toxicological analysis. Finally, an initial CYP activity screening was performed to identify CYP isoenzymes involved in the major metabolic steps. 25I-NBOMe was mainly metabolized by O-demethylation, O,O-bis-demethylation, hydroxylation, and combinations of these reactions as well as by glucuronidation and sulfation of the main phase I metabolites. All in all, 68 metabolites could be identified. Intake of 25I-NBOMe was detectable mainly via its metabolites by both LC-MS approaches, but not by the GC-MS SUSA. Initial CYP activity screening revealed the involvement of CYP1A2 and CYP3A4 in hydroxylation and CYP2C9 and CYP2C19 in O-demethylation. The presented study demonstrated that 25I-NBOMe was extensively metabolized and could be detected only by the LC-MS screening approaches. Since CYP2C9 and CYP3A4 are involved in initial metabolic steps, drug-drug interactions might occur in certain constellations. PMID:26108532

  8. Systematic and quantitative assessment of the effect of chronic kidney disease on CYP2D6 and CYP3A4/5.

    PubMed

    Yoshida, K; Sun, B; Zhang, L; Zhao, P; Abernethy, D R; Nolin, T D; Rostami-Hodjegan, A; Zineh, I; Huang, S-M

    2016-07-01

    Recent reviews suggest that chronic kidney disease (CKD) can affect the pharmacokinetics of nonrenally eliminated drugs, but the impact of CKD on individual elimination pathways has not been systematically evaluated. In this study we developed a comprehensive dataset of the effect of CKD on the pharmacokinetics of CYP2D6- and CYP3A4/5-metabolized drugs. Drugs for evaluation were selected based on clinical drug-drug interaction (CYP3A4/5 and CYP2D6) and pharmacogenetic (CYP2D6) studies. Information from dedicated CKD studies was available for 13 and 18 of the CYP2D6 and CYP3A4/5 model drugs, respectively. Analysis of these data suggested that CYP2D6-mediated clearance is generally decreased in parallel with the severity of CKD. There was no apparent relationship between the severity of CKD and CYP3A4/5-mediated clearance. The observed elimination-route dependency in CKD effects between CYP2D6 and CYP3A4/5 may inform the need to conduct clinical CKD studies with nonrenally eliminated drugs for optimal use of drugs in patients with CKD. PMID:26800425

  9. Antitussive effects of GABAB agonists in the cat and guinea-pig.

    PubMed Central

    Bolser, D. C.; Aziz, S. M.; DeGennaro, F. C.; Kreutner, W.; Egan, R. W.; Siegel, M. I.; Chapman, R. W.

    1993-01-01

    1. GABAB agonists inhibit neuronal processes which are important in the pathogenesis of airway disease, such as bronchospasm. Cough is a prominent symptom of pulmonary disease, but the effects of GABAB agonists on this airway reflex are unknown. Experiments were conducted to determine the antitussive effect of GABAB receptor agonists in comparison to the known antitussive agents, codeine and dextromethorphan. 2. Unanaesthetized guinea-pigs were exposed to aerosols of 0.3 mM capsaicin to elicit coughing, which was detected with a microphone and counted. Cough also was produced in anaesthetized cats by mechanical stimulation of the intrathoracic trachea and was recorded from electromyograms of respiratory muscle activity. 3. In guinea-pigs, the GABAB agonists baclofen and 3-aminopropyl-phosphinic acid (3-APPi) produced dose-dependent inhibition of capsaicin-induced cough when administered by subcutaneous or inhaled routes. The potencies of baclofen and 3-APPi compared favourably with codeine and dextromethorphan. 4. The GABAB antagonist, CGP 35348 (0.3- 30 mg kg-1, s.c.) inhibited the antitussive effect of baclofen (3.0 mg kg-1, s.c.). However, CGP 35348 (10 mg kg-1, s.c.) had no effect on the antitussive activity of codeine (30 mg kg-1, s.c.). The antitussive effect of baclofen was not influenced by the GABAA antagonist, bicuculline (3 mg kg-1, s.c.) or naloxone (0.3 mg kg-1, s.c.). 5. In the cat, baclofen (0.3-3.0 mg kg-1, i.v.) decreased mechanically-induced cough in a dose-dependent manner. In this model, baclofen (ED50 = 0.63 mg kg-1) was less potent than either codeine or dextromethorphan.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8220912

  10. Comparison of the effects of two opioid antitussives, vadocaine hydrochloride, clobutinol and lidocaine on lung mechanics in guinea-pigs.

    PubMed

    Salonen, R O

    1988-04-01

    Intravenous administration of opioids, e.g. morphine and codeine, causes bronchoconstriction in animals and susceptible patients such as asthmatics. Therefore, the effects of two opioid antitussives (codeine and dextromethorphan), two non-opioid antitussives (vadocaine hydrochloride (2',4'-dimethyl-6'-methoxy-3-(2-methylpiperidyl) propionanilide hydrochloride, OR K-242-HCl; INN: vadocaine) and clobutinol), and lidocaine on basal lung mechanics and methacholine (MeCh, 6 micrograms/kg i.v.)-induced airway obstruction were investigated in anaesthetized guinea-pigs. Intravenous administration of codeine (10-20 mg/kg) produced a dual response in the airways; initial bronchoconstriction was followed by attenuation of the MeCh-response. Dextromethorphan (10 and 15 mg/kg) caused bronchoconstriction only. Both the opioids affected dynamic lung compliance (CDyn) more than lung resistance (RL). At doses between 1 and 20 mg/kg i.v., vadocaine, clobutinol, and lidocaine had no obvious effect on the airways. Dextromethorphan and vadocaine, both at doses of 10 and 15 mg/kg, and clobutinol (15 and 20 mg/kg) caused irreversible bradycardia and hypotension, whereas codeine (5-20 mg/kg) increased blood pressure, and to a lesser extent heart rate. These results suggest that intravenous administration of an opioid antitussive influences the small peripheral airways more than the large airways, whether the opioid has euphoric analgesic properties or not. In contrast to this, non-opioid antitussives such as vadocaine and clobutinol are without effect. At large doses, all antitussives influence the cardiovascular system considerably. PMID:3395396

  11. LC for analysis of two sustained-release mixtures containing cough cold suppressant drugs.

    PubMed

    El-Gindy, Alaa; Sallam, Shehab; Abdel-Salam, Randa A

    2010-07-01

    A liquid chromatographic method was applied for the analysis of two sustained-release mixtures containing dextromethorphane hydrobromide, carbinoxamine maleate with either phenylephrine hydrochloride in pharmaceutical capsules (Mix 1) or phenyl-propanolamine, methylparaben, and propylparaben, which bonds as a drug base to ion exchange resin in pharmaceutical syrup (Mix 2). The method was used for their simultaneous determination using a CN column with a mobile phase consisting of acetonitrile-12 mM ammonium acetate in the ratio of 60:40 (v/v, pH 6.0) for Mix 1 and 45:55 (v/v, pH 6.0) for Mix 2. PMID:20822669

  12. "How high do they look?": identification and treatment of common ingestions in adolescents.

    PubMed

    Woo, Teri Moser; Hanley, James R

    2013-01-01

    Adolescents have access to a variety of legal or illicit substances that they use to alter their mood or "get high." The purpose of this review is to provide an overview of common substances adolescents use to get high, including the illicit substances synthetic marijuana or "Spice," salvia, MDMA, synthetic cathinones, and 2C-E. Dextromethorphan and energy drinks are easily accessible substances that teenagers abuse. The toxic effects of common ingestions and treatment of overdose is discussed to inform pediatric providers who provide care for adolescents. PMID:23414979

  13. Cough syrup psychosis.

    PubMed

    Amaladoss, Alfred; O'Brien, Simon

    2011-01-01

    Over-the-counter medications are widely accessible and used. Cough suppressant syrups contain dextromethorphan (DM), which has the potential to be abused, with resultant psychiatric symptoms. This case report describes a young woman presenting with psychotic mania secondary to DM abuse. We also describe the treatment of this toxidrome and include the results of a literature search on this topic. The recognition of cough syrup as an agent of abuse and its toxidrome is important. This will facilitate early diagnostic clarification and promote efficient treatment strategies. PMID:21324299

  14. Pharmacological and neurophysiological aspects of space/motion sickness

    NASA Technical Reports Server (NTRS)

    Lucot, James B.; Crampton, George H.

    1991-01-01

    A motorized motion testing device modeled after a Ferris wheel was constructed to perform motion sickness tests on cats. Details of the testing are presented, and some of the topics covered include the following: xylazine-induced emesis; analysis of the constituents of the cerebrospinal fluid (CSF) during motion sickness; evaluation of serotonin-1A (5-HT sub 1A) agonists; other 5HT receptors; antimuscarinic mechanisms; and antihistaminergic mechanisms. The ability of the following drugs to reduce motion sickness in the cats was examined: amphetamines, adenosinergic drugs, opioid antagonists, peptides, cannabinoids, cognitive enhancers (nootropics), dextromethorphan/sigma ligands, scopolamine, and diphenhydramine.

  15. Is opiate action in cough due to sedation?

    PubMed Central

    Dickinson, Rebecca S.; Morjaria, Jaymin B.; Wright, Caroline E.

    2014-01-01

    Objectives: Opiates have been used for cough suppression for centuries. It is unclear whether this antitussive action is due to their known sedative effects. We aimed to assess correlation between cough suppression and opiate usage. Methods: We performed a post hoc analysis of two published trials with three opioids. In study one, patients with chronic cough were treated with 4 weeks of modified release morphine sulphate (5 mg twice daily) or placebo in a double-blinded placebo-controlled fashion. Cough suppression was assessed subjectively by the Leicester Cough Questionnaire and objectively by citric acid aerosol (CAA) induced cough challenge. In study 2, normal volunteers were given single doses of placebo, codeine 30 mg or dextromethorphan 50 mg and cough suppression assessed using the CAA-induced cough challenge. Sedation was contemporaneously assessed by direct questioning. Results: There were 14 episodes of patient-reported sedation; 2 with modified release morphine sulphate, 9 with codeine and 3 with dextromethorphan. There was no correlation between change in the Leicester Cough Questionnaire or the CAA-induced cough challenge and reported sedation. Conclusion: This observational study suggests that sedation is unlikely to underlie the antitussive properties of these opioids. Eliciting the mechanism of these medications in cough may be a target for future tailored drug development. PMID:25177477

  16. Pseudobulbar affect in multiple sclerosis: toward the development of innovative therapeutic strategies.

    PubMed

    Miller, Ariel

    2006-06-15

    Pseudobulbar affect (PBA), a condition involving involuntary and uncontrollable episodes of crying and/or laughing, occurs frequently in patients with a variety of neurological disorders, including amyotrophic lateral sclerosis (ALS), stroke, traumatic brain injury, dementia including Alzheimer's disease, and multiple sclerosis (MS). Although PBA results in considerable distress for patients and caretakers, it is underrecognized and undertreated. Agents used to treat psychiatric disorders--particularly tricyclic antidepressants and selective serotonin reuptake inhibitors--are useful in alleviating PBA, but act on diffuse neural networks rather than targeting those involved in emotional motor expression. As a result of their nonspecific activity, these agents are associated with a range of unwanted effects that preclude many patients from using them. Dextromethorphan, a common cough suppressant, specifically targets sigma(1) receptors concentrated in the brainstem and cerebellum, thus providing the possibility of targeting regions implicated in emotional expression. When administered in a fixed combination with quinidine, dextromethorphan is effective in treating PBA in patients with ALS, and preliminary results suggest that this therapy also is effective in treating MS-related PBA. PMID:16674978

  17. Rheological characterization and drug release studies of gum exudates of Terminalia catappa Linn.

    PubMed

    Kumar, Sadhis V; Sasmal, Dinakar; Pal, Subodh C

    2008-01-01

    The present study was undertaken to evaluate the gum exudates of Terminalia catappa Linn. (TC gum) as a release retarding excipient in oral controlled drug delivery system. The rheological properties of TC gum were studied and different formulation techniques were used to evaluate the comparative drug release characteristics. The viscosity was found to be dependent on concentration and pH. Temperature up to 60 degrees C did not show significant effect on viscosity. The rheological kinetics evaluated by power law, revealed the shear thinning behavior of the TC gum dispersion in water. Matrix tablets of TC gum were prepared with the model drug dextromethorphan hydrobromide (DH) by direct compression, wet granulation and solid dispersion techniques. The dissolution profiles of the matrix tablets were compared with the pure drug containing capsules using the USP Basket apparatus with 500 ml phosphate buffer of pH 6.8 as a dissolution medium. The drug release from the compressed tablets containing TC gum was comparatively sustained than pure drug containing capsules. Even though all the formulation techniques showed reduction of dissolution rate, aqueous wet granulation showed the maximum sustained release of more than 8 h. The release kinetics estimated by the power law revealed that the drug release mechanism involved in the dextromethorphan matrix is anomalous transport as indicated by the release exponent n values. Thus the study confirmed that the TC gum might be used in the controlled drug delivery system as a release-retarding polymer. PMID:18661243

  18. Exploring Enantiospecific Ligand-Protein Interactions Using Cellular Membrane Affinity Chromatography: Chiral Recognition as a Dynamic Process

    PubMed Central

    Jozwiak, Krzysztof; Moaddel, Ruin; Ravichandran, Sarangan; Plazinska, Anita; Kozak, Joanna; Patel, Sharvil; Yamaguchi, Rika; Wainer, Irving

    2008-01-01

    The chiral recognition mechanisms responsible for the enantioselective binding on the α3β4 nicotinic acetyl choline receptor (α3β4 nAChR) and human organic cation transporter 1 (hOCT1) have been reviewed. The results indicate that chiral recognition on the α3β4 nAChR is a process involving initial tethering of dextromethorphan and levomethorphan at hydrophobic pockets within the central lumen followed by hydrogen bonding interactions favoring dextromethorphan. The second step is the defining enantioselective step. Studies with the hOCT1 indentified four binding sites within the transporter that participated in chiral recognition. Each of the enantiomers of the compounds used in the study interacted with three of these sites, while (R)-verapamil interacted with all four. Chiral recognition arose from the conformational adjustments required to produce optimum interactions. With respect to the prevailing interaction-based models, the data suggest that chiral recognition is a dynamic process and that the static point-based models should be amended to reflect this. PMID:18723411

  19. Corrinoid-Dependent Methyl Transfer Reactions Are Involved in Methanol and 3,4-Dimethoxybenzoate Metabolism by Sporomusa ovata

    PubMed Central

    Stupperich, Erhard; Konle, Ralph

    1993-01-01

    Washed and air-oxidized proteins from Sporomusa ovata cleaved the C-O bond of methanol or methoxyaromatics and transferred the methyl to dl-tetrahydrofolate. The reactions strictly required a reductive activation by titanium citrate, catalytic amounts of ATP, and the addition of dl-tetrahydrofolate. Methylcorrinoid-containing proteins carried the methanol methyl, which was transferred to dl-tetrahydrofolate at a specific rate of 120 nmol h-1 mg of protein-1. Tetrahydrofolate methylation diminished after the addition of 1-iodopropane or when the methyl donor methanol was replaced by 3,4-dimethoxybenzoate. However, whole Sporomusa cells utilize the methoxyl groups of 3,4-dimethoxybenzoate as a carbon source by a sequential O demethylation to 4-hydroxy-3-methoxybenzoate and 3,4-dihydroxybenzoate. The in vitro O demethylation of 3,4-[4-methoxyl-14C]dimethoxybenzoate proceeded via two distinct corrinoid-containing proteins to form 5-[14C]methyltetrahydrofolate at a specific rate of 200 nmol h-1 mg of protein-1. Proteins from 3,4-dimethoxybenzoate-grown cells efficiently used methoxybenzoates with vicinal substituents only, but they were unable to activate methanol. These results emphasized that specific enzymes are involved in methanol activation as well as in the activation of various methoxybenzoates and that similar corrinoid-dependent methyl transfer pathways are employed in 5-methyl-tetrahydrofolate formation from these substrates. Methyl-tetrahydrofolate could be demethylated by a distinct methyl transferase. That enzyme activity was present in washed and air-oxidized cell extracts from methanol-grown cells and from 3,4-dimethoxybenzoate-grown cells. It used cob(I)alamin as the methyl acceptor in vitro, which was methylated at a rate of 48 nmol min-1 mg of protein-1 even when ATP was omitted from the assay mixture. This methyl-cob(III)alamin formation made possible a spectrophotometric quantification of the preceding methyl transfers from methanol or

  20. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-Methoxy-N,N-dimethyltryptamine Metabolism and Pharmacokinetics

    PubMed Central

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (Vmax/Km), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1’-hydroxylase activities (R² = 0.98; p < 0.0001) and CYP2D6 contents (R² = 0.77; p = 0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20 mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pre-treatment of harmaline (5 mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2 mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6. PMID:20206139

  1. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-methoxy-N,N-dimethyltryptamine metabolism and pharmacokinetics.

    PubMed

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-07-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (V(max)/K(m)), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1'-hydroxylase activities (R(2)=0.98; P<0.0001) and CYP2D6 contents (R(2)=0.77; P=0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pretreatment of harmaline (5mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6. PMID:20206139

  2. A simplified procedure for the analysis of formoterol in human urine by liquid chromatography-electrospray tandem mass spectrometry: application to the characterization of the metabolic profile and stability of formoterol in urine.

    PubMed

    Mazzarino, Monica; de la Torre, Xavier; Fiacco, Ilaria; Pompei, Chiara; Calabrese, Fabiana; Botrè, Francesco

    2013-07-15

    Since 1992, formoterol is included in the prohibited list of doping substances and methods, presently reviewed and updated by the World Anti-Doping Agency. Recently a threshold value of 40ng/mL has been established to differentiate between the prohibited (oral) and the permitted (inhalatory) administration of formoterol to athletes. This paper considers the urinary excretion profile of formoterol and its main metabolites after inhalation of different doses of two of the most used medicaments, available in Italy, containing formoterol fumarate bihydrate (12 and 36μg twice a day of Foradil(®) or 9 and 27μg twice a day of Symbicort(®)), focusing also on the effects, on the measured levels of formoterol, of potential alteration processes (thermal and/or microbiological) that may take place after the collection of the urine samples. Urine sample preparation included an enzymatic hydrolysis and a dilution step. Detection of analytes was performed by a newly developed and validated direct LC-ESI-MS/MS procedure, using a triple quadrupole mass spectrometer under positive ion electro-spray ionization conditions and selected reaction monitoring acquisition mode. The results showed the capability and suitability of the direct LC-ESI-MS/MS analysis for the quantitative confirmation analysis of formoterol in urine samples. The data from the analysis of the urine samples obtained in the excretion studies showed that formoterol is excreted mainly as unmodified drug and to a lesser degree as O-demethylated metabolite. The urinary levels of formoterol (40-60%) and its metabolites (O-demethylated metabolite 5-25%; glucuronide metabolites 25-40%) vary significantly depending both on the administered drug formulation and the subject tested. The maximum urinary concentration reached in this study was 15ng/mL (free+glucuronide), that is significantly lower than the threshold value fixed to report an adverse analytical finding. Finally, our results also showed that formoterol is

  3. Bioavailability of Chlorocatechols in Naturally Contaminated Sediment Samples and of Chloroguaiacols Covalently Bound to C2-Guaiacyl Residues

    PubMed Central

    Allard, Ann-Sofie; Hynning, Per-Åke; Remberger, Mikael; Neilson, Alasdair H.

    1994-01-01

    Bacteria in anaerobic enrichment cultures that dechlorinated a range of chlorocatechols were used to examine the stability of endogenous chlorocatechols in a contaminated sediment sample and in interstitial water prepared from it. During incubation of the sediment sample for 450 days with or without added cells, there was a decrease in the concentration of solvent-extractable chlorocatechols but not in that of the total chlorocatechols, including sediment-associated components. In the presence of azide, the decrease in the concentrations of the former was eliminated or substantially decreased. Control experiments in which 3,4,5-trichlorocatechol was added to the sediment suspensions after 130 days showed that its dechlorination was accomplished not only by the added cells but also by the endemic microbial flora. It was concluded that the endogenous chlorocatechols in the sediment were not accessible to microorganisms with dechlorinating activity. On the other hand, microorganisms were apparently responsible for decreasing the solvent extractability of the chlorocatechols, and this effect decreased with increasing length of exposure time. Similar experiments carried out for 70 days with the sediment interstitial water showed that the chlorocatechols that were known to be associated with organic matter were also inaccessible to microbial dechlorination. Experiments with model compounds in which 4,5,6-trichloroguaiacol and tetrachloroguaiacol were covalently linked to C2-guaiacyl residues showed that these compounds were resistant to O demethylation or dechlorination during incubation with a culture having these activities. The only effect of microbial action was the quantitative reduction in 12 days of the C′1 keto group to an alcohol which was stable against further transformation for up to 65 days. The results of these experiments are consistent with the existence of chlorocatechols and chloroguaiacols in contaminated sediments and illustrate the cardinal

  4. Farnesoid X Receptor Agonist Represses Cytochrome P450 2D6 Expression by Upregulating Small Heterodimer Partner.

    PubMed

    Pan, Xian; Lee, Yoon-Kwang; Jeong, Hyunyoung

    2015-07-01

    Cytochrome P450 2D6 (CYP2D6) is a major drug-metabolizing enzyme responsible for eliminating approximately 20% of marketed drugs. Studies have shown that differential transcriptional regulation of CYP2D6 may contribute to large interindividual variability in CYP2D6-mediated drug metabolism. However, the factors governing CYP2D6 transcription are largely unknown. We previously demonstrated small heterodimer partner (SHP) as a novel transcriptional repressor of CYP2D6 expression. SHP is a representative target gene of the farnesoid X receptor (FXR). The objective of this study is to investigate whether an agonist of FXR, 3-(2,6-dichlorophenyl)-4-(3'-carboxy-2-chlorostilben-4-yl)oxymethyl-5-isopropylisoxazole (GW4064), alters CYP2D6 expression and activity. In CYP2D6-humanized transgenic mice, GW4064 decreased hepatic CYP2D6 expression and activity (by 2-fold) while increasing SHP expression (by 2-fold) and SHP recruitment to the CYP2D6 promoter. CYP2D6 repression by GW4064 was abrogated in Shp(-/-);CYP2D6 mice, indicating a critical role of SHP in CYP2D6 regulation by GW4064. Also, GW4064 decreased CYP2D6 expression (by 2-fold) in primary human hepatocytes, suggesting that the results obtained in CYP2D6-humanized transgenic mice can be translated to humans. This proof of concept study provides evidence for CYP2D6 regulation by an inducer of SHP expression, namely, the FXR agonist GW4064. PMID:25926433

  5. Inhibitory Effects of Aschantin on Cytochrome P450 and Uridine 5'-diphospho-glucuronosyltransferase Enzyme Activities in Human Liver Microsomes.

    PubMed

    Kwon, Soon-Sang; Kim, Ju-Hyun; Jeong, Hyeon-Uk; Cho, Yong Yeon; Oh, Sei-Ryang; Lee, Hye Suk

    2016-01-01

    Aschantin is a bioactive neolignan found in Magnolia flos with antiplasmodial, Ca(2+)-antagonistic, platelet activating factor-antagonistic, and chemopreventive activities. We investigated its inhibitory effects on the activities of eight major human cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes of human liver microsomes to determine if mechanistic aschantin-enzyme interactions were evident. Aschantin potently inhibited CYP2C8-mediated amodiaquine N-de-ethylation, CYP2C9-mediated diclofenac 4'-hydroxylation, CYP2C19-mediated [S]-mephenytoin 4'-hydroxylation, and CYP3A4-mediated midazolam 1'-hydroxylation, with Ki values of 10.2, 3.7, 5.8, and 12.6 µM, respectively. Aschantin at 100 µM negligibly inhibited CYP1A2-mediated phenacetin O-de-ethylation, CYP2A6-mediated coumarin 7-hydroxylation, CYP2B6-mediated bupropion hydroxylation, and CYP2D6-mediated bufuralol 1'-hydroxylation. At 200 µM, it weakly inhibited UGT1A1-catalyzed SN-38 glucuronidation, UGT1A6-catalyzed N-acetylserotonin glucuronidation, and UGT1A9-catalyzed mycophenolic acid glucuronidation, with IC50 values of 131.7, 144.1, and 71.0 µM, respectively, but did not show inhibition against UGT1A3, UGT1A4, or UGT2B7 up to 200 µM. These in vitro results indicate that aschantin should be examined in terms of potential interactions with pharmacokinetic drugs in vivo. It exhibited potent mechanism-based inhibition of CYP2C8, CYP2C9, CYP2C19, and CYP3A4. PMID:27128896

  6. Fipronil induces CYP isoforms in rats.

    PubMed

    Caballero, M V; Ares, I; Martínez, M; Martínez-Larrañaga, M R; Anadón, A; Martínez, M A

    2015-09-01

    The goal of the present study was to evaluate fipronil effects on the activities of drug metabolizing enzymes in rat liver microsomes. Rats were orally treated with fipronil at doses of 1, 5, 10 and 15 mg/kg bw/day for 6 days. Determinations of cytochrome P450 (CYP) enzyme activities were carried out in hepatic microsomes isolated from treated rats. The activities of some members of CYP2E, CYP1A, CYP2A, CYP2B and CYP3A subfamilies significantly increased after fipronil treatment in a dose-dependent manner as compared to control. The major effects were observed in the O-deethylation of ethoxyresorufin and O-demethylation of methoxyresorufin (reflecting CYP1A1/2 activities), in the O-depenthylation of pentoxyresorufin and 16β-hydroxylation of testosterone (reflecting CYP2B1/2 activities), and in the N-demethylation of erythromycin and 6β-hydroxylation of testosterone (reflecting CYP3A1/2 activities). Immunoblot studies revealed that fipronil increased the apoprotein levels of CYP1A1. Our results suggest that fipronil is an inducer of hepatic phase I CYP enzymes, causing an increased potential to interact with a wide range of xenobiotics or endogenous chemicals that are substrates of the CYP1A, CYP2B and CYP3A subfamilies. Further investigations are required to in vivo evaluate the potential of the metabolite fipronil sulfone as an inducer of phase I CYP enzymes. PMID:26142839

  7. Carbon-carbon bond cleavage in activation of the prodrug nabumetone.

    PubMed

    Varfaj, Fatbardha; Zulkifli, Siti N A; Park, Hyoung-Goo; Challinor, Victoria L; De Voss, James J; Ortiz de Montellano, Paul R

    2014-05-01

    Carbon-carbon bond cleavage reactions are catalyzed by, among others, lanosterol 14-demethylase (CYP51), cholesterol side-chain cleavage enzyme (CYP11), sterol 17β-lyase (CYP17), and aromatase (CYP19). Because of the high substrate specificities of these enzymes and the complex nature of their substrates, these reactions have been difficult to characterize. A CYP1A2-catalyzed carbon-carbon bond cleavage reaction is required for conversion of the prodrug nabumetone to its active form, 6-methoxy-2-naphthylacetic acid (6-MNA). Despite worldwide use of nabumetone as an anti-inflammatory agent, the mechanism of its carbon-carbon bond cleavage reaction remains obscure. With the help of authentic synthetic standards, we report here that the reaction involves 3-hydroxylation, carbon-carbon cleavage to the aldehyde, and oxidation of the aldehyde to the acid, all catalyzed by CYP1A2 or, less effectively, by other P450 enzymes. The data indicate that the carbon-carbon bond cleavage is mediated by the ferric peroxo anion rather than the ferryl species in the P450 catalytic cycle. CYP1A2 also catalyzes O-demethylation and alcohol to ketone transformations of nabumetone and its analogs. PMID:24584631

  8. Pharmacokinetic and metabolism studies of the antiarrhythmic drug meobentine (N-(4-methoxybenzyl)-N prime , N double prime -dimethylguanidine) and its N-(4-trifluoromethyoxybenzyl)-N prime , N double prime - dimethylguanidine analogue, fluorobentine in the rat, dog and man

    SciTech Connect

    Warren, J.T.

    1988-01-01

    A radioimmunoassay (RIA) was developed that was able to detect 40 pg meobentine (M) in 0.1 ml plasma. Cross-reactivity of suspected M metabolites was very low. This RIA was later also used to assay for fluorobentine (F), a fluorine analogue of M. M exhibits three-compartment open model iv kinetics in the rat, dog, and man. Terminal drug half-life in the rat, dog, and man; total-body clearance in the rat, dog, and man; and terminal-phase volume of distribution in the rat, dog, and man were determined. (14C)-M absorption is essentially complete in the rat and dog, but this parameter could not be directly ascertained in man. Relative oral drug bioavailability is linear in the rat and dog but falls off between 5-10 mg/kg in man. F was synthesized in an attempt to counteract suspected problems with M's poor absorption or extensive metabolism that might be affecting its efficacy in humans. F would likely be unavailable for O-demethylation, might well be more lipophilic than M, and yet still be active.

  9. In vitro cytotoxic activity of isolated acridones alkaloids from Zanthoxylum leprieurii Guill. et Perr.

    PubMed

    Ngoumfo, Rostand M; Jouda, Jean-Bosco; Mouafo, Ferdinand T; Komguem, Justin; Mbazoa, Céline D; Shiao, Tze Chieh; Choudhary, Mohammed I; Laatsch, Hartmut; Legault, Jean; Pichette, André; Roy, René

    2010-05-15

    Chemical investigation of the roots and fruits of Zanthoxylumleprieurii Guill. et Perr. led to the isolation of three new alkaloids including two acridone derivatives, 3-hydroxy-1,4-dimethoxy-10-methyl-9-acridone (2) and 3-hydroxy-1,2-dimethoxy-10-methyl-9-acridone (3) named helebelicine A and B, respectively, and one secobenzo[c]phenantridine, 10-O-demethyl-12-O-methylarnottianamide (10), together with thirteen other compounds. The structures of compounds 2, 3 and 10 as well as those of the known compounds were elucidated by using spectroscopic methods and by comparison with reported data. The brine-shrimp (artemia salina) lethality bioassay of the chloroform extract of the fruits showed modest cytotoxicity with LD(50) at 13.1microg/mL. Isolated compounds 1, 4-6 were found to be moderately active against lung carcinoma cells (A549), colorectal adenocarcinoma cells (DLD-1) and normal cells (WS1) with IC(50) values ranging from 27 to 77microM. In contrast to the positive control etoposide used, the cytotoxicity of the most active compound 4 was found to be selective against cancer cells in comparison to normal cells WS1 with IC(50) of 51+/-8microM and 4.3+/-0.4microM, respectively. PMID:20413315

  10. Urinary metabolites of isorhynchophylline in rats and their neuroprotective activities in the HT22 cell assay

    PubMed Central

    Chen, Fangfang; Qi, Wen; Sun, Jiahong; Simpkins, James W.; Yuan, Dan

    2015-01-01

    Isorhynchophylline is one of the major alkaloids from the Uncaria hook possessing the effects of lowered blood pressure, vasodilatation and protection against ischemia-induced neuronal damage. However, the metabolic pathway of isorhynchophylline has not been fully reported yet. In this paper, the metabolism of isorhynchophylline was investigated in rats. Five metabolites were isolated by using solvent extraction and repeated chromatographic methods, and identified by spectroscopic methods including UV, MS, NMR and CD experiments. Three new compounds were identified as 5-oxoisorhynchophyllic acid-22-O-β-D-glucuronide (M1), 17-O-demethyl-16,17-dihydro isorhynchophylline (M2) and 5-oxoisorhynchophyllic acid (M4) together with two known compounds isorhynchophylline (M0) and rhynchophylline (M3). Possible metabolic pathways of isorhynchophylline are proposed. Furthermore, the activity assay for all the metabolites showed that isorhynchophylline (M0) exhibited potent neuroprotective effects against glutamate-induced HT22 cell death. However, little or weak neuroprotective activities were observed for M1–M4. Our present study is important to further understand its metabolic fate and disposition in humans. PMID:24910000

  11. Studies on the metabolism of mitragynine, the main alkaloid of the herbal drug Kratom, in rat and human urine using liquid chromatography-linear ion trap mass spectrometry.

    PubMed

    Philipp, Anika A; Wissenbach, Dirk K; Zoerntlein, Siegfried W; Klein, Oliver N; Kanogsunthornrat, Jidapha; Maurer, Hans H

    2009-08-01

    Mitragynine (MG) is an indole alkaloid of the Thai medicinal plant Mitragyna speciosa (Kratom in Thai) and reported to have opioid agonistic properties. Because of its stimulant and euphoric effects, Kratom is used as a herbal drug of abuse. The aim of the presented study is to identify the phase I and II metabolites of MG in rat and human urine after solid-phase extraction (SPE) using liquid chromatography-linear ion trap mass spectrometry providing detailed structure information in the MSn mode particularly with high resolution. The seven identified phase I metabolites indicated that MG was metabolized by hydrolysis of the methylester in position 16, O-demethylation of the 9-methoxy group and of the 17-methoxy group, followed, via the intermediate aldehydes, by oxidation to carboxylic acids or reduction to alcohols and combinations of some steps. In rats, four metabolites were additionally conjugated to glucuronides and one to sulfate, but in humans, three metabolites to glucuronides and three to sulfates. PMID:19536806

  12. Isolation and Identification of Twelve Metabolites of Isocorynoxeine in Rat Urine and their Neuroprotective Activities in HT22 Cell Assay

    PubMed Central

    Qi, Wen; Chen, Fangfang; Sun, Jiahong; Simpkins, James W.; Yuan, Dan

    2015-01-01

    Isocorynoxeine, one of the major alkaloids from Uncaria Hook, shows the effects of lowering blood pressure, vasodilatation, and protection against ischemia-induced neuronal damage. In this paper, the metabolism of isocorynoxeine was investigated in rats. Twelve metabolites and the parent drug were isolated by using solvent extraction and repeated chromatographic methods, and determined by spectroscopic methods including UV, MS, NMR, and CD experiments. Seven new compounds were identified as 11-hydroxyisocorynoxeine, 5-oxoisocorynoxeinic acid-22-O-β-D-glucuronide, 10-hydroxyisocorynoxeine, 17-O-demethyl-16,17-dihydro-5-oxoisocorynoxeine, 5-oxoisocorynoxeinic acid, 21-hydroxy-5-oxoisocorynoxeine, and oxireno[18,19]-5-oxoisocorynoxeine, together with six known compounds identified as isocorynoxeine, 18,19-dehydrocorynoxinic acid, 18,19-dehydrocorynoxinic acid B, corynoxeine, isocorynoxeine-N-oxide, and corynoxeine-N-oxide. Possible metabolic pathways of isocorynoxeine are proposed. Furthermore, the activity assay for the parent drug and some of its metabolites showed that isocorynoxeine exhibited a significant neuroprotective effect against glutamate-induced HT22 cell death at the maximum concentration. However, little or weak neuroprotective activities were observed for M-3, M-6, M-7, and M-10. Our present study is important to further understand their metabolic fate and disposition in humans. PMID:25519834

  13. Jacobsen Catalyst as a Cytochrome P450 Biomimetic Model for the Metabolism of Monensin A

    PubMed Central

    Rocha, Bruno Alves; de Oliveira, Anderson Rodrigo Moraes; Pazin, Murilo; Dorta, Daniel Junqueira; Rodrigues, Andresa Piacezzi Nascimento; Berretta, Andresa Aparecida; Peti, Ana Paula Ferranti; de Moraes, Luiz Alberto Beraldo; Lopes, Norberto Peporine; Pospíšil, Stanislav; Gates, Paul Jonathan; Assis, Marilda das Dores

    2014-01-01

    Monensin A is a commercially important natural product isolated from Streptomyces cinnamonensins that is primarily employed to treat coccidiosis. Monensin A selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. In this study, we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model to investigate the oxidation of monensin A. Mass spectrometry analysis of the products from these model systems revealed the formation of two products: 3-O-demethyl monensin A and 12-hydroxy monensin A, which are the same ones found in in vivo models. Monensin A and products obtained in biomimetic model were tested in a mitochondrial toxicity model assessment and an antimicrobial bioassay against Staphylococcus aureus, S. aureus methicillin-resistant, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Our results demonstrated the toxicological effects of monensin A in isolated rat liver mitochondria but not its products, showing that the metabolism of monensin A is a detoxification metabolism. In addition, the antimicrobial bioassay showed that monensin A and its products possessed activity against Gram-positive microorganisms but not for Gram-negative microorganisms. The results revealed the potential of application of this biomimetic chemical model in the synthesis of drug metabolites, providing metabolites for biological tests and other purposes. PMID:24987668

  14. Conversion of spinosyn A and spinosyn D to their respective 9- and 17-pseudoaglycones and their aglycones.

    PubMed

    Creemer, L C; Kirst, H A; Paschal, J W

    1998-08-01

    Forosamine at the 17-position of spinosyns A and D was hydrolyzed under mild acidic conditions to give the corresponding 17-pseudoaglycones. The tri-O-methylrhamnose at the 9-position of the 17-pseudoaglycone of spinosyn A was hydrolyzed under more vigorous acidic conditions to give the aglycone of spinosyn A. However, these conditions led to decomposition of the 17-pseudoaglycone of spinosyn D, presumably due to more facile protonation of the 5,6-double bond to produce a tertiary carbonium ion which undergoes further rearrangements. Spinosyns J and L (3'-O-demethyl spinosyn A and D, respectively) obtained from fermentation of biosynthetically-blocked mutant strains of Saccharopolyspora spinosa, were oxidized to give the corresponding 3'-keto-derivatives and the resultant keto-sugars were then beta-eliminated under basic conditions to give the 9-pseudoaglycones of spinosyns A and D respectively. Forosamine at the 17-position of the 9-pseudoaglycone of spinosyn D was then readily hydrolyzed to yield the aglycone of spinosyn D. PMID:9766471

  15. Acetylcholinesterase and carbonic anhydrase inhibitory properties of novel urea and sulfamide derivatives incorporating dopaminergic 2-aminotetralin scaffolds.

    PubMed

    Özgeriş, Bünyamin; Göksu, Süleyman; Polat Köse, Leyla; Gülçin, İlhami; Salmas, Ramin Ekhteiari; Durdagi, Serdar; Tümer, Ferhan; Supuran, Claudiu T

    2016-05-15

    In the present study a series of urea and sulfamide compounds incorporating the tetralin scaffolds were synthesized and evaluated for their acetylcholinesterase (AChE), human carbonic anhydrase (CA, EC 4.2.1.1) isoenzyme I, and II (hCA I and hCA II) inhibitory properties. The urea and their sulfamide analogs were synthesized from the reactions of 2-aminotetralins with N,N-dimethylcarbamoyl chloride and N,N-dimethylsulfamoyl chloride, followed by conversion to the corresponding phenols via O-demethylation with BBr3. The novel urea and sulfamide derivatives were tested for inhibition of hCA I, II and AChE enzymes. These derivatives exhibited excellent inhibitory effects, in the low nanomolar range, with Ki values of 2.61-3.69nM against hCA I, 1.64-2.80nM against hCA II, and in the range of 0.45-1.74nM against AChE. In silico techniques such as, atomistic molecular dynamics (MD) and molecular docking simulations, were used to understand the scenario of the inhibition mechanism upon approaching of the ligands into the active site of the target enzymes. In light of the experimental and computational results, crucial amino acids playing a role in the stabilization of the enzyme-inhibitor adducts were identified. PMID:27068142

  16. New TFO conjugates containing a carminomycinone-derived chromophore.

    PubMed

    Capobianco, M L; De Champdoré, M; Francini, L; Lena, S; Garbesi, A; Arcamone, F

    2001-01-01

    Conjugates obtained by linking the anthracycline intercalating chromophore to triple helix forming oligonucleotides (TFOs) have been used in a physicochemical study of the stability of triple helices with DNA sequences of pharmacological relevance. The intercalating moiety is represented by carminomycinone derivatives obtained upon O-demethylation and hydrolysis of the glycosidic linkage of daunomycin followed by the introduction of an alkylating residue at two different positions. Results of experiments with a polypurinic region present in the multidrug resistance (MDR) gene indicate that the stability of the triple helix is significantly enhanced by replacement of C's with (5-Me)C's in the TFO sequences tested. The stability is not changed when a 3'-TpT is present in place of a 3'-CpG at the presumed intercalation site of the anthraquinone chromophore. The same carminomycinone derivatives were used for the preparation of conjugates able to form triple helices with the polypurine tract (PPT) present in the human integrated genome of HIV-1 infected cells. Three different TFOs (T(4)(Me)CT(4)(Me)CC, C2; T(4)(Me)CT(4)(Me)CC(Me)CC(Me)CCT, C6; and T(4)(Me)CT(4)G(6), G6) were designed and linked to the anthraquinone moiety. These conjugates showed a significantly enhanced ability to bind the PPT region of HIV with respect to the nonconjugated TFOs. PMID:11459456

  17. Codeine increases pain thresholds to copper vapor laser stimuli in extensive but not poor metabolizers of sparteine.

    PubMed

    Sindrup, S H; Brøsen, K; Bjerring, P; Arendt-Nielsen, L; Larsen, U; Angelo, H R; Gram, L F

    1990-12-01

    The analgesic efficacy and kinetics of a single oral dose of 75 mg codeine was investigated in 12 extensive metabolizers and 12 poor metabolizers of sparteine in a double-blind, placebo-controlled crossover study. The cosegregation of the O-demethylation of codeine to morphine with the sparteine oxidation polymorphism was confirmed. Hence morphine could not be detected in the plasma of any of the poor metabolizers, whereas detectable morphine plasma levels were found in 10 of 12 extensive metabolizers. Pain thresholds to laser stimuli were determined before drug intake and 90, 150, and 210 minutes after drug intake. Codeine significantly increased the pricking pain thresholds in the extensive metabolizers (p less than 0.05), whereas there were no significant changes in the poor metabolizers. No change in pain thresholds occurred with placebo in any of the two phenotypes. In the extensive metabolizers there was a significant positive correlation between the increase in pain threshold and plasma concentration of codeine. The study supports the hypothesis that morphine formation is essential for achievement of analgesia during codeine treatment. PMID:2249379

  18. Methanogenic degradation of lignin-derived monoaromatic compounds by microbial enrichments from rice paddy field soil.

    PubMed

    Kato, Souichiro; Chino, Kanako; Kamimura, Naofumi; Masai, Eiji; Yumoto, Isao; Kamagata, Yoichi

    2015-01-01

    Anaerobic degradation of lignin-derived aromatics is an important metabolism for carbon and nutrient cycles in soil environments. Although there are some studies on degradation of lignin-derived aromatics by nitrate- and sulfate-reducing bacteria, knowledge on their degradation under methanogenic conditions are quite limited. In this study, methanogenic microbial communities were enriched from rice paddy field soil with lignin-derived methoxylated monoaromatics (vanillate and syringate) and their degradation intermediates (protocatechuate, catechol, and gallate) as the sole carbon and energy sources. Archaeal community analysis disclosed that both aceticlastic (Methanosarcina sp.) and hydrogenotrophic (Methanoculleus sp. and Methanocella sp.) methanogens dominated in all of the enrichments. Bacterial community analysis revealed the dominance of acetogenic bacteria (Sporomusa spp.) only in the enrichments on the methoxylated aromatics, suggesting that Sporomusa spp. initially convert vanillate and syringate into protocatechuate and gallate, respectively, with acetogenesis via O-demethylation. As the putative ring-cleavage microbes, bacteria within the phylum Firmicutes were dominantly detected from all of the enrichments, while the dominant phylotypes were not identical between enrichments on vanillate/protocatechuate/catechol (family Peptococcaceae bacteria) and on syringate/gallate (family Ruminococcaceae bacteria). This study demonstrates the importance of cooperation among acetogens, ring-cleaving fermenters/syntrophs and aceticlastic/hydrogenotrophic methanogens for degradation of lignin-derived aromatics under methanogenic conditions. PMID:26399549

  19. Psychedelic 5-Methoxy-N,N-dimethyltryptamine: Metabolism, Pharmacokinetics, Drug Interactions, and Pharmacological Actions

    PubMed Central

    Shen, Hong-Wu; Jiang, Xi-Ling; Winter, Jerrold C.; Yu, Ai-Ming

    2011-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) belongs to a group of naturally-occurring psychoactive indolealkylamine drugs. It acts as a nonselective serotonin (5-HT) agonist and causes many physiological and behavioral changes. 5-MeO-DMT is O-demethylated by polymorphic cytochrome P450 2D6 (CYP2D6) to an active metabolite, bufotenine, while it is mainly inactivated through the deamination pathway mediated by monoamine oxidase A (MAO-A). 5-MeO-DMT is often used with MAO-A inhibitors such as harmaline. Concurrent use of harmaline reduces 5-MeO-DMT deamination metabolism and leads to a prolonged and increased exposure to the parent drug 5-MeO-DMT, as well as the active metabolite bufotenine. Harmaline, 5-MeO-DMT and bufotenine act agonistically on serotonergic systems and may result in hyperserotonergic effects or serotonin toxicity. Interestingly, CYP2D6 also has important contribution to harmaline metabolism, and CYP2D6 genetic polymorphism may cause considerable variability in the metabolism, pharmacokinetics and dynamics of harmaline and its interaction with 5-MeO-DMT. Therefore, this review summarizes recent findings on biotransformation, pharmacokinetics, and pharmacological actions of 5-MeO-DMT. In addition, the pharmacokinetic and pharmacodynamic drug-drug interactions between harmaline and 5-MeO-DMT, potential involvement of CYP2D6 pharmacogenetics, and risks of 5-MeO-DMT intoxication are discussed. PMID:20942780

  20. Psychedelic 5-methoxy-N,N-dimethyltryptamine: metabolism, pharmacokinetics, drug interactions, and pharmacological actions.

    PubMed

    Shen, Hong-Wu; Jiang, Xi-Ling; Winter, Jerrold C; Yu, Ai-Ming

    2010-10-01

    5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) belongs to a group of naturally-occurring psychoactive indolealkylamine drugs. It acts as a nonselective serotonin (5-HT) agonist and causes many physiological and behavioral changes. 5-MeO-DMT is O-demethylated by polymorphic cytochrome P450 2D6 (CYP2D6) to an active metabolite, bufotenine, while it is mainly inactivated through the deamination pathway mediated by monoamine oxidase A (MAO-A). 5-MeO-DMT is often used with MAO-A inhibitors such as harmaline. Concurrent use of harmaline reduces 5-MeO-DMT deamination metabolism and leads to a prolonged and increased exposure to the parent drug 5-MeO-DMT, as well as the active metabolite bufotenine. Harmaline, 5-MeO-DMT and bufotenine act agonistically on serotonergic systems and may result in hyperserotonergic effects or serotonin toxicity. Interestingly, CYP2D6 also has important contribution to harmaline metabolism, and CYP2D6 genetic polymorphism may cause considerable variability in the metabolism, pharmacokinetics and dynamics of harmaline and its interaction with 5-MeO-DMT. Therefore, this review summarizes recent findings on biotransformation, pharmacokinetics, and pharmacological actions of 5-MeO-DMT. In addition, the pharmacokinetic and pharmacodynamic drug-drug interactions between harmaline and 5-MeO-DMT, potential involvement of CYP2D6 pharmacogenetics, and risks of 5-MeO-DMT intoxication are discussed. PMID:20942780

  1. Inhibition of mixed function oxidases in rat liver by trans- and cis-1,2-dichloroethylene.

    PubMed

    Freundt, K J; Macholz, J

    1978-06-01

    A single 8-h exposure to trans-1,2-dichloroethylene (t-DCE) or cis-1,2-dichloroethylene (c-DCE) at 200 ppm (hygienic standard in workplaces) resulted in a significant increase in the hexobarbital sleeping time, the zoxazolamine paralysis time, and the metabolic formation of 4-aminoantipyrine from aminopyrine in adult female Wistar rats. Higher DCE concentrations caused a dose-dependent and substantial enhancement of these effects, the effects of c-DCE being stronger than that of t-DCE. In the course of enzyme-kinetic measurements in isolated rat liver microsomes, t-DCE proved to be a competitive inhibitor of the oxidative N-demethylation of aminopyrine and of the O-demethylation of p-nitroanisole. It is concluded from the results that the inhibition of hepatic drug metabolism is caused by a competitive and reversible interaction of the 2 DCE isomers with the mixed-function oxidase system, the interaction possibly operating at the type I binding site. PMID:684758

  2. Methanogenic degradation of lignin-derived monoaromatic compounds by microbial enrichments from rice paddy field soil

    PubMed Central

    Kato, Souichiro; Chino, Kanako; Kamimura, Naofumi; Masai, Eiji; Yumoto, Isao; Kamagata, Yoichi

    2015-01-01

    Anaerobic degradation of lignin-derived aromatics is an important metabolism for carbon and nutrient cycles in soil environments. Although there are some studies on degradation of lignin-derived aromatics by nitrate- and sulfate-reducing bacteria, knowledge on their degradation under methanogenic conditions are quite limited. In this study, methanogenic microbial communities were enriched from rice paddy field soil with lignin-derived methoxylated monoaromatics (vanillate and syringate) and their degradation intermediates (protocatechuate, catechol, and gallate) as the sole carbon and energy sources. Archaeal community analysis disclosed that both aceticlastic (Methanosarcina sp.) and hydrogenotrophic (Methanoculleus sp. and Methanocella sp.) methanogens dominated in all of the enrichments. Bacterial community analysis revealed the dominance of acetogenic bacteria (Sporomusa spp.) only in the enrichments on the methoxylated aromatics, suggesting that Sporomusa spp. initially convert vanillate and syringate into protocatechuate and gallate, respectively, with acetogenesis via O-demethylation. As the putative ring-cleavage microbes, bacteria within the phylum Firmicutes were dominantly detected from all of the enrichments, while the dominant phylotypes were not identical between enrichments on vanillate/protocatechuate/catechol (family Peptococcaceae bacteria) and on syringate/gallate (family Ruminococcaceae bacteria). This study demonstrates the importance of cooperation among acetogens, ring-cleaving fermenters/syntrophs and aceticlastic/hydrogenotrophic methanogens for degradation of lignin-derived aromatics under methanogenic conditions. PMID:26399549

  3. Mechanisms underlying the inhibition of the cytochrome P450 system by copper ions.

    PubMed

    Letelier, M E; Faúndez, M; Jara-Sandoval, J; Molina-Berríos, A; Cortés-Troncoso, J; Aracena-Parks, P; Marín-Catalán, R

    2009-11-01

    Copper toxicity has been associated to the capacity of free copper ions to catalyze the production of superoxide anion and hydroxyl radical, reactive species that modify the structure and/or function of biomolecules. In addition, nonspecific Cu2+-binding to thiol enzymes, which modifies their catalytic activities, has been reported. Cytochrome P450 (CYP450) monooxygenase is a thiol protein that binds substrates in the first and limiting step of CYP450 system catalytic cycle, necessary for the metabolism of lipophilic xenobiotics. Therefore, copper ions have the potential to oxidize and bind to cysteinyl residues of this monooxygenase, altering the CYP450 system activity. To test this postulate, we studied the effect of Cu2+ alone and Cu2+/ascorbate in rat liver microsomes, to independently evaluate its nonspecific binding and its pro-oxidant effects, respectively. We assessed these effects on the absorbance spectrum of the monooxygenase, as a measure of structural damage, and p-nitroanisole O-demethylating activity of CYP450 system, as a marker of functional impairment. Data obtained indicate that Cu2+ could both oxidize and bind to some amino acid residues of the CYP450 monooxygenase but not to its heme group. The differences observed between the effects of Cu2+ and Cu2+/ascorbate show that both mechanisms are involved in the catalytic activity inhibition of CYP450 system by copper ions. The significance of these findings on the pharmacokinetics and pharmacodynamics of drugs is discussed. PMID:19629952

  4. In vitro Phase I and Phase II metabolism of α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV) and methedrone by human liver microsomes and human liver cytosol.

    PubMed

    Negreira, Noelia; Erratico, Claudio; Kosjek, Tina; van Nuijs, Alexander L N; Heath, Ester; Neels, Hugo; Covaci, Adrian

    2015-07-01

    The aim of the present study was to identify the in vitro Phase I and Phase II metabolites of three new psychoactive substances: α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV), and methedrone, using human liver microsomes and human liver cytosol. Accurate-mass spectra of metabolites were obtained using liquid chromatography-quadrupole time-of-flight mass spectrometry. Six Phase I metabolites of α-PVP were identified, which were formed involving reduction, hydroxylation, and pyrrolidine ring opening reactions. The lactam compound was the major metabolite observed for α-PVP. Two glucuronidated metabolites of α-PVP, not reported in previous in vitro studies, were further identified. MDPV was transformed into 10 Phase I metabolites involving reduction, hydroxylation, and loss of the pyrrolidine ring. Also, six glucuronidated and two sulphated metabolites were detected. The major metabolite of MDPV was the catechol metabolite. Methedrone was transformed into five Phase I metabolites, involving N- and O-demethylation, hydroxylation, and reduction of the ketone group. Three metabolites of methedrone are reported for the first time. In addition, the contribution of individual human CYP enzymes in the formation of the detected metabolites was investigated. PMID:26014283

  5. Identification of a Ruminococcaceae Species as the Methyl tert-Butyl Ether (MTBE) Degrading Bacterium in a Methanogenic Consortium.

    PubMed

    Liu, Tong; Ahn, Hyeri; Sun, Weimin; McGuinness, Lora R; Kerkhof, Lee J; Häggblom, Max M

    2016-02-01

    The widespread use of methyl tert-butyl ether (MTBE) has caused major contamination of groundwater sources and is a concern due to its taste and odor problems, as well as its toxicity. MTBE can be degraded anaerobically which makes bioremediation of contaminated aquifers a potential solution. Nevertheless, the organisms and mechanisms that are responsible for anaerobic MTBE degradation are still unknown. The aim of our research was to identify the organisms actively degrading MTBE. For this purpose we characterized an anaerobic methanogenic culture enriched with MTBE as the sole carbon source from the New Jersey Arthur Kill intertidal strait sediment. The cultures were analyzed using stable isotope probing (SIP) combined with terminal restriction fragment length polymorphism (T-RFLP), high-throughput sequencing and clone library analysis of bacterial 16S rRNA genes. The sequence data indicated that phylotypes belonging to the Ruminococcaceae in the Firmicutes were predominant in the methanogenic cultures. SIP experiments also showed sequential incorporation of the (13)C labeled MTBE by the bacterial community with a bacterium most closely related to Saccharofermentans acetigenes identified as the bacterium active in O-demethylation of MTBE. Identification of the microorganisms responsible for the activity will help us better understand anaerobic MTBE degradation processes in the field and determine biomarkers for monitoring natural attenuation. PMID:26727046

  6. (Bio)transformation of 2,4-dinitroanisole (DNAN) in soils.

    PubMed

    Olivares, Christopher I; Abrell, Leif; Khatiwada, Raju; Chorover, Jon; Sierra-Alvarez, Reyes; Field, Jim A

    2016-03-01

    Recent studies have begun to assess the environmental fate and toxicity of 2,4-dinitroanisole (DNAN), an insensitive munition compound of interest to defense agencies. Aerobic and anaerobic DNAN biotransformation in soils was evaluated in this study. Under aerobic conditions, there was little evidence of transformation; most observed removal was attributed to adsorption and subsequent slow chemical reactions. Under anaerobic conditions, DNAN was reductively (bio)transformed and the rate of the transformation was positively correlated with soil organic carbon (OC) up to a threshold of 2.07% OC. H2 addition enhanced the nitroreduction rate compared to endogenous treatments lacking H2. Heat-killed treatments provided rates similar to the endogenous treatment, suggesting that abiotic factors play a role in DNAN reduction. Ten (bio)transformation products were detected by high-resolution mass spectrometry. The proposed transformation pathway involves reduction of DNAN to aromatic amines, with putative reactive nitroso-intermediates coupling with the amines to form azo dimers. Secondary reactions include N-alkyl substitution, O-demethylation (sometimes followed by dehydroxylation), and removal of an N-containing group. Globally, our results suggest that the main reaction DNAN undergoes in anaerobic soils is nitroreduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by anaerobic coupling reactions yielding azo-dimers. The dimers were subsequently subject to further (bio)transformations. PMID:26551225

  7. Urinary metabolites to assess in vivo ontogeny of hepatic drug metabolism in early neonatal life.

    PubMed

    Allegaert, K; Verbesselt, R; Rayyan, M; Debeer, A; de Hoon, J

    2007-05-01

    In addition to size-dependent allometric metabolic activity, most isoenzymes display age-dependent isoenzyme-specific ontogeny. We therefore need probe drugs to describe isoenzyme-specific ontogeny to develop more sophisticated, physiologically based models. We illustrate the feasibility and the relevance of in vivo assessment of hepatic metabolism, based on observations on urinary elimination of paracetamol and tramadol metabolites in neonates. On the basis of the observations on tramadol disposition, we were able to document that O-demethylation phenotypic activity developed sooner when compared with N-demethylation. During repeated administration of intravenous paracetamol, it was documented that, in addition to postmenstrual and postnatal age (PNA), repeated administration also contributed to the urinary excretion of glucuronidated paracetamol. In both probe drugs evaluated, age only in part explained the interindividual variability observed. Urine metabolites to assess in vivo metabolism of drugs routinely administered in neonates likely increase both the feasibility and clinical relevance of studies on in vivo isoenzyme-specific ontogeny in neonates. PMID:17609736

  8. Marmoset cytochrome P450 2J2 mainly expressed in small intestines and livers effectively metabolizes human P450 2J2 probe substrates, astemizole and terfenadine.

    PubMed

    Uehara, Shotaro; Uno, Yasuhiro; Inoue, Takashi; Okamoto, Eriko; Sasaki, Erika; Yamazaki, Hiroshi

    2016-11-01

    1. Common marmoset (Callithrix jacchus), a New World Monkey, has potential to be a useful animal model in preclinical studies. However, drug metabolizing properties have not been fully understood due to insufficient information on cytochrome P450 (P450), major drug metabolizing enzymes. 2. Marmoset P450 2J2 cDNA was isolated from marmoset livers. The deduced amino acid sequence showed a high-sequence identity (91%) with cynomolgus monkey and human P450 2J2 enzymes. A phylogenetic tree revealed that marmoset P450 2J2 was evolutionarily closer to cynomolgus monkey and human P450 2J2 enzymes, than P450 2J forms in pigs, rabbits, rats or mice. 3. Marmoset P450 2J2 mRNA was abundantly expressed in the small intestine and liver, and to a lesser extent in the brain, lung and kidney. Immunoblot analysis also showed expression of marmoset P450 2J2 protein in the small intestine and liver. 4. Enzyme assays using marmoset P450 2J2 protein heterologously expressed in Escherichia coli indicated that marmoset P450 2J2 effectively catalyzed astemizole O-demethylation and terfenadine t-butyl hydroxylation, similar to human and cynomolgus monkey P450 2J2 enzymes. 5. These results suggest the functional characteristics of P450 2J2 enzymes are similar among marmosets, cynomolgus monkeys and humans. PMID:26899760

  9. Identification of the metabolites of a new oxazolidinone MAO-A inhibitor in rat.

    PubMed

    Naitoh, T; Kakiki, M; Kozaki, T; Mishima, M; Yuzuriha, T; Horie, T

    1997-10-01

    1. Six metabolites present in rat urine after the oral administration of E2011 ((5R)-3-[2-((1S)-3-cyano-1-hydroxypropyl)benzothiazol-6-yl]-5-meth oxymethyl-2- oxazolidinone) were isolated with an Amberlite XAD-4 column and hplc, and termed HPM-1, HPM-2, HPM-31, HPM-32, HPM-33 and HPM-4. 2. To determine the correspondence of the findings of the metabolites between tlc (which was used in our previous study) and hplc, the six metabolites were isolated from rat urine after the administration of 14C-labelled E2011 with an Amberlite XAD-4 column and hplc, and then analysed by tlc. HPM-1, HPM-2, HPM-31, HPM-32, HPM-33 and HPM-4 were identified as IM7, IM3, IM4, IM2, IM1 and E2011, respectively. 3. The structures of the metabolites were identified with nmr and mass spectrometry. One of the compounds identified, HPM-4, was the unchanged drug, E2011, and HPM-2 was O-desmethyl-E2011. Another metabolite (HPM-33), the main metabolite in the urine, was identified as (4S)-hydroxy-E2011, and the others were (4S)-hydroxy-O-desmethyl-E2011 (HPM-1), 2"-hydroxy-E2011 (HPM-31) and (4R)-hydroxy-E2011 (HPM-32). 4. In conclusion, the main metabolic pathway of E2011 in the rat consisted of O-demethylation and hydroxylation. PMID:9364743

  10. Antiviral anthraquinones and azaphilones produced by an endophytic fungus Nigrospora sp. from Aconitum carmichaeli.

    PubMed

    Zhang, Shou-Peng; Huang, Rong; Li, Fang-Fang; Wei, Hong-Xia; Fang, Xiao-Wei; Xie, Xiao-Song; Lin, Dong-Guo; Wu, Shao-Hua; He, Jian

    2016-07-01

    A new hydroanthraquinone derivative, 6-O-demethyl-4-dehydroxyaltersolanol A (1), and two new azaphilones, 8,11-didehydrochermesinone B (6) and (7S)-7-hydroxy-3,7-dimethyl-isochromene-6,8-dione (8), along with five known analogues (2-5 and 7), were isolated from the culture broth of Nigrospora sp. YE3033, an endophytic fungus obtained from Aconitum carmichaeli. Their structures were elucidated on the basis of spectroscopic analyses. Biological activity test indicated that compounds 1-3, and 7 exhibited the inhibitory effects on influenza viral strain of A/Puerto Rico/8/34 (H1N1) with the IC50 values of 2.59, 8.35, 7.82, and 0.80μg/mL, respectively, while the low cytotoxicity of 7 with the CC50 value of 184.75μg/mL, displaying a promising potential of 7 in the development of anti-influenza A virus drugs. PMID:27233986

  11. Enzymatic aryl-O-methyl-/sup 14/C labeling of model lignin monomers

    SciTech Connect

    Frazer, A.C.; Bossert, I.; Young, L.Y.

    1986-01-01

    Aryl-O-methyl ethers are abundant in aerobic and anaerobic environments. In particular, lignin is composed of units of this type. Lignin monomers specifically radiolabeled in methoxy, side chain, and ring carbons have been synthesized by chemical procedures and are important in studies of lignin synthesis and degradation, humus formation, and microbial O-demethylation. In this paper attention is drawn to an enzymatic procedure for preparing O-methyl-/sup 14/C-labeled aromatic lignin monomers which has not previously been exploited in microbial ecology and physiology studies and which has several advantages compared with chemical synthesis procedures. O-(methyl-/sup 14/C)vanillic and O-(methyl-/sup 14/C)ferulic acids were prepared with S-(methyl-/sup 14/C)adenosyl-L-methionine as the methyl donor, using commercially obtained porcine liver catechol-O-methyltransferase (EC 2.1.1.6). The specific activity of the methylated products was the same as that of the methyl donor, a maximum of about 58 ..mu..Ci/..mu..mol, and the yields were 42% (vanillate) and 35% (ferulate). Thus lignin monomers are readily prepared as O-methylated products of the catechol-O-methyltransferase reaction and, with this enzyme method of preparation, would be more widely available than labeled compounds which require chemical synthesis.

  12. Metabolism of the carcinogen alpha-asarone in liver microsomes.

    PubMed

    Cartus, Alexander T; Schrenk, Dieter

    2016-01-01

    Alpha-asarone (1) is a naturally occurring phenylpropene found in several plants, e.g. Acorus calamus. 1-containing plant materials and essential oils thereof are used for flavoring foods and in many phytopharmaceuticals. 1 has been claimed to have positive pharmacological effects, however, it is carcinogenic in male mice (liver) and probably genotoxic. Since the metabolic pathways of 1 have not been investigated and its carcinogenic mode of action is unknown, we investigated the metabolism of 1 in liver microsomes of rat, bovine, porcine, and human origin using HPLC-DAD and LC-ESI-MS/MS and derived kinetic data on the metabolite formation. The main metabolic pathway was the side-chain hydroxylation leading to (E)-3'-hydroxyasarone (2). Epoxidation of 1 presumably led to (E)-asarone-1',2'-epoxide (4) which instantly hydrolyzed to form erythro- and threo-configured diols (5b+5a). As a minor reaction O-demethylation of 1 was observed. The metabolite formation showed little species-specific differences with the exception of porcine liver microsomes for which the formation of diols 5b+5a exceeded the formation of alcohol 2. The kinetic parameters imply a dependence of the pattern of metabolite formation from substrate concentration. On the basis of our results and earlier findings we hypothesize the genotoxic epoxide 4 being the ultimate carcinogen metabolically formed from 1. PMID:26678343

  13. Isolation and identification of twelve metabolites of isocorynoxeine in rat urine and their neuroprotective activities in HT22 cell assay.

    PubMed

    Qi, Wen; Chen, Fangfang; Sun, Jiahong; Simpkins, James W; Yuan, Dan

    2015-01-01

    Isocorynoxeine, one of the major alkaloids from Uncaria Hook, shows the effects of lowering blood pressure, vasodilatation, and protection against ischemia-induced neuronal damage. In this paper, the metabolism of isocorynoxeine was investigated in rats. Twelve metabolites and the parent drug were isolated by using solvent extraction and repeated chromatographic methods, and determined by spectroscopic methods including UV, MS, NMR, and CD experiments. Seven new compounds were identified as 11-hydroxyisocorynoxeine, 5-oxoisocorynoxeinic acid-22-O-β-D-glucuronide, 10-hydroxyisocorynoxeine, 17-O-demethyl-16,17-dihydro-5-oxoisocorynoxeine, 5-oxoisocorynoxeinic acid, 21-hydroxy-5-oxoisocorynoxeine, and oxireno[18, 19]-5-oxoisocorynoxeine, together with six known compounds identified as isocorynoxeine, 18,19-dehydrocorynoxinic acid, 18,19-dehydrocorynoxinic acid B, corynoxeine, isocorynoxeine-N-oxide, and corynoxeine-N-oxide. Possible metabolic pathways of isocorynoxeine are proposed. Furthermore, the activity assay for the parent drug and some of its metabolites showed that isocorynoxeine exhibited a significant neuroprotective effect against glutamate-induced HT22 cell death at the maximum concentration. However, little or weak neuroprotective activities were observed for M-3, M-6, M-7, and M-10. Our present study is important to further understand their metabolic fate and disposition in humans. PMID:25519834

  14. Urinary metabolites of isorhynchophylline in rats and their neuroprotective activities in the HT22 cell assay.

    PubMed

    Chen, Fangfang; Qi, Wen; Sun, Jiahong; Simpkins, James W; Yuan, Dan

    2014-09-01

    Isorhynchophylline is one of the major alkaloids from the Uncaria hook possessing the effects of lowered blood pressure, vasodilatation and protection against ischemia-induced neuronal damage. However, the metabolic pathway of isorhynchophylline has not been fully reported yet. In this paper, the metabolism of isorhynchophylline was investigated in rats. Five metabolites were isolated by using solvent extraction and repeated chromatographic methods, and identified by spectroscopic methods including UV, MS, NMR and CD experiments. Three new compounds were identified as 5-oxoisorhynchophyllic acid-22-O-β-D-glucuronide (M1), 17-O-demethyl-16,17-dihydro isorhynchophylline (M2) and 5-oxoisorhynchophyllic acid (M4) together with two known compounds isorhynchophylline (M0) and rhynchophylline (M3). Possible metabolic pathways of isorhynchophylline are proposed. Furthermore, the activity assay for all the metabolites showed that isorhynchophylline (M0) exhibited potent neuroprotective effects against glutamate-induced HT22 cell death. However, little or weak neuroprotective activities were observed for M1-M4. Our present study is important to further understand its metabolic fate and disposition in humans. PMID:24910000

  15. Cytochrome P450 peroxidase/peroxygenase mediated xenobiotic metabolic activation and cytotoxicity in isolated hepatocytes.

    PubMed

    Anari, M R; Khan, S; Liu, Z C; O'Brien, P J

    1995-12-01

    Cytochrome P450 (P450) can utilize organic hydroperoxides and peracids to support hydroxylation and dealkylation of various P450 substrates. However, the biological significance of this P450 peroxygenase/peroxidase activity in the bioactivation of xenobiotics in intact cells has not been demonstrated. We have shown that tert-butyl hydroperoxide (tBHP) markedly enhances 3-20-fold the cytotoxicity of various aromatic hydrocarbons and their phenolic metabolites. The tBHP-enhanced hepatocyte cytotoxicity of 4-nitroanisole (4-NA) and 4-hydroxyanisole (4-HA) was also accompanied by an increase in the hepatocyte O-demethylation of 4-NA and 4-HA up to 7.5- and 21-fold, respectively. Hepatocyte GSH conjugation by 4-HA was also markedly increased by tBHP. An LC/MS analysis of the GSH conjugates identified hydroquinone-GSH and 4-methoxy-catechol:GSH conjugates as the predominant adducts. Pretreatment of hepatocytes with P450 inhibitors, e.g., phenylimidazole, prevented tBHP-enhanced 4-HA metabolism, GSH depletion, and cytotoxicity. In conclusion, hydroperoxides can therefore be used by intact cells to support the bioactivation of xenobiotics through the P450 peroxidase/peroxygenase system. PMID:8605292

  16. Kinetic isotope effects implicate a single oxidant for cytochrome P450-mediated O-dealkylation, N-oxygenation, and aromatic hydroxylation of 6-methoxyquinoline.

    PubMed

    Dowers, Tamara S; Jones, Jeffrey P

    2006-08-01

    One major point of controversy in the area of cytochrome P450 (P450)-mediated oxidation reactions is the nature of the active-oxygen species. A number of hypotheses have been advanced which implicate a second oxidant besides the iron-oxo species designated as compound I (Cpd 1). This oxygen is thought to be either an iron-hydroperoxy species (Cpd 0) or a second spin-state of Cpd 1. Very little information is available on what fraction of P450 oxidations is mediated by the two different oxidants. Herein, we report results on three cytochrome P450-mediated reactions: O-dealkylation, N-oxygenation, and aromatic hydroxylation, which occur by three distinct chemical mechanisms. We have used kinetic isotope effects to test for branching from O-demethylation to N-oxygenation and aromatic hydroxylation, using 6-methoxyquinoline and 2H3-6-methoxyquinoline as substrates for P4501A2. Identical large inverse isotope effects on Vmax/Km are obtained for the formation of both the N-oxide and the phenol. This indicates that all three reactions occur through the same enzyme-substrate complex and, thus, through a single iron-oxygen species. The nature of the iron-oxygen species is less certain but is more likely to be iron-oxo Cpd 1, given the energetics of these reactions. PMID:16714370

  17. Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

    PubMed Central

    Varfaj, Fatbardha; Zulkifli, Siti N. A.; Park, Hyoung-Goo; Challinor, Victoria L.; De Voss, James J.

    2014-01-01

    Carbon-carbon bond cleavage reactions are catalyzed by, among others, lanosterol 14-demethylase (CYP51), cholesterol side-chain cleavage enzyme (CYP11), sterol 17β-lyase (CYP17), and aromatase (CYP19). Because of the high substrate specificities of these enzymes and the complex nature of their substrates, these reactions have been difficult to characterize. A CYP1A2-catalyzed carbon-carbon bond cleavage reaction is required for conversion of the prodrug nabumetone to its active form, 6-methoxy-2-naphthylacetic acid (6-MNA). Despite worldwide use of nabumetone as an anti-inflammatory agent, the mechanism of its carbon-carbon bond cleavage reaction remains obscure. With the help of authentic synthetic standards, we report here that the reaction involves 3-hydroxylation, carbon-carbon cleavage to the aldehyde, and oxidation of the aldehyde to the acid, all catalyzed by CYP1A2 or, less effectively, by other P450 enzymes. The data indicate that the carbon-carbon bond cleavage is mediated by the ferric peroxo anion rather than the ferryl species in the P450 catalytic cycle. CYP1A2 also catalyzes O-demethylation and alcohol to ketone transformations of nabumetone and its analogs. PMID:24584631

  18. Metabolite profiling of RCS-4, a novel synthetic cannabinoid designer drug, using human hepatocyte metabolism and TOF-MS

    PubMed Central

    Gandhi, Adarsh S; Zhu, Mingshe; Pang, Shaokun; Wohlfarth, Ariane; Scheidweiler, Karl B; Huestis, Marilyn A

    2014-01-01

    Background Since 2009, scheduling legislation of synthetic cannabinoids prompted new compound emergence to circumvent legal restrictions. 2-(4-methoxyphenyl)-1-(1-pentyl-indol-3-yl)methanone (RCS-4) is a potent cannabinoid receptor agonist sold in herbal smoking blends. Absence of parent synthetic cannabinoids in urine suggests the importance of metabolite identification for detecting RCS-4 consumption in clinical and forensic investigations. Materials & methods & Results With 1 h human hepatocyte incubation and TOF high-resolution MS, we identified 18 RCS-4 metabolites, many not yet reported. Most metabolites were hydroxylated with or without demethylation, carboxylation and dealkylation followed by glucuronidation. One additional sulfated metabolite was also observed. O-demethylation was the most common biotransformation and generated the major metabolite. Conclusion For the first time, we present a metabolic scheme of RCS-4 obtained from human hepatocytes, including Phase I and II metabolites. Metabolite structural information and associated high-resolution mass spectra can be employed for developing clinical and forensic laboratory RCS-4 urine screening methods. PMID:25046048

  19. Biotransformation and detectability of the designer drug 2,5-dimethoxy-4-propylphenethylamine (2C-P) studied in urine by GC-MS, LC-MS(n), and LC-high-resolution-MS(n).

    PubMed

    Wink, Carina S D; Meyer, Markus R; Braun, Tina; Turcant, Alain; Maurer, Hans H

    2015-01-01

    2,5-Dimethoxy-4-propylphenethylamine (2C-P) is a hallucinogenic designer drug of the phenethylamine class, the so-called 2Cs, named according to the ethyl spacer between the nitrogen and the aromatic ring. The aims of the present work were to identify the phases I and II metabolites of 2C-P. In addition, the detectability of 2C-P and its metabolites in urine as proof of an intake in clinical or forensic cases was tested. According to the identified metabolites, the following pathways were proposed: N-acetylation; deamination followed by reduction to the corresponding alcohol and oxidation to carbonic acid; mono- and bis-hydroxylation at different positions; mono- and bis-O-demethylation, followed by glucuronidation, sulfation, or both; and combination of these steps. Proof of an intake of a common user's dose of 2C-P was possible by both standard urine screening approaches, the GC-MS as well as the LC-MS(n) approach. PMID:25120185

  20. Induction of cytochromes P450 1A1 and 1A2 suppresses formation of DNA adducts by carcinogenic aristolochic acid I in rats in vivo

    PubMed Central

    Dračínská, Helena; Bárta, František; Levová, Kateřina; Hudecová, Alena; Moserová, Michaela; Schmeiser, Heinz H.; Kopka, Klaus; Frei, Eva; Arlt, Volker M.; Stiborová, Marie

    2016-01-01

    Aristolochic acid I (AAI) is a natural plant alkaloid causing aristolochic acid nephropathy, Balkan endemic nephropathy and their associated urothelial malignancies. One of the most efficient enzymes reductively activating AAI to species forming AAI-DNA adducts is cytosolic NAD(P)H:quinone oxidoreductase 1. AAI is also either reductively activated or oxidatively detoxified to 8-hydroxyaristolochic acid (AAIa) by microsomal cytochrome P450 (CYP) 1A1 and 1A2. Here, we investigated which of these two opposing CYP1A1/2-catalyzed reactions prevails in AAI metabolism in vivo. The formation of AAI-DNA adducts was analyzed in liver, kidney and lung of rats treated with AAI, Sudan I, a potent inducer of CYP1A1/2, or AAI after pretreatment with Sudan I. Compared to rats treated with AAI alone, levels of AAI-DNA adducts determined by the 32P-postlabeling method were lower in liver, kidney and lung of rats treated with AAI after Sudan I. The induction of CYP1A1/2 by Sudan I increased AAI detoxification to its O-demethylated metabolite AAIa, thereby reducing the actual amount of AAI available for reductive activation. This subsequently resulted in lower AAI-DNA adduct levels in the rat in vivo. Our results demonstrate that CYP1A1/2-mediated oxidative detoxification of AAI is the predominant role of these enzymes in rats in vivo, thereby suppressing levels of AAI-DNA adducts. PMID:26845733

  1. Metabolism of the /sup 18/O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria. [Eubacterium limosum; Acetobacterium woodil; Syntrophococcus; Clostridium; Desulfotomaculum; Enterobacter

    SciTech Connect

    DeWeerd, J.A.; Saxena, A.; Nagle, D.P. Jr.; Sulflita, J.M.

    1988-05-01

    The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. We found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium, limosum, and a strain of Acetobacterium woodii metabolized 3-(methoxy-/sup 18/O)methoxybenzoic acid (3-anisic acid) to 3-(hydroxy-/sup 18/O)hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments.

  2. Comparative study of the affinity and metabolism of type I and type II binding quinoline carboxamide analogs by cytochrome P450 3A4

    PubMed Central

    Dahal, Upendra P.; Joswig-Jones, Carolyn; Jones, Jeffrey P.

    2011-01-01

    Compounds that coordinate to the heme-iron of cytochrome P450 (CYP) enzymes are assumed to increase metabolic stability. However, recently we observed that the type II binding quinoline carboxamide (QCA) compounds were metabolically less stable. To test if the higher intrinsic clearance of type II binding compounds relative to type I binding compounds is general for other metabolic transformations, we synthesized a library of QCA compounds that could undergo N-dealkylation, O-dealkylation, benzylic hydroxylation and aromatic hydroxylation. The results demonstrated that type II binding QCA analogs were metabolically less stable (2 to 12 fold) at sub-saturating concentration compared to type I binding counterparts for all the transformations. When the rates of different metabolic transformations between type I and type II binding compounds were compared, they were found to be in the order of N-demethylation>benzylic hydroxylation> O-demethylation> aromatic hydroxylation. Finally, for the QCA analogs with aza-heteroaromatic rings, we did not detect metabolism in aza-aromatic rings (pyridine, pyrazine, pyrimidine) indicating electronegativity of the nitrogen can change regioselectivity in CYP metabolism. PMID:22087535

  3. NPRL-Z-1, as a New Topoisomerase II Poison, Induces Cell Apoptosis and ROS Generation in Human Renal Carcinoma Cells

    PubMed Central

    Wu, Szu-Ying; Pan, Shiow-Lin; Xiao, Zhi-Yan; Hsu, Jui-Ling; Chen, Mei-Chuan; Lee, Kuo-Hsiung; Teng, Che-Ming

    2014-01-01

    NPRL-Z-1 is a 4β-[(4″-benzamido)-amino]-4′-O-demethyl-epipodophyllotoxin derivative. Previous reports have shown that NPRL-Z-1 possesses anticancer activity. Here NPRL-Z-1 displayed cytotoxic effects against four human cancer cell lines (HCT 116, A549, ACHN, and A498) and exhibited potent activity in A498 human renal carcinoma cells, with an IC50 value of 2.38 µM via the MTT assay. We also found that NPRL-Z-1 induced cell cycle arrest in G1-phase and detected DNA double-strand breaks in A498 cells. NPRL-Z-1 induced ataxia telangiectasia-mutated (ATM) protein kinase phosphorylation at serine 1981, leading to the activation of DNA damage signaling pathways, including Chk2, histone H2AX, and p53/p21. By ICE assay, the data suggested that NPRL-Z-1 acted on and stabilized the topoisomerase II (TOP2)–DNA complex, leading to TOP2cc formation. NPRL-Z-1-induced DNA damage signaling and apoptotic death was also reversed by TOP2α or TOP2β knockdown. In addition, NPRL-Z-1 inhibited the Akt signaling pathway and induced reactive oxygen species (ROS) generation. These results demonstrated that NPRL-Z-1 appeared to be a novel TOP2 poison and ROS generator. Thus, NPRL-Z-1 may present a significant potential anticancer candidate against renal carcinoma. PMID:25372714

  4. Biotransformation of colchicinoids into their corresponding 3-O-glucosyl derivatives by selected strains of Bacillus megaterium.

    PubMed

    Ponzone, Cesare; Berlanda, Davide; Donzelli, Fabio; Acquati, Valter; Ciulla, Rosalba; Negrini, Alberto; Rovati, Marco; Evangelista, Douglas; Fata, Emilio; Ciceri, Daniele; Perterlongo, Federico; Cabri, Walter

    2014-07-01

    Natural colchicinoids and their semisynthetic derivatives are important active ingredients for pharmaceutical applications. Thiocolchicoside (3-demethoxy-3-glucosyloxythiocolchicine) is used in several countries as standard therapy for the treatment of diseases of the muscle-skeletal system, due to its potent antiinflammatory and myorelaxant properties. Manufacturing of thiocolchicoside requires a key step, the regioselective demethylation and glucosylation of chemically derivative thiocolchicine. High selectivity and efficiency of this transformation cannot be achieved in a satisfactory way with a chemical approach. In particular, the chemical demethylation, a part from requiring toxic and aggressive reagents, generates a complex mixture of products with no industrial usefulness. We report herein an efficient, direct and green biotransformation of thiocolchicine into thiocolchicoside, performed by a specific strain of Bacillus megaterium. The same process, with minor modifications, can be used to convert the by-product 3-O-demethyl-thiocolchicine into thiocolchicoside. In addition, we describe the B. megaterium strain selection process and the best conditions for this effective double biotransformation. The final product has a pharmaceutical quality, and the process has been industrialised. PMID:24553816

  5. Polyamines and drug oxidations.

    PubMed

    Chapman, S K

    1976-01-01

    The addition of spermine or of spermidine to rat liver assay systems produced marked changes in a number of microsomal drug oxidations. The hydroxylation of aniline and the N-demethylation of ethylmorphine were both enhanced with concentrations of 1-10 mM spermine or of spermidine. The results with putrescine on ethylmorphine metabolism were less dramatic, and no effect could be observed with putrescine in studies with other drug substrates. In contrast to the enhancing effects, inhibition was observed when spermine or spermidine was added to p-nitroanisole O-demethylation assay mixtures, and no effect was observed in assays for acetanilide hydroxylation. The inhibiting and enhancing effects of the polyamines can be observed in assays containing liver preparations from both male and female rats, and those from rats pretreated with phenobarbital or 3-methylcholanthrene. In all studies, the alterations were kinetically noncompetitive. The effects were shown to be independent of the NADPH-generating system and the cation requirements, and were not mediated through an interaction with NADPH-cytochrome c reductase. The possibility is considered that the enhancing and inhibiting effects may be related to the ability of these polycations to bind to microsomal membranes and cause alterations at different sites of substrate interaction. PMID:10139

  6. In Vitro Metabolism of 20(R)-25-Methoxyl-Dammarane-3, 12, 20-Triol from Panax notoginseng in Human, Monkey, Dog, Rat, and Mouse Liver Microsomes

    PubMed Central

    Li, Wei; Liu, Li; Sun, Baoshan; Guo, Zhenghong; Shi, Caihong; Zhao, Yuqing

    2014-01-01

    The present study characterized in vitro metabolites of 20(R)-25-methoxyl-dammarane-3β, 12β, 20-triol (20(R)-25-OCH3-PPD) in mouse, rat, dog, monkey and human liver microsomes. 20(R)-25-OCH3-PPD was incubated with liver microsomes in the presence of NADPH. The reaction mixtures and the metabolites were identified on the basis of their mass profiles using LC-Q/TOF and were quantified using triple quadrupole instrument by multiple reaction monitoring. A total of 7 metabolites (M1–M7) of the phase I metabolites were detected in all species. 25(R)-OCH3-PPD was metabolized by hydroxylation, dehydrogenation, and O-demethylation. Enzyme kinetic of 20(R)-25-OCH3-PPD metabolism was evaluated in rat and human hepatic microsomes. Incubations studies with selective chemical inhibitors demonstrated that the metabolism of 20(R)-25-OCH3-PPD was primarily mediated by CYP3A4. We conclude that 20(R)-25-OCH3-PPD was metabolized extensively in mammalian species of mouse, rat, dog, monkey, and human. CYP3A4-catalyzed oxygenation metabolism played an important role in the disposition of 25(R)-OCH3-PPD, especially at the C-20 hydroxyl group. PMID:24736630

  7. Breath tests to phenotype drug disposition in oncology.

    PubMed

    Opdam, Frans L; Modak, Anil S; Gelderblom, Hans; Guchelaar, Henk-Jan

    2013-11-01

    Breath tests (BTs) have been investigated as diagnostic tools to phenotype drug disposition in cancer patients in the pursuit to individualize drug treatment. The choice of the right phenotype probe is crucial and depends on the metabolic pathway of the anticancer agent of interest. BTs using orally or intravenously administered selective non-radioactive (13)C-labeled probes to non-invasively evaluate dihydropyrimidine dehydrogenase, cytochrome P450 (CYP) 3A4, and CYP2D6 enzyme activity have been published. Clinically, a (13)C-dextromethorphan BT to predict endoxifen levels in breast cancer patients and a (13)C-uracil BT to predict fluoropyrimidine toxicity in colorectal cancer patients are most promising. However, the clinical benefit and cost effectiveness of these phenotype BTs need to be determined in order to make the transition from an experimental setting to clinical practice as companion diagnostic tests. PMID:23868281

  8. Detection of an endogenous urinary biomarker associated with CYP2D6 activity using global metabolomics

    PubMed Central

    Tay-Sontheimer, Jessica; Shireman, Laura M; Beyer, Richard P; Senn, Taurence; Witten, Daniela; Pearce, Robin E; Gaedigk, Andrea; Fomban, Cletus L Gana; Lutz, Justin D; Isoherranen, Nina; Thummel, Kenneth E; Fiehn, Oliver; Leeder, J Steven; Lin, Yvonne S

    2015-01-01

    Aim We sought to discover endogenous urinary biomarkers of human CYP2D6 activity. Patients & methods Healthy pediatric subjects (n = 189) were phenotyped using dextromethorphan and randomized for candidate biomarker selection and validation. Global urinary metabolomics was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Candidate biomarkers were tested in adults receiving fluoxetine, a CYP2D6 inhibitor. Results A biomarker, M1 (m/z 444.3102) was correlated with CYP2D6 activity in both the pediatric training and validation sets. Poor metabolizers had undetectable levels of M1, whereas it was present in subjects with other phenotypes. In adult subjects, a 9.56-fold decrease in M1 abundance was observed during CYP2D6 inhibition. Conclusion Identification and validation of M1 may provide a noninvasive means of CYP2D6 phenotyping. PMID:25521354

  9. Synthesis of stable isotope labelled internal standards for drug-drug interaction (DDI) studies.

    PubMed

    Atzrodt, J; Blankenstein, J; Brasseur, D; Calvo-Vicente, S; Denoux, M; Derdau, V; Lavisse, M; Perard, S; Roy, S; Sandvoss, M; Schofield, J; Zimmermann, J

    2012-09-15

    The syntheses of stable isotope labelled internal standards of important CYP-isoform selective probes, like testosterone 1, diclofenac 3, midazolam 5, and dextromethorphan 7, as well as their corresponding hydroxylated metabolites 6β-hydroxytestosterone 2, 4'-hydroxydiclofenac 4, 1'-hydroxymidazolam 6 and dextrorphan 8 are reported. Microwave-enhanced H/D-exchange reactions applying either acid, base, or homogeneous and heterogeneous transition metal catalysis, or combinations thereof proved to be highly efficient for direct deuterium labelling of the above mentioned probes. Compared to conventional stepwise synthetic approaches, the combination of H/D exchange and biotransformation provides the potential for considerable time- and cost savings, in particular for the synthesis of the stable isotope labelled internal standards of 4'-hydroxydiclofenac 4 and 1'-hydroxymidazolam 6. PMID:22890009

  10. Targeting N-methyl-D-aspartate receptors for treatment of neuropathic pain

    PubMed Central

    Zhou, Hong-Yi; Chen, Shao-Rui; Pan, Hui-Lin

    2011-01-01

    Neuropathic pain remains a major clinical problem and a therapeutic challenge because existing analgesics are often ineffective and can cause serious side effects. Increased N-methyl-D-aspartate receptor (NMDAR) activity contributes to central sensitization in certain types of neuropathic pain. NMDAR antagonists can reduce hyperalgesia and allodynia in animal models of neuropathic pain induced by nerve injury and diabetic neuropathy. Clinically used NMDAR antagonists, such as ketamine and dextromethorphan, are generally effective in patients with neuropathic pain, such as complex regional pain syndrome and painful diabetic neuropathy. However, patients with postherpetic neuralgia respond poorly to NMDAR antagonists. Recent studies on identifying NMDAR-interacting proteins and molecular mechanisms of increased NMDAR activity in neuropathic pain could facilitate the development of new drugs to attenuate abnormal NMDAR activity with minimal impairment of the physiological function of NMDARs. Combining NMDAR antagonists with other analgesics could also lead to better management of neuropathic pain without causing serious side effects. PMID:21686074

  11. Cyanide Suicide After Deep Web Shopping: A Case Report.

    PubMed

    Le Garff, Erwan; Delannoy, Yann; Mesli, Vadim; Allorge, Delphine; Hédouin, Valéry; Tournel, Gilles

    2016-09-01

    Cyanide is a product that is known for its use in industrial or laboratory processes, as well as for intentional intoxication. The toxicity of cyanide is well described in humans with rapid inhibition of cellular aerobic metabolism after ingestion or inhalation, leading to severe clinical effects that are frequently lethal. We report the case of a young white man found dead in a hotel room after self-poisoning with cyanide ordered in the deep Web. This case shows a probable complex suicide kit use including cyanide, as a lethal tool, and dextromethorphan, as a sedative and anxiolytic substance. This case is an original example of the emerging deep Web shopping in illegal drug procurement. PMID:27367575

  12. Efficacy of levodropropizine in pediatric cough.

    PubMed

    De Blasio, Francesco; Dicpinigaitis, Peter V; De Danieli, Gianluca; Lanata, Luigi; Zanasi, Alessando

    2012-10-01

    Cough in children is among the most common problems managed by pediatricians, and occurs more frequently in preschool than in older children. Most acute episodes of cough are due to viral upper respiratory tract infections. The morbidity associated with acute cough in a child extends also to parents, teachers, and other family members and caregivers. Unfortunately, therapeutic options for acute cough in children are severely limited due to the absence of drugs shown to be effective antitussives with an acceptable safety profile. Agents used in the management of adult cough, such as narcotics (codeine, hydrocodone), the non-narcotic opioid dextromethorphan, first-generation, potentially sedating antihistamines, and decongestants such as pseudoephedrine, have all been deemed inadequate for treatment of acute pediatric cough on a risk/benefit basis. A growing body of evidence suggests that the peripherally acting antitussive, levodropropizine, may be an attractive alternative for the treatment of bothersome acute cough in children. PMID:22771902

  13. Therapeutic options for acute cough due to upper respiratory infections in children.

    PubMed

    Paul, Ian M

    2012-02-01

    Cough due to upper respiratory tract infections (URIs) is one of the most frequent complaints encountered by pediatric health-care providers, and one of the most disruptive symptoms for children and families. Despite the frequency of URIs, there is limited evidence to support the few therapeutic agents currently available in the United States (US) to treat acute cough due to URI. Published, well-designed, contemporary research supporting the efficacy of narcotics (codeine, hydrocodone) and US Food and Drug Administration (FDA)-approved over-the-counter (OTC) oral antitussives and expectorants (dextromethorphan, diphenhydramine, chlophedianol, and guaifenesin) is absent for URI-associated pediatric cough. Alternatively, honey and topically applied vapor rubs may be effective antitussives. PMID:21892785

  14. Current and future centrally acting antitussives☆

    PubMed Central

    Bolser, Donald C.

    2011-01-01

    The purpose of this review is to highlight some important issues regarding current centrally acting antitussive drugs as well as discuss the implications of these matters on the development of future cough suppressants. Drugs that act in the central nervous system to inhibit cough are termed centrally acting and this designation is based exclusively on evidence obtained from animal models. This classification can include drugs that act both at peripheral and central sites following systemic administration. These drugs are intended to reduce the frequency and/or intensity of coughing resulting from disorders of any etiology. There are a number of central cough suppressants identified by their efficacy in animal models and the most prominent of these are codeine and dextromethorphan. Although the exact neural elements on which these drugs act are currently unknown, they are thought to inhibit a functionally identified component of the central system for cough known as the gating mechanism. The efficacy of codeine and dextromethorphan in humans has recently been questioned. These drugs are less effective on cough induced by upper airway disorders than in pathological conditions involving the lower airways in humans. The reasons for this difference in antitussive sensitivity are not clear. We propose that sensory afferents from different regions of the airways actuate coughing in humans by antitussive sensitive and insensitive control elements in the central nervous system. This hypothesis is consistent with results from an animal model in which laryngeal and tracheobronchial cough had different sensitivities to codeine. Other factors that may be very important in the action of central antitussive drugs in humans include the role of sensations produced by a tussigenic stimulus as well as plasticity of central pathways in response to airway inflammation. Resolution of these issues in the human will be a challenging process, but one which will lay the foundation for the

  15. Characterization of pulmonary sigma receptors by radioligand binding

    PubMed Central

    Lever, John R.; Litton, Tyler P.; Fergason-Cantrell, Emily A.

    2015-01-01

    This study establishes the expression of appreciable populations of sites on mouse lung membranes that exhibit radioligand binding properties and pharmacology consistent with assignment as sigma1 and sigma2 receptors. Specific binding of the sigma1 receptor radioligand [3H](+)-pentazocine reached steady state within 6 h at 37 °C. Saturation studies revealed high affinity binding to a single class of sites (Kd 1.36 ± 0.04 nM; Bmax 967 ± 11 fmol / mg protein). Inhibition studies showed appropriate sigma1 receptor pharmacology, including higher affinity for (+)-N-allylnormetazocine with respect to the (−)-enantiomer, and positive allosteric modulation of dextromethorphan binding by phenytoin. Using [3H]1,3-di(2-tolyl)guanidine in the presence of (+)-pentazocine to assess sigma2 receptor binding, steady state was achieved within 2 min at 25 °C. Cold saturation studies revealed one high affinity, low capacity binding site (Kd 31.8 ± 8.3 nM; Bmax 921 ± 228 fmol / mg protein) that displayed sigma2 receptor pharmacology. A very low affinity, high capacity interaction also was observed that represents saturable, but not sigma receptor specific, binding. A panel of ligands showed rank order inhibition of radioligand binding appropriate for the sigma2 receptor, with ifenprodil displaying the highest apparent affinity. In vivo, dextromethorphan inhibited the specific binding of a radioiodinated sigma1 receptor ligand in lung with an ED50 of 1.2 µmol / kg, a value near the recommended dosage for the drug as a cough suppressant. Overall, the present work provides a foundation for studies of drug interactions with pulmonary sigma1 and sigma2 receptors in vitro and in vivo. PMID:26004528

  16. Characterization of pulmonary sigma receptors by radioligand binding.

    PubMed

    Lever, John R; Litton, Tyler P; Fergason-Cantrell, Emily A

    2015-09-01

    This study establishes the expression of appreciable populations of sites on mouse lung membranes that exhibit radioligand binding properties and pharmacology consistent with assignment as sigma1 and sigma2 receptors. Specific binding of the sigma1 receptor radioligand [(3)H](+)-pentazocine reached steady state within 6h at 37°C. Saturation studies revealed high affinity binding to a single class of sites (Kd 1.36±0.04nM; Bmax 967±11fmol/mg protein). Inhibition studies showed appropriate sigma1 receptor pharmacology, including higher affinity for (+)-N-allylnormetazocine with respect to the (-)-enantiomer, and positive allosteric modulation of dextromethorphan binding by phenytoin. Using [(3)H]1,3-di(2-tolyl)guanidine in the presence of (+)-pentazocine to assess sigma2 receptor binding, steady state was achieved within 2min at 25°C. Cold saturation studies revealed one high affinity, low capacity binding site (Kd 31.8±8.3nM; Bmax 921±228fmol/mg protein) that displayed sigma2 receptor pharmacology. A very low affinity, high capacity interaction also was observed that represents saturable, but not sigma receptor specific, binding. A panel of ligands showed rank order inhibition of radioligand binding appropriate for the sigma2 receptor, with ifenprodil displaying the highest apparent affinity. In vivo, dextromethorphan inhibited the specific binding of a radioiodinated sigma1 receptor ligand in lung with an ED50 of 1.2μmol/kg, a value near the recommended dosage for the drug as a cough suppressant. Overall, the present work provides a foundation for studies of drug interactions with pulmonary sigma1 and sigma2 receptors in vitro and in vivo. PMID:26004528

  17. The Effect of Yokukansan, a Traditional Herbal Preparation Used for the Behavioral and Psychological Symptoms of Dementia, on the Drug-Metabolizing Enzyme Activities in Healthy Male Volunteers.

    PubMed

    Soraoka, Hiromi; Oniki, Kentaro; Matsuda, Kazuki; Ono, Tatsumasa; Taharazako, Kosuke; Uchiyashiki, Yoshihiro; Kamihashi, Ryoko; Kita, Ayana; Takashima, Ayaka; Nakagawa, Kazuko; Yasui-Furukori, Norio; Kadowaki, Daisuke; Miyata, Keishi; Saruwatari, Junji

    2016-01-01

    The concomitant use of herb and prescription medications is increasing globally. Herb-drug interactions are therefore a clinically important problem. Yokukansan (YKS), a Japanese traditional herbal medicine, is one of the most frequently used herbal medicines. It is effective for treating the behavioral and psychological symptoms of dementia. We investigated the potential effects of YKS on drug-metabolizing enzyme activities in humans. An open-label repeat-dose study was conducted in 26 healthy Japanese male volunteers (age: 22.7±2.3 years) with no history of smoking. An 8-h urine sample was collected after a 150-mg dose of caffeine and a 30-mg dose of dextromethorphan before and after the administration of YKS (2.5 g, twice a day for 1 week). The activities of cytochrome P450 (CYP) 1A2, CYP2D6, CYP3A, xanthine oxidase (XO) and N-acetyltransferase 2 (NAT2) were assessed based on the urinary metabolic indices of caffeine and dextromethorphan, and the urinary excretion ratio of 6β-hydroxycortisol to cortisol. There were no statistically significant differences in the activities of the examined enzymes before or after the 7-d administration of YKS. Although further studies assessing the influence of YKS on the pharmacokinetics and pharmacodynamics of the substrates of the drug-metabolizing enzymes are needed to verify the present results, YKS is unlikely that a pharmacokinetic interaction will occur with concomitantly administered medications that are predominantly metabolized by the CYP1A2, CYP2D6, CYP3A, XO and NAT2. PMID:27582327

  18. Effect of memantine on cough reflex sensitivity: translational studies in guinea pigs and humans.

    PubMed

    Dicpinigaitis, Peter V; Canning, Brendan J; Garner, Rachel; Paterson, Blake

    2015-03-01

    Cough is the most common complaint for which outpatients in the United States seek medical attention, and yet available therapeutic options for cough lack proven efficacy and are further limited by safety and abuse liabilities. Thus, safe and effective cough suppressants are needed. Recent preclinical studies described the antitussive effects of memantine, an N-methyl-d-aspartate receptor channel blocker used in the treatment of Alzheimer's disease. The goals of the present study were to compare the antitussive effects of memantine, dextromethorphan, and codeine in guinea pigs; to relate the dose-dependent actions of memantine in these studies to peak plasma concentrations achieved following oral administration; and to provide the first ever evaluation of the antitussive effect of memantine in humans. In guinea pigs, memantine and codeine were comparable in efficacy and potency but both were superior to dextromethorphan in the citric acid cough challenge model. The pharmacokinetic analyses suggest that memantine was active in guinea pigs at micromolar plasma concentrations. Subsequently, 14 healthy volunteers as well as 14 otherwise healthy adults with acute viral upper respiratory tract infection (URI) underwent capsaicin cough challenges 6 hours after ingestion of 20 mg memantine and matched placebo in a randomized, double-blind, crossover fashion. In healthy volunteers, memantine significantly inhibited cough reflex sensitivity (P = 0.034). In subjects with URI, responsiveness to capsaicin was markedly increased, and in these patients, the inhibition of cough reflex sensitivity by memantine relative to placebo did not reach statistical significance (P = 0.088). These data support further research to investigate the potential of memantine as a clinically useful antitussive. PMID:25525191

  19. CYP3A4 drug interactions: correlation of 10 in vitro probe substrates

    PubMed Central

    Kenworthy, K E; Bloomer, J C; Clarke, S E; Houston, J B

    1999-01-01

    Aims Many substrates of cytochrome P450 (CYP) 3A4 are used for in vitro investigations of drug metabolism and potential drug–drug interactions. The aim of the present study was to determine the relationship between 10 commonly used CYP3A4 probes using modifiers with a range of inhibitory potency. Methods The effects of 34 compounds on CYP3A4-mediated metabolism were investigated in a recombinant CYP3A4 expression system. Inhibition of erythromycin, dextromethorphan and diazepam N-demethylation, testosterone 6β-hydroxylation, midazolam 1-hydroxylation, triazolam 4-hydroxylation, nifedipine oxidation, cyclosporin oxidation, terfenadine C-hydroxylation and N-dealkylation and benzyloxyresorufin O-dealkylation was evaluated at the apparent Km or S50 (for substrates showing sigmoidicity) value for each substrate and at an inhibitor concentration of 30 μm. Results While all CYP3A4 probe substrates demonstrate some degree of similarity, examination of the coefficients of determination, together with difference and cluster analysis highlighted that seven substrates can be categorized into two distinct substrate groups. Erythromycin, cyclosporin and testosterone form the most closely related group and dextromethorphan, diazepam, midazolam and triazolam form a second group. Terfenadine can be equally well placed in either group, while nifedipine shows a distinctly different relationship. Benzyloxyresorufin shows the weakest correlation with all the other CYP3A4 probes. Modifiers that caused negligible inhibition or potent inhibition are generally comparable in all assays, however, the greatest variability is apparent with compounds causing, on average, intermediate inhibition. Modifiers of this type may cause substantial inhibition, no effect or even activation depending on the substrate employed. Conclusions It is recommended that multiple CYP3A4 probes, representing each substrate group, are used for the in vitro assessment of CYP3A4-mediated drug interactions. PMID

  20. Practice Parameter update: The care of the patient with amyotrophic lateral sclerosis: Multidisciplinary care, symptom management, and cognitive/behavioral impairment (an evidence-based review)

    PubMed Central

    Miller, R G.; Jackson, C E.; Kasarskis, E J.; England, J D.; Forshew, D; Johnston, W; Kalra, S; Katz, J S.; Mitsumoto, H; Rosenfeld, J; Shoesmith, C; Strong, M J.; Woolley, S C.

    2009-01-01

    Objective: To systematically review evidence bearing on the management of patients with amyotrophic lateral sclerosis (ALS). Methods: The authors analyzed studies from 1998 to 2007 to update the 1999 practice parameter. Topics covered in this section include breaking the news, multidisciplinary clinics, symptom management, cognitive and behavioral impairment, communication, and palliative care for patients with ALS. Results: The authors identified 2 Class I studies, 8 Class II studies, and 30 Class III studies in ALS, but many important areas have been little studied. More high-quality, controlled studies of symptomatic therapies and palliative care are needed to guide management and assess outcomes in patients with ALS. Recommendations: Multidisciplinary clinic referral should be considered for managing patients with ALS to optimize health care delivery and prolong survival (Level B) and may be considered to enhance quality of life (Level C). For the treatment of refractory sialorrhea, botulinum toxin B should be considered (Level B) and low-dose radiation therapy to the salivary glands may be considered (Level C). For treatment of pseudobulbar affect, dextromethorphan and quinidine should be considered if approved by the US Food and Drug Administration (Level B). For patients who develop fatigue while taking riluzole, withholding the drug may be considered (Level C). Because many patients with ALS demonstrate cognitive impairment, which in some cases meets criteria for dementia, screening for cognitive and behavioral impairment should be considered in patients with ALS (Level B). Other management strategies all lack strong evidence. GLOSSARY ALS = amyotrophic lateral sclerosis; ALS-FTD = amyotrophic lateral sclerosis with a dementia meeting the Neary criteria for frontotemporal dementia; ALSbi = amyotrophic lateral sclerosis with behavioral impairment; ALSci = amyotrophic lateral sclerosis with cognitive impairment; BTxA = botulinum toxin type A; BTxB = botulinum

  1. Antitussive Effects of Memantine in Guinea Pigs

    PubMed Central

    Smith, Jaclyn A.; Hilton, Emma C. Y.; Saulsberry, Loren

    2012-01-01

    Background: The treatment of cough is a significant clinical unmet need because there is little evidence that current therapies are effective. Based on evidence supporting a role for N-methyl d-aspartate receptors (NMDARs) in cough, we hypothesized that memantine, a low-affinity, uncompetitive NMDAR channel blocker in routine use for the treatment of Alzheimer disease, could be an effective, well-tolerated, antitussive therapy. The aim of this study was to establish preclinical evidence that memantine has antitussive effects. Methods: We studied the influence of memantine on experimentally induced coughing in response to citric acid and bradykinin inhalation in guinea pigs. We also compared the potency and efficacy of memantine as an antitussive to other NMDAR antagonists, dextromethorphan and ketamine, and to the γ-aminobutyric acid class B receptor agonist baclofen. Results: Compared with control subjects, 10 mg/kg memantine significantly reduced the cumulative number of coughs evoked by both citric acid (median, 24.0 [interquartile range (IQR), 13.0-25.5] vs 1.5 [IQR, 0.3-10.3] coughs; P = .012) and bradykinin aerosols (median, 16.0 [IQR, 9.5-18.5] vs 0.0 [IQR, 0-0.75] coughs; P = .002). Memantine 10 mg/kg produced a similar reduction in the cumulative number of coughs to baclofen 3 mg/kg and demonstrated comparatively greater cough suppression than 30 mg/kg dextromethorphan or 30 mg/kg ketamine. This dose of memantine produced no sedative or respiratory depressive effects. Conclusions: This study illustrates that memantine has marked antitussive effects in guinea pigs, most likely mediated through NMDAR channel blockade. Memantine, therefore, has the potential to be a safe, effective, and well-tolerated antitussive agent. PMID:22016492

  2. Chronic Enhancement of Serotonin Facilitates Excitatory Transcranial Direct Current Stimulation-Induced Neuroplasticity.

    PubMed

    Kuo, Hsiao-I; Paulus, Walter; Batsikadze, Giorgi; Jamil, Asif; Kuo, Min-Fang; Nitsche, Michael A

    2016-04-01

    Serotonin affects memory formation via modulating long-term potentiation (LTP) and depression (LTD). Accordingly, acute selective serotonin reuptake inhibitor (SSRI) administration enhanced LTP-like plasticity induced by transcranial direct current stimulation (tDCS) in humans. However, it usually takes some time for SSRI to reduce clinical symptoms such as anxiety, negative mood, and related symptoms of depression and anxiety disorders. This might be related to an at least partially different effect of chronic serotonergic enhancement on plasticity, as compared with single-dose medication. Here we explored the impact of chronic application of the SSRI citalopram (CIT) on plasticity induced by tDCS in healthy humans in a partially double-blinded, placebo (PLC)-controlled, randomized crossover study. Furthermore, we explored the dependency of plasticity induction from the glutamatergic system via N-methyl-D-aspartate receptor antagonism. Twelve healthy subjects received PLC medication, combined with anodal or cathodal tDCS of the primary motor cortex. Afterwards, the same subjects took CIT (20 mg/day) consecutively for 35 days. During this period, four additional interventions were performed (CIT and PLC medication with anodal/cathodal tDCS, CIT and dextromethorphan (150 mg) with anodal/cathodal tDCS). Plasticity was monitored by motor-evoked potential amplitudes elicited by transcranial magnetic stimulation. Chronic application of CIT increased and prolonged the LTP-like plasticity induced by anodal tDCS for over 24 h, and converted cathodal tDCS-induced LTD-like plasticity into facilitation. These effects were abolished by dextromethorphan. Chronic serotonergic enhancement results in a strengthening of LTP-like glutamatergic plasticity, which might partially explain the therapeutic impact of SSRIs in depression and other neuropsychiatric diseases. PMID:26329381

  3. [Effect of Fuzheng Huayu recipe on CYP450 isozymes in normal and liver fibrosis rats].

    PubMed

    Zheng, Tian-hui; Liu, Wei; Li, Shu-ping; Yang, Tao; Wang, Chang-hong; Liu, Cheng-hai

    2015-03-01

    To study the effect of Fuzheng Huayu recipe (FZHY) on five types of isozymes of cytochrome P450 (CYP450) of normal and liver fibrosis rats by using the cocktail probe method. Dimethylnitrosamine ( DMN) was injected to induce the liver fibrosis model. After the tail vein injection with Cocktail probe solutions prepared with five CYP450s probe substrates (phenacetin-CYP1A2, omeprazole-CYP2C9, tolbutamide-CYP2C19, dextromethorphan-CYP2D6, midazolam-CYP3A4), the plasma concentrations of the five probe substrates were determined by LC-MS/MS, and the pharmacokinetic parameters were calculated by PK solutions 2. After the oral administration with FZHY, normal rats given phenacetin, omeprazole, tolbutamide and dextromethorphan showed increase in AUC(0-t) and decrease in CL to varying degrees, indicating that FZHY obviously inhibited the activities of CYP1A2, CYP2C9, CYP2C19 and CYP2D6 in normal rats, but with no obvious effect on the activity of CYP3A4. After the oral administration with FZHY, liver fibrosis rats treated with CYP2C9 showed the significant increase in AUC(0-t) and significant decrease in Vd, hut with no obvious changes in the pharmacokinetic parameters of other four types of prove substances, suggesting that FZHY could significantly inhibit the activity of CYP2C9 in rats but had no effect on the activities of CYP1A2, CYP2C19, CYP2D6 and CYP3A4. The changes in the activity of CYP450 isozymes in liver fibrosis rats may be the reason for FZHY's different effects on CYP450 isozymes in normal and liver fibrosis rats. PMID:26226765

  4. Characterization of Atomoxetine Biotransformation and Implications for Development of PBPK Models for Dose Individualization in Children.

    PubMed

    Dinh, Jean C; Pearce, Robin E; Van Haandel, Leon; Gaedigk, Andrea; Leeder, J Steven

    2016-07-01

    Atomoxetine (ATX) is a second-line nonstimulant medication used to control symptoms of attention deficit hyperactivity disorder (ADHD). Inconsistent therapeutic efficacy has been reported with ATX, which may be related to variable CYP2D6-mediated drug clearance. We characterized ATX metabolism in a panel of human liver samples as a basis for a bottom-up PBPK model to aid in ATX exposure prediction and control. Km, Vmax, and Clint values in pooled human liver microsomes (HLMs) were 2.4 µM, 479 pmol/min/mg protein, and 202 µl/min/mg protein, respectively. Mean population values of kinetic parameters are not adequate to describe variability in a population, given that Km, Vmax, and Clint values from single-donor HLMs ranged from 0.93 to 79.2 µM, 20.0 to 1600 pmol/min/mg protein, and 0.3 to 936 µl/min/mg protein. All kinetic parameters were calculated from 4-hydroxyatomoxetine (4-OH-ATX) formation. CYP2E1 and CYP3A contributed to 4-OH-ATX formation in livers with CYP2D6 intermediate and poor metabolizer status. In HLMs with lower CYP2D6 activity levels, 2-hydroxymethylatomoxetine (2-CH2OH-ATX) formation became a more predominant pathway of metabolism, which appeared to be catalyzed by CYP2B6. ATX biotransformation at clinically relevant plasma concentrations was characterized in a panel of pediatric HLM (n = 116) samples by evaluating primary metabolites. Competing pathways of ATX metabolism [N-desmethylatomoxetine (NDM-ATX) and 2-CH2OH-ATX formation] had increasing importance in livers with lesser CYP2D6 activity, but, overall ATX clearance was still compromised. Modeling ATX exposure to individualize therapy would require comprehensive knowledge of factors that affect CYP2D6 activity as well as an understanding of competing pathways, particularly for individuals with lower CYP2D6 activity. PMID:27052878

  5. CYP2D6*2 Polymorphism as a Predictor of Failed Outpatient Tramadol Therapy in Postherpetic Neuralgia Patients.

    PubMed

    Nasare, Namita Vilas; Banerjee, Basu Dev; Suryakantrao Deshmukh, Pravin; Mediratta, Pramod Kumari; Saxena, Ashok Kumar; Ahmed, Rafat Sultana; Bhattacharya, Sambit Nath

    2016-01-01

    Human cytochrome P4502D6 (CYP2D6) gene is highly polymorphic, leading to wide interindividual ethnic differences in CYP2D6-mediated drug metabolism. Its activity ranges from complete deficiency to excessive activity, potentially causing toxicity of the medication or therapeutic failure with recommended drug dosages. The aim of the study was to find the association of CYP2D6*2 polymorphisms with demographic characters (age, sex, and weight), pain intensity scales [numerical rating scale (NRS) sleep, global perceived effect (GPE)], and adverse drug effects in postherpetic neuralgia (PHN) patients receiving tramadol. The study comprised 246 patients [including 123 nonresponders (NRs) and 123 responders (Rs)] with PHN undergoing analgesic treatment at the pain clinic, Out Patient Department, University College of Medical Sciences, Guru Teg Bahadur Hospital, Delhi, India. Patients with any history of diabetes mellitus, human immunodeficiency virus, malignancy, hematological or liver disease, psychiatric illness, alcohol abuse, and tramadol sensitivity were excluded from the study. The NRSs of (resting and movement), NRS-sleep, and GPE were evaluated by the treating physician. Adverse drug effects during the time of the study were recorded. All samples were analyzed for CYP2D6*2 polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. The genotype distribution did not vary significantly among genders [NR (P = 0.723); R (P = 0.947)] and different age groups in NRs (P = 0.763) and Rs (P = 0.268). Clinically, statistically significant (P < 0.001) results were obtained in both the groups when compared with baseline in the NRS-sleep and GPE scores, whereas no association was found between NRS-sleep and GPE scores when compared with CYP2D6*2 genotype (P > 0.05). In addition, CYP2D6*2 genotype was not related to the adverse effects of analgesic therapy. The overall results suggested that CYP2D6*2 polymorphism plays no role in the PHN

  6. Polymorphism of human cytochrome P-450.

    PubMed

    Guengerich, F P; Umbenhauer, D R; Churchill, P F; Beaune, P H; Böcker, R; Knodell, R G; Martin, M V; Lloyd, R S

    1987-03-01

    The cytochrome P-450 forms involved in debrisoquine 4-hydroxylation (P-450DB), phenacetin O-deethylation (P-450PA), S-mephenytoin 4-hydroxylation (P-450MP), and nifedipine 1,4-oxidation (P-450NF) have been purified to electrophoretic homogeneity from human liver microsomes. All of these reactions show in vivo polymorphism in humans. Evidence for the roles of the purified proteins in these processes comes from in vitro reconstitution and immunoinhibition studies. The rat orthologs of these enzymes are as follows--P-450DB: P-450UT-H; P-450PA: P-450ISF-G; P-450MP: P-450UT-I; P-450NF: P-450PCN-E. Only in the case of P-450UT-H is the primary rat ortholog the same cytochrome P-450 which catalyses the catalytic reaction under consideration. Reconstitution and immunochemical studies establish that the following reactions are catalysed by the individual P-450s--P-450DB: debrisoquine 4-hydroxylation, sparteine delta 5-oxidation, bufuralol 1'-hydroxylation, encainide O-demethylation, and propanolol 4-hydroxylation; P-450PA: phenacetin O-deethylation; P-450MP: S-mephenytoin 4-hydroxylation and tolbutamide methyl hydroxylation; P-450NF: oxidation of nifedipine and 16 other substituted dihydropyridines, estradiol 2- and 4-hydroxylation, aldrin epoxidation, benzphetamine N-demethylation and 6 beta-hydroxylation of testosterone, androstenedione and cortisol. A cDNA clone has been isolated that corresponds to rat P-450UT-H, as shown by a number of criteria. Studies with this probe establish that the sex and strain variation in debrisoquine 4-hydroxylase and related activities is related to differences in the levels of a 2.0 kb length mRNA present.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3577206

  7. Anti-austeric activity of phenolic constituents of seeds of Arctium lappa.

    PubMed

    Tezuka, Yasuhiro; Yamamoto, Keiichi; Awale, Suresh; Lia, Feng; Yomoda, Satoshi; Kadota, Shigetoshi

    2013-04-01

    From seeds of Arctium lappa L. (Asteraceae) we obtained arctigenin (1), arctiin (2), chlorogenic acid (3), 4,5-dicaffeoylquinic acid (4), 3,5-dicaffeoylquinic acid (5), 3,4-dicaffeoylquinic acid (6), matairesinol (11), isolappaol A (12), lappaol F (14), and lappaol B (15), together with 1:1 mixtures of isolappaol C (7) and lappaol C (8), arctignan E (9) and arctignan D (10), and 12 and lappaol A (13), while 3,3',4'-tri-O-demethylarctigenin (16), 3,3'-di-O-demethyl-4'-dehydroxyarctigenin (17), and 3-O-demethylarctigenin (18) were obtained by anaerobic microbiological metabolism of 1. Then, we evaluated the in vitro preferential cytotoxic activity of these pure compounds and 1:1 mixtures, together with enterodiol (19) and enterolactone (20), against human pancreatic cancer PANC-1 cells in nutrient-deprived medium (NDM). Among them, 1 and 18 showed potent activity, with PC50 values of 1.75 and 4.38 microM, respectively, while 11, 15, and 17 showed mild activity with PC50 values of 31.1, 30.9, and 38.7 microM, respectively. By comparing their structures and PC50 values, the following structural moieties could be concluded to be important for the preferential cytotoxicity of 1: 1) the 3-hydroxy-4-methoxyphenyl group at the 2-position on the gamma-butyrolactone ring, 2) the less polar substituent at the 3-position on the gamma-butyrolactone ring, and 3) the gamma-butyrolactone ring. PMID:23738454

  8. Effect of proglycosyn and other phenolic compounds on glycogen metabolism in isolated hepatocytes. Potential role of glucuronidated metabolites.

    PubMed

    Van Schaftingen, E; de Hoffmann, E

    1993-12-01

    The mechanism by which proglycosyn (LY 177,507) stimulates glycogen synthesis in isolated hepatocytes [Harris, R. A., Yamanouchi, K., Roach, P. J., Yen, T. T., Dominiani, S. J. & Stephens, T. W. (1989) J. Biol. Chem. 264, 13674-13680] has been investigated. When incubated in the presence of hepatocytes, proglycosyn was metabolized to an O-demethylated glucuronidated derivative, as determined by fast-atom-bombardment mass spectrometry and enzymic analysis. This metabolite accumulated almost linearly inside the cells to reach a concentration of approximately 3 mumol/g protein after 50 min, without apparent release into the medium. In confirmation of previous work, proglycosyn decreased the level of phosphorylase a and increased that of synthase a in hepatocytes. Washing of cells incubated with proglycosyn for 30 min considerably decreased the concentration of the drug without significantly modifying the intracellular concentration of the metabolite and the activation state of glycogen synthase. Several compounds bearing structural analogy with proglycosyn were also tested for their effect on glycogen metabolism. At millimolar or submillimolar concentrations, resorcinol, m-anisidine, phenol, 3-hydroxyacetophenone, and 3-acetamidophenol, although not 4-acetamidophenol, stimulated the incorporation of [14C]glucose into glycogen, decreased the level of phosphorylase a and increased the level of synthase a. In the case of phenol, the effect on the glycogen enzymes paralleled the intracellular accumulation of phenylglucuronide. Furthermore, ethanol and D-galactosamine, which decreased the conversion of phenol to phenylglucuronide and the intracellular concentration of phenylglucuronide, counteracted the effect of phenol on the synthase and on the phosphorylase. From these results, it is suggested that the effect of proglycosyn and of simpler phenol derivatives is mediated by glucuronidated metabolites, which act on an intracellular target. PMID:8269965

  9. Inhibitory effects of phytochemicals on metabolic capabilities of CYP2D6*1 and CYP2D6*10 using cell-based models in vitro

    PubMed Central

    Qu, Qiang; Qu, Jian; Han, Lu; Zhan, Min; Wu, Lan-xiang; Zhang, Yi-wen; Zhang, Wei; Zhou, Hong-hao

    2014-01-01

    Aim: Herbal products have been widely used, and the safety of herb-drug interactions has aroused intensive concerns. This study aimed to investigate the effects of phytochemicals on the catalytic activities of human CYP2D6*1 and CYP2D6*10 in vitro. Methods: HepG2 cells were stably transfected with CYP2D6*1 and CYP2D6*10 expression vectors. The metabolic kinetics of the enzymes was studied using HPLC and fluorimetry. Results: HepG2-CYP2D6*1 and HepG2-CYP2D6*10 cell lines were successfully constructed. Among the 63 phytochemicals screened, 6 compounds, including coptisine sulfate, bilobalide, schizandrin B, luteolin, schizandrin A and puerarin, at 100 μmol/L inhibited CYP2D6*1- and CYP2D6*10-mediated O-demethylation of a coumarin compound AMMC by more than 50%. Furthermore, the inhibition by these compounds was dose-dependent. Eadie-Hofstee plots demonstrated that these compounds competitively inhibited CYP2D6*1 and CYP2D6*10. However, their Ki values for CYP2D6*1 and CYP2D6*10 were very close, suggesting that genotype-dependent herb-drug inhibition was similar between the two variants. Conclusion: Six phytochemicals inhibit CYP2D6*1 and CYP2D6*10-mediated catalytic activities in a dose-dependent manner in vitro. Thus herbal products containing these phytochemicals may inhibit the in vivo metabolism of co-administered drugs whose primary route of elimination is CYP2D6. PMID:24786236

  10. Determination of N,N-dimethyltryptamine and beta-carboline alkaloids in human plasma following oral administration of Ayahuasca.

    PubMed

    Yritia, Mercedes; Riba, Jordi; Ortuño, Jordi; Ramirez, Ariel; Castillo, Araceli; Alfaro, Yolanda; de la Torre, Rafael; Barbanoj, Manel J

    2002-11-01

    Ayahuasca is a South American psychotropic beverage prepared from plants native to the Amazon River Basin. It combines the hallucinogenic agent and 5-HT(2A/2C) agonist N,N-dimethyltryptamine (DMT) with beta-carboline alkaloids showing monoamine oxidase-inhibiting properties. In the present paper, an analytical methodology for the plasma quantification of the four main alkaloids present in ayahuasca plus two major metabolites is described. DMT was extracted by liquid-liquid extraction with n-pentane and quantified by gas chromatography with nitrogen-phosphorus detection. Recovery was 74%, and precision and accuracy were better than 9.9%. The limit of quantification (LOQ) was 1.6 ng/ml. Harmine, harmaline, and tetrahydroharmine (THH), the three main beta-carbolines present in ayahuasca, and harmol and harmalol (O-demethylation metabolites of harmine and harmaline, respectively) were measured in plasma by means of high-performance liquid chromatography (HPLC) with fluorescence detection. Sample preparation was accomplished by solid-phase extraction, which facilitated the automation of the process. All five beta-carbolines were measured using a single detector by switching wavelengths. Separation of harmol and harmalol required only slight changes in the chromatographic conditions. Method validation demonstrated good recoveries, above 87%, and accuracy and precision better than 13.4%. The LOQ was 0.5 ng/ml for harmine, 0.3 ng/ml for harmaline, 1.0 ng/ml for THH, and 0.3 ng/ml for harmol and harmalol. Good linearity was observed in the concentration ranges evaluated for DMT (2.5-50 ng/ml) and the beta-carbolines (0.3-100 ng/ml). The gas chromatography and HPLC methods described allowed adequate characterization of the pharmacokinetics of the four main alkaloids present in ayahuasca, and also of two major beta-carboline metabolites not previously described in the literature. PMID:12361741

  11. Studies on the metabolism and toxicological detection of glaucine, an isoquinoline alkaloid from Glaucium flavum (Papaveraceae), in rat urine using GC-MS, LC-MS(n) and LC-high-resolution MS(n).

    PubMed

    Meyer, Golo M J; Meyer, Markus R; Wissenbach, Dirk K; Maurer, Hans H

    2013-01-01

    Glaucine ((S)-5,6,6a,7-tetrahydro-1,2,9,10-tetramethoxy-6-methyl-4H-dibenzo [de,g]quinoline) is an isoquinoline alkaloid and main component of Glaucium flavum (Papaveraceae). It was described to be consumed as recreational drug alone or in combination with other drugs. Besides this, glaucine is used as therapeutic drug in Bulgaria and other countries as cough suppressant. Currently, there are no data available concerning metabolism and toxicological analysis of glaucine. To study both, glaucine was orally administered to Wistar rats and urine was collected. For metabolism studies, work-up of urine samples consisted of protein precipitation or enzymatic cleavage followed by solid-phase extraction. Samples were afterwards measured by liquid chromatography (LC) coupled to low or high-resolution mass spectrometry (HR-MS). The phase I and II metabolites were identified by detailed interpretation of the corresponding fragmentations, which were further confirmed by determination of their elemental composition using HR-MS. From these data, the following metabolic pathways could be proposed: O-demethylation at position 2, 9 and 10, N-demethylation, hydroxylation, N-oxidation and combinations of them as well as glucuronidation and/or sulfation of the phenolic metabolites. For monitoring a glaucine intake in case of abuse or poisoning, the O- and N-demethylated metabolites were the main targets for the gas chromatography-MS and LC-MS(n) screening approaches described by the authors. Both allowed confirming an intake of glaucine in rat urine after a dose of 2 mg/kg body mass corresponding to a common abuser's dose. PMID:23303745

  12. Effects of CYP2D6 Status on Harmaline Metabolism, Pharmacokinetics and Pharmacodynamics, and a Pharmacogenetics-Based Pharmacokinetic Model

    PubMed Central

    Wu, Chao; Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

    2009-01-01

    Harmaline is a β-carboline alkaloid showing neuroprotective and neurotoxic properties. Our recent studies have revealed an important role for cytochrome P450 2D6 (CYP2D6) in harmaline O-demethylation. This study, therefore, aimed to delineate the effects of CYP2D6 phenotype/genotype on harmaline metabolism, pharmacokinetics (PK) and pharmacodynamics (PD), and to develop a pharmacogenetics mechanism-based compartmental PK model. In vitro kinetic studies on metabolite formation in human CYP2D6 extensive metabolizer (EM) and poor metabolizer (PM) hepatocytes indicated that harmaline O-demethylase activity (Vmax/Km) was about 9-fold higher in EM hepatocytes. Substrate depletion showed mono-exponential decay trait, and estimated in vitro harmaline clearance (CLint, μL/min/106 cells) was significantly lower in PM hepatocytes (28.5) than EM hepatocytes (71.1). In vivo studies in CYP2D6-humanized and wild-type mouse models showed that wild-type mice were subjected to higher and longer exposure to harmaline (5 and 15 mg/kg; i.v. and i.p.), and more severe hypothermic responses. The PK/PD data were nicely described by our pharmacogenetics-based PK model involving the clearance of drug by CYP2D6 (CLCYP2D6) and other mechanisms (CLother), and an indirect response PD model, respectively. Wild-type mice were also more sensitive to harmaline in marble-burying tests, as manifested by significantly lower ED50 and steeper Hill slope. These findings suggest that distinct CYP2D6 status may cause considerable variations in harmaline metabolism, PK and PD. In addition, the pharmacogenetics-based PK model may be extended to define PK difference caused by other polymorphic drug-metabolizing enzyme in different populations. PMID:19445902

  13. Degradation of Triazine-2-(14)C Metsulfuron-Methyl in Soil from an Oil Palm Plantation.

    PubMed

    Ismail, B S; Eng, O K; Tayeb, M A

    2015-01-01

    Triazine-2-(14)C metsulfuron-methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-(14)C metsulfuron-methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP-1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of (14)CO2 in (14)C-triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine "ring-opened." PMID:26437264

  14. Effect of encainide and its two major metabolites on cardiac conduction.

    PubMed

    Dresel, P E

    1984-01-01

    The effect of encainide and its two major metabolites, O-demethylated encainide (MJ 9444) and 3-O-methoxy encainide (MJ 14030), on cardiac conduction was studied by recording His bundle potentials in isolated perfused rabbit hearts and Purkinje and muscle conduction in vivo in dog hearts after destruction of the atrioventricular node. Both metabolites are 4 to 15 times more potent than encainide in slowing conduction through the atria, the AV-node and the His-Purkinje system of the rabbit heart. They did not differ from each other in potency but MJ 9444 increased the duration and decreased the height of the ventricular potential whereas MJ 14030 had no effect at doses which caused conduction block. In the dog, encainide (0.8-3.2 mg/kg i.v.) slowed conduction of extrasystoles in both Purkinje and muscle at all coupling intervals, increased the effective refractory period and the functional refractory period of the Purkinje pathway. MJ 9444 (0.05-0.4 mg/kg) speeded Purkinje conduction of early (less than 300 msec) without affecting or while slowing conduction of late (greater than 350 msec) extrasystoles. Higher doses (0.4-1.6 mg/kg) slowed conduction at all intervals. The effective refractory period and the functional refractory period were decreased but in some cases returned to control values at the higher doses. Muscle conduction was slowed at doses of 0.4 mg/kg or more. MJ 14030 (0.05-3.2 mg/kg) had variable effects, behaving like MJ 9444 in three experiments but like the parent compound in two others. Only slowing of conduction was seen with the three drugs when heart rate was changed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6420542

  15. Studies on the Biotransformation of Veratric Acid, a Human Metabolite of Mebeverine, by Using the Incubated Hen's Egg.

    PubMed

    Kiep, L; Göhl, M; Schmidt, J; Seifert, K

    2015-09-01

    Metabolism studies with selected test substances have shown that a model on the basis of the incubated hen's egg is suitable as a supplement to animal experimentation. Because of its 3,4-dimethoxyphenyl structure veratric acid (3,4-dimethoxybenzoic acid), a known human metabolite of mebeverine, was chosen as model substance for the present investigations and the parent compound as well as 4-hydroxy-3-methoxybenzoic acid were identified as main metabolites. The absence of 3-hydroxy-4-methoxybenzoic acid lets conclude that the O-demethylation takes place exclusively at the p-methoxyl function. In addition, 3,3',4,4'-tetramethoxy-l-ornithuric acid (2,5-bis-(3,4-dimethoxybenzoylamino)pentanoic acid) and its O-desmethyl derivative could be characterized as further metabolites. So far an amino acid conjugate has not been described after veratric acid administration in a vertebrate. There were no indications for the appearance of 3,4-dihydroxybenzoic acid in the veratric acid metabolism. This was confirmed by corresponding studies having the isomeric guaiacol acids as precursor. Furthermore, it could be proved that in ovo the O-methylation of 3,4-dihydroxybenzoic acid occurs regioselective at the m-hydroxyl group. The results which broaden the knowledge on the metabolic fate of veratric acid are discussed in comparison with those in mammals. The metabolites were identified by GC-MS, ESI-HRMS and LC/ESI-MS/MS. The structure of the synthesized reference substance was confirmed by MS, (1)H and (13)C NMR spectral data. PMID:25310250

  16. Cytochrome P450-like substrate oxidation catalyzed by cytochrome c and immobilized cytochrome c.

    PubMed

    Akasaka, R; Mashino, T; Hirobe, M

    1993-03-01

    Cytochrome c (cyt.c) was shown to catalyze cytochrome P450 (P450)-like oxidative reactions, such as N-, and O-demethylation, S-oxidation, and epoxidation of olefins. A more detailed examination showed that (i) N-methylcarbazole and thioanisole oxidation with H2(18)O2 catalyzed by cyt.c resulted in introduction of 18O into the product, and (ii) during the epoxidation of cis-stilbene catalyzed by cyt.c, the stereochemistry of the substrate was retained and 18O was introduced when H2(18)O2 was used as an oxidant. These results show that cyt.c catalyzed N-demethylation, S-oxidation, and epoxidation in the same manner as P450. To utilize these P450-like reactivities effectively, cyt.c was immobilized on poly-gamma-methyl-L-glutamate. Up to 99% of the cyt.c used was immobilized. This immobilized cyt.c catalyzed N-demethylation, S-oxidation, and epoxidation in the same manner as both P450 and free cyt.c, and the activities of these reactions were increased by the immobilization. In N-demethylation of N,N-dimethylaniline with cumene hydroperoxide (CHP) catalyzed by cyt.c, the Vmax for CHP was increased by 4.4-fold by the immobilization of the enzyme, while the Km remained unchanged. Since P450 is involved in the metabolism of many xenobiotics, the above results suggest that immobilized cyt.c may be useful in drug metabolism research. PMID:7681661

  17. Characterization of the 5-Carboxyvanillate Decarboxylase Gene and Its Role in Lignin-Related Biphenyl Catabolism in Sphingomonas paucimobilis SYK-6

    PubMed Central

    Peng, Xue; Masai, Eiji; Kitayama, Hirotaka; Harada, Kyo; Katayama, Yoshihiro; Fukuda, Masao

    2002-01-01

    Sphingomonas paucimobilis SYK-6 degrades a lignin-related biphenyl compound, 5,5′-dehydrodivanillate (DDVA), to 5-carboxyvanillate (5CVA) by the enzyme reactions catalyzed by the DDVA O-demethylase (LigX), the ring cleavage oxygenase (LigZ), and the meta-cleavage compound hydrolase (LigY). In this study we examined the degradation step of 5CVA. 5CVA was transformed to vanillate, O-demethylated, and further degraded via the protocatechuate 4,5-cleavage pathway by this strain. A cosmid clone which conferred the 5CVA degradation activity to a host strain was isolated. In the 7.0-kb EcoRI fragment of the cosmid we found a 1,002-bp open reading frame responsible for the conversion of 5CVA to vanillate, and we designated it ligW. The gene product of ligW (LigW) catalyzed the decarboxylation of 5CVA to produce vanillate along with the specific incorporation of deuterium from deuterium oxide, indicating that LigW is a nonoxidative decarboxylase of 5CVA. LigW did not require any metal ions or cofactors for its activity. The decarboxylase activity was specific to 5CVA. Inhibition experiments with 5CVA analogs suggested that two carboxyl groups oriented meta to each other in 5CVA are important to the substrate recognition by LigW. Gene walking analysis indicated that the ligW gene was located on the 18-kb DNA region with other DDVA catabolic genes, including ligZ, ligY, and ligX. PMID:12200294

  18. In vitro metabolism of l-corydalmine, a potent analgesic drug, in human, cynomolgus monkey, beagle dog, rat and mouse liver microsomes.

    PubMed

    Tang, Xiange; Di, Xinyu; Zhong, Zeyu; Xie, Qiushi; Chen, Yang; Wang, Fan; Ling, Zhaoli; Xu, Ping; Zhao, Kaijing; Wang, Zhongjian; Liu, Li; Liu, Xiaodong

    2016-09-01

    l-Corydalmine (l-CDL) was under development as an oral analgesic agent, exhibiting potent analgesic activity in preclinical models. The objective of this study was to compare metabolic profiles of l-CDL in liver microsomes from mouse, rat, monkey, dog and human. Six metabolites (M1-M6) were identified using LC-Q/TOF in liver microsomes from the five species. The metabolism of l-CDL included O-demethylation (M1-3) and hydroxylation (M4-6). The desmethyl metabolites were the major ones among the five species, which accounted for more than 84%. Data from chemical inhibition in human liver microsomes (HLM) and human recombinant CYP450s demonstrated that CYP2D6 exhibited strong catalytic activity towards M1 and M2 formations, while CYP2C9 and CYP2C19 also catalyzed M2 formation. Formations of M3 and hydroxyl metabolites (M4 and M5) were mainly catalyzed by CYP3A4. Further studies showed that M1 and M2 were main metabolites in HLM. The kinetics of M1 and M2 formations in HLM and recombinant CYP450s were also investigated. The results showed that M1 and M2 formations in HLM and recombinant CYP2D6 characterized biphasic kinetics, whereas sigmoid Vmax model was better used to fit M2 formation by recombinant CYP2C9 and CYP2C19. The contributions of CYP2D6 to M1 and M2 formations in HLM were estimated to be 75.3% and 50.7%, respectively. However, the contributions of CYP2C9 and CYP2C19 to M2 formation were only 5.0% and 4.1%, respectively. All these data indicated that M1 and M2 were main metabolites in HLM, and CYP2D6 was the primary enzyme responsible for their formations. PMID:27239758

  19. Identification of new oxycodone metabolites in human urine by capillary electrophoresis-multiple-stage ion-trap mass spectrometry.

    PubMed

    Baldacci, A; Caslavska, J; Wey, A B; Thormann, W

    2004-10-01

    Capillary electrophoresis-electrospray ionization multiple-stage ion-trap mass spectrometry (CE-MSn) and computer simulation of fragmentation are demonstrated to be effective tools to detect and identify phase I and phase II metabolites of oxycodone (OCOD) in human urine. OCOD is a strong analgesic used for the management of moderate to severe mainly postoperative or cancer-related pain whose metabolism in man is largely unknown. Using an aqueous pH 9 ammonium acetate buffer and CE-MSn (n < or = 5), OCOD and its phase I metabolites produced by O-demethylation, N-demethylation, 6-ketoreduction and N-oxidation (such as oxymorphone, noroxycodone, noroxymorphone, 6-oxycodol, nor-6-oxycodol, oxycodone-N-oxide and 6-oxycodol-N-oxide) and phase II conjugates with glucuronic acid of several of these compounds could be detected in alkaline solid-phase extracts of a patient urine that was collected during a pharmacotherapy episode with daily ingestion of 240-320 mg of OCOD chloride. The data for three known OCOD metabolites for which the standards had to be synthesized in-house, 6-oxycodol, nor-6-oxycodol and oxycodone-N-oxide, were employed to identify two new metabolites, the N-oxidized derivative of 6-oxycodol and an O-glucuronide of this compound. CE-MSn and computer simulation of fragmentation also led to the identification of the N-glucuronide of noroxymorphone, another novel OCOD metabolite for which no standard compound or mass spectra library data were available. PMID:15532584

  20. Pharmacokinetics and metabolism of the prodrug DB289 (2,5-bis[4-(N-methoxyamidino)phenyl]furan monomaleate) in rat and monkey and its conversion to the antiprotozoal/antifungal drug DB75 (2,5-bis(4-guanylphenyl)furan dihydrochloride).

    PubMed

    Midgley, Ian; Fitzpatrick, Karen; Taylor, Lynne M; Houchen, Tara L; Henderson, Simon J; Wright, Sarah J; Cybulski, Zbigniew R; John, Brian A; McBurney, Alan; Boykin, David W; Trendler, Kerri L

    2007-06-01

    DB289 (pafuramidine maleate; 2,5-bis[4-(N-methoxyamidino)phenyl]furan monomaleate) is a prodrug of DB75 (furamidine dihydrochloride; 2,5-bis(4-guanylphenyl)furan dihydrochloride), an aromatic dication related to pentamidine that has demonstrated good efficacy against African trypanosomiasis, Pneumocystis carinii pneumonia, and malaria, but lacks adequate oral availability. The pharmacokinetics and metabolism of 14C-DB289 have been investigated in rat and monkey after oral and intravenous administration. Oral doses were well absorbed (approximately 50-70%) and effectively converted to DB75 in both species but subject to first-pass metabolism and hepatic retention, limiting its systemic bioavailability to 10 to 20%. Clearance of DB289 approximated the liver plasma flow and its large volume of distribution was consistent with extensive tissue binding. Plasma protein binding of DB289 was 97 to 99% in four animal species and humans, but that of DB75 was noticeably less and more species- and concentration-dependent. Together, prodrug and active metabolite accounted for less than 20% of the plasma radioactivity after an oral dose, but DB75 was the major radiochemical component in key organs such as brain and liver and was largely responsible for the persistence of 14C in the body. The predominant route of excretion of radioactivity was via the feces, although biliary secretion was not particularly extensive. High-performance liquid chromatography and liquid chromatography-mass spectrometry investigations showed that the formation of DB75 from the prodrug involved the sequential loss of the two N-methoxy groups, either directly or by O-demethylation followed by reduction of the resulting oxime to the amidine. It was estimated that almost half of an oral dose of DB289 to rats and about one-third of that to monkeys was metabolized to DB75. PMID:17360833

  1. Search for fungi-specific metabolites of four model drugs in postmortem blood as potential indicators of postmortem fungal metabolism.

    PubMed

    Martínez-Ramírez, Jorge A; Strien, Juliane; Walther, Grit; Peters, Frank T

    2016-05-01

    Fungi colonizing cadavers are capable of drug metabolism and may thus change the metabolite pattern or concentration of drugs in forensic postmortem samples. The purpose of this study was to check for the presence of such changes by searching fungi-specific metabolites of four model drugs (amitriptyline, metoprolol, mirtazapine, and zolpidem) in decomposed postmortem blood samples from 33 cases involving these drugs. After isolation and identification of fungal strains present in the samples, each isolate was incubated in Sabouraud medium at 25°C for up to 120h with each model drug. One part of the supernatants was directly analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), another after liquid-liquid extraction with chlorobutane and concentration. From 21 out of 33 decomposed postmortem blood samples (64%) a total of 30 different strains could be isolated, one from the class of Ascomycete and the rest belonging to 15 species from 8 different genera (number of species): Aspergillus (2), Botrytis (1), Candida (8), Fusarium (1), Mucor (1), Penicillium (1), and Rodothorula (1). In the in vitro studies, these microorganisms were found capable of N-demethylation and N-oxidation of amitriptyline and mirtazapine, O-demethylation followed by side chain oxidation of metoprolol as well as hydroxylation of all four-model drugs. In two of the postmortem blood samples, from which the fungi Aspergillus jensenii, Candida parapsilosis. and Mucor circinelloides had been isolated, a fungi-specific hydroxy zolpidem metabolite was detected. The presence of this metabolite in postmortem samples likely indicates postmortem fungal biodegradation. PMID:27022860

  2. Degradation of Triazine-2-14C Metsulfuron–Methyl in Soil from an Oil Palm Plantation

    PubMed Central

    B. S., Ismail

    2015-01-01

    Triazine-2-14C metsulfuron–methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-14C metsulfuron–methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP–1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of 14CO2 in 14C- triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine “ring-opened.” PMID:26437264

  3. Amlodipine metabolism in human liver microsomes and roles of CYP3A4/5 in the dihydropyridine dehydrogenation.

    PubMed

    Zhu, Yanlin; Wang, Fen; Li, Quan; Zhu, Mingshe; Du, Alicia; Tang, Wei; Chen, Weiqing

    2014-02-01

    Amlodipine is a commonly prescribed calcium channel blocker for the treatment of hypertension and ischemic heart disease. The drug is slowly cleared in humans primarily via dehydrogenation of its dihydropyridine moiety to a pyridine derivative (M9). Results from clinical drug-drug interaction studies suggest that CYP3A4/5 mediate metabolism of amlodipine. However, attempts to identify a role of CYP3A5 in amlodipine metabolism in humans based on its pharmacokinetic differences between CYP3A5 expressers and nonexpressers failed. Objectives of this study were to determine the metabolite profile of amlodipine (a racemic mixture and S-isomer) in human liver microsomes (HLM), and to identify the cytochrome P450 (P450) enzyme(s) involved in the M9 formation. Liquid chromatography/mass spectrometry analysis showed that amlodipine was mainly converted to M9 in HLM incubation. M9 underwent further O-demethylation, O-dealkylation, and oxidative deamination to various pyridine derivatives. This observation is consistent with amlodipine metabolism in humans. Incubations of amlodipine with HLM in the presence of selective P450 inhibitors showed that both ketoconazole (an inhibitor of CYP3A4/5) and CYP3cide (an inhibitor of CYP3A4) completely blocked the M9 formation, whereas chemical inhibitors of other P450 enzymes had little effect. Furthermore, metabolism of amlodipine in expressed human P450 enzymes showed that only CYP3A4 had significant activity in amlodipine dehydrogenation. Metabolite profiles and P450 reaction phenotyping data of a racemic mixture and S-isomer of amlodipine were very similar. The results from this study suggest that CYP3A4, rather than CYP3A5, plays a key role in metabolic clearance of amlodipine in humans. PMID:24301608

  4. Pharmacogenetics of drug oxidation via cytochrome P450 (CYP) in the populations of Denmark, Faroe Islands and Greenland.

    PubMed

    Brosen, Kim

    2015-09-01

    Denmark, the Faroe Islands and Greenland are three population-wise small countries on the northern part of the Northern Hemisphere, and studies carried out here on the genetic control over drug metabolism via cytochrome P450 have led to several important discoveries. Thus, CYP2D6 catalyzes the 2-hydroxylation, and CYP2C19 in part catalyzes the N-demethylation of imipramine. The phenomenon of phenocopy with regard to CYP2D6 was first described when Danish patients changed phenotype from extensive to poor metabolizers during treatment with quinidine. It was a Danish extensive metabolizer patient that became a poor metabolizer during paroxetine treatment, and this was due to the potent inhibition of CYP2D6 by paroxetine, which is also is metabolized by this enzyme. Fluoxetine and norfluoxetine are also potent inhibitors of CYP2D6, and fluvoxamine is a potent inhibitor of both CYP1A2 and CYP2C19. The bioactivation of proguanil to cycloguanil is impaired in CYP2C19 poor metabolizers. The O-demethylation of codeine and tramadol to their respective my-opioid active metabolites, morphine and (+)-O-desmethyltramadol was markedly impaired in CYP2D6 poor metabolizers compared to extensive metabolizers, and this impairs the hypoalgesic effect of the two drugs in the poor metabolizers. The frequency of CYP2D6 poor metabolizers is 2%-3% in Greenlanders and nearly 15% in the Faroese population. The frequency of CYP2C19 poor metabolizers in East Greenlanders is approximately 10%. A study in Danish mono and dizygotic twins showed that the non-polymorphic 3-N-demethylation of caffeine catalyzed by CYP1A2 is subject to approximately 70% genetic control. PMID:25719307

  5. Isoxanthohumol--Biologically active hop flavonoid.

    PubMed

    Żołnierczyk, Anna Katarzyna; Mączka, Wanda Krystyna; Grabarczyk, Małgorzata; Wińska, Katarzyna; Woźniak, Edyta; Anioł, Mirosław

    2015-06-01

    Isoxanthohumol (IXN), apart from xanthohumol (XN) and 8-prenylnaringenin (8PN), is one of the most important prenylflavonoids found in hops. Another natural source of this compound is a shrub Sophora flavescens, used in traditional Chinese medicine. Main dietary source of IXN is beer, and the compound is produced from XN during wort boiling. In the human body, the compound is O-demethylated to 8PN, the strongest known phytoestrogen. This process takes place in the liver and in the intestine, where it is mediated by local microflora. It has been reported in some studies that even though beer contains small amounts of hops and its preparations, these compounds may affect the functioning of the human body. IXN exhibits an antiproliferative activity against human cell lines typical for breast cancer (MCF-7), ovarian cancer (A-2780), prostate cancer (DU145 and PC-3), and colon cancer (HT-29 and SW620) cells. It strongly inhibits the activation of the following carcinogens: 2-amino-3-methylimidazol-[4,5-f]quinoline and aflatoxin B1 (AFB1) via human cytochrome P450 (CYP1A2). It also inhibits the production of prostate specific antigen (PSA). IXN significantly reduces the expression of transforming growth factor-β (TGF-β) in the case of invasive breast cancer MDA-MB-231. It interferes with JAK/STAT signaling pathway and inhibits the expression of pro1inflammatory genes in the monoblastic leukemia cell line (MonoMac6). It activates apoptosis in human umbilical vein endothelial cells (HUVEC) and human aortic smooth muscle cells (HASMCs). In addition, IXN shows an antiviral activity towards herpes viruses (HSV1 and HSV2) and bovine viral diarrhea virus (BVDV). PMID:25771121

  6. Synthesis and resolution of (+-)-7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro- 1H-3- benzazepine (TISCH): A high affinity and selective iodinated ligand for CNS D1 dopamine receptor

    SciTech Connect

    Chumpradit, S.; Kung, M.P.; Billings, J.J.; Kung, H.F. )

    1991-03-01

    The synthesis and resolution of (+-)-7-chloro-8-hydroxy-1-(3'-iodophenyl)-3-methyl-2,3,4,5-tetrahydro-1 H-3- benzazepine, (+/-)-TISCH (8) has been achieved by resolution of intermediate 4, the O-methoxyl, 3'-bromo derivative, as the diastereomeric camphor sulfonate salt. The final products, R-(+)-8 and S-(-)-8, were prepared by treatment of R-(+)- or S-(-)-7, the 3'-tributyltin intermediates, with iodine in chloroform, followed by O-demethylation. By using HPLC with a chiral column, the optical purity (greater than 99%) of the intermediates and the final compounds was determined. Radioiodination was achieved by an iodo-destannylation reaction with sodium (125I)iodide and hydrogen peroxide. As expected, the R-(+)-(125I)-8 (the active isomer) displayed high affinity and selectivity to the CNS D-1 receptor in rat striatum tissue preparation (Kd = 0.205 nM). The rank order of potency was as follows: SCH-23390 (1a) greater than (+/-)-8 greater than (+)-butaclamol greater than spiperone, WB4101 greater than dopamine, 5-HT. After an iv injection, the R-(+)-(125I)-8 penetrated the blood-brain barrier with ease and displayed specific regional distribution corresponding to the D-1 receptor density, while the S-(-)-(125I)-8 showed no specific uptake. The data suggest that the ligand may be useful as a pharmacological tool for characterizing the D-1 dopamine receptor. When labeled with I-123, this ligand is a potential agent for in vivo imaging of CNS D-1 dopamine receptor.

  7. Metabolism of the 18O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria.

    PubMed

    DeWeerd, K A; Saxena, A; Nagle, D P; Suflita, J M

    1988-05-01

    O-methyl substituents of aromatic compounds can provide C1 growth substrates for facultative and strict anaerobic bacteria isolated from diverse environments. The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. Using high-pressure liquid chromatography and gas chromatography-mass spectral analysis, we found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium limosum, and a strain of Acetobacterium woodii metabolized 3-[methoxy-18O]methoxybenzoic acid (3-anisic acid) to 3-[hydroxy-18O]hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium, Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments. The results clearly indicate a methyl rather than methoxy group removal mechanism for such reactions. PMID:3389815

  8. Metabolism of the 18O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria.

    PubMed Central

    DeWeerd, K A; Saxena, A; Nagle, D P; Suflita, J M

    1988-01-01

    O-methyl substituents of aromatic compounds can provide C1 growth substrates for facultative and strict anaerobic bacteria isolated from diverse environments. The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. Using high-pressure liquid chromatography and gas chromatography-mass spectral analysis, we found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium limosum, and a strain of Acetobacterium woodii metabolized 3-[methoxy-18O]methoxybenzoic acid (3-anisic acid) to 3-[hydroxy-18O]hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium, Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments. The results clearly indicate a methyl rather than methoxy group removal mechanism for such reactions. PMID:3389815

  9. Hydrastine pharmacokinetics and metabolism after a single oral dose of goldenseal (Hydrastis canadensis) to humans.

    PubMed

    Gupta, Prem K; Barone, Gary; Gurley, Bill J; Fifer, E Kim; Hendrickson, Howard P

    2015-04-01

    The disposition and metabolism of hydrastine was investigated in 11 healthy subjects following an oral dose of 2.7 g of goldenseal supplement containing 78 mg of hydrastine. Serial blood samples were collected for 48 hours, and urine was collected for 24 hours. Hydrastine serum and urine concentrations were determined by Liquid Chromatography-tandem mass spectrometry (LC-MS/MS). Pharmacokinetic parameters for hydrastine were calculated using noncompartmental methods. The maximal serum concentration (Cmax) was 225 ± 100 ng/ml, Tmax was 1.5 ± 0.3 hours, and area under the curve was 6.4 ± 4.1 ng ⋅ h/ml ⋅ kg. The elimination half-life was 4.8 ± 1.4 hours. Metabolites of hydrastine were identified in serum and urine by using liquid chromatography coupled to high-resolution mass spectrometry. Hydrastine metabolites were identified by various mass spectrometric techniques, such as accurate mass measurement, neutral loss scanning, and product ion scanning using Quadrupole-Time of Flight (Q-ToF) and triple quadrupole instruments. The identity of phase II metabolites was further confirmed by hydrolysis of glucuronide and sulfate conjugates using bovine β-glucuronidase and a Helix pomatia sulfatase/glucuronidase enzyme preparation. Hydrastine was found to undergo rapid and extensive phase I and phase II metabolism. Reduction, O-demethylation, N-demethylation, hydroxylation, aromatization, lactone hydrolysis, and dehydrogenation of the alcohol group formed by lactone hydrolysis to the ketone group were observed during phase I biotransformation of hydrastine. Phase II metabolites were primarily glucuronide and sulfate conjugates. Hydrastine undergoes extensive biotransformation, and some metabolites may have pharmacological activity. Further study is needed in this area. PMID:25609220

  10. Novel Three-Component Rieske Non-Heme Iron Oxygenase System Catalyzing the N-Dealkylation of Chloroacetanilide Herbicides in Sphingomonads DC-6 and DC-2

    PubMed Central

    Chen, Qing; Wang, Cheng-Hong; Deng, Shi-Kai; Wu, Ya-Dong; Li, Yi; Yao, Li; Jiang, Jian-Dong; Yan, Xin; Li, Shun-Peng

    2014-01-01

    Sphingomonads DC-6 and DC-2 degrade the chloroacetanilide herbicides alachlor, acetochlor, and butachlor via N-dealkylation. In this study, we report a three-component Rieske non-heme iron oxygenase (RHO) system catalyzing the N-dealkylation of these herbicides. The oxygenase component gene cndA is located in a transposable element that is highly conserved in the two strains. CndA shares 24 to 42% amino acid sequence identities with the oxygenase components of some RHOs that catalyze N- or O-demethylation. Two putative [2Fe-2S] ferredoxin genes and one glutathione reductase (GR)-type reductase gene were retrieved from the genome of each strain. These genes were not located in the immediate vicinity of cndA. The four ferredoxins share 64 to 72% amino acid sequence identities to the ferredoxin component of dicamba O-demethylase (DMO), and the two reductases share 62 to 65% amino acid sequence identities to the reductase component of DMO. cndA, the four ferredoxin genes, and the two reductases genes were expressed in Escherichia coli, and the recombinant proteins were purified using Ni-affinity chromatography. The individual components or the components in pairs displayed no activity; the enzyme mixture showed N-dealkylase activities toward alachlor, acetochlor, and butachlor only when CndA-His6 was combined with one of the four ferredoxins and one of the two reductases, suggesting that the enzyme consists of three components, a homo-oligomer oxygenase, a [2Fe-2S] ferredoxin, and a GR-type reductase, and CndA has a low specificity for the electron transport component (ETC). The N-dealkylase utilizes NADH, but not NADPH, as the electron donor. PMID:24928877

  11. Repurposing psychiatric medicines to target activated microglia in anxious mild cognitive impairment and early Parkinson’s disease

    PubMed Central

    Lauterbach, Edward C

    2016-01-01

    Anxiety is common in the Mild Cognitive Impairment (MCI) stage of Alzheimer’s disease (AD) and the pre-motor stages of Parkinson’s disease (PD). A concomitant and possible cause of this anxiety is microglial activation, also considered a key promoter of neurodegeneration in MCI and early PD via inflammatory mechanisms and the generation of degenerative proinflammatory cytokines. Psychiatric disorders, prevalent in AD and PD, are often treated with psychiatric drugs (psychotropics), raising the question of whether psychotropics might therapeutically affect microglial activation, MCI, and PD. The literature of common psychotropics used in treating psychiatric disorders was reviewed for preclinical and clinical findings regarding microglial activation. Findings potentially compatible with reduced microglial activation or reduced microglial inflammogen release were evident for: antipsychotics including neuroleptics (chlorpromazine, thioridazine, loxapine) and atypicals (aripiprazole, olanzapine, quetiapine, risperidone, ziprasidone); mood stabilizers (carbamazepine, valproate, lithium); antidepressants including tricyclics (amitriptyline, clomipramine, imipramine, nortriptyline), SSRIs (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline), venlafaxine, and bupropion; benzodiazepine anxiolytics (clonazepam, diazepam); cognitive enhancers (donepezil, galantamine, memantine); and other drugs (dextromethorphan, quinidine, amantadine). In contrast, pramipexole and methylphenidate might promote microglial activation. The most promising replicated findings of reduced microglial activation are for quetiapine, valproate, lithium, fluoxetine, donepezil, and memantine but further study is needed and translation of their microglial effects to human disease still requires investigation. In AD-relevant models, risperidone, valproate, lithium, fluoxetine, bupropion, donepezil, and memantine have therapeutic microglial effects in need of replication. Limited

  12. Repurposing psychiatric medicines to target activated microglia in anxious mild cognitive impairment and early Parkinson's disease.

    PubMed

    Lauterbach, Edward C

    2016-01-01

    Anxiety is common in the Mild Cognitive Impairment (MCI) stage of Alzheimer's disease (AD) and the pre-motor stages of Parkinson's disease (PD). A concomitant and possible cause of this anxiety is microglial activation, also considered a key promoter of neurodegeneration in MCI and early PD via inflammatory mechanisms and the generation of degenerative proinflammatory cytokines. Psychiatric disorders, prevalent in AD and PD, are often treated with psychiatric drugs (psychotropics), raising the question of whether psychotropics might therapeutically affect microglial activation, MCI, and PD. The literature of common psychotropics used in treating psychiatric disorders was reviewed for preclinical and clinical findings regarding microglial activation. Findings potentially compatible with reduced microglial activation or reduced microglial inflammogen release were evident for: antipsychotics including neuroleptics (chlorpromazine, thioridazine, loxapine) and atypicals (aripiprazole, olanzapine, quetiapine, risperidone, ziprasidone); mood stabilizers (carbamazepine, valproate, lithium); antidepressants including tricyclics (amitriptyline, clomipramine, imipramine, nortriptyline), SSRIs (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline), venlafaxine, and bupropion; benzodiazepine anxiolytics (clonazepam, diazepam); cognitive enhancers (donepezil, galantamine, memantine); and other drugs (dextromethorphan, quinidine, amantadine). In contrast, pramipexole and methylphenidate might promote microglial activation. The most promising replicated findings of reduced microglial activation are for quetiapine, valproate, lithium, fluoxetine, donepezil, and memantine but further study is needed and translation of their microglial effects to human disease still requires investigation. In AD-relevant models, risperidone, valproate, lithium, fluoxetine, bupropion, donepezil, and memantine have therapeutic microglial effects in need of replication. Limited

  13. Evaluation of 89 compounds for identification of substrates for cynomolgus monkey CYP2C76, a new bupropion/nifedipine oxidase.

    PubMed

    Hosaka, Shinya; Murayama, Norie; Satsukawa, Masahiro; Shimizu, Makiko; Uehara, Shotaro; Fujino, Hideki; Iwasaki, Kazuhide; Iwano, Shunsuke; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-01-01

    Cynomolgus monkeys are widely used in preclinical studies during drug development because of their evolutionary closeness to humans, including their cytochrome P450s (P450s). Most cynomolgus monkey P450s are almost identical (≥90%) to human P450s; however, CYP2C76 has low sequence identity (approximately 80%) to any human CYP2Cs. Although CYP2C76 has no ortholog in humans and is partly responsible for species differences in drug metabolism between cynomolgus monkeys and humans, a broad evaluation of potential substrates for CYP2C76 has not yet been conducted. In this study, a screening of 89 marketed compounds, including human CYP2C and non-CYP2C substrates or inhibitors, was conducted to find potential CYP2C76 substrates. Among the compounds screened, 19 chemicals were identified as substrates for CYP2C76, including substrates for human CYP1A2 (7-ethoxyresorufin), CYP2B6 (bupropion), CYP2D6 (dextromethorphan), and CYP3A4/5 (dextromethorphan and nifedipine), and inhibitors for CYP2B6 (sertraline, clopidogrel, and ticlopidine), CYP2C8 (quercetin), CYP2C19 (ticlopidine and nootkatone), and CYP3A4/5 (troleandomycin). CYP2C76 metabolized a wide variety of the compounds with diverse structures. Among them, bupropion and nifedipine showed high selectivity to CYP2C76. As for nifedipine, CYP2C76 formed methylhydroxylated nifedipine, which was not produced by monkey CYP2C9, CYP2C19, or CYP3A4, as identified by mass spectrometry and estimated by a molecular docking simulation. This unique oxidative metabolite formation of nifedipine could be one of the selective marker reactions of CYP2C76 among the major CYP2Cs and CYP3As tested. These results suggest that monkey CYP2C76 contributes to bupropion hydroxylation and formation of different nifedipine oxidative metabolites as a result of its relatively large substrate cavity. PMID:25318994

  14. Ropizine concurrently enhances and inhibits ( sup 3 H) dextromethorpan binding to different structures of the guinea pig brain: Autoradiographic evidence for multiple binding sites

    SciTech Connect

    Canoll, P.D.; Smith, P.R.; and Musacchio, J.M. )

    1990-01-01

    Ropizine produces a simultaneous enhancement and inhibition of ({sup 3}H) dextromethorphan (DM) high-affinity binding to different areas of the guinea pig brain. These results imply that there are two distinct types of high-affinity ({sup 3}H)DM binding sites, which are present in variable proportions in different brain structures. The ropizine-enhances ({sup 3}H)DM binding type was preferentially inhibited by (+)-pentazocine. This is consistent with the presumption that the (+)-pentazocine-sensitive site is identical with the common site for DM and 3-(-3-Hydroxphenyl)-N-(1-propyl)piperidine ((+)-3-PPP). The second binding type, which is inhibited by ropizine and is not so sensitive to (+){minus} pentazocine, has not been fully characterized. This study demonstrates that the biphasic effects to ropizine are due, at least in part, to the effects of ropizine on two different types of ({sup 3}H)DM binding sites. However, this study does not rule out that the common DM/(+)-3-PPP site also might be inhibited by higher concentrations of ropizine.

  15. Allosteric modulation of ligand binding to [3H](+)pentazocine-defined sigma recognition sites by phenytoin.

    PubMed

    DeHaven-Hudkins, D L; Ford-Rice, F Y; Allen, J T; Hudkins, R L

    1993-01-01

    The allosteric modulation of sigma recognition sites by phenytoin (diphenylhydantoin) has been demonstrated by the ability of phenytoin to stimulate binding of various [3H] sigma ligands, as well as to slow dissociation from sigma sites and to shift sigma sites from a low- to a high-affinity state. Phenytoin stimulated the binding of the sigma 1- selective ligand [3H](+)pentazocine in a dose-dependent manner. Stimulation of binding at a final concentration of 250 microM phenytoin was associated with a decrease in the KD. The affinities of the sigma reference compounds caramiphen, dextromethorphan, dextrophan, (+)3-PPP and (+)SKF-10,047 were three- to eight-fold higher, while the affinities of benzetimide, BMY-14802, carbetapentane, DTG and haloperidol were unchanged in the presence of 250 microM phenytoin. The relative sensitivity of sigma compounds to allosteric modulation by phenytoin is not a property of all sigma ligands, and may provide an in vitro basis for distinguishing actions of sigma compounds and predicting sigma effects in vivo. PMID:8515681

  16. Development and validation of a generic high-performance liquid chromatography for the simultaneous separation and determination of six cough ingredients: Robustness study on core-shell particles.

    PubMed

    Yehia, Ali Mohamed; Essam, Hebatallah Mohamed

    2016-09-01

    A generally applicable high-performance liquid chromatographic method for the qualitative and quantitative determination of pharmaceutical preparations containing phenylephrine hydrochloride, paracetamol, ephedrine hydrochloride, guaifenesin, doxylamine succinate, and dextromethorphan hydrobromide is developed. Optimization of chromatographic conditions was performed for the gradient elution using different buffer pH values, flow rates and two C18 stationary phases. The method was developed using a Kinetex® C18 column as a core-shell stationary phase with a gradient profile using buffer pH 5.0 and acetonitrile at 2.0 mL/min flow rate. Detection was carried out at 220 nm and linear calibrations were obtained for all components within the studied ranges. The method was fully validated in agreement with ICH guidelines. The proposed method is specific, accurate and precise (RSD% < 3%). Limits of detection are lower than 2.0 μg/mL. Qualitative and quantitative responses were evaluated using experimental design to assist the method robustness. The method was proved to be highly robust against 10% change in buffer pH and flow rate (RSD% < 10%), however, the flow rate may significantly influence the quantitative responses of phenylephrine, paracetamol, and doxylamine (RSD% > 10%). Satisfactory results were obtained for commercial combinations analyses. Statistical comparison between the proposed chromatographic and official methods revealed no significant difference. PMID:27404374

  17. An update on the treatment of canine atopic dermatitis.

    PubMed

    Saridomichelakis, Manolis N; Olivry, Thierry

    2016-01-01

    Canine atopic dermatitis is a common skin disease seen in veterinary clinical practice. Several factors appear to contribute to the cutaneous inflammation and pruritus. The therapeutic strategy should focus on control of those factors that can be identified and for which interventional measures are feasible; these include ectoparasites, bacterial/fungal infection and dietary hypersensitivity. Ectoparasites, particularly fleas, are not the cause of atopic dermatitis, but they are a confounding factor, which can exacerbate pruritus, and preventative measures are therefore indicated. Bacterial and yeast infections are frequently associated with atopic dermatitis and initial systemic and/or topical therapy should be considered, followed by regular topical treatment for preventing relapse. Concurrent dietary hypersensitivity should be investigated by undertaking an elimination/provocation trial, followed by feeding of a hypoallergenic diet where appropriate. Depending on the severity of the clinical signs of atopic dermatitis and the willingness and expectations of owners, symptomatic treatment and/or specific interventional therapy for environmental allergy (allergen avoidance, allergen-specific immunotherapy) may be implemented. Symptomatic treatment includes use of glucocorticoids (systemically or topically), ciclosporin and oclacitinib. Other treatment modalities of lower or less proven efficacy include antihistamines, dextromethorphan, fatty acids, feline interferon-omega, misoprostol, pentoxifylline, specific serotonin re-uptake inhibitors and tricyclic antidepressant drugs. The therapeutic approach should be reviewed at regular intervals and tailored to the individual's needs. A successful long-term outcome can usually be achieved by combining the various treatment approaches in a way that maximises their benefits and minimises their drawbacks. PMID:26586215

  18. Aloe vera juice: IC₅₀ and dual mechanistic inhibition of CYP3A4 and CYP2D6.

    PubMed

    Djuv, Ane; Nilsen, Odd Georg

    2012-03-01

    The aim of this study was to evaluate the inhibitory potency (IC₅₀ values) of ethanol extracts of two commercially available aloe vera juice (AVJ) products, on CYP3A4 and CYP2D6 activities in vitro and to determine if such inhibitions could be mechanism-based. Recombinant human CYP3A4 and CYP2D6 enzymes were used and the activities were expressed by the metabolism of testosterone and dextromethorphan with ketoconazole and quinidine as positive inhibitor controls, respectively. The formed metabolites were quantified by validated HPLC techniques. Time- and NADPH- dependent inhibition assays were performed to evaluate a possible mechanism-based inhibition. One of the AVJ extracts showed about twice the inhibitory potency towards both CYP enzymes over the other with IC₅₀ values of 8.35 ± 0.72 and 12.5 ± 2.1 mg/mL for CYP3A4 and CYP2D6, respectively. The AVJ was found to exert both CYP mediated and non-CYP mediated inhibition of both CYP3A4 and CYP2D6. This dual mechanistic inhibition, however, seems to be governed by different mechanisms for CYP3A4 and CYP2D6. Estimated IC₅₀ inhibition values indicate no major interference of AVJ with drug metabolism in man, but the dual mechanistic inhibition of both enzymes might be of clinical significance. PMID:21842479

  19. Liquid chromatography and chemometric-assisted spectrophotometric methods for the analysis of two multicomponent mixtures containing cough suppressant drugs.

    PubMed

    El-Gindy, Alaa; Emara, Samy; Mesbah, Mostafa K; Hadad, Ghada M

    2005-01-01

    Three methods were applied for the analysis of 2 multicomponent mixtures containing dextromethorphan hydrobromide, phenylephrine hydrochloride, chlorpheniramine maleate, methylparaben, and propylparaben, together with either sodium benzoate (Mix 1) or ephedrine hydrochloride and benzoic acid (Mix 2). In the first method, liquid chromatography was used for their simultaneous determination using an ODS column with a mobile phase consisting of acetonitrile-phosphate buffer, pH 2.7 (40 + 60, v/v), containing 5mM heptanesulfonic acid sodium salt and ultraviolet (UV) detection at 214 nm. Also, 2 chemometric methods, principal component regression, and partial least squares were used. For both chemometric calibrations, a concentration set of the mixture consisting of each compound in each mixture was prepared in distilled water. The absorbance data in the UV spectra were measured for the 76 or 71 wavelength points in the spectral region 210-240 or 210-224 nm considering the intervals of deltagamma = 0.4 or 0.2 nm for Mix 1 and Mix 2, respectively. The 2 chemometric methods did not require any separation step. These methods were successfully applied for the analysis of the 2 multicomponent combinations in synthetic mixtures and in commercial syrups, and the results were compared with each other. PMID:16152922

  20. New recombinant cyclohexylamine oxidase variants for deracemization of secondary amines by orthogonally assaying designed mutants with structurally diverse substrates

    NASA Astrophysics Data System (ADS)

    Li, Guangyue; Yao, Peiyuan; Cong, Peiqian; Ren, Jie; Wang, Lei; Feng, Jinhui; Lau, Peter C. K.; Wu, Qiaqing; Zhu, Dunming

    2016-05-01

    To further expand the substrate range of the cyclohexylamine oxidase (CHAO) from Brevibacterium oxydans, a library of diverse mutants was created and assayed toward a group of structurally diverse substrates. Among them, mutants T198A and M226A exhibited enhanced activity relative to wt CHAO for most (S)-enantiomers of primary amines and some secondary amines. While mutants T198I, L199I, L199F, M226I and M226T were more active than wt CHAO toward the primary amines, mutants T198F, L199T, Y321A, Y321T, Y321I and Y321F enhanced the enzyme activity toward the secondary amines. In particular, mutant Y321I displayed an enhanced catalytic efficiency toward 1-(4-methoxybenzyl)-1, 2, 3, 4, 5, 6, 7, 8-octahydroisoquinoline (13). Whereas a double mutant, Y321I/M226T, acted on (S)-N-(prop-2-yn-1-yl)-2, 3-dihydro-1H-inden-1-amine [(S)-8]. Since (R)-8 is an irreversible inhibitor of monoamine oxidase and (S)-13 is an intermediate of dextromethorphan, a cough suppressant drug, deracemizations of 8 and 13 were carried out with crude enzyme extracts of the respective mutants. This resulted in 51% and 78% isolated yields of (R)-8 and (S)-13, respectively, each with high enantiomeric excess (93% and 99% ee). The results demonstrated the application potential of the evolved CHAO mutants in drug synthesis requiring chiral secondary amines.

  1. Neuroprotection by NMDA receptor antagonists in a variety of neuropathologies.

    PubMed

    Palmer, G C

    2001-09-01

    Because of adverse reactions, early efforts to introduce high affinity competitive or use-dependent NMDA receptor antagonists into patients suffering from stroke, head trauma or epilepsy met with failure. Later it was discovered that both low affinity use-dependent NMDA receptor antagonists and compounds with selective affinity for the NR2B receptor subunit met the criteria for safe administration into patients. Furthermore, these low affinity antagonists exhibit significant mechanistic differences from their higher affinity counterparts. Success of the latter is attested to the ability of the following low affinity compounds to be marketed: 1) Cough suppressant-dextromethorphan (available for decades); 2) Parkinson's disease--amantadine, memantine and budipine; 3) Dementia--memantine; and 4) Epilepsy--felbamate. Moreover, Phase III clinical trials are ongoing with remacemide for epilepsy and Huntington's disease and head trauma for HU-211. A host of compounds are or were under evaluation for the possible treatment of stroke, head trauma, hyperalgesia and various neurodegenerative disorders. Despite the fact that other drugs with associated NMDA receptor mechanisms have reached clinical status, this review focuses only on those competitive and use-dependent NMDA receptor antagonists that reached clinical trails. The ensuing discussions link the in vivo pharmacological investigations that led to the success/mistakes/ failures for eventual testing of promising compounds in the clinic. PMID:11554551

  2. [Effect of oligosaccharide esters and polygalaxanthone Ill from Polygala tenuifolia willd towards cytochrome P450].

    PubMed

    Li, Zhao-liang; Dong, Xian-zhe; Wang, Dong-xiao; Dong, Rui-hua; Guo, Ting-ting; Sun, Yan; Liu, Ping

    2014-11-01

    Five compounds (tenuifoliside C, tenuifoliside D, telephiose A, telephiose C and polygalaxanthone III) from polygala tenuifolia wild were incubated together with CYP probe substrate in human liver microsomes to investigate the inhibitory effect towards CYP450 enzyme. Phenacetin (CYP1A2), coumarin (CYP2A6), paclitaxel (CYP2C8), diclofenac (CYP2C9), S-mepheriytoin (CYP2C19), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1), midazolam (CYP3A) were selected as the isoforfn specific substrate. And the formation of paracetamol, 7-hydroxycoumarin, 6alpha-hydroxy paclitaxel, 4'-hydroxydiclofenac, dextrorphan, 6-hydroxychlorzoxazone, 1'-hydroxymidazolam, 4'-hydroxymephenytoin were detected respectively to measure the effect towards CYP450 by high-pressure liquid chromatography (HPLC). The result shows that five compounds from polygala tenuifolia willd significantly inhibit chlorzoxazone 6-hydroxylation catalyzed by CYP2E1, while showed no effect towards CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A. And IC50 value was 38.73, 54.14, 61.77, 62.22, 50.56 micromol x L(-1), respectively. PMID:25850285

  3. Maintenance of liver functions in rat hepatocytes cultured as spheroids in a rotating wall vessel.

    PubMed

    Brown, Lanika A; Arterburn, Linda M; Miller, Ana P; Cowger, Nancy L; Hartley, Sonya M; Andrews, Annette; Silber, Paul M; Li, Albert P

    2003-01-01

    Rat hepatocytes were cultured initially as spheroids on culture plates and then transferred into a rotating wall vessel (high-aspect ratio vessel [HARV]) for further culturing. Morphological evaluation based on electron microscopy showed that hepatocyte spheroids cultured for 30 d in the HARV had a compact structure with tight cell-cell junctions, numerous smooth and rough endoplasmic reticulum, intact mitochondria, and bile canaliculi lined with microvilli. The viability and differentiated properties of the hepatocytes cultured in the HARV were further substantiated by the presence of both phase I oxidation and phase II conjugation drug-metabolizing enzyme activities, as well as albumin synthesis. Homogenates prepared from freshly isolated hepatocytes and hepatocytes cultured in the HARV showed similar cytochrome P450 2B activities measured as pentoxyresorufin-O-dealkylase and testosterone 16beta-hydroxylase. Further, intact hepatocytes cultured in the HARV were found to metabolize chlorzoxazone to 6-hydroxychlorzoxazone; dextromethorphan to dextrorphan, 3-methoxymorphinan, and 3-hydroxymorphinan; midazolam to 1-hydroxymidazolam and 4-hydroxymidazolam; and 7-hydroxycoumarin to its glucuronide and sulfate conjugates. In conclusion, we found that hepatocyte spheroids could be cultured in a HARV to retain cellular and physiological properties of the intact liver, including drug-metabolizing enzyme activities, plasma protein production, and long-term (1 mo) maintenance of viability and cellular function. PMID:12892522

  4. Spectrophotometric determination of some anti-tussive and anti-spasmodic drugs through ion-pair complex formation with thiocyanate and cobalt(II) or molybdenum(V)

    NASA Astrophysics Data System (ADS)

    El-Shiekh, Ragaa; Zahran, Faten; El-Fetouh Gouda, Ayman Abou

    2007-04-01

    Two rapid, simple and sensitive extractive specrophotometric methods has been developed for the determination of anti-tussive drugs, e.g., dextromethorphan hydrobromide (DEX) and pipazethate hydrochloride (PiCl) and anti-spasmodic drugs, e.g., drotaverine hydrochloride (DvCl) and trimebutine maleate (TM) in bulk and in their pharmaceutical formulations. The proposed methods depend upon the reaction of cobalt(II)-thiocyanate (method A) and molybdenum(V)-thiocyanate ions (method B) with the cited drugs to form stable ion-pair complexes which extractable with an n-butnol-dichloromethane solvent mixture (3.5:6.5) and methylene chloride for methods A and B, respectively. The blue and orange red color complexes are determined either colorimetrically at λmax 625 nm (using method A) and 467 or 470 nm for (DEX and PiCl) or (DvCl and TM), respectively (using method B). The concentration range is 20-400 and 2.5-50 μg mL -1 for methods A and B, respectively. The proposed method was successfully applied for the determination of the studied drugs in pure and in pharmaceutical formulations applying the standard additions technique and the results obtained in good agreement well with those obtained by the official method.

  5. Spectrophotometric determination of some anti-tussive and anti-spasmodic drugs through ion-pair complex formation with thiocyanate and cobalt(II) or molybdenum(V).

    PubMed

    El-Shiekh, Ragaa; Zahran, Faten; El-Fetouh Gouda, Ayman Abou

    2007-04-01

    Two rapid, simple and sensitive extractive specrophotometric methods has been developed for the determination of anti-tussive drugs, e.g., dextromethorphan hydrobromide (DEX) and pipazethate hydrochloride (PiCl) and anti-spasmodic drugs, e.g., drotaverine hydrochloride (DvCl) and trimebutine maleate (TM) in bulk and in their pharmaceutical formulations. The proposed methods depend upon the reaction of cobalt(II)-thiocyanate (method A) and molybdenum(V)-thiocyanate ions (method B) with the cited drugs to form stable ion-pair complexes which extractable with an n-butnol-dichloromethane solvent mixture (3.5:6.5) and methylene chloride for methods A and B, respectively. The blue and orange red color complexes are determined either colorimetrically at lambdamax 625 nm (using method A) and 467 or 470 nm for (DEX and PiCl) or (DvCl and TM), respectively (using method B). The concentration range is 20-400 and 2.5-50 microg mL-1 for methods A and B, respectively. The proposed method was successfully applied for the determination of the studied drugs in pure and in pharmaceutical formulations applying the standard additions technique and the results obtained in good agreement well with those obtained by the official method. PMID:17142094

  6. Pathophysiology and therapy of chronic cough.

    PubMed

    Chung, K F

    2005-02-01

    Cough is an essential protective mechanism for the airways and lungs. Cough receptors are situated in the larynx and tracheobronchial tree, and are mediated by rapidly-adapting (irritant) Adelta fibers, although other receptors such as C-fiber receptors may contribute. Cough plasticity and interactions of cough pathways may occur centrally to enhance the cough reflex. The presence of an increased cough reflex as measured by a tussive response to capsaicin or citric acid in patients with a chronic cough indicate that there is sensitisation of the cough reflex. The most common cause of acute cough is that after a common cold, which usually lasts for less than 2 weeks. Cough that persists longer may be due to asthma and its variant forms (cough variant asthma and eosinophilic bronchitis), rhinosinusitis (postnasal drip), gastro-esophageal reflux, bronchiectasis, chronic bronchitis, and angiotensin-converting enzyme (ACE) inhibitor therapy. Chronic persistent cough can contribute to a significant worsening of quality of life measures. Bronchial tumors must be excluded with a chest radiograph. The management of chronic cough includes investigation and treatment of any associated causes, which sometimes leads to control of cough. In a proportion of patients, cough may be idiopathic and remain uncontrolled. Currently-available antitussives such as dextromethorphan or codeine are modestly successful in controlling cough. New antitussives may be developed that act on the sensory receptors or prevent their sensitisation. PMID:15827540

  7. Modulation of CYP2D6 and CYP3A4 metabolic activities by Ferula asafetida resin

    PubMed Central

    Al-Jenoobi, Fahad I.; Al-Thukair, Areej A.; Alam, Mohd Aftab; Abbas, Fawkeya A.; Al-Mohizea, Abdullah M.; Alkharfy, Khalid M.; Al-Suwayeh, Saleh A.

    2014-01-01

    Present study investigated the potential effects of Ferula asafetida resin on metabolic activities of human drug metabolizing enzymes: CYP2D6 and CYP3A4. Dextromethorphan (DEX) was used as a marker to assess metabolic activities of these enzymes, based on its CYP2D6 and CYP3A4 mediated metabolism to dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. In vitro study was conducted by incubating DEX with human liver microsomes and NADPH in the presence or absence of Asafetida alcoholic extract. For clinical study, healthy human volunteers received a single dose of DEX alone (phase-I) and repeated the same dose after a washout period and four-day Asafetida treatment (phase-II). Asafetida showed a concentration dependent inhibition on DOR formation (in vitro) and a 33% increase in DEX/DOR urinary metabolic ratio in clinical study. For CYP3A4, formation of 3-MM in microsomes was increased at low Asafetida concentrations (10, 25 and 50 μg/ml) but slightly inhibited at the concentration of 100 μg/ml. On the other hand, in vivo observations revealed that Asafetida significantly increased DEX/3-MM urinary metabolic ratio. The findings of this study suggest that Asafetida may have a significant effect on CYP3A4 metabolic activity. Therefore, using Ferula asafetida with CYP3A4 drug substrates should be cautioned especially those with narrow therapeutic index such as cyclosporine, tacrolimus and carbamazepine. PMID:25561870

  8. Recreational use of D-lysergamide from the seeds of Argyreia nervosa, Ipomoea tricolor, Ipomoea violacea, and Ipomoea purpurea in Poland.

    PubMed

    Juszczak, Grzegorz R; Swiergiel, Artur H

    2013-01-01

    Recently, there are important changes in recreational drug use. The aim of the present study was to analyse reports published on a recreational web site by drug users who ingested seeds of plants belonging to the Convolvulaceae family and to compare them with available medical case reports. We have also included reports describing the effects induced by "druids fantasy," which is a new drug allegedly containing the same alkaloid as the seeds of A. nervosa. Our search reveals the reoccurrence of recreational use of I. tricolor and violacea (morning glory), which had not been reported in medical literature since 1968. We have also found that drug users are experimenting with other species, such as I. purpurea, whose psychoactive properties are unknown. Symptoms and doses reported by drug users were comparable with the few available medical case reports. The most worrying symptom was suicidal ideation reported by two subjects who ingested A. nervosa and Ipomoea seeds. Effects induced by druids fantasy were comparable with the effects induced by A. nervosa and various Ipomoea species. The ingestion of seeds was frequently associated with taking drugs such as cannabis and hashish, although other combinations, for example with dextromethorphan, were also reported. PMID:23662334

  9. Over-the-counter medicine abuse – a review of the literature

    PubMed Central

    2013-01-01

    Background: The sale of over-the-counter (OTC) medicines from pharmacies can help individuals self-manage symptoms. However, some OTC medicines may be abused, with addiction and harms being increasingly recognised. This review describes the current knowledge and understanding of OTC medicine abuse. Approach: Comprehensive search of international empirical and review literature between 1990 and 2011. Findings: OTC medicine abuse was identified in many countries and although implicated products varied, five key groups emerged: codeine-based (especially compound analgesic) medicines, cough products (particularly dextromethorphan), sedative antihistamines, decongestants and laxatives. No clear patterns relating to those affected or their experiences were identified and they may represent a hard-to-reach group, which coupled with heterogeneous data, makes estimating the scale of abuse problematic. Associated harms included direct physiological or psychological harm (e.g. opiate addiction), harm from another ingredient (e.g. ibuprofen-related gastric bleeding) and associated social and economic problems. Strategies and interventions included limiting supplies, raising public and professional awareness and using existing services and Internet support groups, although associated evaluations were lacking. Terminological variations were identified. Conclusions: OTC medicine abuse is a recognised problem internationally but is currently incompletely understood. Research is needed to quantify scale of abuse, evaluate interventions and capture individual experiences, to inform policy, regulation and interventions. PMID:23525509

  10. [Club drugs: old medicines as new party drugs].

    PubMed

    Abanades, Sergio; Peiró, Ana M; Farré, Magí

    2004-09-11

    During the last few years the term club drugs has been used for defining an heterogeneous group of chemical substances in permanent evolution, that are consumed for recreational purposes. These substances have been extensively used, firstly by the Rave culture and later by the so called Club culture. These movements are characterized by the search of amplified sensations, by means of the combination of electronic music, marathon dancing and substance abuse. After years with a predominating consumption of designer amphetamines in these groups, it seems that the use of another type of substances is increasing, fundamentally drugs with hallucinogenic effects. This review focus in four of these substances; ketamine, dextromethorphan, nitrous oxide and gamma-hydroxybutyric acid (GHB, liquid ecstasy), and includes a discussion of their pharmacology, recreational use, adverse effects and patient management. These drugs are, at he same time, drugs of abuse and medicines with concrete indications in therapeutics, with an important increase of their consumption in the last few years. The Rave and Club cultures are also described. PMID:15373979

  11. Evaluation of antitussive agents in man.

    PubMed

    Parvez, L; Vaidya, M; Sakhardande, A; Subburaj, S; Rajagopalan, T G

    1996-01-01

    Methodology to evaluate the efficacy of antitussive drugs rely largely on subjective methods and cough counts. There are few studies in cough due to natural disease especially using objective techniques. This paper presents data from a series of randomized, double blind, placebo controlled clinical trials in cough due to both chronic bronchopulmonary disease and acute upper respiratory tract infections. In these studies, cough was quantified using a standardized and validated computerized system for the acquisition and multidimensional analysis of the cough sound. Key objective parameters like cough counts, intensity, latency and total effort expended were studied. Guaiphenesin and bromhexine showed significant expectorant effects in patients with productive cough due to chronic bronchopulmonary disease. Differences were observed in speed of action, and objective and subjective measures, that probably indicate differences in drug action. More recently, three studies evaluated the antitussive drug dextromethorphan in non-productive cough due to uncomplicated upper respiratory tract infections. Reproducible cough suppressant effects were demonstrated after a single 30 mg dose using objective measures of cough counts, latency and total effort. These results establish the sensitivity and robustness of the cough quantitation methodology in the objective evaluation of cough treatments. PMID:9232667

  12. The Neuroprotective Disease-Modifying Potential of Psychotropics in Parkinson's Disease

    PubMed Central

    Lauterbach, Edward C.; Fontenelle, Leonardo F.; Teixeira, Antonio L.

    2012-01-01

    Neuroprotective treatments in Parkinson's disease (PD) have remained elusive. Psychotropics are commonly prescribed in PD without regard to their pathobiological effects. The authors investigated the effects of psychotropics on pathobiological proteins, proteasomal activity, mitochondrial functions, apoptosis, neuroinflammation, trophic factors, stem cells, and neurogenesis. Only findings replicated in at least 2 studies were considered for these actions. Additionally, PD-related gene transcription, animal model, and human neuroprotective clinical trial data were reviewed. Results indicate that, from a PD pathobiology perspective, the safest drugs (i.e., drugs least likely to promote cellular neurodegenerative mechanisms balanced against their likelihood of promoting neuroprotective mechanisms) include pramipexole, valproate, lithium, desipramine, escitalopram, and dextromethorphan. Fluoxetine favorably affects transcription of multiple genes (e.g., MAPT, GBA, CCDC62, HIP1R), although it and desipramine reduced MPTP mouse survival. Haloperidol is best avoided. The most promising neuroprotective investigative priorities will involve disease-modifying trials of the safest agents alone or in combination to capture salutary effects on H3 histone deacetylase, gene transcription, glycogen synthase kinase-3, α-synuclein, reactive oxygen species (ROS), reactive nitrogen species (RNS), apoptosis, inflammation, and trophic factors including GDNF and BDNF. PMID:22254151

  13. Nonketotic hyperglycinemia case series

    PubMed Central

    Iqbal, Mehtab; Prasad, Manish; Mordekar, Santosh R.

    2015-01-01

    To present three cases who presented with neonatal hiccups and who were later diagnosed with nonketotic hyperglycinemia (NKH). Case series. We present three babies who presented in neonatal life with hiccups who later were diagnosed with NKH. Two babies presented on the 2nd day of life with hypotonia, poor feeding, and abnormal movements including jitteriness, hiccups, and twitching. The third baby only had transient hiccups lasting for a couple of days in the 1st week of life but later presented at 3 months of age with poor feeding, drowsiness, and jerky movements. All three cases needed extensive investigations before reaching the diagnosis including metabolic screen, lumbar puncture, electroencephalography, and computed tomography/magnetic resonance imaging. The first two babies needed intubation on their 2nd day of life because of apneas in whom later, the care was withdrawn after reaching the diagnosis of NKH because of poor prognosis. The third baby was discharged home on oral dextromethorphan and ketogenic diet. We discuss the importance of early recognition of symptoms (frequent hiccups) and investigation needed to reach the diagnosis early as it helps in making decision to either carry on treatment or withdraw care because of poor prognosis. It also helps in genetic counseling and prenatal diagnosis can be offered at the subsequent pregnancy. PMID:26962342

  14. Using an innovative combination of quality-by-design and green analytical chemistry approaches for the development of a stability indicating UHPLC method in pharmaceutical products.

    PubMed

    Boussès, Christine; Ferey, Ludivine; Vedrines, Elodie; Gaudin, Karen

    2015-11-10

    An innovative combination of green chemistry and quality by design (QbD) approach is presented through the development of an UHPLC method for the analysis of the main degradation products of dextromethorphan hydrobromide. QbD strategy was integrated to the field of green analytical chemistry to improve method understanding while assuring quality and minimizing environmental impacts, and analyst exposure. This analytical method was thoroughly evaluated by applying risk assessment and multivariate analysis tools. After a scouting phase aimed at selecting a suitable stationary phase and an organic solvent in accordance with green chemistry principles, quality risk assessment tools were applied to determine the critical process parameters (CPPs). The effects of the CPPs on critical quality attributes (CQAs), i.e., resolutions, efficiencies, and solvent consumption were further evaluated by means of a screening design. A response surface methodology was then carried out to model CQAs as function of the selected CPPs and the optimal separation conditions were determined through a desirability analysis. Resulting contour plots enabled to establish the design space (DS) (method operable design region) where all CQAs fulfilled the requirements. An experimental validation of the DS proved that quality within the DS was guaranteed; therefore no more robustness study was required before the validation. Finally, this UHPLC method was validated using the concept of total error and was used to analyze a pharmaceutical drug product. PMID:26183807

  15. Multiple P450 substrates in a single run: rapid and comprehensive in vitro interaction assay.

    PubMed

    Turpeinen, Miia; Uusitalo, Jouko; Jouko, Uusitalo; Jalonen, Jorma; Jorma, Jalonen; Pelkonen, Olavi; Olavi, Pelkeonen

    2005-01-01

    The dramatically increased number of new chemical entities (NCE) used in drug discovery has raised a demand for efficient and rapid drug metabolism screening techniques. The aim of this study was to develop a global in vitro metabolic interaction screening test utilising the N-in-1 approach. A cocktail consisting of 10 CYP-selective probes with known kinetic, metabolic and interaction properties in vivo was incubated in a pool of human liver microsomes, and metabolites of melatonin (CYP1A2), coumarin (CYP2A6), bupropion (CYP2B6), amodiaquine (CYP2C8), tolbutamide (CYP2C9), omeprazole (CYP2C19 and CYP3A4), dextromethorphan (CYP2D6), chlorzoxazone (CYP2E1), midazolam (CYP3A4) and testosterone (CYP3A4) were analysed simultaneously using LC/TOF-MS. Performance of the method was assessed with cDNA expressed P450s and diagnostic CYP-specific inhibitors. The results were in good accordance with literature and our previous studies. The cocktail developed is suitable for fast and reliable in vitro screening of the interaction potential and characteristics of NCEs. PMID:15626586

  16. Gateways to clinical trials.

    PubMed

    Bayés, M; Rabasseda, X; Prous, J R

    2005-03-01

    Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: 3-AP, 667-coumate, 9-aminocamptothecin; Ad5CMV-p53, AES-14, alefacept, anecortave acetate, APC-8024, APD-356, asoprisnil; Bevacizumab, bimakalim, bimatoprost, BLP-25, BR-1; Caspofungin acetate, cetuximab, cypher; Darbepoetin alfa, dexanabinol, dextromethorphan/quinidine sulfate, DNA.HIVA; Efaproxiral sodium, ertapenem sodium; Frovatriptan; HuMax-EGFr, HYB-2055, gamma-hydroxybutyrate sodium, Id-KLH vaccine, imatinib mesylate; Lapatinib, lonafarnib, Motexafin lutetium, MVA.HIVA, mycophenolic acid sodium salt; Nesiritide, NS-2330; Olmesartan medoxomil; Peginterferon alfa-2a, peginterferon alfa-2b, peginterferon alfa-2b/ribavirin, pemetrexed disodium, perifosine, pimecrolimus, pregabalin; QbG-10; Ralfinamide, rasburicase, rFGF-2, Ro-31-7453; Sitaxsentan sodium, sorafenib; Tadalafil, TC-1734, telmisartan/hydrochlorothiazide, tenofovir disoproxil fumarate, thymus nuclear protein, tipifarnib; Vandetanib, vibriolysin, vildagliptin, voriconazole. PMID:15834466

  17. Neuroleptic malignant syndrome in an adolescent with CYP2D6 deficiency.

    PubMed

    Butwicka, Agnieszka; Krystyna, Szymańska; Retka, Włodzimierz; Wolańczyk, Tomasz

    2014-12-01

    We describe a patient with dystonia and psychotic symptoms treated with standard doses of antipsychotics, who developed neuroleptic malignant syndrome (NMS). A 16-year-old male with a history of misuse of dextromethorphan and pseudoephedrine for recreational purpose presented with dystonia and a psychotic episode. Following continuous treatment with olanzapine (10 mg/day), repeated injections of levomepromazine (37.5 mg/day), and a single injection of haloperidol (2.5 mg), the patient developed NMS. Muscular rigidity, fever (up to 41 °C), hypotension (100/70 mmHg), tachycardia (120 beats per minute), tachypnea (26 breaths per minute), elevated leukocyte count (up to 16.6 × 10(3)/μL), and elevated serum creatinine phosphokinase (CPK) (up to 15,255 U/L) were observed. A diagnosis of NMS was made according to the DSM-IV TR criteria. Genotyping revealed that he was homozygous for a non-functional CYP2D6*4 allele. The case highlights the importance of therapeutic drug monitoring in identification and differentiation of drug-induced effects in psychiatric disorder to prevent NMS and its complications. In addition, genotyping of CYP2D6 might be considered in patients with symptoms suggestive of drug toxicity who are treated with neuroleptics metabolized via the CYP2D6 pathway, as carriage of one or more non-functional alleles may increase the risk for adverse reactions, such as NMS. PMID:24253372

  18. Odds and ends in psychopharmacology from the past 10 years.

    PubMed

    Howland, Robert H

    2015-01-01

    Seven topics previously described in this column are revisited. The use of quantitative electroencephalography has been shown in a prospective study to be effective for predicting antidepressant treatment response. A novel antidepressant drug, agomelatine, has generated much controversy, and its development for the U.S. market was discontinued. A long awaited revised system for categorizing the safety of medications during pregnancy and lactation has finally been published by the Food and Drug Administration. Dextromethorphan/quinidine, eslicarbazepine acetate, levomilnacipran, and esketamine are recent examples of drugs that were developed based on the complex concepts of chirality and stereochemistry. Lisdexamfetamine, a stimulant drug, failed to show benefit as an augmentation therapy for the treatment of depression. The combination drug naltrexone/bupropion was finally approved as a therapy for obesity, after its cardiovascular safety was confirmed in a prospective premarketing study. Further development of the glucocorticoid receptor antagonist drug mifepristone as a treatment for psychotic depression was stopped based on a large negative trial, but the drug continues to be investigated for other potential psychiatric indications. These examples illustrate how the field of psychopharmacology continues to evolve. PMID:25622272

  19. The effects of drugs on cough.

    PubMed

    Irwin, R S; Curley, F J; Pratter, M R

    1987-01-01

    The pharmacologic treatment of cough can be divided into two main categories: therapy with controls, prevents or eliminates cough (i.e., antitussive) and therapy that makes cough more effective (i.e., pro-tussive). Definitive antitussive therapy depends on determining the aetiology or operant pathophysiologic mechanism and then initiating specific treatment; it can be almost uniformly successful. Non-specific antitussive therapy is directed at the symptom; it is indicated when definitive therapy cannot be given. For pathologic cough in man, predominantly studied in patients with chronic bronchitis, the following non-specific antitussive drugs have been shown to be effective: aerosolized ipratropium bromide, all narcotics of the phenanthrene alkaloid group (e.g., morphine and codeine), and the non-narcotics, dextromethorphan, glaucine, diphenhydramine, caramiphen, viminol and diviminol. Although studies have shown that hypertonic saline aerosol can improve cough clearance, there are no data, to date, that have convincingly demonstrated this agent or any other pro-tussive drug to be clinically useful. PMID:3322860

  20. Simultaneous determination of some active ingredients in cough and cold preparations by gas chromatography, and method validation.

    PubMed

    Harsono, Thresiana; Yuwono, Mochammad; Indrayanto, Gunawan

    2005-01-01

    A simple and rapid gas chromatographic (GC) method has been developed for the simultaneous determination of combinations of acetaminophen, phenylpropanolamine hydrochloride, guaifenesin, pseudoephedrine hydrochloride, caffeine, chlorpheniramine maleate, and dextromethorphan hydrobromide in cough and cold tablets and syrups. After extraction of the analyte with alkaline ethyl acetate, 2 microL extract was injected (splitting ratio of 50:1) into a gas chromatograph equipped with a CBP1-M25-025 fused silica capillary column (25 m x 0.22 mm; film thickness, 0.25 microm). The column temperature was held at 150 degrees C for 5 min, increased to 175 degrees C at 3 degrees C/min, and increased to 270 degreesC at 10 degrees C/min. The temperatures of the flame ionization detector and injector were maintained at 300 degrees C. The GC method is inexpensive, rapid, accurate, and precise, and thus it can be used for routine analysis of tablet and syrup preparations in quality control laboratories of pharmaceutical companies. PMID:16152925

  1. The use of isolated enterocytes to study Phase I intestinal drug metabolism: validation with rat and pig intestine.

    PubMed

    Bonnefille, Philippe; Sezgin-Bayindir, Zerrin; Belkhelfa, Haouaria; Arellano, Cécile; Gandia, Peggy; Woodley, John; Houin, Georges

    2011-02-01

    An important step in the development of new drugs is to evaluate the extent of their metabolism during absorption in the small intestine. Reliable in vitro systems to do this can expediate the development process, but the current systems are often unsuitable because they lack the appropriate metabolic enzymes (e.g. Caco-2 cell monolayers) or are not representative of the physiological conditions present in the intact intestinal cells (e.g. isolated microsomes). The aim of this study was to validate the use of isolated intestinal epithelial cells (enterocytes), equivalent to hepatocytes, to evaluate Phase I drug metabolism. A method was developed to prepare enterocytes from rat and pig (as metabolically closer to man) that maintained good viability and activity for up to 90 min as judged by trypan blue exclusion and the release of the cytosolic enzyme lactate dehydrogenase. The Phase I metabolism of the established marker drugs: midazolam, bupropion and dextromethorphan were measured by LC-MS and confirmed the activities of the 3A, 2B and 2D families of CYP isoforms, respectively. The kinetic parameters, K(m) and V(max), were compared between isolated cells and isolated intestinal microsomes from the rat. The use of isolated intestinal cells is a simple and practical method to study the Phase I metabolism of drugs during their absorption and the potential for drug-drug interactions. The method could eventually be modified and usefully applied to human studies. PMID:21121944

  2. Gateways to clinical trials.

    PubMed

    Bayes, M; Rabasseda, X; Prous, J R

    2006-06-01

    Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: 131-I-chlorotoxin; Ad5CMV-p53, adalimumab, albumin interferon alfa, alemtuzumab, aliskiren fumarate, aminolevulinic acid methyl ester, anakinra, AR-C126532, atomoxetine hydrochloride; Bevacizumab, bosentan, botulinum toxin type B, brimonidine tartrate/timolol maleate; Calcipotriol/betamethasone dipropionate, cangrelor tetrasodium, cetuximab, ciclesonide, cinacalcet hydrochloride, collagen-PVP, Cypher; Darbepoetin alfa, darusentan, dasatinib, denosumab, desloratadine, dexosome vaccine (lung cancer), dexrazoxane, dextromethorphan/quinidine sulfate, duloxetine hydrochloride; ED-71, eel calcitonin, efalizumab, entecavir, etoricoxib; Falciparum merozoite protein-1/AS02A, fenretinide, fondaparinux sodium; gamma-Hydroxybutyrate sodium, gefitinib, ghrelin (human); hLM609; Icatibant acetate, imatinib mesylate, ipsapirone, irofulven; LBH-589, LE-AON, levocetirizine, LY-450139; Malaria vaccine, mapatumumab, motexafin gadolinium, muraglitazar, mycophenolic acid sodium salt; nab-paclitaxel, nelarabine; O6-Benzylguanine, olmesartan medoxomil, orbofiban acetate; Panitumumab, peginterferon alfa-2a, peginterferon alfa-2b, pemetrexed disodium, peptide YY3-36, pleconaril, prasterone, pregabalin; Ranolazine, rebimastat, recombinant malaria vaccine, rosuvastatin calcium; SQN-400; Taxus, tegaserod maleate, tenofovir disoproxil fumarate, teriparatide, troxacitabine; Valganciclovir hydrochloride, Val-Tyr sardine peptidase, VNP-40101M, vorinostat. PMID:16845450

  3. Zonated quantification of steatosis in an entire mouse liver.

    PubMed

    Schwen, Lars Ole; Homeyer, André; Schwier, Michael; Dahmen, Uta; Dirsch, Olaf; Schenk, Arne; Kuepfer, Lars; Preusser, Tobias; Schenk, Andrea

    2016-06-01

    Many physiological processes and pathological conditions in livers are spatially heterogeneous, forming patterns at the lobular length scale or varying across the organ. Steatosis, a common liver disease characterized by lipids accumulating in hepatocytes, exhibits heterogeneity at both these spatial scales. The main goal of the present study was to provide a method for zonated quantification of the steatosis patterns found in an entire mouse liver. As an example application, the results were employed in a pharmacokinetics simulation. For the analysis, an automatic detection of the lipid vacuoles was used in multiple slides of histological serial sections covering an entire mouse liver. Lobuli were determined semi-automatically and zones were defined within the lobuli. Subsequently, the lipid content of each zone was computed. The steatosis patterns were found to be predominantly periportal, with a notable organ-scale heterogeneity. The analysis provides a quantitative description of the extent of steatosis in unprecedented detail. The resulting steatosis patterns were successfully used as a perturbation to the liver as part of an exemplary whole-body pharmacokinetics simulation for the antitussive drug dextromethorphan. The zonated quantification is also applicable to other pathological conditions that can be detected in histological images. Besides being a descriptive research tool, this quantification could perspectively complement diagnosis based on visual assessment of histological images. PMID:27104496

  4. Evidence-based guideline: Assessment and management of psychiatric disorders in individuals with MS

    PubMed Central

    Minden, Sarah L.; Feinstein, Anthony; Kalb, Rosalind C.; Miller, Deborah; Mohr, David C.; Patten, Scott B.; Bever, Christopher; Schiffer, Randolph B.; Gronseth, Gary S.; Narayanaswami, Pushpa

    2014-01-01

    Objective: To make evidence-based recommendations for screening, diagnosing, and treating psychiatric disorders in individuals with multiple sclerosis (MS). Methods: We reviewed the literature (1950 to August 2011) and evaluated the available evidence. Results and recommendations: Clinicians may consider using the Center for Neurologic Study Emotional Lability Scale to screen for pseudobulbar affect (Level C). Clinicians may consider the Beck Depression Inventory and a 2-question tool to screen for depressive disorders and the General Health Questionnaire to screen for broadly defined emotional disturbances (Level C). Evidence is insufficient to support/refute the use of other screening tools, the possibility that somatic/neurovegetative symptoms affect these tools' accuracy, or the use of diagnostic instruments or clinical evaluation procedures for identifying psychiatric disorders in MS (Level U). Clinicians may consider a telephone-administered cognitive behavioral therapy program for treating depressive symptoms (Level C). Although pharmacologic and nonpharmacologic therapies are widely used to treat depressive and anxiety disorders in individuals with MS, evidence is insufficient to support/refute the use of the antidepressants and individual and group therapies reviewed herein (Level U). For pseudobulbar affect, a combination of dextromethorphan and quinidine may be considered (Level C). Evidence is insufficient to determine the psychiatric effects in individuals with MS of disease-modifying and symptomatic therapies and corticosteroids; risk factors for suicide; and treatment of psychotic disorders (Level U). Research is needed on the effectiveness in individuals with MS of pharmacologic and nonpharmacologic treatments frequently used in the non-MS population. PMID:24376275

  5. Safety and pharmacokinetics of the CIME combination of drugs and their metabolites after a single oral dosing in healthy volunteers.

    PubMed

    Lenuzza, Natacha; Duval, Xavier; Nicolas, Grégory; Thévenot, Etienne; Job, Sylvie; Videau, Orianne; Narjoz, Céline; Loriot, Marie-Anne; Beaune, Philippe; Becquemont, Laurent; Mentré, France; Funck-Brentano, Christian; Alavoine, Loubna; Arnaud, Philippe; Delaforge, Marcel; Bénech, Henri

    2016-04-01

    This phase I, pilot clinical study was designed to evaluate the safety and the pharmacokinetic (PK) profiles of the CIME (Metabolic Identity Card) combination of ten drugs, with a view to its use as a phenotyping cocktail. Ten healthy Caucasian subjects were orally dosed with the CIME combination (caffeine-CYP1A2, repaglinide-CYP2C8, tolbutamide-CYP2C9, omeprazole-CYP2C19, dextromethorphan-CYP2D6, midazolam-CYP3A, acetaminophen-UGT1A1, 6&9 and 2B15, digoxin-P-gp, rosuvastatin-OATP1B1&3 and memantine-active renal transport). Blood was collected over 3 days and on day 7. CIME probes and relevant metabolites were assayed by LC-MS/MS and PK parameters were calculated. Main results were: (1) good safety with reversible mild or moderate adverse effects, (2) an analytical method able to quantify simultaneously the 10 probes and the major metabolites, (3) calculation of PK parameters for all probes in general agreed with published values, and (4) identification of the low CYP2D6 metabolizer. This pilot study showed that the CIME combination was well tolerated and that its pharmacokinetics could be accurately measured in healthy volunteers. This combination can now confidently be checked for sensitivity and specificity and for lack of interaction to be validated as a phenotyping cocktail. PMID:25465228

  6. Effects of Papaver rhoeas (L.) extract on formalin-induced pain and inflammation in mice.

    PubMed

    Saeed-Abadi, S; Ranjbaran, M; Jafari, F; Najafi-Abedi, A; Rahmani, B; Esfandiari, B; Delfan, B; Mojabi, N; Ghahramani, M; Sahraei, H

    2012-11-01

    Stress amelioration can improve its metabolic as well as other side effects. In the present study, the effects of hydro-alcoholic extract of Papver rhoeas (L.) on formalin-induced pain and inflammation were investigated in male Swiss-Webster mice (20-25 g). Formalin injects in the plantar portion of mice hind paw and pain was studied for 60 min. The plant extract and other drugs were administered intraperitoneally 30 min before formalin. Experiments showed that administration of extract (25, 50 and 100 mg kg(-1)) could induced analgesia in a dose-response manner in both phases of formalin test. More over, the extract inhibits inflammation induced by formalin injection. Naloxone (4 mg kg(-1)), dextromethorphan (20 mg kg(-1)) and NG-nitro-L-arginine-methylester (L-NAME; 10 mg kg(-1)) reduced the extract analgesia in first but not late phase. Extract administration also increased plasma corticosterone level in dose-dependent manner. It could be concluded that Papaver rhoeas (L.) extract could inhibits acute phase of formalin test in mice by opioidergic, glutamatergic and nitricergic mechanisms. In addition, the extract can induce corticosterone plasma level which may be responsible for inhibition of inflammation and chronic phase of pain induced by formalin. PMID:24163947

  7. Neuroprotective Effects of Psychotropic Drugs in Huntington’s Disease

    PubMed Central

    Lauterbach, Edward C.

    2013-01-01

    Psychotropics (antipsychotics, mood stabilizers, antidepressants, anxiolytics, etc.) are commonly prescribed to treat Huntington’s disease (HD). In HD preclinical models, while no psychotropic has convincingly affected huntingtin gene, HD modifying gene, or huntingtin protein expression, psychotropic neuroprotective effects include upregulated huntingtin autophagy (lithium), histone acetylation (lithium, valproate, lamotrigine), miR-222 (lithium-plus-valproate), mitochondrial protection (haloperidol, trifluoperazine, imipramine, desipramine, nortriptyline, maprotiline, trazodone, sertraline, venlafaxine, melatonin), neurogenesis (lithium, valproate, fluoxetine, sertraline), and BDNF (lithium, valproate, sertraline) and downregulated AP-1 DNA binding (lithium), p53 (lithium), huntingtin aggregation (antipsychotics, lithium), and apoptosis (trifluoperazine, loxapine, lithium, desipramine, nortriptyline, maprotiline, cyproheptadine, melatonin). In HD live mouse models, delayed disease onset (nortriptyline, melatonin), striatal preservation (haloperidol, tetrabenazine, lithium, sertraline), memory preservation (imipramine, trazodone, fluoxetine, sertraline, venlafaxine), motor improvement (tetrabenazine, lithium, valproate, imipramine, nortriptyline, trazodone, sertraline, venlafaxine), and extended survival (lithium, valproate, sertraline, melatonin) have been documented. Upregulated CREB binding protein (CBP; valproate, dextromethorphan) and downregulated histone deacetylase (HDAC; valproate) await demonstration in HD models. Most preclinical findings await replication and their limitations are reviewed. The most promising findings involve replicated striatal neuroprotection and phenotypic disease modification in transgenic mice for tetrabenazine and for sertraline. Clinical data consist of an uncontrolled lithium case series (n = 3) suggesting non-progression and a primarily negative double-blind, placebo-controlled clinical trial of lamotrigine. PMID:24248060

  8. Human Cytosolic Sulfotransferase SULT1A3 Mediates the Sulfation of Dextrorphan.

    PubMed

    Yamamoto, Akihiro; Kurogi, Katsuhisa; Schiefer, Isaac Thomas; Liu, Ming-Yih; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2016-01-01

    Dextrorphan, an active metabolite of the antitussive dextromethorphan, has been shown to be subjected to sulfation by several zebrafish cytosolic sulfotransferases (SULTs). We were interested in finding out which of the human SULT(s) is(are) capable of catalyzing the sulfation of dextrorphan, and to verify whether sulfation of dextrorphan may occur in cultured human cells and human organ cytosols. Data from the enzymatic assays showed that, of all thirteen known human SULTs, SULT1A3 displayed the strongest dextrorphan-sulfating activity. Cell culture experiments using HepG2 human hepatoma cells and Caco-2 human colon carcinoma cells incubated with [(35)S]sulfate together with varying concentrations of dextrorphan revealed indeed the production and release of [(35)S]sulfated dextrorphan in a concentration-dependent manner. Additionally, significant dextrorphan-sulfating activity was detected in human liver, small intestine and lung cytosols. Taken together, these results provided a biochemical basis for the sulfation of dextrorphan in humans. PMID:27582324

  9. Geneva cocktail for cytochrome p450 and P-glycoprotein activity assessment using dried blood spots.

    PubMed

    Bosilkovska, M; Samer, C F; Déglon, J; Rebsamen, M; Staub, C; Dayer, P; Walder, B; Desmeules, J A; Daali, Y

    2014-09-01

    The suitability of the capillary dried blood spot (DBS) sampling method was assessed for simultaneous phenotyping of cytochrome P450 (CYP) enzymes and P-glycoprotein (P-gp) using a cocktail approach. Ten volunteers received an oral cocktail capsule containing low doses of the probes bupropion (CYP2B6), flurbiprofen (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), midazolam (CYP3A), and fexofenadine (P-gp) with coffee/Coke (CYP1A2) on four occasions. They received the cocktail alone (session 1), and with the CYP inhibitors fluvoxamine and voriconazole (session 2) and quinidine (session 3). In session 4, subjects received the cocktail after a 7-day pretreatment with the inducer rifampicin. The concentrations of probes/metabolites were determined in DBS and plasma using a single liquid chromatography-tandem mass spectrometry method. The pharmacokinetic profiles of the drugs were comparable in DBS and plasma. Important modulation of CYP and P-gp activities was observed in the presence of inhibitors and the inducer. Minimally invasive one- and three-point (at 2, 3, and 6 h) DBS-sampling methods were found to reliably reflect CYP and P-gp activities at each session. PMID:24722393

  10. Small Molecule Docking from Theoretical Structural Models

    NASA Astrophysics Data System (ADS)

    Novoa, Eva Maria; de Pouplana, Lluis Ribas; Orozco, Modesto

    Structural approaches to rational drug design rely on the basic assumption that pharmacological activity requires, as necessary but not sufficient condition, the binding of a drug to one or several cellular targets, proteins in most cases. The traditional paradigm assumes that drugs that interact only with a single cellular target are specific and accordingly have little secondary effects, while promiscuous molecules are more likely to generate undesirable side effects. However, current examples indicate that often efficient drugs are able to interact with several biological targets [1] and in fact some dirty drugs, such as chlorpromazine, dextromethorphan, and ibogaine exhibit desired pharmacological properties [2]. These considerations highlight the tremendous difficulty of designing small molecules that both have satisfactory ADME properties and the ability of interacting with a limited set of target proteins with a high affinity, avoiding at the same time undesirable interactions with other proteins. In this complex and challenging scenario, computer simulations emerge as the basic tool to guide medicinal chemists during the drug discovery process.

  11. Gas chromatographic method using nitrogen-phosphorus detection for the measurement of tramadol and its O-desmethyl metabolite in plasma and brain tissue of mice and rats.

    PubMed

    Tao, Q; Stone, D J; Borenstein, M R; Jean-Bart, V; Codd, E E; Coogan, T P; Desai-Krieger, D; Liao, S; Raffa, R B

    2001-11-01

    A method that allows the measurement of plasma and brain levels of the centrally-acting analgesic tramadol and its major metabolite (O-desmethyl tramadol) in mice and rats was developed using gas chromatography equipped with nitrogen-phosphorus detection (GC-NPD). Plasma samples were extracted with methyl tert.-butyl ether (MTBE) and were injected directly into the GC system. Brain tissue homogenates were precipitated with methanol, the resulting supernatant was dried then acidified with hydrochloric acid. The aqueous solution was washed with MTBE twice, alkalinized, and extracted with MTBE. The MTBE layer was dried, reconstituted and injected into the GC system. The GC assay used a DB-1 capillary column with an oven temperature ramp (135 to 179 degrees C at 4 degrees C/min). Dextromethorphan was used as the internal standard. The calibration curves for tramadol and O-desmethyl tramadol in plasma and brain tissue were linear in the range of 10 to 10000 ng/ml (plasma) and ng/g (brain). Assay accuracy and precision of back calculated standards were within +/- 15%. PMID:11710575

  12. Important drugs for cough in advanced cancer.

    PubMed

    Homsi, J; Walsh, D; Nelson, K A

    2001-11-01

    Cough is a defense mechanism that prevents the entry of noxious materials into the respiratory system and clears foreign materials and excess secretions from the lungs and respiratory tract. In advanced cancer, it is a common symptom that interferes with the patient's daily activity and quality of life. Empiric treatment with antitussive agents is often needed. Two classes of antitussive drugs are available: (1) centrally acting: (a) opioids and (b) non-opioids; (2) peripherally acting: (a) directly and (b) indirectly. Antitussive availability varies widely around the world. Many antitussives, such as benzonatate, codeine, hydrocodone, and dextromethorphan, were extensively studied in the acute and chronic cough settings and showed relatively high efficacy and safety profiles. Benzonatate, clobutinol, dihydrocodeine, hydrocodone, and levodropropizine were the only antitussives specifically studied in cancer and advanced cancer cough. They all have shown to be effective and safe in recommended daily dose for cough. In advanced cancer the patient's current medications, previous antitussive use, the availability of routes of administration, any history of drug abuse, the presence of other symptoms and other factors, all have a role in the selection of antitussives for prescription. A good knowledge of the pharmacokinetics, dosage, efficacy, and side effects of the available antitussives provides for better management. PMID:11762966

  13. Effects of common antitussive drugs on the hERG potassium channel current.

    PubMed

    Deisemann, Heike; Ahrens, Nadine; Schlobohm, Irene; Kirchhoff, Christian; Netzer, Rainer; Möller, Clemens

    2008-12-01

    A common over-the-counter (OTC) non-opioid antitussive drug, clobutinol, was recently withdrawn from the market due to its potential to induce cardiac arrhythmias by a blockade of the potassium channel coded by the human ether-à-go-go-related gene (hERG). In this study, we investigated the effects of a number of antitussive compounds on the hERG ion channel current using patch-clamp electrophysiology, and compared the effects to that of clobutinol. The compounds clobutinol, pentoxyverine, dextromethorphan, and codeine inhibited the outward current in hERG transfected cells with half-maximal inhibition concentrations (IC50) of 1.9 microM, 3.0 microM, 5.1 microM, and 97 microM, respectively. For theobromine, no significant effect on the hERG current at a concentration up to 100 microM was detected. Safety margins between the effects of the drugs on the hERG ion channel current and their calculated maximal free therapeutic plasma concentration were calculated. These results were compared to assess potential risks of the compounds to induce torsade de pointes-type arrhythmias. PMID:19034038

  14. Antitussive Efficacy and Safety Profile of Ethyl Acetate Fraction of Terminalia chebula

    PubMed Central

    Wahab, Abdul; Ayub, Khurshed; Sherkheli, M. Azhar; Khan, Rafeeq Alam; Raza, Mohsin

    2013-01-01

    Antitussive effects of ethyl acetate fraction of Terminalia chebula on sulphur dioxide (SO2) gas induced cough have been examined in mice. Safety profile of Terminalia chebula was established by determining LD50 and acute neurotoxicity. The result showed that extract of Terminalia chebula dose dependently suppressed SO2 gas induced cough in mice. Terminalia chebula, after i.p. administration at dose level 500 mg/kg, offered maximum cough suppressive effects; that is, number of coughs at 60 min was 12 ± 1.52 (mean ± SEM) as compared to codeine 10 mg/kg; i.p., dextromethorphan 10 mg/kg; i.p., and saline, having frequency of cough 10.375 ± 0.866, 12.428 ± 0.81, and 46 ± 2.61, respectively. LD50 value of Terminalia chebula was approximately 1265 mg/kg, respectively. No sign of neural impairment was observed at antitussive doses of extract. Antitussive effect of Terminalia chebula was partly reversed with treatment by naloxone (3 mg/kg; s.c.) while rimcazole (3 mg/kg; s.c.) did not antagonize its cough suppression activity. This may suggest that opioid receptors partially contribute in antitussive action of Terminalia chebula. Along with this, the possibility of presence of single or multiple mechanisms activated by several different pharmacological actions (mainly anti-inflammatory, antioxidant, spasmolytic, antibacterial, and antiphlegmatic) could not be eliminated. PMID:24024039

  15. New recombinant cyclohexylamine oxidase variants for deracemization of secondary amines by orthogonally assaying designed mutants with structurally diverse substrates.

    PubMed

    Li, Guangyue; Yao, Peiyuan; Cong, Peiqian; Ren, Jie; Wang, Lei; Feng, Jinhui; Lau, Peter C K; Wu, Qiaqing; Zhu, Dunming

    2016-01-01

    To further expand the substrate range of the cyclohexylamine oxidase (CHAO) from Brevibacterium oxydans, a library of diverse mutants was created and assayed toward a group of structurally diverse substrates. Among them, mutants T198A and M226A exhibited enhanced activity relative to wt CHAO for most (S)-enantiomers of primary amines and some secondary amines. While mutants T198I, L199I, L199F, M226I and M226T were more active than wt CHAO toward the primary amines, mutants T198F, L199T, Y321A, Y321T, Y321I and Y321F enhanced the enzyme activity toward the secondary amines. In particular, mutant Y321I displayed an enhanced catalytic efficiency toward 1-(4-methoxybenzyl)-1, 2, 3, 4, 5, 6, 7, 8-octahydroisoquinoline (13). Whereas a double mutant, Y321I/M226T, acted on (S)-N-(prop-2-yn-1-yl)-2, 3-dihydro-1H-inden-1-amine [(S)-8]. Since (R)-8 is an irreversible inhibitor of monoamine oxidase and (S)-13 is an intermediate of dextromethorphan, a cough suppressant drug, deracemizations of 8 and 13 were carried out with crude enzyme extracts of the respective mutants. This resulted in 51% and 78% isolated yields of (R)-8 and (S)-13, respectively, each with high enantiomeric excess (93% and 99% ee). The results demonstrated the application potential of the evolved CHAO mutants in drug synthesis requiring chiral secondary amines. PMID:27138090

  16. Effects of N-methyl-D-aspartate antagonists on different measures of motion sickness in cats.

    PubMed

    Lucot, J B

    1998-11-15

    Because N-methyl-D-aspartate (NMDA) antagonists prevent cisplatin-induced emesis and NMDA receptors are in both emetic pathways and structures associated with the final common pathway for vomiting, they have the potential to be broad-spectrum antiemetics. This was evaluated by determining their effects on motion sickness in cats. The measures included the number vomiting, the number of symptom points, which reflect activity early in the final common path and the duration of the retch/vomit sequence, which reflects activity late in the path. Dextrorphan, ketamine and dextromethorphan decreased the number vomiting with the same rank order of potency as at NMDA receptors. Additional studies with 1,3-dio-tolylguaninidine (DTG) and haloperidol ruled out a role for sigma receptors. The NMDA antagonists produced a nonsignificant dose-dependent decrease in symptoms and had no effects on the duration of vomiting. They also produced motor abnormalities at the highest doses. The competitive antagonist LY 233053 also decreased the number vomiting without altering the duration. It produced a nonsignificant non-dose-dependent decrease in symptoms and had no effects on gross motor output. The results are consistent with a broad spectrum of antiemetic efficacy with at least a part of its action in the early to middle portions of the final common pathway for vomiting. Additional actions on the vestibular nuclei are possible. PMID:10052568

  17. Physostigmine (alone and together with adjunct) pretreatment against soman, sarin, tabun and vx intoxication. (Reannouncement with new availability information)

    SciTech Connect

    Harris, L.W.; Talbot, B.G.; Lennox, W.J.; Anderson, D.R.; Solana, R.P.

    1991-12-31

    A pretreatment for organophosphorus (OP) anticholinesterase (e. g. , soman) intoxication should prevent lethality and convulsions (CNV) at 2 LD50s and be behavioral-decrement-free when given alone. Behavioral-deficit-free pretreatment regimens (PRGs) for guinea pigs consisted of Physostigmine (0.15 mg/kg, im) and adjunct. Adjuncts MG/KG, IM tested were akineton 0.25, aprophen 8, trihexyphenidyl 2, atropine 16, azaprophen 51, BENACTYZINE 1.25, cogentin 4, dextromethorphan 7.5, ethopropazine 12, kemadrin 11, MEMANTINE 5, promethazine 5, scopolamine 0.081 AND CONTROL 2. PRGs were given 30 min before soman (60 ug/kg, sc; 2 LD50S) or other OP agents. Animals were then observed and graded for signs of intoxication, including CNV at 7 time points and at 24 hr. Physostigmine alone reduced the incidence of CNV and lethality induced by 2 LD50s of soman by 42 and 60%, respectively. All of the PRGs tested abolished lethality and 12 shortened recovery time to 2 hr or less. Also, PRGs including azaprophen or atropine prevented CNV. When selected PRGs were tested against intoxication by sarin, tabun or VX, the efficacy was generally superior to that for soman. The data show that several PRGs are effective against soman intoxication in guinea pigs. Pretreatment, physostigmine, anticholinesterases, soman (GD).

  18. Ion mobility spectrometry for the rapid analysis of over-the-counter drugs and beverages

    PubMed Central

    Fernández-Maestre, Roberto

    2009-01-01

    In the pharmaceutical industry, there are increasing requirements for analytical methods in quality assessment for the production of drugs. In this investigation, ion mobility spectrometry (IMS) was used for the rapid qualitative separation and identification of active ingredients in generic over-the-counter drugs and food additives in beverages. The active ingredients determined in drugs were acetaminophen, aspartame, bisacodyl, caffeine, dextromethorphan, diphenhydramine, famotidine, glucosamine, guaifenesin, loratadine, niacin, phenylephrine, pyridoxine, thiamin, and tetrahydrozoline. Aspartame and caffeine were determined in beverages. Fourteen over-the-counter drugs and beverages were analyzed. Analysis times below 10 s were obtained for IMS, and reduced mobilities were reported for the first time for 12 compounds. A quadrupole mass spectrometer coupled to a mobility spectrometer was used to assure a correct peak assignation. The combination of fast analysis, low cost, and inexpensive maintenance of IMS instruments makes IMS an attractive technique for the qualitative determination of the active ingredients in over-the-counter drugs and food additives in manufacture quality control and cleaning verification for the drug and food industries. PMID:20835390

  19. New recombinant cyclohexylamine oxidase variants for deracemization of secondary amines by orthogonally assaying designed mutants with structurally diverse substrates

    PubMed Central

    Li, Guangyue; Yao, Peiyuan; Cong, Peiqian; Ren, Jie; Wang, Lei; Feng, Jinhui; Lau, Peter C.K.; Wu, Qiaqing; Zhu, Dunming

    2016-01-01

    To further expand the substrate range of the cyclohexylamine oxidase (CHAO) from Brevibacterium oxydans, a library of diverse mutants was created and assayed toward a group of structurally diverse substrates. Among them, mutants T198A and M226A exhibited enhanced activity relative to wt CHAO for most (S)-enantiomers of primary amines and some secondary amines. While mutants T198I, L199I, L199F, M226I and M226T were more active than wt CHAO toward the primary amines, mutants T198F, L199T, Y321A, Y321T, Y321I and Y321F enhanced the enzyme activity toward the secondary amines. In particular, mutant Y321I displayed an enhanced catalytic efficiency toward 1-(4-methoxybenzyl)-1, 2, 3, 4, 5, 6, 7, 8-octahydroisoquinoline (13). Whereas a double mutant, Y321I/M226T, acted on (S)-N-(prop-2-yn-1-yl)-2, 3-dihydro-1H-inden-1-amine [(S)-8]. Since (R)-8 is an irreversible inhibitor of monoamine oxidase and (S)-13 is an intermediate of dextromethorphan, a cough suppressant drug, deracemizations of 8 and 13 were carried out with crude enzyme extracts of the respective mutants. This resulted in 51% and 78% isolated yields of (R)-8 and (S)-13, respectively, each with high enantiomeric excess (93% and 99% ee). The results demonstrated the application potential of the evolved CHAO mutants in drug synthesis requiring chiral secondary amines. PMID:27138090

  20. Nabumetone: therapeutic use and safety profile in the management of osteoarthritis and rheumatoid arthritis.

    PubMed

    Hedner, Thomas; Samulesson, Ola; Währborg, Peter; Wadenvik, Hans; Ung, Kjell-Arne; Ekbom, Anders

    2004-01-01

    Nabumetone is a nonsteroidal anti-inflammatory prodrug, which exerts its pharmacological effects via the metabolite 6-methoxy-2-naphthylacetic acid (6-MNA). Nabumetone itself is non-acidic and, following absorption, it undergoes extensive first-pass metabolism to form the main circulating active metabolite (6-MNA) which is a much more potent inhibitor of preferentially cyclo-oxygenase (COX)-2. The three major metabolic pathways of nabumetone are O-demethylation, reduction of the ketone to an alcohol, and an oxidative cleavage of the side-chain occurs to yield acetic acid derivatives. Essentially no unchanged nabumetone and < 1% of the major 6-MNA metabolite are excreted unchanged in the urine from which 80% of the dose can be recovered and another 10% in faeces. Nabumetone is clinically used mainly for the management of patients with osteoarthritis (OA) or rheumatoid arthritis (RA) to reduce pain and inflammation. The clinical efficacy of nabumetone has also been evaluated in patients with ankylosing spondylitis, soft tissue injuries and juvenile RA. The optimum oral dosage of nabumetone for OA patients is 1 g once daily, which is well tolerated. The therapeutic response is superior to placebo and similar to nonselective COX inhibitors. In RA patients, nabumetone 1 g at bedtime is optimal, but an additional 0.5-1 g can be administered in the morning for patients with persistent symptoms. In RA, nabumetone has shown a comparable clinical efficacy to aspirin (acetylsalicylic acid), diclofenac, piroxicam, ibuprofen and naproxen. Clinical trials and a decade of worldwide safety data and long-term postmarketing surveillance studies show that nabumetone is generally well tolerated. The most frequent adverse effects are those commonly seen with COX inhibitors, which include diarrhoea, dyspepsia, headache, abdominal pain and nausea. In common with other COX inhibitors, nabumetone may increase the risk of GI perforations, ulcerations and bleedings (PUBs). However, several

  1. Pharmacokinetic interactions between monoamine oxidase A inhibitor harmaline and 5-methoxy-N,N-dimethyltryptamine, and the impact of CYP2D6 status.

    PubMed

    Jiang, Xi-Ling; Shen, Hong-Wu; Mager, Donald E; Yu, Ai-Ming

    2013-05-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT or street name "5-MEO") is a newer designer drug belonging to a group of naturally occurring indolealkylamines. Our recent study has demonstrated that coadministration of monoamine oxidase A (MAO-A) inhibitor harmaline (5 mg/kg) increases systemic exposure to 5-MeO-DMT (2 mg/kg) and active metabolite bufotenine. This study is aimed at delineating harmaline and 5-MeO-DMT pharmacokinetic (PK) interactions at multiple dose levels, as well as the impact of CYP2D6 that affects harmaline PK and determines 5-MeO-DMT O-demethylation to produce bufotenine. Our data revealed that inhibition of MAO-A-mediated metabolic elimination by harmaline (2, 5, and 15 mg/kg) led to a sharp increase in systemic and cerebral exposure to 5-MeO-DMT (2 and 10 mg/kg) at all dose combinations. A more pronounced effect on 5-MeO-DMT PK was associated with greater exposure to harmaline in wild-type mice than CYP2D6-humanized (Tg-CYP2D6) mice. Harmaline (5 mg/kg) also increased blood and brain bufotenine concentrations that were generally higher in Tg-CYP2D6 mice. Surprisingly, greater harmaline dose (15 mg/kg) reduced bufotenine levels. The in vivo inhibitory effect of harmaline on CYP2D6-catalyzed bufotenine formation was confirmed by in vitro study using purified CYP2D6. Given these findings, a unified PK model including the inhibition of MAO-A- and CYP2D6-catalyzed 5-MeO-DMT metabolism by harmaline was developed to describe blood harmaline, 5-MeO-DMT, and bufotenine PK profiles in both wild-type and Tg-CYP2D6 mouse models. This PK model may be further employed to predict harmaline and 5-MeO-DMT PK interactions at various doses, define the impact of CYP2D6 status, and drive harmaline-5-MeO-DMT pharmacodynamics. PMID:23393220

  2. Pharmacokinetic Interactions between Monoamine Oxidase A Inhibitor Harmaline and 5-Methoxy-N,N-Dimethyltryptamine, and the Impact of CYP2D6 Status

    PubMed Central

    Jiang, Xi-Ling; Shen, Hong-Wu; Mager, Donald E.

    2013-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT or street name “5-MEO”) is a newer designer drug belonging to a group of naturally occurring indolealkylamines. Our recent study has demonstrated that coadministration of monoamine oxidase A (MAO-A) inhibitor harmaline (5 mg/kg) increases systemic exposure to 5-MeO-DMT (2 mg/kg) and active metabolite bufotenine. This study is aimed at delineating harmaline and 5-MeO-DMT pharmacokinetic (PK) interactions at multiple dose levels, as well as the impact of CYP2D6 that affects harmaline PK and determines 5-MeO-DMT O-demethylation to produce bufotenine. Our data revealed that inhibition of MAO-A–mediated metabolic elimination by harmaline (2, 5, and 15 mg/kg) led to a sharp increase in systemic and cerebral exposure to 5-MeO-DMT (2 and 10 mg/kg) at all dose combinations. A more pronounced effect on 5-MeO-DMT PK was associated with greater exposure to harmaline in wild-type mice than CYP2D6-humanized (Tg-CYP2D6) mice. Harmaline (5 mg/kg) also increased blood and brain bufotenine concentrations that were generally higher in Tg-CYP2D6 mice. Surprisingly, greater harmaline dose (15 mg/kg) reduced bufotenine levels. The in vivo inhibitory effect of harmaline on CYP2D6-catalyzed bufotenine formation was confirmed by in vitro study using purified CYP2D6. Given these findings, a unified PK model including the inhibition of MAO-A- and CYP2D6-catalyzed 5-MeO-DMT metabolism by harmaline was developed to describe blood harmaline, 5-MeO-DMT, and bufotenine PK profiles in both wild-type and Tg-CYP2D6 mouse models. This PK model may be further employed to predict harmaline and 5-MeO-DMT PK interactions at various doses, define the impact of CYP2D6 status, and drive harmaline–5-MeO-DMT pharmacodynamics. PMID:23393220

  3. Microbial biotransformation of bioactive flavonoids.

    PubMed

    Cao, Hui; Chen, Xiaoqing; Jassbi, Amir Reza; Xiao, Jianbo

    2015-01-01

    The bioactive flavonoids are considered as the most important phytochemicals in food, which exert a wide range of biological benefits for human being. Microbial biotransformation strategies for production of flavonoids have attracted considerable interest because they allow yielding novel flavonoids, which do not exist in nature. In this review, we summarize the existing knowledge on the production and biotransformation of flavonoids by various microbes. The main reactions during microbial biotransformation are hydroxylation, dehydroxylation, O-methylation, O-demethylation, glycosylation, deglycosylation, dehydrogenation, hydrogenation, C ring cleavage of the benzo-γ-pyrone system, cyclization, and carbonyl reduction. Cunninghamella, Penicillium, and Aspergillus strains are very popular to biotransform flavonoids and they can perform almost all the reactions with excellent yields. Aspergillus niger is one of the most applied microorganisms in the flavonoids' biotransformation; for example, A. niger can transfer flavanone to flavan-4-ol, 2'-hydroxydihydrochalcone, flavone, 3-hydroxyflavone, 6-hydroxyflavanone, and 4'-hydroxyflavanone. The hydroxylation of flavones by microbes usually happens on the ortho position of hydroxyl group on the A ring and C-4' position of the B ring and microbes commonly hydroxylate flavonols at the C-8 position. The microorganisms tend to hydroxylate flavanones at the C-5, 6, and 4' positions; however, for prenylated flavanones, dihydroxylation often takes place on the C4α=C5α double bond on the prenyl group (the side chain of A ring). Isoflavones are usually hydroxylated at the C-3' position of the B ring by microorganisms. The microbes convert flavonoids to their 7-O-glycosides and 3-O-glycosides (when flavonoids have a hydroxyl moiety at the C-3 position). The demethylation of multimethoxyl flavonoids by microbes tends to happen at the C-3' and C-4' positions of the B ring. Multimethoxyl flavanones and isoflavone are demethylated at

  4. In vitro assessment of metabolic drug-drug interaction potential of apixaban through cytochrome P450 phenotyping, inhibition, and induction studies.

    PubMed

    Wang, Lifei; Zhang, Donglu; Raghavan, Nirmala; Yao, Ming; Ma, Li; Frost, Charles E; Frost, Charles A; Maxwell, Brad D; Chen, Shiang-yuan; He, Kan; Goosen, Theunis C; Humphreys, W Griffith; Grossman, Scott J

    2010-03-01

    Apixaban is an oral, direct, and highly selective factor Xa inhibitor in late-stage clinical development for the prevention and treatment of thromboembolic diseases. The metabolic drug-drug interaction potential of apixaban was evaluated in vitro. The compound did not show cytochrome P450 inhibition (IC(50) values >20 microM) in incubations of human liver microsomes with the probe substrates of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4/5. Apixaban did not show any effect at concentrations up to 20 muM on enzyme activities or mRNA levels of selected P450 enzymes (CYP1A2, 2B6, and 3A4/5) that are sensitive to induction in incubations with primary human hepatocytes. Apixaban showed a slow metabolic turnover in incubations of human liver microsomes with formation of O-demethylation (M2) and hydroxylation products (M4 and M7) as prominent in vitro metabolites. Experiments with human cDNA-expressed P450 enzymes and P450 chemical inhibitors and correlation with P450 activities in individual human liver microsomes demonstrated that the oxidative metabolism of apixaban for formation of all metabolites was predominantly catalyzed by CYP3A4/5 with a minor contribution of CYP1A2 and CYP2J2 for formation of M2. The contribution of CYP2C8, 2C9, and 2C19 to metabolism of apixaban was less significant. In addition, a human absorption, distribution, metabolism, and excretion study showed that more than half of the dose was excreted as unchanged parent (f(m CYP) <0.5), thus significantly reducing the overall metabolic drug-drug interaction potential of apixaban. Together with a low clinical efficacious concentration and multiple clearance pathways, these results demonstrate that the metabolic drug-drug interaction potential between apixaban and coadministered drugs is low. PMID:19940026

  5. Pharmacokinetic evaluation of a new oral sustained release dosage form of tramadol

    PubMed Central

    Malonne, H; Sonet, B; Streel, B; Lebrun, S; De Niet, S; Sereno, A; Vanderbist, F

    2004-01-01

    Aims To compare the pharmacokinetic profile of a new modified release formulation of tramadol (Tramadol LP 200 mg, SMB Technology, Marche-en-Famenne, Belgium) with that of an immediate release capsule (Topalgic® 50 mg, Grünenthal, Aachen, Germany) after single and multiple dosing and to assess the potential effect of food on its relative bioavailability. Methods The first study had an open, single-dose, three-treatment, three-period, six-sequence, randomised, crossover design with at least a five-day wash-out. The second study had an open, steady-state, two-treatment, two-period, two-sequence, randomised crossover design with at least a seven-day wash-out. Both studies contained 30 healthy subjects. Both enantiomers of tramadol and O-demethyl-tramadol (the only active metabolite of tramadol) were assayed in the plasma using an LC-MS/MS method. AUC∞, AUCt, Cmax, Tmax, and T1/2 were estimated. Statistical analysis was performed using univariate anova, the Wilcoxon nonparametric method or Friedman's nonparametric anova where appropriate. Results Tramadol had a significantly lower Cmax and longer Tmax than the conventional formulation. Thus, the mean (± sd) Cmax of tramadol were 646 ± 192 and 300 ± 94 ng ml−1 for Topalgic® 4 × 50mg and Tramadol LP 200 mg, respectively (95% confidence interval on the difference expressed as a percentage 42–51). AUC of tramadol from both formulations was comparable (similar AUC∞ and AUCt). Thus, the mean AUC∞ of (+/–)tramadol obtained after multiple dosing were 4611 ± 1944 and 5105 ± 2101 ngh ml−1 after Topalgic® 4 × 50mg and Tramadol LP 200 mg, respectively (95%CI 102–123%). We also demonstrate that the pharmacokinetics of the drug are not influenced by the intake of food. Thus, the mean AUC∞ of (+/–) tramadol were 5444 ± 1637 and 5169 ± 1580 ngh ml−1 after Tramadol LP 200 mg given in the fasting and fed states, respectively (95%CI = 88–103%). Conclusions The new sustained release form of tramadol

  6. Analysis of erlotinib and its metabolites in rat tissue sections by MALDI quadrupole time-of-flight mass spectrometry.

    PubMed

    Signor, Luca; Varesio, Emmanuel; Staack, Roland F; Starke, Volkmar; Richter, Wolfgang F; Hopfgartner, Gérard

    2007-07-01

    A qualitative and quantitative analysis of erlotinib (RO0508231) and its metabolites was carried out on rat tissue sections from liver, spleen and muscle. Following oral administration at a dose of 5 mg/kg, samples were analyzed by matrix-assisted laser desorption ionization (MALDI) with mass spectrometry (MS) using an orthogonal quadrupole time-of-flight instrument. The parent compound was detected in all tissues analyzed. The metabolites following drug O-dealkylation could also be detected in liver sections. Sinapinic acid (SA) matrix combined with the dried-droplet method resulted in better conditions for our analysis on tissues. Drug quantitation was investigated by the standard addition method and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis on the tissue extracts. The presence of the parent compound and of its O-demethylated metabolites was confirmed in all tissue types and their absolute amounts calculated. In liver the intact drug was found to be 3.76 ng/mg tissue, while in spleen and muscle 6- and 30-fold lower values, respectively, were estimated. These results were compared with drug quantitation obtained by whole-body autoradiography, which was found to be similar. The potential for direct quantitation on tissue sections in the presence of an internal standard was also investigated using MALDI-MS. The use of alpha-cyano-4-hydroxycinnamic acid (CHCA) as the matrix resulted in better linearity for the calibration curves obtained with reference solutions of the drug when compared to SA, but on tissue samples no reliable quantitative analysis was possible owing to the large variability in the signal response. MS imaging experiments using MALDI in MS/MS mode allowed visualizing the distribution of the parent compound in liver and spleen tissues. By calculating the ratio between the total ion intensities of MS images for liver and spleen sections, a value of 6 : 1 was found, which is in good agreement with the quantitative data obtained

  7. The Toxicology Investigators Consortium Case Registry--the 2012 experience.

    PubMed

    Wiegand, Timothy; Wax, Paul; Smith, Eric; Hart, Katherine; Brent, Jeffrey

    2013-12-01

    fragments were administered in 109 cases or 82 % of cases in which a snake envenomation occurred. There were 57 deaths reported in the Registry in 2012. The most common associated agent alone or in combination was the non-opioid analgesic acetaminophen, being reported in 10 different cases. Other common agents and agent classes involved in death cases included ethanol, opioids, the anti-diabetic agent metformin, sedatives-hypnotics and cardiovascular agents, in particular amlodipine. There were significant trends identified during 2012. Abuse of over-the-counter medications such as dextromethorphan remains prevalent. Cases involving dextromethorphan continued to be reported at frequencies higher than other commonly abused drugs including many stimulants, phencyclidine, synthetic cannabinoids and designer amphetamines such as bath salts. And, while cases involving synthetic cannabinoids and psychoactive bath salts remained relatively constant from 2011 to 2012 several designer amphetamines and novel psychoactive substances were first reported in the Registry in 2012 including the NBOME compounds or "N-bomb" agents. LSD cases also spiked dramatically in 2012 with an 18-fold increase from 2011 although many of these cases are thought to be ultra-potent designer amphetamines misrepresented as "synthetic" LSD. The 2012 Registry included over 400 Adverse Drug Reactions (ADRs) involving 4 % of all Registry cases with 106 agents causing at least 2 ADRs. Additional data including supportive cares, decontamination, and chelating agent use are also included in the 2012 annual report. The Registry remains a valuable toxico-surveillance and research tool. The ToxIC Registry is a unique tool for identifying and characterizing confirmed cases of significant or potential toxicity or complexity to require bedside care by a medical toxicologist. PMID:24178902

  8. Medicine utilization review at a university teaching hospital in New Delhi

    PubMed Central

    Aqil, M.; Bhadana, V.; Alam, M.S.; Pillai, K. K.; Kapur, P.

    2012-01-01

    Objective: A prospective medicine usage evaluation based on prescription monitoring was conducted in the medicine OPD of our university teaching hospital to know prescribing trends of different categories of medicines. Materials and Methods: A total of 600 patients were included in the study comprising of 339 (56.5%) males and 261 (43.5%) females. The data were recorded within the OPD by a registered pharmacist on a medicine usage evaluation form, approved by The University Institutional Review Board (IRB). Results: A total of 2365 medicines were prescribed to 600 patients during the 3 months study period. The mean number of medicines per prescription were found to be 3.94. Medicines were most frequently prescribed as solid dosage forms (85.62%), especially tablets (70.82%), and liquid formulations (14.12%). Oral route (96.17%) was the most preferred mode of administration, followed by topical (2.11%) and parenteral (1.60%) routes. Combination therapy (94.33%) was more prevalent than monotherapy (5.66%). An overwhelming tendency for prescribing medicines by brand names (99%) was observed by the physicians. The most frequently prescribed class of medicines were antimicrobials > analgesics > cardiovascular > gastrointestinal agents. The most prescribed individual medicines among various therapeutic classes included isoniazid (antimicrobial), amlodipine (cardiovascular), metformin (hypoglycemic), cetirizine (antiallergic), rabeprazole (GI medicine), atorvastatin (hypolipidemic), dextromethorphan (respiratory medicine), alprazolam (sedative-hypnotic), paracetamol (analgesic). Conclusions: There is a considerable scope of improvement in the existing prescribing practice, especially prescribing by generic names, needs to be encouraged and a hospital formulary has to be developed for the purpose. The number of medicines to be included per prescription should be judged rationally and polypharmacy ought to be curbed. Use of antimicrobial also needs to be rationalized as

  9. Evaluation of Mutual Drug-Drug Interaction within Geneva Cocktail for Cytochrome P450 Phenotyping using Innovative Dried Blood Sampling Method.

    PubMed

    Bosilkovska, Marija; Samer, Caroline; Déglon, Julien; Thomas, Aurélien; Walder, Bernhard; Desmeules, Jules; Daali, Youssef

    2016-09-01

    Cytochrome P450 (CYP) activity can be assessed using a 'cocktail' phenotyping approach. Recently, we have developed a cocktail (Geneva cocktail) which combines the use of low-dose probes with a low-invasiveness dried blood spots (DBS) sampling technique and a single analytical method for the phenotyping of six major CYP isoforms. We have previously demonstrated that modulation of CYP activity after pre-treatment with CYP inhibitors/inducer could be reliably predicted using Geneva cocktail. To further validate this cocktail, in this study, we have verified whether probe drugs contained in the latter cause mutual drug-drug interactions. In a randomized, four-way, Latin-square crossover study, 30 healthy volunteers received low-dose caffeine, flurbiprofen, omeprazole, dextromethorphan and midazolam (a previously validated combination with no mutual drug-drug interactions); fexofenadine alone; bupropion alone; or all seven drugs simultaneously (Geneva cocktail). Pharmacokinetic profiles of the probe drugs and their metabolites were determined in DBS samples using both conventional micropipette sampling and new microfluidic device allowing for self-sampling. The 90% confidence intervals for the geometric mean ratios of AUC metabolite/AUC probe for CYP probes administered alone or within Geneva cocktail fell within the 0.8-1.25 bioequivalence range indicating the absence of pharmacokinetic interaction. The same result was observed for the chosen phenotyping indices, that is metabolic ratios at 2 hr (CYP1A2, CYP3A) or 3 hr (CYP2B6, CYP2C9, CYP2C19, CYP2D6) post-cocktail administration. DBS sampling could successfully be performed using a new microfluidic device. In conclusion, Geneva cocktail combined with an innovative DBS sampling device can be used routinely as a test for simultaneous CYP phenotyping. PMID:27009433

  10. Mucolytics, expectorants, and mucokinetic medications.

    PubMed

    Rubin, Bruce K

    2007-07-01

    In health, the airways are lined by a layer of protective mucus gel that sits atop a watery periciliary fluid. Mucus is an adhesive, viscoelastic gel, the biophysical properties of which are largely determined by entanglements of long polymeric gel-forming mucins, MUC5AC and MUC5B. This layer entraps and clears bacteria and inhibits bacterial growth and biofilm formation. It also protects the airway from inhaled irritants and from fluid loss. In diseases such as cystic fibrosis there is almost no mucin (and thus no mucus) in the airway; secretions consist of inflammatory-cell derived DNA and filamentous actin polymers, which is similar to pus. Retention of this airway pus leads to ongoing inflammation and airway damage. Mucoactive medications include expectorants, mucolytics, and mucokinetic drugs. Expectorants are meant to increase the volume of airway water or secretion in order to increase the effectiveness of cough. Although expectorants, such as guaifenesin (eg, Robatussin or Mucinex), are sold over the counter, there is no evidence that they are effective for the therapy of any form of lung disease, and when administered in combination with a cough suppressant such as dextromethorphan (the "DM" in some medication names) there is a potential risk of increased airway obstruction. Hyperosmolar saline and mannitol powder are now being used as expectorants in cystic fibrosis. Mucolytics that depolymerize mucin, such as N-acetylcysteine, have no proven benefit and carry a risk of epithelial damage when administered via aerosol. DNA-active medications such as dornase alfa (Pulmozyme) and potentially actin-depolymerizing drugs such as thymosin beta(4) may be of value in helping to break down airway pus. Mucokinetic agents can increase the effectiveness of cough, either by increasing expiratory cough airflow or by unsticking highly adhesive secretions from the airway walls. Aerosol surfactant is one of the most promising of this class of medications. PMID:17594730

  11. Antitussive activity of sigma-1 receptor agonists in the guinea-pig

    PubMed Central

    Brown, Claire; Fezoui, Malika; Selig, William M; Schwartz, Carl E; Ellis, James L

    2003-01-01

    Current antitussive medications have limited efficacy and often contain the opiate-like agent dextromethorphan (DEX). The mechanism whereby DEX inhibits cough is ill defined. DEX displays affinity at both NMDA and sigma receptors, suggesting that the antitussive activity may involve central or peripheral activity at either of these receptors. This study examined and compared the antitussive activity of DEX and various putative sigma receptor agonists in the guinea-pig citric-acid cough model. Intraperitoneal (i.p.) administration of DEX (30 mg kg−1) and the sigma-1 agonists SKF-10,047 (1–5 mg kg−1), Pre-084 (5 mg kg−1), and carbetapentane (1–5 mg kg−1) inhibited citric-acid-induced cough in guinea-pigs. Intraperitoneal administration of a sigma-1 antagonist, BD 1047 (1–5 mg kg−1), reversed the inhibition of cough elicited by SKF-10,047. In addition, two structurally dissimilar sigma agonists SKF-10,047 (1 mg ml−1) and Pre-084 (1 mg ml−1) inhibited cough when administered by aerosol. Aerosolized BD 1047 (1 mg ml−1, 30 min) prevented the antitussive action of SKF-10,047 (5 mg kg−1) or DEX (30 mg kg−1) given by i.p. administration and, likewise, i.p. administration of BD 1047 (5 mg kg−1) prevented the antitussive action of SKF-10,047 given by aerosol (1 mg ml−1). These results therefore support the argument that antitussive effects of DEX may be mediated via sigma receptors, since both systemic and aerosol administration of sigma-1 receptor agonists inhibit citric-acid-induced cough in guinea-pigs. While significant systemic exposure is possible with aerosol administration, the very low doses administered (estimated <0.3 mg kg−1) suggest that there may be a peripheral component to the antitussive effect. PMID:14691051

  12. Encapsulation of liver microsomes into a thermosensitive hydrogel for characterization of drug metabolism and toxicity.

    PubMed

    Yang, Huiying; Zheng, Yuanting; Zhao, Bei; Shao, Tengfei; Shi, Qingling; Zhou, Ning; Cai, Weimin

    2013-12-01

    This study reported the encapsulation of liver microsomes into a thermosensitive hydrogel to characterize drug metabolism and predict drug effects. Pluronic(®)F-127 (F127) and acrylamide-bisacrylamide (Acr-Bis) were utilized as the two precursors. After chemical crosslinking catalyzed by ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED), the resulting Pluronic F127-acrylamide-bisacrylamide (FAB) hydrogel could encapsulate microsomes at 4 °C and facilitate metabolic reactions at 37 °C. The gel morphology at different Acr-Bis concentrations was characterized using field emission scanning electron microscopy (FE-SEM). Higher concentrations of Acr-Bis could lead to higher degrees of cross-linking of the gel. A fluorescent staining assay was subsequently used to demonstrate successful encapsulation of microsomes into the gel as well as the free diffusion process of micromolecular substrates. The thermosensitivity of the FAB gel was studied using swelling ratio and protein release assay to verify its ability to encapsulate microsomes. The metabolic activity of microsomes encapsulated in gels was investigated by detecting the metabolites of FDA-approved substrates, including dextromethorphan, chlorzoxazone and testosterone. Compared with the traditional method of microsomal incubation, the FAB gel maintained 60%-70% of microsome activity. Lastly, the classic anticancer prodrug cyclophosphamide (CTX) was chosen as a model drug for the study of drug metabolism and the prediction of drug effects. When the microsomes encapsulated in the FAB gel were used in the cell culture system, CTX induced a higher level of apoptosis in MCF-7 cells compared with traditional microsomes. PMID:24075480

  13. Effect of crude extract of Eugenia jambolana Lam. on human cytochrome P450 enzymes.

    PubMed

    Chinni, Santhivardhan; Dubala, Anil; Kosaraju, Jayasankar; Khatwal, Rizwan Basha; Satish Kumar, M N; Kannan, Elango

    2014-11-01

    The fruit of Eugenia jambolana Lam. is very popular for its anti-diabetic property. Previous studies on the crude extract of E. jambolana (EJE) have successfully explored the scientific basis for some of its traditional medicinal uses. Considering its wide use and consumption as a seasonal fruit, the present study investigates the ability of E. jambolana to interact with cytochrome P450 enzymes. The standardized EJE was incubated with pooled human liver microsomes to assess the CYP2C9-, CYP2D6-, and CYP3A4-mediated metabolism of diclofenac, dextromethorphan, and testosterone, respectively. The metabolites formed after the enzymatic reactions were quantified by high performance liquid chromatography. EJE showed differential effect on cytochrome P450 activities with an order of inhibitory potential as CYP2C9 > CYP3A4 > CYP2D6 having IC50 of 76.69, 359.02, and 493.05 µg/mL, respectively. The selectivity of EJE for CYP2C9 rather than CYP3A4 and CYP2D6 led to perform the enzyme kinetics to explicate the mechanism underlying the inhibition of CYP2C9-mediated diclofenac 4'-hydroxylation. EJE was notably potent in inhibiting the reaction in a non-competitive manner with Ki of 84.85 ± 5.27 µg/mL. The results revealed the CYP2C9 inhibitory potential of EJE with lower Ki value suggesting that EJE should be examined for its potential pharmacokinetic and pharmacodynamic interactions when concomitantly administered with other drugs. PMID:24590863

  14. Comparisons between abiotic nitration and biotransformation reactions of phenolic micropollutants in activated sludge.

    PubMed

    Jewell, Kevin S; Wick, Arne; Ternes, Thomas A

    2014-01-01

    The transformation of selected phenolic substances was investigated during biological wastewater treatment. A main emphasis was put on the relevance of abiotic processes leading to toxic nitrophenolic transformation products (TPs). Due to their environmental relevance, the antiseptic ortho-phenylphenol (OPP), the plastics additive bisphenol A (BPA) and the psychoactive drug dextrorphan have been studied. Batch experiments confirmed that nitro- and nitroso-phenolic TPs can be formed under acidic conditions when nitrite is present. HNO2, N2O3 and NO and NO2 radicals are likely involved in the abiotic process. It was found that the process was promoted by the freezing of water samples, since this can lead to an unexpected pH drop. However, under conditions present at wastewater treatment plants (neutral pH, low nitrite concentrations), the formation of appreciable concentrations is rather unlikely through this process, since HNO2 concentrations are extremely low and NO and NO2 radicals will also react with other wastewater constituents. Thus, the transformation of phenolic substances such as OPP and BPA is mainly caused by biotic transformation. In addition to hydroxylation as a common reaction under aerobic conditions, the formation of sulfate conjugates was detected with the original compounds as well as with nitrophenolic TPs. Therefore, even when nitro-phenolic substances are formed it is likely that they are further transformed to sulfate conjugates. In raw wastewater and WWTP effluent nitrated BPA and NO2-dextrorphan were not detected. Only nitro-OPP was found in the influent of a WWTP with 2.3 ng/L, but it was not identified in the WWTP effluents. The concentrations of dextrorphan increased slightly during WWTP passage, possibly due to the cleavage of the glucuronide-conjugate, its human metabolite form, or demethylation of the prodrug dextromethorphan. PMID:24238259

  15. Chronic administration of caderofloxacin, a new fluoroquinolone, increases hepatic CYP2E1 expression and activity in rats

    PubMed Central

    Liu, Li; Miao, Ming-xing; Zhong, Ze-yu; Xu, Ping; Chen, Yang; Liu, Xiao-dong

    2016-01-01

    Aim: Caderofloxacin is a new fluoroquinolone that is under phase III clinical trials in China. Here we examined the effects of caderofloxacin on rat hepatic cytochrome P450 (CYP450) isoforms as well as the potential of caderofloxacin interacting with co-administered drugs. Methods: Male rats were treated with caderofloxacin (9 mg/kg, ig) once or twice daily for 14 consecutive days. The effects of caderofloxacin on CYP3A, 2D6, 2C19, 1A2, 2E1 and 2C9 were evaluated using a “cocktail” of 6 probes (midazolam, dextromethorphan, omeprazole, theophylline, chlorzoxazone and diclofenac) injected on d 0 (prior to caderofloxacin exposure) and d 15 (after caderofloxacin exposure). Hepatic microsomes from the caderofloxacin-treated rats were used to assess CYP2E1 activity and chlorzoxazone metabolism. The expression of CYP2E1 mRNA and protein in hepatic microsomes was analyzed with RT-PCR and Western blotting, respectively. Results: Fourteen-day administration of caderofloxacin significantly increased the activity of hepatic CYP2E1, leading to enhanced metabolism of chlorzoxazone. In vitro microsomal study confirmed that CYP2E1 was a major metabolic enzyme involved in chlorzoxazone metabolism, and the 14-d administration of caderofloxacin significantly increased the activity of CYP2E1 in hepatic microsomes, resulting in increased formation of 6-hydroxychlorzoxazone. Furthermore, the 14-d administration of caderofloxacin significantly increased the expression of CYP2E1 mRNA and protein in liver microsomes, which was consistent with the pharmacokinetic results. Conclusion: Fourteen-day administration of caderofloxacin can induce the expression and activity of hepatic CYP2E1 in rats. When caderofloxacin is administered, a potential drug-drug interaction mediated by CYP2E1 induction should be considered. PMID:26838075

  16. Pharmacological approach to the mechanisms of transcranial DC-stimulation-induced after-effects of human motor cortex excitability.

    PubMed

    Liebetanz, David; Nitsche, Michael A; Tergau, Frithjof; Paulus, Walter

    2002-10-01

    Weak transcranial direct current stimulation (tDCS) induces persisting excitability changes in the human motor cortex. These plastic excitability changes are selectively controlled by the polarity, duration and current strength of stimulation. To reveal the underlying mechanisms of direct current (DC)-induced neuroplasticity, we combined tDCS of the motor cortex with the application of Na(+)-channel-blocking carbamazepine (CBZ) and the N-methyl-D-aspartate (NMDA)-receptor antagonist dextromethorphan (DMO). Monitored by transcranial magnetic stimulation (TMS), motor cortical excitability changes of up to 40% were achieved in the drug-free condition. Increase of cortical excitability could be selected by anodal stimulation, and decrease by cathodal stimulation. Both types of excitability change lasted several minutes after cessation of current stimulation. DMO suppressed the post-stimulation effects of both anodal and cathodal DC stimulation, strongly suggesting the involvement of NMDA receptors in both types of DC-induced neuroplasticity. In contrast, CBZ selectively eliminated anodal effects. Since CBZ stabilizes the membrane potential voltage-dependently, the results reveal that after-effects of anodal tDCS require a depolarization of membrane potentials. Similar to the induction of established types of short- or long-term neuroplasticity, a combination of glutamatergic and membrane mechanisms is necessary to induce the after-effects of tDCS. On the basis of these results, we suggest that polarity-driven alterations of resting membrane potentials represent the crucial mechanisms of the DC-induced after-effects, leading to both an alteration of spontaneous discharge rates and to a change in NMDA-receptor activation. PMID:12244081

  17. Inhibitory Mechanisms of Human CYPs by Three Alkaloids Isolated from Traditional Chinese Herbs.

    PubMed

    Zhao, Yong; Hellum, Bent Håvard; Liang, Aihua; Nilsen, Odd Georg

    2015-06-01

    The three purified herbal compounds tetrahydropalmatine (Tet), neferine and berberine (Ber) were explored in vitro for basic inhibition mechanisms towards recombinant human CYP1A2, CYP2D6 and CYP3A4 metabolic activities. Phenacetin, dextromethorphan and testosterone, respectively, were used as CYP1A2, CYP2D6 and CYP3A4 substrates, and their metabolites were determined by validated HPLC methodologies. Positive inhibition controls were used. Mechanism-based (irreversible) inhibition was assessed by time-dependent and nicotinamide adenine dinucleotide phosphate-dependent and reversible inhibition by Lineweaver-Burk plot assessments. Inhibition mechanisms were also assessed by computerized interaction prediction by using the Discovery Studio CDOCKER software (Accelrys, San Diego, CA, USA). Tetrahydropalmatine showed a mechanism-based inhibition of both CYP1A2 and CYP2D6, and Ber of CYP2D6. Neferine and Ber both showed a nonmechanistic inhibition of CYP1A2. All compounds showed a similar and significant mechanism-based inhibition of CYP3A4. Tetrahydropalmatine and Ber demonstrated both reversible and irreversible inhibition of CYP2D6 and CYP3A4. Tetrahydropalmatine and Ber displayed H-bond and several Pi-bond connections with specific amino acid residues of CYP1A2, CYP2D6 and CYP3A4, giving further knowledge to the identified reversible and irreversible herb-drug interactions. Tetrahydropalmatine and Ber should be considered for herb-drug interactions in clinical therapy until relevant clinical studies are available. PMID:25640685

  18. Structural Basis of Activation of Bitter Taste Receptor T2R1 and Comparison with Class A G-protein-coupled Receptors (GPCRs)*

    PubMed Central

    Singh, Nisha; Pydi, Sai Prasad; Upadhyaya, Jasbir; Chelikani, Prashen

    2011-01-01

    The human bitter taste receptors (T2Rs) are non-Class A members of the G-protein-coupled receptor (GPCR) superfamily, with very limited structural information. Amino acid sequence analysis reveals that most of the important motifs present in the transmembrane helices (TM1–TM7) of the well studied Class A GPCRs are absent in T2Rs, raising fundamental questions regarding the mechanisms of activation and how T2Rs recognize bitter ligands with diverse chemical structures. In this study, the bitter receptor T2R1 was used to systematically investigate the role of 15 transmembrane amino acids in T2Rs, including 13 highly conserved residues, by amino acid replacements guided by molecular modeling. Functional analysis of the mutants by calcium imaging analysis revealed that replacement of Asn-662.65 and the highly conserved Asn-241.50 resulted in greater than 90% loss of agonist-induced signaling. Our results show that Asn-241.50 plays a crucial role in receptor activation by mediating an hydrogen bond network connecting TM1-TM2-TM7, whereas Asn-662.65 is essential for binding to the agonist dextromethorphan. The interhelical hydrogen bond between Asn-241.50 and Arg-552.54 restrains T2R receptor activity because loss of this bond in I27A and R55A mutants results in hyperactive receptor. The conserved amino acids Leu-1975.50, Ser-2005.53, and Leu-2015.54 form a putative LXXSL motif which performs predominantly a structural role by stabilizing the helical conformation of TM5 at the cytoplasmic end. This study provides for the first time mechanistic insights into the roles of the conserved transmembrane residues in T2Rs and allows comparison of the activation mechanisms of T2Rs with the Class A GPCRs. PMID:21852241

  19. Differential expression of bitter taste receptors in non-cancerous breast epithelial and breast cancer cells.

    PubMed

    Singh, Nisha; Chakraborty, Raja; Bhullar, Rajinder Pal; Chelikani, Prashen

    2014-04-01

    The human bitter taste receptors (T2Rs) are chemosensory receptors that belong to the G protein-coupled receptor superfamily. T2Rs are present on the surface of oral and many extra-oral cells. In humans 25 T2Rs are present, and these are activated by hundreds of chemical molecules of diverse structure. Previous studies have shown that many bitter compounds including chloroquine, quinidine, bitter melon extract and cucurbitacins B and E inhibit tumor growth and induce apoptosis in cancer cells. However, the existence of T2Rs in cancer cell is not yet elucidated. In this report using quantitative (q)-PCR and flow cytometry, we characterized the expression of T2R1, T2R4, T2R10, T2R38 and T2R49 in the highly metastatic breast cancer cell line MDA-MB-231, poorly metastatic cell line MCF-7, and non-cancerous mammary epithelial cell line MCF-10A. Among the 5 T2Rs analyzed by qPCR and flow cytometry, T2R4 is expressed at 40-70% in mammary epithelial cells in comparison to commonly used breast cancer marker proteins, estrogen receptor and E-cadherin. Interestingly, the expression of T2R4 was downregulated in breast cancer cells. An increase in intracellular calcium mobilization was observed after the application of bitter agonists, quinine, dextromethorphan, and phenylthiocarbamide that are specific for some of the 5 T2Rs. This suggests that the endogenous T2Rs expressed in these cells are functional. Taken together, our novel findings suggest that T2Rs are differentially expressed in mammary epithelial cells, with some T2Rs downregulated in breast cancer cells. PMID:24613843

  20. Drug reaction with eosinophilia and systemic symptoms syndrome (DRESS) syndrome associated with azithromycin presenting like septic shock: a case report

    PubMed Central

    2014-01-01

    Introduction Drug reaction with eosinophilia and systemic symptoms syndrome is a potentially life-threatening cutaneous hypersensitivity reaction characterized by extensive mucocutaneous eruption, fever, hematologic abnormalities including eosinophilia and/or atypical lymphocytosis, and extensive organ involvement. The drugs most often responsible for causing drug reaction with eosinophilia and systemic symptoms syndrome are anticonvulsants, antimicrobial agents and antipyretic or anti-inflammatory analgesics. Although azithromycin is widely prescribed in clinical practice, serious cutaneous reactions from this agent have been rarely described. We report the first adult case of drug reaction with eosinophilia and systemic symptoms syndrome associated with azithromycin. Case presentation A 44-year-old previously healthy Caucasian man with history of tobacco use presented to his primary care physician with fever and productive cough. He was prescribed azithromycin, promethazine hydrochloride and dextromethorphan hydrobromide syrup. One week later, he developed a blistering erythematous rash over both hands, which over the next two weeks spread to involve nearly his entire body surface, sparing only his face. He was admitted to an outside hospital with signs of systemic inflammatory response syndrome and severe sepsis, presumably from a skin infection. Despite aggressive therapy he deteriorated, with worsening diffuse erythema, and was transferred to our institution. He developed multiple organ failure requiring ventilatory and hemodynamic support. Pertinent laboratory studies included a leukocytosis with a white blood cell count of 17.6×109/L and 47% eosinophils. A skin biopsy showed evidence of spongiotic lichenoid dermatitis with eosinophils and neutrophils, compatible with a systemic drug-induced hypersensitivity reaction. Our patient was started on high-dose steroids and showed dramatic improvement within 48 hours. Conclusions We report the first adult case of

  1. Gateways to clinical trials.

    PubMed

    Bayes, M; Rabasseda, X; Prous, J R

    2006-09-01

    Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com This issue focuses on the following selection of drugs: A-007, A6, adalimumab, adenosine triphosphate, alefacept, alemtuzumab, AllerVax Ragweed, amphora, anakinra, angiotensin-(1-7), anidulafungin, apomine, aripiprazole, atomoxetine hydrochloride, avanafil; BAL-8557, becatecarin, bevacizumab, biphasic insulin aspart, BMS-188797, bortezomib, bosentan, botulinum toxin type B, brivudine; Calcipotriol/betamethasone dipropionate, caspofungin acetate, catumaxomab, certolizumab pegol, cetuximab, CG-0070, ciclesonide, cinacalcet hydrochloride, clindamycin phosphate/benzoyl peroxide, cryptophycin 52, Cypher; Dabigatran etexilate, darapladib, darbepoetin alfa, decitabine, deferasirox, desloratadine, dexanabinol, dextromethorphan/quinidine sulfate, DMF, drotrecogin alfa (activated), duloxetine hydrochloride; E-7010, edaravone, efalizumab, emtricitabine, entecavir, eplerenone, erlotinib hydrochloride, escitalopram oxalate, estradiol valerate/dienogest, eszopiclone, exenatide, ezetimibe; Fondaparinux sodium, fulvestrant; Gefitinib, gestodene, GYKI-16084; Hyaluronic acid, hydralazine hydrochloride/isosorbide dinitrate; Imatinib mesylate, indiplon, insulin glargine; Juzen-taiho-to; Lamivudine/zidovudine/abacavir sulfate, L-arginine hydrochloride, lasofoxifene tartrate, L-BLP-25, lenalidomide, levocetirizine, levodopa/carbidopa/entacapone, lexatumumab, lidocaine/prilocaine, lubiprostone, lumiracoxib; MAb-14.18, mitoquidone; Natalizumab, neridronic acid, neuradiab; Olpadronic acid sodium salt, omalizumab; p53-DC vaccine, parathyroid hormone (human recombinant), peginterferon alfa-2a, peginterferon alfa-2b, pemetrexed disodium, perifosine, pimecrolimus, prasterone, prasugrel, PRO-2000

  2. In vitro metabolic interactions between black cohosh (Cimicifuga racemosa) and tamoxifen via inhibition of cytochromes P450 2D6 and 3A4.

    PubMed

    Li, Jinghu; Gödecke, Tanja; Chen, Shao-Nong; Imai, Ayano; Lankin, David C; Farnsworth, Norman R; Pauli, Guido F; van Breemen, Richard B; Nikolić, Dejan

    2011-08-01

    Women who experience hot flashes as a side effect of tamoxifen (TAM) therapy often try botanical remedies such as black cohosh to alleviate these symptoms. Since pharmacological activity of TAM is dependent on the metabolic conversion into active metabolites by the action of cytochromes P450 2D6 (CYP2D6) and 3A4, the objective of this study was to evaluate whether black cohosh extracts can inhibit formation of active TAM metabolites and possibly reduce its clinical efficacy. At 50 μg/mL, a 75% ethanolic extract of black cohosh inhibited formation of 4-hydroxy- TAM by 66.3%, N-desmethyl TAM by 74.6% and α-hydroxy TAM by 80.3%. In addition, using midazolam and dextromethorphan as probe substrates, this extract inhibited CYP3A4 and CYP2D6 with IC(50) values of 16.5 and 50.1 μg/mL, respectively. Eight triterpene glycosides were identified as competitive CYP3A4 inhibitors with IC(50) values ranging from 2.3-5.1 µM, while the alkaloids protopine and allocryptopine were identified as competitive CYP2D6 inhibitors with K(i) values of 78 and 122 nM, respectively. The results of this study suggests that co-administration of black cohosh with TAM might interfere with the clinical efficacy of this drug. However, additional clinical studies are needed to determine the clinical significance of these in vitro results. PMID:21827327

  3. The Effects of Milk Thistle (Silybum marianum) on Human Cytochrome P450 Activity

    PubMed Central

    Kawaguchi-Suzuki, Marina; Frye, Reginald F.; Zhu, Hao-Jie; Brinda, Bryan J.; Chavin, Kenneth D.; Bernstein, Hilary J.

    2014-01-01

    Milk thistle (Silybum marianum) extracts are widely used as a complementary and alternative treatment of various hepatic conditions and a host of other diseases/disorders. The active constituents of milk thistle supplements are believed to be the flavonolignans contained within the extracts. In vitro studies have suggested that some milk thistle components may significantly inhibit specific cytochrome P450 (P450) enzymes. However, determining the potential for clinically significant drug interactions with milk thistle products has been complicated by inconsistencies between in vitro and in vivo study results. The aim of the present study was to determine the effect of a standardized milk thistle supplement on major P450 drug-metabolizing enzymes after a 14-day exposure period. CYP1A2, CYP2C9, CYP2D6, and CYP3A4/5 activities were measured by simultaneously administering the four probe drugs, caffeine, tolbutamide, dextromethorphan, and midazolam, to nine healthy volunteers before and after exposure to a standardized milk thistle extract given thrice daily for 14 days. The three most abundant falvonolignans found in plasma, following exposure to milk thistle extracts, were silybin A, silybin B, and isosilybin B. The concentrations of these three major constituents were individually measured in study subjects as potential perpetrators. The peak concentrations and areas under the time-concentration curves of the four probe drugs were determined with the milk thistle administration. Exposure to milk thistle extract produced no significant influence on CYP1A2, CYP2C9, CYP2D6, or CYP3A4/5 activities. PMID:25028567

  4. A possible trend suggesting increased abuse from Coricidin exposures reported to the Texas Poison Network: comparing 1998 to 1999.

    PubMed

    Baker, S David; Borys, Douglas J

    2002-06-01

    Coricidin products seemed to be one of the over-the-counter medications being reportedly abused by adolescents, as observed from the Texas Poison Center Network data. This retrospective chart review investigated the occurrence of abuse, developed a patient profile, and defined the clinical effects resulting from the abuse of Coricidin products. Data collected from the Texas Poison Center Network Toxic Exposure Surveillance System database included human exposures between 1998 and 1999, patients > or = 10y old, intentional use or abuse, and single substance ingestion of I of the tablet formulations of Coricidin. Thirty-three cases from 1998 and 59 cases from 1999 were reviewed. Of these cases, 85% met the inclusion criteria. Of the 7 medications searched, only 4 substances were coded for: Coricidin D, Coricidin D (long acting), Coricidin D (cold, flu & sinus) and Coriciding HBP. These contain a combination of dextromethorphan hydrobromide, chlorpheniramine maleate, phenylpropanolamine hydrochloride, and acetaminophen. Of the 78 cases, 63% were male and 38% were female. The mean age was 14.67 years, 77% being between 13 to 17 years old. Eighteen different symptoms were reported: tachycardia 50%, somnolence 24.4%, mydriasis and hypertension 16.7%, agitation 12.8%, disorientation 10.3%, slurred speech 9%, ataxia 6.4%, vomiting 5.1%, dry mouth and hallucinations 3.9%, tremor 2.6%, and headache, dizziness, syncope, seizure, chest pain, and nystagmus each 1.3%; 12.8% of the calls originated from the school nurse. The incidence of abuse reported increased 60% from 1998 to 1999. This worrisome trend suggests increased abuse of these products. PMID:12046973

  5. Development of a new multi-analyte assay for the simultaneous detection of opioids in serum and other body fluids using liquid chromatography-tandem mass spectrometry.

    PubMed

    Eckart, K; Röhrich, J; Breitmeier, D; Ferner, M; Laufenberg-Feldmann, R; Urban, R

    2015-09-15

    A liquid chromatography-tandem mass spectrometry method using electrospray ionization in positive ionization mode was developed for the simultaneous detection of multiple opioid-type drugs in plasma. The presented assay allows the quantitative determination of alfentanil, buprenorphine, codeine, desomorphine, dextromethorphan, dextrorphan, dihydrocodeine, dihydromorphine, ethylmorphine, fentanyl, hydrocodone, hydromorphone, methadone, morphine, naloxone, naltrexone, oxycodone, oxymorphone, pentazocine, pethidine, pholcodine, piritramide, remifentanil, sufentanil, and tramadol as well as the metabolites 6-monoacetylmorphine, bisnortilidine, morphine-3-glucuronide, morphine-6-glucuronide, naltrexol, norbuprenorphine, norfentanyl, norpethidine, nortilidine, and O-desmethyltramadol. Serum and blood samples were purified by solid-phase extraction. The analytes were separated on a phenyl-hexyl (100mm) column by formic acid/acetonitrile gradient elution using an UPLC 1290 Infinity coupled with a 6490 Triple Quadrupole mass spectrometer. The limits of detection ranged from 0.02 to 0.6ng/mL and the lower limits of quantification ranged from 0.1 to 2.0ng/mL. The calibration curves were linear between Calibration Levels 1-6 for all 35 substances. Recovery rates ranged between 51 and 88% for all compounds except alfentanil, bisnortilidine, pethidine, and morphine-3-glucuronide. The matrix effect ranged from 86% for ethylmorphine to 105% for desomorphine. Using the validation procedure proposed by the German Society of Toxicological and Forensic Chemistry, acceptable precision and accuracy data for almost all analytes were obtained. The method was successfully applied to 206 authentic serum samples provided by the palliative and intensive care units of the University Medical Center and the police authorities. Furthermore, a suspected fatal intoxication is demonstrated by an analysis of the sufentanil in post mortem body fluids and tissues. PMID:26241181

  6. Multi-drug and metabolite quantification in postmortem blood by liquid chromatography-high-resolution mass spectrometry: comparison with nominal mass technology.

    PubMed

    Rosano, Thomas G; Na, Seo; Ihenetu, Kenneth; Swift, Thomas A; Wood, Michelle

    2014-10-01

    High-resolution mass spectrometry (HRMS) is being applied in postmortem drug screening as an alternative to nominal mass spectrometry, and additional evaluation in quantitative casework is needed. We report quantitative analysis of benzoylecgonine, citalopram, cocaethylene, cocaine, codeine, dextromethorphan, dihydrocodeine, diphenhydramine, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, hydrocodone, hydromorphone, meperidine, methadone, morphine, oxycodone and oxymorphone in postmortem blood by ultra-performance liquid chromatography (UPLC)-MS(E)/time-of-flight (TOF). The method employs analyte-matched deuterated internal standardization and MS(E) acquisition of precursor and product ions at low (6 eV) and ramped (10-40 eV) collision energies, respectively. Quantification was performed using precursor ion data obtained with a mass extraction window of ± 5 ppm. Fragment and residual precursor ion acquisitions at ramped collision energies were evaluated as additional analyte identifiers. Extraction recovery of >60% and matrix effect of <20% were determined for all analytes and internal standards. Defined limits of detection (10 ng/mL) and quantification (25 ng/mL) were validated along with a linearity analytical range of 25-3,000 ng/mL (R(2) > 0.99) for all analytes. Parallel UPLC-MS(E)/TOF and UPLC-MS/MS analysis showed comparable precision and bias along with concordance of 253 positive (y = 1.002x + 1.523; R(2) = 0.993) and 2,269 negative analyte findings in 159 postmortem cases. Analytical performance and correlation studies demonstrate accurate quantification by UPLC-MS(E)/TOF and extended application of HRMS in postmortem casework. PMID:25217537

  7. GABAA agonist reduces visual awareness: a masking-EEG experiment.

    PubMed

    van Loon, Anouk M; Scholte, H Steven; van Gaal, Simon; van der Hoort, Björn J J; Lamme, Victor A F

    2012-04-01

    Consciousness can be manipulated in many ways. Here, we seek to understand whether two such ways, visual masking and pharmacological intervention, share a common pathway in manipulating visual consciousness. We recorded EEG from human participants who performed a backward-masking task in which they had to detect a masked figure form its background (masking strength was varied across trials). In a within-subject design, participants received dextromethorphan (a N-methyl-d-aspartate receptor antagonist), lorazepam (LZP; a GABA(A) receptor agonist), scopolamine (a muscarine receptor antagonist), or placebo. The behavioral results show that detection rate decreased with increasing masking strength and that of all the drugs, only LZP induced a further decrease in detection rate. Figure-related ERP signals showed three neural events of interest: (1) an early posterior occipital and temporal generator (94-121 msec) that was not influenced by any pharmacological manipulation nor by masking, (2) a later bilateral perioccipital generator (156-211 msec) that was reduced by masking as well as LZP (but not by any other drugs), and (3) a late bilateral occipital temporal generator (293-387 msec) that was mainly affected by masking. Crucially, only the intermediate neural event correlated with detection performance. In combination with previous findings, these results suggest that LZP and masking both reduce visual awareness by means of modulating late activity in the visual cortex but leave early activation intact. These findings provide the first evidence for a common mechanism for these two distinct ways of manipulating consciousness. PMID:22264199

  8. An improved substrate cocktail for assessing direct inhibition and time-dependent inhibition of multiple cytochrome P450s

    PubMed Central

    Chen, Zhong-hua; Zhang, Su-xing; Long, Na; Lin, Li-shan; Chen, Tao; Zhang, Fei-peng; Lv, Xue-qin; Ye, Pei-zhen; Li, Ning; Zhang, Ke-zhi

    2016-01-01

    Aim: The substrate cocktail is frequently used to evaluate cytochrome P450 (CYP) enzyme-mediated drug interactions and potential interactions among the probe substrates. Here, we re-optimized the substrate cocktail method to increase the reliability and accuracy of screening for candidate compounds and expanded the method from a direct CYP inhibition assay to a time-dependent inhibition (TDI) assay. Methods: In the reaction mixtures containing human liver microsome (0.1 mg/mL), both the concentrations of a substrate cocktail (phenacetin for 1A2, coumarin for 2A6, bupropion for 2B6, diclofenac for 2C9, dextromethorphan for 2D6, and testosterone for 3A4) and the incubation time were optimized. Metabolites of the substrate probes were simultaneously analyzed by multiple-reaction monitoring (MRM) using a routine LC/MS/MS. Direct CYP inhibition was validated using 7 inhibitors (α-naphthoflavone, tranylcypromine, ticlopidine, fluconazole, quinidine, ketoconazole and 1-ABT). The time-dependent inhibition was partially validated with 5 inhibitors (ketoconazole, verapamil, quinidine, paroxetine and 1-ABT). Results: The inhibition curve profiles and IC50 values of 7 CYP inhibitors were approximate when a single substrate and the substrate cocktail were tested, and were consistent with the previously reported values. Similar results were obtained in the IC50 shifts of 5 inhibitors when a single substrate and the substrate cocktail were tested in the TDI assay. Conclusion: The 6-in-1 substrate cocktail (for 1A2, 2A6, 2B6, 2C9, 2D6 and 3A) is reliable for assessing CYP inhibition and time-dependent inhibition of drug candidates. PMID:27063220

  9. Modulation of microglial immune responses by a novel thiourea derivative.

    PubMed

    Chern, Jyh-Haur; Hsu, Pei-Chien; Wang, Li-Wen; Tsay, Huey-Jen; Kang, Iou-Jiun; Shie, Feng-Shiun

    2010-10-01

    Increasing evidence indicates that microglial activation plays an important role in the pathogenesis of Alzheimer's disease (AD). In AD, activated microglia may facilitate the clearance of beta-amyloid (Abeta), a neurotoxic component in AD pathogenesis. However, microglial activation comes at the cost of triggering neuro-inflammation, which contributes to cerebral dysfunction. Thus, pharmacological approaches that can achieve a favorable combination of a reduced microglia-mediated neuro-inflammation, and an enhanced Abeta clearance may be beneficial for preventing the progression of the disease. Here, we show that some newly synthesized compounds may exert such a combination of functions. Using mouse primary microglia and RAW264.7 cells, we found that some thiourea derivatives significantly enhanced microglial Abeta phagocytosis and suppressed microglial immune responses, as evidenced by the reduced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2). Of note, some commercially available inhibitors for iNOS and/or COX-2, such as ibuprofen, dextromethorphan, and N(G)-methyl-l-arginine (l-NMA), show negligible effects on microglial Abeta phagocytosis. Among the thiourea derivatives, our data show that a lead compound, designated as compound #326, (1-Naphthalen-1-yl-3-[5-(3-thioureido-phenoxy)-pentyl]-thiourea) appears to be the most potent in promoting Abeta phagocytosis and in inhibiting the LPS-induced expression of iNOS and COX-2 (when used at concentrations in the low muM range). The potency of compound #326 may have beneficial effects on modulating microglial activation in AD. The structure-activity relationship indicates that the thiourea group, alkyl linker, and the hydrophobic aryl group largely influence the dual functions of the compounds. These findings may indicate a structural basis for the improved design of future drug therapies for AD. PMID:20637185

  10. A Physiologically Based Pharmacokinetic Model to Predict Disposition of CYP2D6 and CYP1A2 Metabolized Drugs in Pregnant Women

    PubMed Central

    Ke, Alice Ban; Nallani, Srikanth C.; Zhao, Ping; Rostami-Hodjegan, Amin; Isoherranen, Nina

    2013-01-01

    Conducting pharmacokinetic (PK) studies in pregnant women is challenging. Therefore, we asked if a physiologically based pharmacokinetic (PBPK) model could be used to evaluate different dosing regimens for pregnant women. We refined and verified our previously published pregnancy PBPK model by incorporating cytochrome P450 CYP1A2 suppression (based on caffeine PK) and CYP2D6 induction (based on metoprolol PK) into the model. This model accounts for gestational age–dependent changes in maternal physiology and hepatic CYP3A activity. For verification, the disposition of CYP1A2–metabolized drug theophylline (THEO) and CYP2D6–metabolized drugs paroxetine (PAR), dextromethorphan (DEX), and clonidine (CLO) during pregnancy was predicted. Our PBPK model successfully predicted THEO disposition during the third trimester (T3). Predicted mean postpartum to third trimester (PP:T3) ratios of THEO area under the curve (AUC), maximum plasma concentration, and minimum plasma concentration were 0.76, 0.95, and 0.66 versus observed values 0.75, 0.89, and 0.72, respectively. The predicted mean PAR steady-state plasma concentration (Css) ratio (PP:T3) was 7.1 versus the observed value 3.7. Predicted mean DEX urinary ratio (UR) (PP:T3) was 2.9 versus the observed value 1.9. Predicted mean CLO AUC ratio (PP:T3) was 2.2 versus the observed value 1.7. Sensitivity analysis suggested that a 100% induction of CYP2D6 during T3 was required to recover the observed PP:T3 ratios of PAR Css, DEX UR, and CLO AUC. Based on these data, it is prudent to conclude that the magnitude of hepatic CYP2D6 induction during T3 ranges from 100 to 200%. Our PBPK model can predict the disposition of CYP1A2, 2D6, and 3A drugs during pregnancy. PMID:23355638

  11. A physiologically based pharmacokinetic model to predict disposition of CYP2D6 and CYP1A2 metabolized drugs in pregnant women.

    PubMed

    Ke, Alice Ban; Nallani, Srikanth C; Zhao, Ping; Rostami-Hodjegan, Amin; Isoherranen, Nina; Unadkat, Jashvant D

    2013-04-01

    Conducting pharmacokinetic (PK) studies in pregnant women is challenging. Therefore, we asked if a physiologically based pharmacokinetic (PBPK) model could be used to evaluate different dosing regimens for pregnant women. We refined and verified our previously published pregnancy PBPK model by incorporating cytochrome P450 CYP1A2 suppression (based on caffeine PK) and CYP2D6 induction (based on metoprolol PK) into the model. This model accounts for gestational age-dependent changes in maternal physiology and hepatic CYP3A activity. For verification, the disposition of CYP1A2-metabolized drug theophylline (THEO) and CYP2D6-metabolized drugs paroxetine (PAR), dextromethorphan (DEX), and clonidine (CLO) during pregnancy was predicted. Our PBPK model successfully predicted THEO disposition during the third trimester (T3). Predicted mean postpartum to third trimester (PP:T3) ratios of THEO area under the curve (AUC), maximum plasma concentration, and minimum plasma concentration were 0.76, 0.95, and 0.66 versus observed values 0.75, 0.89, and 0.72, respectively. The predicted mean PAR steady-state plasma concentration (Css) ratio (PP:T3) was 7.1 versus the observed value 3.7. Predicted mean DEX urinary ratio (UR) (PP:T3) was 2.9 versus the observed value 1.9. Predicted mean CLO AUC ratio (PP:T3) was 2.2 versus the observed value 1.7. Sensitivity analysis suggested that a 100% induction of CYP2D6 during T3 was required to recover the observed PP:T3 ratios of PAR Css, DEX UR, and CLO AUC. Based on these data, it is prudent to conclude that the magnitude of hepatic CYP2D6 induction during T3 ranges from 100 to 200%. Our PBPK model can predict the disposition of CYP1A2, 2D6, and 3A drugs during pregnancy. PMID:23355638

  12. Characterization of biotransformation enzyme activities in primary rat proximal tubular cells.

    PubMed

    Schaaf, G J; de Groene, E M; Maas, R F; Commandeur, J N; Fink-Gremmels, J

    2001-04-16

    The proximal tubule is a frequent target for nephrotoxic compounds due to it's ability to transport and accumulate xenobiotics and their metabolites, as well as by the presence of an organ-selective set of biotransformation enzymes. The aim of the present study was to characterize the activities of different biotransformation enzymes during primary culturing of rat proximal tubular cells (PT cells). Specific marker substrates for determining cytochrome P450 (CYP450) activity of primary cultured PT cells include 7-ethoxyresorufin (CYP1A1), caffeine (CYP1A), testosterone (CY2B/C, CYP3A), tolbutamide (CYP2C) and dextromethorphan (CYP2D1). Activities of the CYP450 isoenzymes decreased considerably during culture with the greatest loss in activity within 24 h of culture. In addition, expression of CYP450 apoprotein, including CYP1A, CYP2C, CYP2D, CYP2E and CYP4A, was detected in microsomes from freshly isolated PT cells by immunoblotting using specific antibodies. CYP2B and CYP3A apoprotein could not be detected. Activity of the phase II biotransformation enzymes GST, GGT, beta-lyase and UGT was determined with 1-chloro-2,4-dinitrobenzene, L-glutamic acid gamma-(7-amido-4-methyl-coumarin), S-(1,1,2,2-tetrafluoroethyl)-L-cysteine and 1-naphthol, respectively, as marker substrates. Activity of the phase II enzymes remained more stable and, in contrast to CYP450 activity, significant activity was still expressed after 1 week of PT cell culture. Thus, despite the obvious advantages of PT cells as an in-vitro model for studies of biotransformation mediated toxicity, the strong time dependency of especially phase I and, to a lesser extent, phase II biotransformation activities confers limitations to their application. PMID:11311212

  13. A cross-sectional examination of medicinal substance abuse and use of nonmedicinal substances among Canadian youth: findings from the 2012-2013 Youth Smoking Survey

    PubMed Central

    Leos-Toro, Cesar; Hammond, David; Manske, Stephen

    2015-01-01

    Background: Medicinal substance abuse is prevalent in Canada; however, little is known about patterns of abuse among young people. In this study, we sought to characterize the abuse of medicinal substances, such as prescription medications and selected over-the-counter substances, as well as that of licit and illicit nonmedicinal substances, using a nationally representative sample of young people. Methods: Cross-sectional, nationally representative data for children in grades 7-12 were obtained from Health Canada's 2012-2013 Youth Smoking Survey (n = 38 667). Multinomial regression analyses were conducted to examine subgroup differences in medicinal substance abuse and comorbid abuse of both medicinal and nonmedicinal substances. Results: About 5% of youth reported abusing medicinal substances in the previous year. Dextromethorphan, a substance found in many cough and cold syrups, was the most widely abused (2.9%), followed by pain medications (2.6%), sleeping medications (1.8%), stimulants (1.7%) and sedatives (1.0%). Abuse of nonmedicinal substances aside from tobacco and alcohol was reported by 21.3% of the population, and abuse of any substances was detected in 23.0% of the surveyed population. Girls at each grade level reported higher rates of abuse of medicinal substances than boys. Regional differences were seen with regard to the types of substances abused across Canada. Interpretation: A substantial minority of Canadian youth report abusing medicinal substances, including over-the-counter medications (e.g., cough syrup) and prescriptions medications (e.g., pain medication). In contrast to nonmedicinal substances, girls were more likely than boys to report abuse of medicinal substances. PMID:27570758

  14. Simultaneous and comprehensive in vivo analysis of cytochrome P450 activity by using a cocktail approach in rats.

    PubMed

    Uchida, Shinya; Tanaka, Shimako; Namiki, Noriyuki

    2014-05-01

    A cocktail approach can detect the activities of multiple cytochrome P450 (CYP) isoforms following the administration of multiple CYP-specific substrates in a single experiment. This study aimed to develop a simultaneous and comprehensive in vivo analysis of CYP activity in rats. The rats received an oral administration of losartan (10 mg/kg) and omeprazole (40 mg/kg). Caffeine (1 mg/kg), dextromethorphan (10 mg/kg) and midazolam (10 mg/kg) were administered 15 min later. In the drug-interaction phase, the rats were treated orally with dexamethasone (80 mg/kg) 24 h before, or with ketoconazole (10 mg/kg), fluvoxamine (100 mg kg) or fluconazole (10 mg/kg) 1 h before the administration of cocktail drugs. The concentrations of the drugs and their metabolites were determined by LC/MS/MS. Plasma concentrations of five CYP substrates and their metabolites were simultaneously evaluated after the oral drug administration. Fluvoxamine and fluconazole significantly increased the Cmax and AUC of caffeine, and the AUC of omeprazole and midazolam. Dexamethasone significantly increased Cmax and AUC of losartan, while it decreased the Cmax of midazolam. Ketoconazole showed no significant effect on the pharmacokinetic parameters of the tested drugs. In conclusion, a cocktail approach was developed for simultaneous and comprehensive analysis of the activities of multiple CYP isoforms in rats. In this approach, the effects of inhibitors and an inducer of various CYP isoforms were examined. Although further studies are necessary to predict the effects in humans, this approach may be expected to serve as a convenient method for detecting drug-drug interactions in rats. PMID:24395703

  15. Multidrug toxicity involving sumatriptan.

    PubMed

    Knittel, Jessica L; Vorce, Shawn P; Levine, Barry; Hughes, Rhome L; Bosy, Thomas Z

    2015-01-01

    A multidrug fatality involving sumatriptan is reported. Sumatriptan is a tryptamine derivative that acts at 5-HT(1B/1D) receptors and is used for the treatment of migraines. The decedent was a 21-year-old white female found dead in bed by her spouse. No signs of physical trauma were observed and a large number of prescription medications were discovered at the scene. Toxicological analysis of the central blood revealed sumatriptan at a concentration of 1.03 mg/L. Following therapeutic dosing guidelines, sumatriptan concentrations do not exceed 0.095 mg/L. Sumatriptan was isolated by solid-phase extraction and analyzed using liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode. A tissue distribution study was completed with the following concentrations measured: 0.61 mg/L in femoral blood, 0.56 mg/L in iliac blood, 5.01 mg/L in urine, 0.51 mg/kg in liver, 3.66 mg/kg in kidney, 0.09 mg/kg in heart, 0.32 mg/kg in spleen, 0.01 mg/kg in brain, 15.99 mg/kg in lung and 78.54 mg/45 mL in the stomach contents. Carisoprodol, meprobamate, fluoxetine, doxylamine, orphenadrine, dextromethorphan and hydroxyzine were also present in the blood at the following concentrations: 3.35, 2.36, 0.63, 0.19, 0.06, 0.55 and 0.16 mg/L. The medical examiner ruled the cause of death as acute mixed drug toxicity and the manner of death as accident. PMID:25324526

  16. Detection of drugs in 275 alcohol-positive blood samples of Korean drivers.

    PubMed

    Kim, Eunmi; Choe, Sanggil; Lee, Juseon; Jang, Moonhee; Choi, Hyeyoung; Chung, Heesun

    2016-08-01

    Since driving under the influence of drugs (DUID) is as dangerous as drink-driving, many countries regulate DUID by law. However, laws against the use of drugs while driving are not yet established in Korea. In order to investigate the type and frequency of drugs used by drivers in Korea, we analyzed controlled and non-controlled drugs in alcohol-positive blood samples. Total 275 blood samples were taken from Korean drivers, which were positive in roadside alcohol testing. The following analyses were performed: blood alcohol concentrations by GC; screening for controlled drugs by immunoassay and confirmation for positive samples by GC-MS. For the detection of DUID related drugs in blood samples, a total of 49 drugs were selected and were examined by GC-MS. For a rapid detection of these drugs, an automated identification software called "DrugMan" was used. Concentrations of alcohol in 275 blood samples ranged from 0.011 to 0.249% (average 0.119%). Six specimens showed positive results by immunoassay: one methamphetamine and five benzodiazepines I. By GC-MS confirmation, only benzodiazepines in four cases were identified, while methamphetamine and benzodiazepine in two cases were not detected from the presumptive positive blood samples. Using DrugMan, four drugs were detected; chlorpheniramine (5)*, diazepam (4), dextromethorphan (1) and doxylamine (1). In addition, ibuprofen (1), lidocaine (1) and topiramate (1) were also detected as general drugs in blood samples ('*' indicates frequency). The frequency of drug abuse by Korean drivers was relatively low and a total 14 cases were positive in 275 blood samples with a ratio of 5%. However it is necessary to analyze more samples including alcohol negative blood, and to expand the range of drug lists to get the detailed information. PMID:27015372

  17. Currently available cough suppressants for chronic cough.

    PubMed

    Chung, Kian Fan

    2008-01-01

    Chronic cough is a common symptom but only a fraction of patients seek medical attention. Addressing the causes of chronic cough may lead to control of cough; however, this approach is not always successful since there is a certain degree of failure even when the cause(s) of cough are adequately treated; in idiopathic cough, there is no cause to treat. Persistent cough may be associated with deterioration of quality of life, and treatment with cough suppressants is indicated. Currently available cough suppressants include the centrally acting opioids such as morphine, codeine, and dextromethorphan. Peripherally acting antitussives include moguisteine and levodropropizine. Early studies report success in reducing cough in patients with chronic bronchitis or COPD; however, a carefully conducted study showed no effect of codeine on cough of COPD. Success with these cough suppressants can be achieved at high doses that are associated with side effects. Slow-release morphine has been reported to be useful in controlling intractable cough with good tolerance to constipation and drowsiness. There have been case reports of the success of centrally acting drugs such as amitryptiline, paroxetine, gabapentin, and carbamezepine in chronic cough. New opioids such as nociceptin or antagonists of TRPV1 may turn out to be more effective. Efficacy of cough suppressants must be tested in double-blind randomised trials using validated measures of cough in patients with chronic cough not responding to specific treatments. Patients with chronic cough are in desperate need of effective antitussives that can be used either on demand or on a long-term basis. PMID:17909897

  18. The effects of CYP2D6 and CYP3A activities on the pharmacokinetics of immediate release oxycodone

    PubMed Central

    Samer, CF; Daali, Y; Wagner, M; Hopfgartner, G; Eap, CB; Rebsamen, MC; Rossier, MF; Hochstrasser, D; Dayer, P; Desmeules, JA

    2010-01-01

    Background and purpose: There is high interindividual variability in the activity of drug-metabolizing enzymes catalysing the oxidation of oxycodone [cytochrome P450 (CYP) 2D6 and 3A], due to genetic polymorphisms and/or drug–drug interactions. The effects of CYP2D6 and/or CYP3A activity modulation on the pharmacokinetics of oxycodone remains poorly explored. Experimental approach: A randomized crossover double-blind placebo-controlled study was performed with 10 healthy volunteers genotyped for CYP2D6 [six extensive (EM), two deficient (PM/IM) and two ultrarapid metabolizers (UM)]. The volunteers randomly received on five different occasions: oxycodone 0.2 mg·kg−1 and placebo; oxycodone and quinidine (CYP2D6 inhibitor); oxycodone and ketoconazole (CYP3A inhibitor); oxycodone and quinidine+ketoconazole; placebo. Blood samples for plasma concentrations of oxycodone and metabolites (oxymorphone, noroxycodone and noroxymorphone) were collected for 24 h after dosing. Phenotyping for CYP2D6 (with dextromethorphan) and CYP3A (with midazolam) were assessed at each session. Key results: CYP2D6 activity was correlated with oxymorphone and noroxymorphone AUCs and Cmax (−0.71 < Spearman correlation coefficient ρs < −0.92). Oxymorphone Cmax was 62% and 75% lower in PM than EM and UM. Noroxymorphone Cmax reduction was even more pronounced (90%). In UM, oxymorphone and noroxymorphone concentrations increased whereas noroxycodone exposure was halved. Blocking CYP2D6 (with quinidine) reduced oxymorphone and noroxymorphone Cmax by 40% and 80%, and increased noroxycodone AUC∞ by 70%. Blocking CYP3A4 (with ketoconazole) tripled oxymorphone AUC∞ and reduced noroxycodone and noroxymorphone AUCs by 80%. Shunting to CYP2D6 pathway was observed after CYP3A4 inhibition. Conclusions and implications: Drug–drug interactions via CYP2D6 and CYP3A affected oxycodone pharmacokinetics and its magnitude depended on CYP2D6 genotype. PMID:20590587

  19. Application of a cocktail approach to screen cytochrome P450 BM3 libraries for metabolic activity and diversity.

    PubMed

    Reinen, Jelle; Postma, Geert; Tump, Cornelis; Bloemberg, Tom; Engel, Jasper; Vermeulen, Nico P E; Commandeur, Jan N M; Honing, Maarten

    2016-02-01

    In the present study, the validity of using a cocktail screening method in combination with a chemometrical data mining approach to evaluate metabolic activity and diversity of drug-metabolizing bacterial Cytochrome P450 (CYP) BM3 mutants was investigated. In addition, the concept of utilizing an in-house-developed library of CYP BM3 mutants as a unique biocatalytic synthetic tool to support medicinal chemistry was evaluated. Metabolic efficiency of the mutant library towards a selection of CYP model substrates, being amitriptyline (AMI), buspirone (BUS), coumarine (COU), dextromethorphan (DEX), diclofenac (DIC) and norethisterone (NET), was investigated. First, metabolic activity of a selection of CYP BM3 mutants was screened against AMI and BUS. Subsequently, for a single CYP BM3 mutant, the effect of co-administration of multiple drugs on the metabolic activity and diversity towards AMI and BUS was investigated. Finally, a cocktail of AMI, BUS, COU, DEX, DIC and NET was screened against the whole in-house CYP BM3 library. Different validated quantitative and qualitative (U)HPLC-MS/MS-based analytical methods were applied to screen for substrate depletion and targeted product formation, followed by a more in-depth screen for metabolic diversity. A chemometrical approach was used to mine all data to search for unique metabolic properties of the mutants and allow classification of the mutants. The latter would open the possibility of obtaining a more in-depth mechanistic understanding of the metabolites. The presented method is the first MS-based method to screen CYP BM3 mutant libraries for diversity in combination with a chemometrical approach to interpret results and visualize differences between the tested mutants. PMID:26753974

  20. Role of Endogenous Sleep-Wake and Analgesic Systems in Anesthesia

    PubMed Central

    LU, JUN; NELSON, LAURA E.; FRANKS, NICK; MAZE, MERVYN; CHAMBERLIN, NANCY L.; SAPER, CLIFFORD B.

    2016-01-01

    Classical anesthetics of the γ-aminobutyric acid type A receptor (GABAA)-enhancing class (e.g., pentobarbital, chloral hydrate, muscimol, and ethanol) produce analgesia and unconsciousness (sedation). Dissociative anesthetics that antagonize the N-methyl-D-aspartate (NMDA) receptor (e.g., ketamine, MK-801, dextromethorphan, and phencyclidine) produce analgesia but do not induce complete loss of consciousness. To understand the mechanisms underlying loss of consciousness and analgesia induced by general anesthetics, we examined the patterns of expression of c-Fos protein in the brain and correlated these with physiological effects of systemically administering GABAergic agents and ketamine at dosages used clinically for anesthesia in rats. We found that GABAergic agents produced predominantly delta activity in the electroencephalogram (EEG) and sedation. In contrast, anesthetic doses of ketamine induced sedation, followed by active arousal behaviors, and produced a faster EEG in the theta range. Consistent with its behavioral effects, ketamine induced Fos expression in cholinergic, monoaminergic, and orexinergic arousal systems and completely suppressed Fos immunoreactivity in the sleep-promoting ventrolateral preoptic nucleus (VLPO). In contrast, GABAergic agents suppressed Fos in the same arousal-promoting systems but increased the number of Fos-immunoreactive neurons in the VLPO compared with waking control animals. All anesthetics tested induced Fos in the spinally projecting noradrenergic A5–7 groups. 6-hydroxydopamine lesions of the A5–7 groups or ibotenic acid lesions of the ventrolateral periaqueductal gray matter (vlPAG) attenuated antinociceptive responses to noxious thermal stimulation (tail-flick test) by both types of anesthetics. We hypothesize that neural substrates of sleep-wake behavior are engaged by low-dose sedative anesthetics and that the mesopontine descending noradrenergic cell groups contribute to the analgesic effects of both NMDA

  1. Effects of Eleutheroside B and Eleutheroside E on activity of cytochrome P450 in rat liver microsomes

    PubMed Central

    2014-01-01

    Background Chemicals of herbal products may cause unexpected toxicity or adverse effect by the potential for alteration of the activity of CYP450 when co-administered with other drugs. Eleutherococcus senticosus (ES), has been widely used as a traditional herbal medicine and popular herbal dietary supplements, and often co-administered with many other drugs. The main bioactive constituents of ES were considered to be eleutherosides including eleutheroside B (EB) and eleutheroside E (EE). This study was to investigate the effects of EB and EE on CYP2C9, CYP2D6, CYP2E1 and CYP3A4 in rat liver microsomes in vitro. Method Probe drugs of tolbutamide (TB), dextromethorphan (DM), chlorzoxazone (CLZ) and testosterone (TS) as well as eleutherosides of different concentrations were added to incubation systems of rat liver microsomes in vitro. After incubation, validated HPLC methods were used to quantify relevant metabolites. Results The results suggested that EB and EE exhibited weak inhibition against the activity of CYP2C9 and CYP2E1, but no effects on CYP2D6 and CYP3A4 activity. The IC50 values for EB and EE were calculated to be 193.20 μM and 188.36 μM for CYP2E1, 595.66 μM and 261.82 μM for CYP2C9, respectively. Kinetic analysis showed that inhibitions of CYP2E1 by EB and EE were best fit to mixed-type with Ki value of 183.95 μM and 171.63 μM, respectively. Conclusions These results indicate that EB and EE may inhibit the metabolism of drugs metabolized via CYP2C9 and CYP2E1, and have the potential to increase the toxicity of the drugs. PMID:24383621

  2. Development of a LC-MS/MS method to analyze 5-methoxy-N,N-dimethyltryptamine and bufotenine, and application to pharmacokinetic study

    PubMed Central

    Shen, Hong-Wu; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-01-01

    Introduction 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a psychoactive indolealkylamine substance that has been used for recreational purpose and may lead to fatal toxicity. While 5-MeO-DMT is mainly inactivated via deamination, it is O-demethylated to an active metabolite, bufotenine. Quantitation of 5-MeO-DMT and bufotenine is essential to understand the exposure to and the effects of drug and metabolite. This study, therefore, aimed to develop and validate a LC-MS/MS method for simultaneous analysis of 5-MeO-DMT and bufotenine in mouse serum. Methods A simple protein precipitation method coupled with an optimal gradient elution was used for sample preparation and separation. Detection of 5-MeO-DMT and bufotenine was accomplished using multiple reaction monitoring of m/z 219.2→174.2 and 205.2→160.2, respectively, in the positive ion mode. 5-Methyl-N,N-dimethyltrypamine (m/z 203.2→158.3) was used as internal standard for quantification. Accuracy and precision were determined after the analyses of quality control samples. Validated assay was then employed to determine drug and metabolite concentrations in serum samples collected from mice at different time points after intraperitoneal administration of 5-MeO-DMT (2 mg/kg). Results With a total run time of 9 min, 5-MeO-DMT and bufotenine were eluted at 2.8 and 5.6 min, respectively. The assay was linear over the range 0.90–5,890 ng/mL (1.12–7,360 pg on-column) for 5-MeO-DMT and 2.52–5,510 ng/mL (3.14–6,890 pg) for bufotenine. Intra- and inter-day precision and accuracy were within 15% for both analytes. The recovery of each analyte from 20 µL of serum containing 8.08, 72.7 and 655 ng/mL of 5-MeO-DMT and 7.56, 68.1 and 613 ng/mL of bufotenine was more than 75%. Pharmacokinetic analysis revealed that the systemic exposure (area under the curve) to metabolite bufotenine was about 1/14 of that to 5-MeO-DMT. Conclusion This LC-MS/MS method is a sensitive and reliable assay for quantitation of blood 5

  3. Development of a LC-MS/MS method to analyze 5-methoxy-N,N-dimethyltryptamine and bufotenine, and application to pharmacokinetic study.

    PubMed

    Shen, Hong-Wu; Jiang, Xi-Ling; Yu, Ai-Ming

    2009-04-01

    INTRODUCTION: 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a psychoactive indolealkylamine substance that has been used for recreational purpose and may lead to fatal toxicity. While 5-MeO-DMT is mainly inactivated via deamination, it is O-demethylated to an active metabolite, bufotenine. Quantitation of 5-MeO-DMT and bufotenine is essential to understand the exposure to and the effects of drug and metabolite. This study, therefore, aimed to develop and validate a LC-MS/MS method for simultaneous analysis of 5-MeO-DMT and bufotenine in mouse serum. METHODS: A simple protein precipitation method coupled with an optimal gradient elution was used for sample preparation and separation. Detection of 5-MeO-DMT and bufotenine was accomplished using multiple reaction monitoring of m/z 219.2→174.2 and 205.2→160.2, respectively, in the positive ion mode. 5-Methyl-N,N-dimethyltrypamine (m/z 203.2→158.3) was used as internal standard for quantification. Accuracy and precision were determined after the analyses of quality control samples. Validated assay was then employed to determine drug and metabolite concentrations in serum samples collected from mice at different time points after intraperitoneal administration of 5-MeO-DMT (2 mg/kg). RESULTS: With a total run time of 9 min, 5-MeO-DMT and bufotenine were eluted at 2.8 and 5.6 min, respectively. The assay was linear over the range 0.90-5,890 ng/mL (1.12-7,360 pg on-column) for 5-MeO-DMT and 2.52-5,510 ng/mL (3.14-6,890 pg) for bufotenine. Intra- and inter-day precision and accuracy were within 15% for both analytes. The recovery of each analyte from 20 µL of serum containing 8.08, 72.7 and 655 ng/mL of 5-MeO-DMT and 7.56, 68.1 and 613 ng/mL of bufotenine was more than 75%. Pharmacokinetic analysis revealed that the systemic exposure (area under the curve) to metabolite bufotenine was about 1/14 of that to 5-MeO-DMT. CONCLUSION: This LC-MS/MS method is a sensitive and reliable assay for quantitation of blood 5-Me

  4. Subchronic oral toxicity and metabolite profiling of the p53 stabilizing agent, CP-31398, in rats and dogs.

    PubMed

    Johnson, William D; Muzzio, Miguel; Detrisac, Carol J; Kapetanovic, Izet M; Kopelovich, Levy; McCormick, David L

    2011-11-18

    maximum tolerated dose (MTD) for subchronic oral administration of CP-31398 is 80mg/kg/day (480mg/m(2)/day) in rats and 20mg/kg/day (400mg/m(2)/day) in dogs. Although only modest and apparently reversible toxicities (microscopic changes in rats; reductions in body weight gain and alterations in red cell parameters in dogs) were seen in the low dose groups, no observed adverse effect levels (NOAELs) for CP-31398 could not be established for either species. The toxicity of CP-31398 suggests that this agent may not be suitable for use in cancer prevention. However, should in vivo antitumor efficacy be achievable at doses that do not induce limiting toxicity, CP-31398 may have utility as a cancer therapeutic. Modification of the primary sites of CP-31398 metabolism (N-demethylation of the alkyl side chain; hydroxylation and O-demethylation of the styryl benzene group) may result in the development of CP-31398 analogs with comparable pharmacologic activity and reduced toxicity. PMID:21864638

  5. Hepatic metabolism of carcinogenic β-asarone.

    PubMed

    Cartus, Alexander T; Stegmüller, Simone; Simson, Nadine; Wahl, Andrea; Neef, Sylvia; Kelm, Harald; Schrenk, Dieter

    2015-09-21

    compounds (E)- and (Z)-3'-oxoasarone (5, 7). 1'-Oxoasarone (3) was probably also formed in incubations with 1 but was not detectable, possibly due to its rapid reaction with nucleophiles. Eventually, three mono-O-demethylated metabolites of 1 were detected in minor concentrations. The time course of metabolite formation and determined kinetic parameters show little species-specific differences in the microsomal metabolism of 1. Furthermore, the kinetic parameters imply a very low dependence of the pattern of metabolite formation from substrate concentration. In human liver microsomes, 71-75% of 1 will be metabolized via epoxidation, 21-15% via hydroxylation (and further oxidation), and 8-10% via demethylation at lower as well as higher concentrations of 1, respectively (relative values). On the basis of our results, we hypothesize that the genotoxic epoxides of 1 are the ultimate carcinogens formed from 1. PMID:26273788

  6. The Psychostimulant Khat (Catha edulis) Inhibits CYP2D6 Enzyme Activity in Humans.

    PubMed

    Bedada, Worku; de Andrés, Fernando; Engidawork, Ephrem; Pohanka, Anton; Beck, Olof; Bertilsson, Leif; Llerena, Adrián; Aklillu, Eleni

    2015-12-01

    The use of khat (Catha edulis) while on medication may alter treatment outcome. In particular, the influence of khat on the metabolic activities of drug-metabolizing enzymes is not known. We performed a comparative 1-way crossover study to evaluate the effect of khat on cytochrome P450 (CYP)2D6 and CYP3A4 enzyme activity. After 1 week of khat abstinence, baseline CYP2D6 and CYP3A4 metabolic activities were determined in 40 Ethiopian male volunteers using 30 mg dextromethorphan (DM) as a probe drug and then repeated after 1 week of daily use of 400 g fresh khat leaves. Urinary concentrations of cathinone and cathine were determined to monitor the subjects' compliance to the study protocol. Genotyping for CYP2D6*3 and CYP2D6*4 was done. Plasma DM, dextrorphan and 3-methoxymorphinan concentrations were quantified. CYP2D6 and CYP3A4 enzyme activities were assessed by comparing plasma log DM/dextrorphan and log DM/methoxymorphinan metabolic ratio (MR) respectively in the presence and absence of khat. Cytochrome 2D6 MR was significantly increased from baseline by concurrent khat use (paired t test, P = 0.003; geometric mean ratio, 1.38; 95% confidence interval [95% CI], 1.12-1.53). Moreover, the inhibition of CYP2D6 activity by khat was more pronounced in CYP2D6*1/*1 compared with CYP2D6*1/*4 genotypes (P = 0.01). A marginal inhibition of CYP3A4 activity in the presence of khat was observed (P = 0.24). The mean percentage increase of CYP2D6 and CYP3A4 MR from baseline by khat use was 46% (95% CI, 20-72) and 31% (95% CI, 8-54), respectively. This is the first report linking khat use with significant inhibition of CYP2D6 metabolic activity in humans. PMID:26444948

  7. Spreading depression: imaging and blockade in the rat neocortical brain slice.

    PubMed

    Anderson, Trent R; Andrew, R David

    2002-11-01

    Spreading depression (SD) is a profound but transient depolarization of neurons and glia that migrates across the cortical and subcortical gray at 2-5 mm/min. Under normoxic conditions, SD occurs during migraine aura where it precedes migraine pain but does not damage tissue. During stroke and head trauma, however, SD can arise repeatedly near the site of injury and may promote neuronal damage. We developed a superfused brain slice preparation that can repeatedly support robust SD during imaging and electrophysiological recording to test drugs that may block SD. Submerged rat neocortical slices were briefly exposed to artificial cerebrospinal fluid (ACSF) with KCl elevated to 26 mM. SD was evoked within 2 min, recorded in layers II/III both as a negative DC shift and as a propagating front of elevated light transmittance (LT) representing transient cell swelling in all cortical layers. An SD episode was initiated focally and could be repeatedly evoked and imaged with no damage to slices. As reported in vivo, pretreatment with one of several N-methyl-D-aspartate (NMDA) receptor antagonists blocked SD, but a non-NMDA glutamate receptor antagonist (CNQX) had no effect. NMDA receptor (NMDAR) activation does not initiate SD nor are NMDAR antagonists tolerated therapeutically so we searched for more efficacious drugs to block SD generation. Pretreatment with the sigma-one receptor (sigma(1)R) agonists dextromethorphan (10-100 microM), carbetapentane (100 microM), or 4-IBP (30 microM) blocked SD, even when KCl exposure was extended beyond 5 min. The block was independent of NMDA receptor antagonism. Two sigma(1)R antagonists [(+)-3PPP and BD-1063] removed this block but had no effect upon SD alone. Remarkably, the sigma(1)R agonists also substantially reduced general cell swelling evoked by bath application of 26 mM KCl. More potent sigma(1)R ligands that are therapeutically tolerated could prove useful in reducing SD associated with migraine and be of potential use in

  8. Toxicology findings in cases of hanging in the City and County of San Francisco over the 3-year period from 2011 to 2013.

    PubMed

    San Nicolas, A C; Lemos, N P

    2015-10-01

    In postmortem cases where the cause of death is hanging, toxicological analyses may be considered unnecessary by some medical examiners, toxicologists, and other persons involved in medico-legal investigations because the cause of death seems "obvious." To ascertain if toxicological analyses are necessary when the cause of death is hanging, all 102 hanging cases (25 females; 77 males) from 2011 to 2013 that came under the jurisdiction of the San Francisco Office of the Chief Medical Examiner were examined from a total of 3912 sudden, unexpected, or violent death cases in the same period. Suicide was the manner of death in 99 of these cases, with two accidental and one undetermined death. The average age of decedents was 43.9 years (median 41), the youngest was an 11-year old male and the oldest was an 86-year old female. Of the 102 cases, 33 had negative toxicology while 69 cases had at least one positive toxicology result. Females were equally likely to have negative or positive results (12 and 13 cases respectively), but males were 37.5% more likely to have positive toxicology (n=56) rather than negative toxicology (n=21). For females, alcohol, mirtazapine, venlafaxine, and trazodone were the top psychoactive substances in peripheral blood while THC, cocaine, hydrocodone, bupropion, olanzapine, doxylamine, quetiapine and dextromethorphan were also reported. For males, alcohol, THC, cocaine, amphetamine, methamphetamine, bupropion, and diphenhydramine were the top psychoactive substances in blood, but several other drugs were also found in individual cases. Our study of hanging cases over a 3-year period support the idea that complete postmortem toxicology investigation of hangings should be performed, even when the "obvious" cause of death is asphyxia due to hanging. Many of these cases involved psychoactive substances (most often alcohol and cannabis), and having such knowledge provides a better understanding of the circumstances surrounding the decedent's death

  9. Gateways to clinical trials.

    PubMed

    Bayés, M; Rabasseda, X; Prous, J R

    2006-10-01

    Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issues focuses on the following selection of drugs: (-)-Epigallocatechin gallate, (-)-gossypol, 2-deoxyglucose, 3,4-DAP, 7-monohydroxyethylrutoside; Ad5CMV-p53, adalimumab, adefovir dipivoxil, ADH-1, alemtuzumab, aliskiren fumarate, alvocidib hydrochloride, aminolevulinic acid hydrochloride, aminolevulinic acid methyl ester, amrubicin hydrochloride, AN-152, anakinra, anecortave acetate, antiasthma herbal medicine intervention, AP-12009, AP-23573, apaziquone, aprinocarsen sodium, AR-C126532, AR-H065522, aripiprazole, armodafinil, arzoxifene hydrochloride, atazanavir sulfate, atilmotin, atomoxetine hydrochloride, atorvastatin, avanafil, azimilide hydrochloride; Bevacizumab, biphasic insulin aspart, BMS-214662, BN-83495, bortezomib, bosentan, botulinum toxin type B; Caspofungin acetate, cetuximab, chrysin, ciclesonide, clevudine, clofarabine, clopidogrel, CNF-1010, CNTO-328, CP-751871, CX-717, Cypher; Dapoxetine hydrochloride, darifenacin hydrobromide, dasatinib, deferasirox, dextofisopam, dextromethorphan/quinidine sulfate, diclofenac, dronedarone hydrochloride, drotrecogin alfa (activated), duloxetine hydrochloride, dutasteride; Edaravone, efaproxiral sodium, emtricitabine, entecavir, eplerenone, epratuzumab, erlotinib hydrochloride, escitalopram oxalate, etoricoxib, ezetimibe, ezetimibe/simvastatin; Finrozole, fipamezole hydrochloride, fondaparinux sodium, fulvestrant; Gabapentin enacarbil, gaboxadol, gefitinib, gestodene, ghrelin (human); Human insulin, human papillomavirus vaccine; Imatinib mesylate, immunoglobulin intravenous (human), indiplon, insulin detemir, insulin glargine, insulin glulisine, intranasal insulin, istradefylline, i.v. gamma

  10. Blockade by sigma site ligands of high voltage-activated Ca2+ channels in rat and mouse cultured hippocampal pyramidal neurones.

    PubMed Central

    Church, J.; Fletcher, E. J.

    1995-01-01

    1. The effects of a series of structurally-dissimilar sigma site ligands were examined on high voltage-activated Ca2+ channel activity in two preparations of cultured hippocampal pyramidal neurones. 2. In mouse hippocampal neurones under whole-cell voltage-clamp, voltage-activated Ca2+ channel currents carried by barium ions (IBa) were reduced with the rank order (IC50 values in microM): 1S,2R-(-)-cis-N-methyl-N-[2-(3,4-dichlorophenyl)ethyl]- 2-(1-pyrrolidinyl)cyclohexylamine (7.8) > rimcazole (13) > haloperidol (16) > ifenprodil (18) > opipramol (32) > carbetapentane (40) = 1-benzylspiro[1,2,3,4-tetrahydronaphthalene-1,4-piperidine] (42) > caramiphen (47) > dextromethorphan (73). At the highest concentrations tested, the compounds almost abolished IBa in the absence of any other pharmacological agent. 3. The current-voltage characteristics of the whole-cell IBa were unaffected by the test compounds. The drug-induced block was rapid in onset and offset, with the exceptions of carbetapentane and caramiphen where full block was achieved only after two to three voltage-activated currents and was associated with an apparent increase in the rate of inactivation of IBa. 4. In rat hippocampal neurones loaded with the Ca(2+)-sensitive dye Fura-2, rises in intracellular free Ca2+ concentration evoked by transient exposure to 50 mM K(+)-containing medium, either in the absence or in the presence of 10 microM nifedipine (to block L-type high voltage-activated Ca2+ channels), were also reversibly attenuated by the sigma ligands. The rank order potencies for the compounds in these experimental paradigms were similar to that observed for blockade of IBa in the electrophysiological studies. 5. These results indicate that, at micromolar concentrations, the compounds tested block multiple subtypes of high voltage-activated Ca2+ channels. These actions, which do not appear to be mediated by high-affinity sigma binding sites, may play a role in some of the functional effects

  11. Blockade by sigma site ligands of N-methyl-D-aspartate-evoked responses in rat and mouse cultured hippocampal pyramidal neurones.

    PubMed Central

    Fletcher, E. J.; Church, J.; Abdel-Hamid, K.; MacDonald, J. F.

    1995-01-01

    1. The effects of a range of structurally-dissimilar compounds which possess affinity for sigma binding sites were examined on the responses of cultured hippocampal pyramidal neurones to the excitatory amino acid analogues N-methyl-D-aspartate (NMDA), kainate and (RS)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). 2. In mouse hippocampal neurones under whole-cell voltage-clamp, the compounds tested reversibly attenuated NMDA-, but not kainate- or AMPA-, evoked currents with a rank order potency (IC50 values in microM): ifenprodil (0.8) > (+)-N-allylnormetazocine (1.1) > dextromethorphan (1.8) = haloperidol (1.9) > (+)-pentazocine (7.2) > 1S,2R-(-)-cis-N-methyl-N-[2-(3, 4-dichlorophenyl) ethyl]-2-(1-pyrrolidinyl)cyclohexylamine (17) = rimcazole (18) > 1,3-di(2-tolyl)guanidine (37) > opipramol (96) > caramiphen (110) = carbetapentane (112) > > (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine (485). 3. The attenuation of NMDA-evoked responses was not mediated through interactions with the agonist, glycine (except haloperidol) or polyamine (except ifenprodil) binding sites on the NMDA receptor-channel complex but, in the light of the voltage- and, in some cases, use-dependent nature of their antagonism, an interaction with the ion channel appears to be a likely mechanism of action for many of the compounds. 4. Micromolar concentrations of selected sigma site ligands also reduced NMDA-evoked rises in intracellular free calcium concentration in Fura-2-loaded cultured hippocampal neurones of the rat with the same rank order potency as observed in the electrophysiological studies. 5. The data indicate that, at micromolar concentrations, the sigma site ligands tested act as NMDA receptor antagonists, an action which does not appear to be mediated by high-affinity sigma binding site(s). The functional effects of micromolar concentrations of sigma site ligands cannot, therefore, be attributed exclusively to interactions with high-affinity sigma binding sites

  12. Gateways to clinical trials.

    PubMed

    Bayes, M; Rabasseda, X; Prous, J R

    2005-01-01

    Gateways to Clinical Trials are a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: (-)-Epigallocatechin gallate; ACP-103, Ad.Egr.TNF.11 D, adalimumab, AF-IL 12, AIDSVAX gp120 B/B, alefacept, alemtuzumab, a-Galactosylceramide, ALVAC vCP 1452, alvimopan hydrate, alvocidib hydrochloride, aminolevulinic acid hydrochloride, aminolevulinic acid methyl ester, anakinra, anidulafungin, antarelix, aprepitant, aripiprazole, arsenic sulfide, asoprisnil, atazanavir sulfate, atomoxetine hydrochloride; Bevacizumab, bimatoprost, BMS-184476, bortezomib, bosentan, botulinum toxin type B, BrachySil, brivudine; Caffeine, calcipotriol/betamethasone dipropionate, cannabidiol, capsaicin for injection, caspofungin acetate, CC-4047, cetuximab, CGP-36742, clofazimine, CpG-7909, Cypher; Darbepoetin alfa, dextromethorphan/quinidine sulfate, dimethylfumarate, dronabinol/cannabidiol, drotrecogin alfa (activated), duloxetine hydrochloride, dutasteride; Ecogramostim, efalizumab, eletriptan, emtricitabine, enfuvirtide, eplerenone, esomeprazole magnesium, estradiol acetate, eszopiclone, etoricoxib, exenatide, ezetimibe, ezetimibe/simvastatin; Fampridine, fondaparinux sodium, fosamprenavir calcium; Gefitinib, GPI-0100; hA 20, HTU-PA, human insulin, HuOKT 3 gamma 1(Ala 234-Ala 235), hyaluronic acid; Icatibant, imatinib mesylate, Indiplon, INKP-100, INKP-102, iodine (I131) tositumomab, istradefylline, IV gamma-globulin, ivabradine hydrochloride, ixabepilone; Lacosamide, landiolol, lanthanum carbonate, lasofoxifene tartrate, LB-80380, lenalidomide, lidocaine/tetracaine, linezolid, liposomal doxorubicin, liposomal vincristine sulfate, lopinavir, lopinavir/ritonavir, lumiracoxib, lurtotecan; Maribavir, morphine glucuronide, MVA-5 T

  13. Polymorphism of human cytochrome P450 2D6 and its clinical significance: part II.

    PubMed

    Zhou, Shu-Feng

    2009-01-01

    , perphenazine, risperidone and thioridazine, which are all metabolized by CYP2D6. It is possible to merge therapeutic drug monitoring and pharmacogenetic testing for CYP2D6 into clinical practice. There is a clear gene-dose effect on the formation of O-demethylated metabolites from multiple opioids, but the clinical significance of this may be minimal, as the analgesic effect is not altered in poor metabolizers (PMs). Genetically caused inactivity of CYP2D6 renders codeine ineffective owing to lack of morphine formation, decreases the efficacy of tramadol owing to reduced formation of the active O-desmethyl-tramadol and reduces the clearance of methadone. Genetically precipitated drug interactions might render a standard opioid dose toxic. Because of the important role of CYP2D6 in tamoxifen metabolism and activation, PMs are likely to exhibit therapeutic failure, and ultrarapid metabolizers (UMs) are likely to experience adverse effects and toxicities. There is a clear gene-concentration effect for the formation of endoxifen and 4-OH-tamoxifen. Tamoxifen-treated cancer patients carrying CYP2D6*4, *5, *10, or *41 associated with significantly decreased formation of antiestrogenic metabolites had significantly more recurrences of breast cancer and shorter relapse-free periods. Many studies have identified the genetic CYP2D6 status as an independent predictor of the outcome of tamoxifen treatment in women with breast cancer, but others have not observed this relationship. Thus, more favourable tamoxifen treatment seems to be feasible through a priori genetic assessment of CYP2D6, and proper dose adjustment may be needed when the CYP2D6 genotype is determined in a patient. Dolasetron, ondansetron and tropisetron, all in part metabolized by CYP2D6, are less effective in UMs than in other patients. Overall, there is a strong gene-concentration relationship only for tropisetron. CYP2D6 genotype screening prior to antiemetic treatment may allow for modification of antiemetic dosing

  14. Pharmacologic approaches to treatment resistant depression: Evidences and personal experience

    PubMed Central

    Tundo, Antonio; de Filippis, Rocco; Proietti, Luca

    2015-01-01

    AIM: To review evidence supporting pharmacological treatments for treatment-resistant depression (TRD) and to discuss them according to personal clinical experience. METHODS: Original studies, clinical trials, systematic reviews, and meta-analyses addressing pharmacological treatment for TRD in adult patients published from 1990 to 2013 were identified by data base queries (PubMed, Google Scholar e Quertle Searches) using terms: “treatment resistant depression”, “treatment refractory depression”, “partial response depression”, “non responder depression”, “optimization strategy”, “switching strategy”, “combination strategy”, “augmentation strategy”, selective serotonin reuptake inhibitors antidepressants (SSRI), tricyclic antidepressants (TCA), serotonin norepinephrine reuptake inhibitors antidepressants, mirtazapine, mianserine, bupropione, monoamine oxidase inhibitor antidepressant (MAOI), lithium, thyroid hormones, second generation antipsychotics (SGA), dopamine agonists, lamotrigine, psychostimulants, dextromethorphan, dextrorphan, ketamine, omega-3 fatty acids, S-adenosil-L-metionine, methylfolat, pindolol, sex steroids, glucocorticoid agents. Other citations of interest were further identified from references reported in the accessed articles. Selected publications were grouped by treatment strategy: (1) switching from an ineffective antidepressant (AD) to a new AD from a similar or different class; (2) combining the current AD regimen with a second AD from a different class; and (3) augmenting the current AD regimen with a second agent not thought to be an antidepressant itself. RESULTS: Switching from a TCA to another TCA provides only a modest advantage (response rate 9%-27%), while switching from a SSRI to another SSRI is more advantageous (response rate up to 75%). Evidence supports the usefulness of switching from SSRI to venlafaxine (5 positive trials out 6), TCA (2 positive trials out 3), and MAOI (2 positive trials out