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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. 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

  3. Enantioselective accumulation of (--)-pinoresinol through O-demethylation of (+/-)-eudesmin by Aspergillus niger.

    PubMed

    Kasahara, H; Miyazawa, M; Kameoka, H

    1997-04-01

    Microbial transformation of (+/-)-eudesmin by Aspergillus niger was investigated. Enantioselective accumulation of (--)-pinoresinol was shown through O-demethylation of (+/-)-eudesmin. This fungus O- demethylated both enantiomers of eudesmin, but the conversion rates for each enantiomer were clearly different.

  4. 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

  5. Adolescent abuse of dextromethorphan.

    PubMed

    Schwartz, Richard H

    2005-09-01

    Dextromethorphan hydrobromide (DXM), a constituent of more than 125 patent cough/cold remedies, is the most popular antitussive medication in the United States. Cough syrups or capsules also contain additional ingredients such as acetaminophen, chlorpheniramine maleate, guaifenesin, and/or pseudoephedrine, and toxicity with overdosage is additive to that of dextromethorphan alone. An unknown number of adolescents in the United States and Europe intoxicate themselves with acute megadoses of dextromethorphan. A megadose of DXM is defined as 5 to 10 times the dose recommended for control of annoying nonproductive coughs. Although a moderate overdose of pure DXM hydrobromide is free of serious adverse effects, approximately 5% of persons of European ethnicity lack the ability to metabolize the drug normally, leading to rapid acute toxic levels. Variable quantities of pure dextromethorphan powder in multiples of 1 gram are easily available from the worldwide web, including e-Bay. Recipe-like extraction procedures are quickly available on the Internet for seemingly simple and inexpensive home manufacture of concentrated dextromethorphan powder from Coricidin HBP Cough & Cold tablets (street name triple C). Adolescents intoxicate themselves at parties and even before or after school since the drug is legal, relatively inexpensive, and easily purchased or shoplifted at drug or convenient stores. Acute megadoses of the drug have profound psychological and physiological effects similar to those of phencyclidine (PCP). Megadoses of dextromethorphan used to self-intoxicate, can produce a false-positive screening test for phencyclidine in a urine specimen.

  6. 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

  7. 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

  8. Evaluating the safety and efficacy of dextromethorphan/quinidine in the treatment of pseudobulbar affect

    PubMed Central

    Schoedel, Kerri A; Morrow, Sarah A; Sellers, Edward M

    2014-01-01

    Pseudobulbar affect (PBA) is a common manifestation of brain pathology associated with many neurological diseases, including amyotrophic lateral sclerosis, Alzheimer’s disease, stroke, multiple sclerosis, Parkinson’s disease, and traumatic brain injury. PBA is defined by involuntary and uncontrollable expressed emotion that is exaggerated and inappropriate, and also incongruent with the underlying emotional state. Dextromethorphan/quinidine (DM/Q) is a combination product indicated for the treatment of PBA. The quinidine component of DM/Q inhibits the cytochrome P450 2D6-mediated metabolic conversion of dextromethorphan to its active metabolite dextrorphan, thereby increasing dextromethorphan systemic bioavailability and driving the pharmacology toward that of the parent drug and away from adverse effects of the dextrorphan metabolite. Three published efficacy and safety studies support the use of DM/Q in the treatment of PBA; significant effects were seen on the primary end point, the Center for Neurologic Study-Lability Scale, as well as secondary efficacy end points and quality of life. While concentration–effect relationships appear relatively weak for efficacy parameters, concentrations of DM/Q may have an impact on safety. Some special safety concerns exist with DM/Q, primarily because of the drug interaction and QT prolongation potential of the quinidine component. However, because concentrations of dextrorphan (which is responsible for many of the parent drug’s side effects) and quinidine are lower than those observed in clinical practice with these drugs administered alone, some of the perceived safety issues may not be as relevant with this low dose combination product. However, since patients with PBA have a variety of other medical problems and are on numerous other medications, they may not tolerate DM/Q adverse effects, or may be at risk for drug interactions. Some caution is warranted when initiating DM/Q treatment, particularly in patients

  9. 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.

  10. O-Demethylation and successive oxidative dechlorination of methoxychlor by Bradyrhizobium sp. strain 17-4, isolated from river sediment.

    PubMed

    Satsuma, Koji; Masuda, Minoru; Sato, Kiyoshi

    2012-08-01

    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.

  11. The roles of a flavone-6-hydroxylase and 7-O-demethylation in the flavone biosynthetic network of sweet basil.

    PubMed

    Berim, Anna; Gang, David R

    2013-01-18

    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

  12. Dioxygenases catalyze O-demethylation and O,O-demethylenation with widespread roles in benzylisoquinoline alkaloid metabolism in opium poppy.

    PubMed

    Farrow, Scott C; Facchini, Peter J

    2013-10-01

    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.

  13. O-demethylation, dehydroxylation, ring-reduction and cleavage of aromatic substrates by Enterobacteriaceae under anaerobic conditions.

    PubMed

    Grbić-Galić, D

    1986-12-01

    Four fermentative facultative anaerobes, members of the genera Enterobacter and Escherichia, were tested for their ability to transform an aromatic lignin derivative, 3-methoxy-4-hydroxy-cinnamic acid (ferulic acid), under anaerobic (fermentative) conditions. The pure cultures studied were shown to O-demethylate, dehydroxylate, reduce the double bond in the side-chain, decarboxylate the aromatic ring to the stage of benzoate and to reduce the ring to an alicyclic acid. Aromatic hydrocarbons (toluene, ethylbenzene and propylbenzene), as well as phenols (phenol, o-cresol, p-cresol, 2-ethylphenol and 3-hydroxy-4-ethylphenol) were also produced. In addition, during 3 months incubation, the cleavage of the aromatic ring occurred, whereby a small fraction of the substrate was converted to straight-chain and branched (methylated, ethylated) five- to eight-carbon aliphatic acids. The results indicate that pure cultures of fermentative facultative anaerobes might be capable of degrading substituted aromatic acids to aliphatic products under strictly anaerobic (fermentative) conditions. These abilities, which have so far been found only in denitrifying pseudomonads among facultative anaerobes, might be common in Enterobacteriaceae. It is conceivable that these bacteria are important as degraders of aromatic compounds in anaerobic ecosystems.

  14. 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

  15. Molecular analysis of the dmpM gene encoding an O-demethyl puromycin O-methyltransferase from Streptomyces alboniger.

    PubMed

    Lacalle, R A; Ruiz, D; Jiménez, A

    1991-12-20

    The nucleotide (nt) sequence of a 1332-bp fragment of Streptomyces alboniger DNA containing the gene (dmpM), which encodes an O-demethyl puromycin O-methyltransferase (DMPM), has been determined. The dmpM gene contains a 1131-nt open reading frame which encodes a polypeptide of Mr 40,303; this is consistent with the 44 +/- 2.5- and 160-kDa sizes of the DMPM monomer and its native form, respectively. The ATG start codon of dmpM is 50 bp downstream from the coding sequence of the gene (pac), which determines a puromycin N-acetyltransferase. S1 mapping experiments indicate that pac and dmpM are transcribed on a single transcript, which ends at least 500 nt downstream from the dmpM stop codon. The deduced amino acid sequence of DMPM shows significant similarities to those of a hydroxyindole O-methyltransferase, which is involved in the biosynthesis of melatonin by bovine pineal glands [Ishida et al., J. Biol. Chem. 262 (1987) 2895-2899], a hydroxyneurosporene methyltransferase, which is involved in carotenoid biosynthesis in the purple nonsulfur bacterium, Rhodobacter capsulatus [Armstrong et al., Mol. Gen. Genet. 216 (1989) 254-268] and two O-methyltransferases of the tetracenomycin biosynthesis pathway from Streptomyces glaucescens.

  16. Dextromethorphan and pain after total abdominal hysterectomy.

    PubMed

    McConaghy, P M; McSorley, P; McCaughey, W; Campbell, W I

    1998-11-01

    Dextromethorphan is an N-methyl-D-aspartate (NMDA) receptor antagonist which has been shown to inhibit the development of cutaneous secondary hyperalgesia after tissue trauma. We studied 60 ASA I-II patients undergoing total abdominal hysterectomy in a randomized, double-blind, placebo-controlled study. Patients received either dextromethorphan 27 mg capsules, two doses before operation and three doses in the first 24 h after operation, or placebo. Visual analogue pain scores (VAS) at 24 and 48 h were assessed at rest, on coughing and on sitting up, and were not significantly different between groups. Morphine consumption from a patient-controlled analgesia (PCA) device was also not significantly different between groups. Evidence of secondary hyperalgesia was assessed with von Frey hairs 10 cm above the Pfannenstiel incision. Both groups of patients exhibited evidence of secondary hyperalgesia after 24 and 48 h but there were no significant differences between groups. There was also no difference between groups in VAS scores at 1 month.

  17. 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

  18. “Robo-Tripping”: Dextromethorphan Abuse and its Anesthetic Implications

    PubMed Central

    Linn, Kelly A; Long, Micah T; Pagel, Paul S

    2014-01-01

    Introduction: We describe a patient scheduled for elective surgery who regularly consumed approximately 12 to 15 times the maximum recommended daily dose of dextromethorphan. We describe the clinical pharmacology of dextromethorphan and discuss its anesthetic implications. Case Presentation: A 30-year-old man with a history of a nasal fracture was scheduled to undergo an elective septorhinoplasty. He reported daily consumption of large quantities (1440 to 1800 mg) of dextromethorphan for six years. He was previously treated for dextromethorphan dependency on several occasions with urine dextromethorphan levels exceeding 2000 ng/mL. He described marked dissociative effects when abusing the drug, but had abstained from use for 48 hours before his elective surgery. Considering that dextromethorphan has a relatively short half-life and that the patient did not suffer major withdrawal symptoms after voluntarily discontinuing the drug, the authors proceeded with the case while recognizing that the drug has significant neuropsychiatric and sympathetic nervous system stimulant effects resulting from its actions as a N-methyl-D-aspartate receptor antagonist. Conclusions: Anesthesiologists need to be aware of dextromethorphan’s clinical pharmacology because recreational abuse of the drug has become increasingly common in adolescents and young adults. PMID:25793175

  19. Combined dextromethorphan and chlorpheniramine intoxication in impaired drivers.

    PubMed

    Logan, Barry K

    2009-09-01

    Dextromethorphan is a nonprescription antitussive which has been gaining in popularity as an abused drug, because of the hallucinogenic, dissociative, and intoxicating effects it produces at high doses. This report describes a series of eight drivers arrested for driving under the influence of the combined effects of dextromethorphan and chlorpheniramine, and a further four drivers under the influence of dextromethorphan alone. In the combined dextromethorphan/chlorpheniramine cases, blood dextromethorphan concentrations ranged from 150 to 1220 ng/mL (n = 8; mean 676 ng/mL, median 670 ng/mL), and chlorpheniramine concentrations ranged from 70 to 270 ng/mL (n = 8; mean 200 ng/mL, median 180 ng/mL). The four cases without chlorpheniramine present had blood dextromethorphan concentrations between 190 and 1000 ng/mL (mean 570 ng/mL, median 545 ng/mL). Some drivers had therapeutic concentrations of other drugs present. Drivers generally displayed symptoms of central nervous system (CNS) depressant intoxication, and there was gross evidence of impairment in their driving, including weaving, leaving the lane of travel, failing to obey traffic signals, and involvement in collisions. Drug Recognition Expert opinions confirmed that the subjects were under the influence of a drug in the CNS-depressant category.

  20. Slow O-demethylation of methyl triclosan to triclosan, which is rapidly glucuronidated and sulfonated in channel catfish liver and intestine.

    PubMed

    James, Margaret O; Marth, Christopher J; Rowland-Faux, Laura

    2012-11-15

    The antibacterial personal care product triclosan is discharged in municipal waste, and converted in part by bacteria in sewage sludge and soil to its more lipid-soluble methyl ether, methyl triclosan. Triclosan and methyl triclosan have been detected in water, sediment, fish and invertebrates near sewage treatment facilities. Understanding the biotransformation of methyl triclosan and triclosan in a model food fish, the channel catfish, will be of value in assessing the likelihood that these compounds will bioaccumulate in exposed fish, and therefore potentially pass up the food chain. We hypothesize that cytochrome P450 will catalyze the O-demethylation of methyl triclosan to yield triclosan, which is likely to undergo glucuronidation or sulfonation of the phenolic hydroxyl group. Conversion of methyl triclosan to triclosan was measured by LC/MS/MS following aerobic incubation of varying concentrations of methyl triclosan with NADPH and hepatic and intestinal microsomes from untreated, 3-methylcholanthrene-treated (10 mg/kg, i.p.) or PCB-126-treated (0.1 mg/kg, i.p.) channel catfish (n=4 per treatment group). The K(m) values for methyl triclosan were similar for untreated, 3-methylcholanthrene-treated and PCB-126-treated catfish liver microsomes, ranging from 80 to 250 μM. V(max) values for O-demethylation ranged from 30 to 150 pmol/min/mg protein, with no significant differences between controls, PCB-126-treated or 3-methylcholanthrene-treated fish, suggesting that methyl triclosan O-demethylation was not a CYP1-catalyzed reaction. Methyl triclosan O-demethylation activities in intestinal microsomes were similar to or lower than those found with liver microsomes. The calculated rate of O-demethylation of methyl triclosan in catfish liver at 1 μM, a concentration reported in exposed fish, and 21°C, an early summer water temperature, is 0.10 pmol/min/mg protein. This slow rate of metabolism suggests that upon continued exposure, methyl triclosan may

  1. 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

  2. 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

  3. [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

  4. The phenolic vir gene inducer ferulic acid is O-demethylated by the VirH2 protein of an Agrobacterium tumefaciens Ti plasmid.

    PubMed

    Kalogeraki, V S; Zhu, J; Eberhard, A; Madsen, E L; Winans, S C

    1999-11-01

    Some or possibly all Ti plasmids of Agrobacterium tumefaciens encode a bicistronic operon designated virH, which encodes two proteins, VirH1 and VirH2, that resemble a family of cytochrome P450-type monooxygenases. Expression of this operon is induced by a family of phenolic compounds that induce all other operons within the vir regulon. We hypothesized that either or both of these proteins might metabolize some or all of these phenolic compounds. We therefore tested induction of a vir promoter by a variety of phenolic compounds in isogenic strains that express or lack virH1 and virH2. Although some compounds were equally effective inducers regardless of the virH status, other compounds induced vir expression far more effectively in the virH mutant than in the virH-proficient host. For all tested compounds, VirH2 appeared to be solely responsible for this effect. One such compound, ferulic acid, was chosen for biochemical analysis. Ferulic acid was degraded by a VirH-proficient host but not by a VirH mutant. The wild-type strain released large amounts of a more hydrophilic compound into the cell supernatant. This compound was tested by mass spectroscopy, nuclear magnetic resonance and UV spectroscopy and found to consist of caffeic acid. This indicates that wild-type strains convert virtually all added ferulic acid to caffeic acid, and that VirH2 is essential for this O-demethylation reaction. Ferulic acid was far more toxic than caffeic acid to the wild-type strain, although the wild-type strain was more resistant to ferulic acid than was the virH mutant. Caffeic acid was slowly removed from the broth, suggesting further metabolic reactions. PMID:10564493

  5. 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

  6. Dextromethorphan hydrobromide preparations on the Belgian market--a comparative study.

    PubMed

    Fierens, C; Corthout, J

    2009-03-01

    Liquid preparations for oral use containing dextromethorphan hydrobromide were verified on identity, content and microbiological quality. The assay method was previously validated according to international guidelines. All examined products complied with the postulated requirements.

  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. 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

  9. 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

  10. Human cytochrome P450-catalyzed conversion of the proestrogenic pesticide methoxychlor into an estrogen. Role of CYP2C19 and CYP1A2 in O-demethylation.

    PubMed

    Stresser, D M; Kupfer, D

    1998-09-01

    1,1,1-Trichloro-2,2-bis(4-methoxyphenyl)ethane (methoxychlor) is a widely used pesticide that is pro-estrogenic. We have elucidated the human cytochrome P450 enzymes responsible for conversion of methoxychlor into its major metabolite, the mono-O-demethylated derivative (mono-OH-M) that is estrogenic. Incubation of methoxychlor with microsomes from insect cells overexpressing either CYP1A2, CYP2C18, or CYP2C19 yielded mono-OH-M with turnover numbers of 14.9, 15.5, and 39.1 nmol/min/nmol of P450, respectively. CYP2B6 and CYP2C9 were much less active. Incubations with purified CYP2C19 and CYP2C18 resulted in formation of mono-OH-M, and also the bis-demethylated metabolite. Co-incubation of liver microsomes with methoxychlor and various P450 isoform-selective inhibitors suggested involvement of several P450s in mono-O-demethylation, including CYP1A2, CYP2A6, CYP2C9, and CYP2C19. A role for CYP2C19, CYP1A2, and CYP2A6 was also indicated by multivariate regression analysis of the mono-O-demethylase activity in a panel of human liver microsomes characterized for isoform-specific catalytic activities (R2 = 0.96). Based on the totality of the evidence, CYP2C19 appears to be the major catalyst of methoxychlor mono-O-demethylation. However, in individuals lacking functional CYP2C19 (e.g. the "poor metabolizer" phenotype), CYP1A2 may play the predominant role. CYP2A6, CYP2C9, and CYP2B6 probably contribute to a lesser extent. Although CYP2C18 is an efficient methoxychlor demethylase, its expression in liver is reportedly low or absent, suggesting a negligible role for this enzyme in methoxychlor metabolism. Lengthy incubations of liver microsomes with methoxychlor produced other secondary and tertiary metabolites. Efficient conversion of methoxychlor to estrogenic mono-OH-M by liver microsomes suggests that methoxychlor has the potential to be estrogenic in humans, as observed in several animal species.

  11. 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

  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. 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

  14. Dextromethorphan mediated bitter taste receptor activation in the pulmonary circuit causes vasoconstriction.

    PubMed

    Upadhyaya, Jasbir D; Singh, Nisha; Sikarwar, Anurag S; 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

  15. Dextromethorphan abuse masquerading as a recurrent seizure disorder.

    PubMed

    Majlesi, Nima; Lee, David C; Ali, Sayed S

    2011-03-01

    Dextromethorphan (DXM) has unique toxicity that may be difficult to diagnose. We present a case of a young woman who presented to our emergency department (ED) initially diagnosed with recurrent seizures. Paramedics brought a 19-year-old woman to the ED. Witnesses noted "shaking," which the patient did not recall. The patient denied fever, antecedent trauma, or neurological complaint. She was recently administered lamotrigine for bipolar disorder. She was a former alcoholic with no history of developing withdrawal. She admitted to marijuana use but denied use of any other illicit substances. Her vital signs and physical examination were unremarkable. She had a normal brain computed tomography, electrocardiogram, and laboratory evaluation. There was no alcohol detected. Her urine drug screen was negative for opiates, benzodiazepines, cocaine, amphetamines, barbiturates, phencyclidine, and tricyclic antidepressants. She was diagnosed with new-onset seizure and discharged home. No abnormalities were seen in the brain magnetic resonance imaging scan and electroencephalogram. She was scheduled for a cardiac syncope workup, but never followed through. Two months later, she presented to the hospital again for a similar complaint. Coworkers reported witnessing sudden tonic-clonic movements and confusion. On ED presentation, the patient was tachycardic with a heart rate of 110 beats/min and had horizontal nystagmus. She was alert with a flat affect. She did not recall events but answered questions appropriately. Repeat radiographic and laboratory evaluations were normal including urine drug screen and computed tomography. Upon questioning, she admitted to abusing DXM for the past several months. A serum DXM level at this time was 988.3 ng/mL. She was admitted to the hospital for 24 hours without sequelae. All further diagnostic testing was cancelled, and she was referred to a drug rehabilitation program. Abuse of DXM is increasing in incidence. The serum level of our

  16. 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

  17. An evaluation of the genotoxicity of the antitussive drug Dextromethorphan.

    PubMed

    Aardema, Marilyn J; Robison, Steven H; Gatehouse, David; Johnston, Gail

    2008-04-01

    Dextromethorphan (DMP) is an effective and widely used antitussive drug. While DMP has over a 50 year safe-marketing history, the only available genotoxicity data was an unpublished, negative Ames assay (Roche). Lack of a complete genotoxicity profile on DMP, specifically covering the chromosomal damage endpoint, prompted a regulatory request for an in vitro chromosome aberration assay. In accordance with EC and CPMP Guidance, we evaluated data for a number of chemicals with a structural relationship to DMP. DMP contains no structural alerts for genotoxicity or carcinogenicity using the Deductive Estimation of Risk from Existing Knowledge (DEREK) software tool, confirming the negative results obtained in the existing Ames assay. This is also consistent with the mostly negative genotoxicity and carcinogenicity data available on structurally related chemicals including morphine, codeine, nalbuphine, buprenorphine, naloxone, hydromorphone, levorphanol, and oxycodone. A state-of-the-science, in vitro chromosome aberration assay was also conducted, which demonstrated a lack of genotoxicity for DMP. The overall weight of evidence for DMP and its structural analogues, supports the conclusion that this class of phenanthrene-based chemicals, and DMP, in particular, are not genotoxic in vitro or in vivo, and do not represent a carcinogenic risk to patients.

  18. 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

  19. 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

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

    2015-11-18

    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.

  20. 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

  1. 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

  2. A Placebo Double-Blind Pilot Study of Dextromethorphan for Problematic Behaviors in Children with Autism

    ERIC Educational Resources Information Center

    Woodard, Cooper; Groden, June; Goodwin, Matthew; Bodfish, James

    2007-01-01

    We used a mixed group/single-case, double-blind, placebo-controlled, ABAB design to examine the safety and efficacy of the glutamate antagonist dextromethorphan for the treatment of problematic behaviors and core symptoms in eight children diagnosed with autism. All participants had increased levels of irritability at baseline as measured by the…

  3. 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,…

  4. 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,…

  5. 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.

  6. Comparison of various urine collection intervals for caffeine and dextromethorphan phenotyping in children.

    PubMed

    Kennedy, Mary Jayne; Abdel-Rahman, Susan M; Kashuba, Angela D M; Leeder, J Steven

    2004-07-01

    Caffeine and dextromethorphan have been used successfully both alone and in combination to assess phenotype and enzyme activity in children of various ages. Previous pediatric phenotyping studies with these agents have used varying durations of urine collection. However, the minimum duration required for accurate phenotypic assessment with these compounds in children remains unknown. We calculated the cumulative metabolite recoveries and molar ratios in urine collected from children for 2, 4, 6, and 8 hours after caffeine and dextromethorphan administration to determine when respective urinary molar ratios stabilize and thus likely accurately reflect enzyme activity. Subjects (n = 24, ages 3-8 years) were given 4 oz of Coca-Cola(R) ( approximately 11.5 mg caffeine) and a single oral dose of dextromethorphan (0.5 mg/kg). Urine was collected at discrete intervals (0-2, 2-4, 4-6, and 6-8 h) during an 8-hour period, and the cumulative metabolite recoveries and urinary molar ratios were calculated. CYP2D6 genotyping was also performed in 21 of 24 subjects. In CYP2D6 extensive metabolizers, the extent of recovery for relevant metabolites was equivalent by 4 hours and represented 45% to 60% of the total amount recovered in the 8-hour period. The 2-hour CYP1A2 ratio was significantly different from those of longer collection intervals. Metabolite ratios for all other enzymes (i.e., NAT-2, XO, and CYP2D6) were independent of the duration of urine collection. These data suggest that a 4-hour urine collection is adequate for the concurrent assessment of hepatic CYP1A2, NAT-2, XO, and CYP2D6 activity in children ages 3 to 8 years who are CYP2D6 extensive metabolizers, using standard caffeine and dextromethorphan phenotyping methods. Longer collection periods may be required, however, in younger children or CYP2D6 poor metabolizers. PMID:15199075

  7. 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.

  8. 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

  9. 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

  10. New potentiometric and spectrophotometric methods for the determination of dextromethorphan in pharmaceutical preparations.

    PubMed

    Elmosallamy, Mohamed A F; Amin, Alaa S

    2014-01-01

    New, simple and convenient potentiometric and spectrophotometric methods are described for the determination of dextromethorphan hydrobromide (DXM) in pharmaceutical preparations. The potentiometric technique is based on developing a potentiometric sensor incorporating the dextromethorphan tetrakis(p-chlorophenyl)borate ion-pair complex as an electroactive species in a plasticized PVC matrix membrane with o-nitophenyl octyl ether or dioctyl phthalate. The sensor shows a rapid near Nernstian response of over 1 × 10(-5) - 1 × 10(-2) mol L(-1) dextromethorphan in the pH range of 3.0 - 9.0. The detection limit is 2 × 10(-6) mol L(-1) DXM and the response time is instantaneous (2 s). The proposed spectrophotometric technique involves the reaction of DXM with eriochrom black T (EBT) to form an ion-associate complex. Solvent extraction is used to improve the selectivity of the method. The optimal extraction and reaction conditions have been studied, and the analytical characteristics of the method have been obtained. Linearity is obeyed in the range of 7.37 - 73.7 × 10(-5) mol L(-1) DXM, and the detection limit of the method is 1.29 × 10(-5) mol L(-1). The relative standard deviation (RSD) and relative error for six replicate measurements of 3.685 × 10(-4) mol L(-1) are 0.672 and 0.855%, respectively. The interference effect of some excepients has also been tested. The drug contents in pharmaceutical preparations were successfully determined by the proposed methods by applying the standard-addition technique.

  11. 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

  12. 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…

  13. Rationale and design of a multicenter randomized clinical trial with memantine and dextromethorphan in ketamine-responder patients.

    PubMed

    Pickering, Gisèle; Pereira, Bruno; Morel, Véronique; Tiberghien, Florence; Martin, Elodie; Marcaillou, Fabienne; Picard, Pascale; Delage, Noémie; de Montgazon, Géraldine; Sorel, Marc; Roux, Delphine; Dubray, Claude

    2014-07-01

    The N-methyl-D-aspartate receptor plays an important role in central sensitization of neuropathic pain and N-methyl-D-aspartate receptor antagonists, such as ketamine, memantine and dextromethorphan may be used for persistent pain. However, ketamine cannot be repeated too often because of its adverse events. A drug relay would be helpful in the outpatient to postpone or even cancel the next ketamine infusion. This clinical trial evaluates if memantine and/or dextromethorphan given as a relay to ketamine responders may maintain or induce a decrease of pain intensity and have a beneficial impact on cognition and quality of life. This trial is a multi-center, randomized, controlled and single-blind clinical study (NCT01602185). It includes 60 ketamine responder patients suffering from neuropathic pain. They are randomly allocated to memantine, dextromethorphan or placebo. After ketamine infusion, 60 patients received either memantine (maximal dose 20 mg/day), or dextromethorphan (maximal dose 90 mg/day), or placebo for 12 weeks. The primary endpoint is pain measured on a (0-10) Numeric Rating Scale 1 month after inclusion. Secondary outcomes include assessment of neuropathic pain, sleep, quality of life, anxiety/depression and cognitive function at 2 and 3 months. Data analysis is performed using mixed models and the tests are two-sided, with a type I error set at α=0.05. This study will explore if oral memantine and/or dextromethorphan may be a beneficial relay in ketamine responders and may diminish ketamine infusion frequency. Preservation of cognitive function and quality of life is also a central issue that will be analyzed in these vulnerable patients.

  14. Simultaneous determination of dextromethorphan, diphenhydramine and phenylephrine in expectorant and decongestant syrups by capillary electrophoresis.

    PubMed

    Gomez, María R; Olsina, Roberto A; Martínez, Luis D; Silva, María F

    2002-10-15

    The separation of basic nitrogenous compounds commonly used as active ingredients in cold medicine formulations by micellar electrokinetic capillary chromatography and capillary zone electrophoresis with direct absorptiometric detection was investigated. The type and composition of the background electrolyte (BGE) were investigated with respect to separation selectivity and BGE stability. BGE of 10 mM sodium dihydrogenphosphate-sodium tetraborate buffer containing 10 mM SDS and 10% acetonitrile, pH 9.0 was found to be optimal. Dextromethorphan hydrobhromide, diphenhydramine hydrochloride and phenylephrine hydrochloride were baseline-separated in less than 11 min, giving separation efficiencies of up to 494,000 theoretical plates, reproducibility of corrected peaks areas below 3% relative standard deviation and concentration detection limits from 2.5 to 5.5 microg ml(-1). Detection was performed at 196 and 214 nm.

  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. 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

  17. 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.

  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. Comparative Effects of Triflusal, S-Adenosylmethionine, and Dextromethorphan over Intestinal Ischemia/Reperfusion Injury

    PubMed Central

    Cámara-Lemarroy, Carlos R.; Guzmán-de la Garza, Francisco J.; Cordero-Pérez, Paula; Alarcón-Galván, Gabriela; Torres-Gonzalez, Liliana; Muñoz-Espinosa, Linda E.; Fernández-Garza, Nancy E.

    2011-01-01

    Ischemia/reperfusion (I/R) is a condition that stimulates an intense inflammatory response. No ideal treatment exists. Triflusal is an antiplatelet salicylate derivative with anti-inflammatory effects. S-adenosylmethionine is a metabolic precursor for glutathione, an endogenous antioxidant. Dextromethorphan is a low-affinity N-methyl-D-aspartate receptor inhibitor. There is evidence that these agents modulate some of the pathways involved in I/R physiopathology. Intestinal I/R was induced in rats by clamping the superior mesenteric artery for 60 minutes, followed by 60 minutes of reperfusion. Rats either received saline or the drugs studied. At the end of the procedure, serum concentrations of tumor necrosis factor-alpha (TNF-alpha), malonaldehyde (MDA), and total antioxidant capacity (TAC) were determined and intestinal morphology analyzed. I/R resulted in tissue damage, serum TNF-alpha and MDA elevations, and depletion of TAC. All drugs showed tissue protection. Only triflusal reduced TNF-alpha levels. All drugs lowered MDA levels, but only triflusal and S-adenosylmethionine maintained the serum TAC. PMID:22125445

  2. Neuroprotective profile of dextromethorphan in an experimental model of penetrating ballistic-like brain injury.

    PubMed

    Shear, Deborah A; Williams, Anthony J; Sharrow, Keith; Lu, Xi-Chun M; Tortella, Frank C

    2009-11-01

    Dextromethorphan (DM) has been well-characterized as a neuroprotective agent in experimental models of CNS injury. The goal of this study was to determine the neuroprotective profile of DM in a military-relevant model of penetrating ballistic-like brain injury (PBBI). In an acute (3 day) dose-response study, anesthetized male Sprague-Dawley rats were exposed to a unilateral frontal PBBI with DM (0.156-10 mg/kg) or vehicle delivered as an i.v. bolus from 30 min to 48 h post-injury. In a follow-up (7 day) experiment, the 10-mg/kg bolus injections of DM were administered in conjunction with a 6-h infusion (5 mg/kg/h). DM bolus injections alone produced a dose-dependent improvement in motor recovery on a balance beam task at 3 days post-injury. However, more rapid recovery (24 h) was observed on this task when the bolus injections were combined with the 6-h infusion. Moreover, the DM bolus/infusion treatment regimen resulted in a significant (76%) improvement in cognitive performance in a novel object recognition (NOR) task at 7 days post-injury. Although post-injury administration of DM (all doses) failed to reduce core lesion size, the maximum dose of DM (10 mg/kg) was effective in reducing silver-stained axonal fiber degeneration in the cortical regions adjacent to the injury.

  3. Comparative effects of triflusal, S-adenosylmethionine, and dextromethorphan over intestinal ischemia/reperfusion injury.

    PubMed

    Cámara-Lemarroy, Carlos R; Guzmán-de la Garza, Francisco J; Cordero-Pérez, Paula; Alarcón-Galván, Gabriela; Torres-Gonzalez, Liliana; Muñoz-Espinosa, Linda E; Fernández-Garza, Nancy E

    2011-01-01

    Ischemia/reperfusion (I/R) is a condition that stimulates an intense inflammatory response. No ideal treatment exists. Triflusal is an antiplatelet salicylate derivative with anti-inflammatory effects. S-adenosylmethionine is a metabolic precursor for glutathione, an endogenous antioxidant. Dextromethorphan is a low-affinity N-methyl-D-aspartate receptor inhibitor. There is evidence that these agents modulate some of the pathways involved in I/R physiopathology. Intestinal I/R was induced in rats by clamping the superior mesenteric artery for 60 minutes, followed by 60 minutes of reperfusion. Rats either received saline or the drugs studied. At the end of the procedure, serum concentrations of tumor necrosis factor-alpha (TNF-alpha), malonaldehyde (MDA), and total antioxidant capacity (TAC) were determined and intestinal morphology analyzed. I/R resulted in tissue damage, serum TNF-alpha and MDA elevations, and depletion of TAC. All drugs showed tissue protection. Only triflusal reduced TNF-alpha levels. All drugs lowered MDA levels, but only triflusal and S-adenosylmethionine maintained the serum TAC.

  4. Effects of dextromethorphan on glial cell function: proliferation, maturation, and protection from cytotoxic molecules.

    PubMed

    Lisak, Robert P; Nedelkoska, Liljana; Benjamins, Joyce A

    2014-05-01

    Dextromethorphan (DM), a sigma receptor agonist and NMDA receptor antagonist, protects neurons from glutamate excitotoxicity, hypoxia and ischemia, and inhibits microglial activation, but its effects on differentiation and protection of cells in the oligodendroglial lineage are unknown. It is important to protect oligodendroglia (OL) to prevent demyelination and preserve axons, and to protect oligodendroglial progenitors (OPC) to optimize myelination during development and remyelination following damage. Enriched glial cultures from newborn rat brain were used 1-2 days or 6-8 days after shakeoff for OPC or mature OL. DM had large effects on glial proliferation in less mature cultures in contrast to small variable effects in mature cultures; 1 μM DM stimulated proliferation of OPC by 4-fold, microglia (MG) by 2.5-fold and astroglia (AS) by 2-fold. In agreement with increased OPC proliferation, treatment of OPC with DM for 3 days increased the % of OPC relative to OL, with a smaller difference by 5 days, suggesting that maturation of OPC to OL was "catching up" by 5 days. DM at 2 and 20 μM protected both OL and OPC from killing by glutamate as well as NMDA, AMPA, quinolinic acid, staurosporine, and reactive oxygen species (ROS). DM did not protect against kynurenic acid, and only modestly against NO. These agents and DM were not toxic to AS or MG at the concentrations used. Thus, DM stimulates proliferation of OPC, and protects both OL and OPC against excitotoxic and inflammatory insults. PMID:24526455

  5. Separation and determination of pseudoephedrine, dextromethorphan, diphenhydramine and chlorpheniramine in cold medicines by nonaqueous capillary electrophoresis.

    PubMed

    Dong, Yuming; Chen, Xiaofeng; Chen, Yonglei; Chen, Xingguo; Hu, Zhide

    2005-09-01

    An easy, rapid and simple nonaqueous capillary electrophoresis (NACE) method was developed for the identification and determination of four basic nitrogenous compounds, i.e. pseudoephedrine (PE), dextromethorphan (DXM), diphenhydramine (DHM) and chlorpheniramine (CLP). The most suitable running buffer was composed of 40 mM ammonium acetate, 10% acetonitrile (ACN) in methanol with a fused-silica capillary column (47 cm x 75 microm i.d.), 25 kV applied voltage and 25 degrees C capillary temperature. The calibration curves revealed linear relationships between the peak area for each analyte and its concentration (correlation coefficients: 0.9993 for PE, 0.9971 for DXM, 0.9991 for DHM, and 0.9995 for CLP, respectively). The relative standard deviations of the migration time and peak area of the four compounds were 0.37, 3.90, 0.73 and 0.68, and 2.80, 3.50, 1.60 and 3.70%, respectively. The method was successfully applied to determine the four compounds in five cold medicines, the recoveries of the four constituents ranging between 91 and 109%.

  6. 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

  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. 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

  10. 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

  11. 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.

  12. 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

  13. A COMBINED EFFECT OF DEXTROMETHORPHAN AND MELATONIN ON NEUROPATHIC PAIN BEHAVIOR IN RATS

    PubMed Central

    Wang, Shuxing; Zhang, Lin; Lim, Grewo; Sung, Backil; Tian, Yinghong; Chou, Chiu-Wen; Hernstadt, Hayley; Rusanescu, Gabriel; Ma, Yuxin; Mao, Jianren

    2009-01-01

    Previous study has shown that administration of melatonin into the anterior cingulate cortex contralateral to peripheral nerve injury prevented exacerbation of mechanical allodynia with a concurrent improvement of depression-like behavior in Wistar-Kyoto (WKY) rats, a genetic variation of Wistar rats. In the present study, we examined the effect of the individual versus combined treatment of melatonin and/or dextromethorphan (DM), a clinically available N-methyl-D-aspartate (NMDA) receptor antagonist, on pain behaviors in WKY rats with chronic constriction sciatic nerve injury (CCI). Pain behaviors (thermal hyperalgesia and mechanical allodynia) were established at one week after CCI. WKY rats were then treated intraperitoneally with various doses of melatonin, DM or their combination once daily for the following week. At the end of this one-week treatment, behavioral tests were repeated in these same rats. While DM alone was effective in reducing thermal hyperalgesia at three tested doses (15, 30 or 60 mg/kg), it reduced mechanical allodynia only at high doses (30 or 60 mg/kg). By comparison, administration of melatonin alone was effective in reducing thermal hyperalgesia only at the highest dose (120 mg/kg, but not 30 or 60 mg/kg) tested in this experiment. Melatonin alone failed to reverse allodynia at all three tested doses (30, 60 and 120 mg/kg). However, the combined intraperitoneal administration of melatonin (30 mg/kg) and DM (15 mg/kg) effectively reversed both thermal hyperalgesia and mechanical allodynia although each individual dose alone did not reduce pain behaviors. These results suggest that a combination of melatonin with a clinically available NMDA receptor antagonist might be more effective than either drug alone for the treatment of neuropathic pain. PMID:19595681

  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. 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

  16. 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

  17. Simultaneous determination of pseudoephdrine, pheniramine, guaifenisin, pyrilamine, chlorpheniramine and dextromethorphan in cough and cold medicines by high performance liquid chromatography.

    PubMed

    Louhaichi, M R; Jebali, S; Loueslati, M H; Adhoum, N; Monser, L

    2009-05-15

    A new simple, rapid and sensitive liquid chromatographic method has been developed and validated for the simultaneous determination of pseudoephdrine, pheniramine, guaifenisin, pyrilamine, chlorpheniramine and dextromethorphan in cough and cold pharmaceuticals. The separation of these compounds was achieved within 13 min on a Kromasil C18 column using an isocratic mobile phase consisting of methanol-dihydrogenphosphate buffer at pH 3 (45:55, v/v). The analysis was performed at a flow rate of 1 mL min(-1) and at a detection wavelength of 220 nm. The selectivity, linearity of calibration, accuracy, within and between-days precision and recovery were examined as parts of the method validation. The concentration-response relationship was linear over a concentration range of 5-50 microg mL(-1) for pseudoephdrine, pheniramine, chlorpheniramine and 50-600 microg mL(-1) for guaifenisin, pyrilamine, dextromethorphan, methylparaben and sodium benzoate with correlation coefficients better than 0.998. The standard deviations of the intraday and interday were all less than 2%. The proposed liquid chromatographic method was successfully applied for the routine analysis of these compounds in different cough and cold pharmaceutical preparations such as syrups, capsules, tablets and sachets. The presence of preservatives (sodium benzoate and methylparaben) and other excipients did not show any significant interference on the determination of these compounds.

  18. The abuse of dextromethorphan-based cough syrup: a pilot study of the community of Waynesboro, Pennsylvania.

    PubMed

    Darboe, M N; Keenan, G R; Richards, T K

    1996-01-01

    Drug abuse has been a national social problem in the United States for decades and is often complicated by the emergence of new types of abused drugs or new forms of abuse. In the late 1980s, the community of Waynesboro, Pennsylvania began to detect behavior among its teenagers that suggested a new form of drug abuse and thus a new social problem. The drug was dextromethorphan, used in cough syrup-principally Robitussin DM. The form of abuse is often referred to as "roboing" or "robo-copping." This paper presents the results of the first phase of a comprehensive investigation of this phenomenon in the Waynesboro school district. Data from a survey of school personnel indicate that abuse of cough syrup (Robitussin or other brands) has increased over the years and is increasingly perceived as a problem by the community.

  19. 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

  20. Prediction of relative in vivo metabolite exposure from in vitro data using two model drugs: dextromethorphan and omeprazole.

    PubMed

    Lutz, Justin D; Isoherranen, Nina

    2012-01-01

    Metabolites can have pharmacological or toxicological effects, inhibit metabolic enzymes, and be used as probes of drug-drug interactions or specific cytochrome P450 (P450) phenotypes. Thus, better understanding and prediction methods are needed to characterize metabolite exposures in vivo. This study aimed to test whether in vitro data could be used to predict and rationalize in vivo metabolite exposures using two model drugs and P450 probes: dextromethorphan and omeprazole with their primary metabolites dextrorphan, 5-hydroxyomeprazole (5OH-omeprazole), and omeprazole sulfone. Relative metabolite exposures were predicted using metabolite formation and elimination clearances. For dextrorphan, the formation clearances of dextrorphan glucuronide and 3-hydroxymorphinan from dextrorphan in human liver microsomes were used to predict metabolite (dextrorphan) clearance. For 5OH-omeprazole and omeprazole sulfone, the depletion rates of the metabolites in human hepatocytes were used to predict metabolite clearance. Dextrorphan/dextromethorphan in vivo metabolite/parent area under the plasma concentration versus time curve ratio (AUC(m)/AUC(p)) was overpredicted by 2.1-fold, whereas 5OH-omeprazole/omeprazole and omeprazole sulfone/omeprazole were predicted within 0.75- and 1.1-fold, respectively. The effect of inhibition or induction of the metabolite's formation and elimination on the AUC(m)/AUC(p) ratio was simulated. The simulations showed that unless metabolite clearance pathways are characterized, interpretation of the metabolic ratios is exceedingly difficult. This study shows that relative in vivo metabolite exposure can be predicted from in vitro data and characterization of secondary metabolism of probe metabolites is critical for interpretation of phenotypic data.

  1. Mecamylamine, dihydro-beta-erythroidine, and dextromethorphan block conditioned responding evoked by the conditional stimulus effects of nicotine.

    PubMed

    Struthers, Amanda M; Wilkinson, Jamie L; Dwoskin, Linda P; Crooks, Peter A; Bevins, Rick A

    2009-12-01

    Current smokers express the desire to quit. However, the majority find it difficult to remain abstinent. As such, research efforts continually seek to develop more effective treatment. One such area of research involves the interoceptive stimulus effects of nicotine as either a discriminative stimulus in an operant drug discrimination task, or more recently as a conditional stimulus (CS) in a discriminated goal-tracking task. The present work investigated the potential role nicotinic acetylcholine receptors play in the CS effects of nicotine (0.4mg/kg) using antagonists with differential selectivity for beta2*, alpha7*, alpha6beta2*, and alpha3beta4* receptors. Methyllycaconitine (MLA) had no effect on nicotine-evoked conditioned responding. Mecamylamine and dihydro-beta-erythroidine (DHbetaE) dose-dependently blocked responding evoked by the nicotine CS. In a time-course assessment of mecamylamine and DHbetaE, each blocked conditioned responding when given 5min before testing and still blocked conditioned responding when administered 200min before testing. Two novel bis-picolinium analogs (N, N'-(3, 3'-(dodecan-1,12-diyl)-bis-picolinium dibromide [bPiDDB], and N, N'-(decan-1,10-diyl)-bis-picolinium diiodide [bPiDI]) did not block nicotine-evoked conditioned responding. Finally, pretreatment with low dose combinations of mecamylamine, dextromethorphan, and/or bupropion was used to target alpha3beta4* receptors. No combination blocked conditioned responding evoked by the training dose of nicotine. However, a combination of mecamylamine and dextromethorphan partially blocked nicotine-evoked conditioned responding to a lower dose of nicotine (0.1mg/kg). These results indicate that beta2* and potentially alpha3beta4* nicotinic acetylcholine receptors play a role in the CS effects of nicotine and are potential targets for the development of nicotine cessation aids.

  2. 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

  3. 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.

  4. 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

  5. Synthesis, in vitro and in vivo studies, and molecular modeling of N-alkylated dextromethorphan derivatives as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptor.

    PubMed

    Jozwiak, Krzysztof; Targowska-Duda, Katarzyna M; Kaczor, Agnieszka A; Kozak, Joanna; Ligeza, Agnieszka; Szacon, Elzbieta; Wrobel, Tomasz M; Budzynska, Barbara; Biala, Grazyna; Fornal, Emilia; Poso, Antti; Wainer, Irving W; Matosiuk, Dariusz

    2014-12-15

    9 N-alkylated derivatives of dextromethorphan are synthesized and studied as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptors (nAChRs). In vitro activity towards α3β4 nicotinic acetylcholine receptor is determined using a patch-clamp technique and is in the micromolar range. Homology modeling, molecular docking and molecular dynamics of ligand-receptor complexes in POPC membrane are used to find the mode of interactions of N-alkylated dextromethorphan derivatives with α3β4 nAChR. The compounds, similarly as dextromethorphan, interact with the middle portion of α3β4 nAChR ion channel. Finally, behavioral tests confirmed potential application of the studied compounds for the treatment of addiction.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. Treatment Resistant Depression with Loss of Antidepressant Response: Rapid—Acting Antidepressant Action of Dextromethorphan, A Possible Treatment Bridging Molecule

    PubMed Central

    Lauterbach, Edward C.

    2016-01-01

    Dextromethorphan (DM) may have ketamine—like rapid—acting, treatment—resistant, and conventional antidepressant effects.1,2 This reports our initial experience with DM in unipolar Major Depressive Disorder (MDD). A patient with treatment—resistant MDD (failing adequate trials of citalopram and vortioxetine) with loss of antidepressant response (to fluoxetine and bupropion) twice experienced a rapid—acting antidepressant effect within 48 hours of DM administration and lasting 7 days, sustained up to 20 days with daily administration, then gradually developing labile loss of antidepressant response over the ensuing 7 days. Upon full relapse in DSM-5 MDD while taking 600 mg/day of the strong CYP2D6 inhibitor bupropion XL, a 300 mg oral loading dose of DM was given, followed by 60 mg po bid after an additional dose—finding period, without side effects. DM exhibited a ketamine—like rapid—acting antidepressant effect, thought to be mediated by mTOR activation (related to NMDA PCP site antagonism, sigma-1 and beta adrenergic receptor stimulation) and 5HTT inhibition, resulting in AMPA receptor trafficking, and dendritogenesis, spinogenesis, synaptogenesis, and increased neuronal survival (related to NMDA antagonism and sigma-1 and mTOR signaling). This report appears to be the first report of a rapid—acting effect in unipolar MDD and adds to antidepressant effects observed in the retrospective chart review of 77 patients with Bipolar II Disorder (Kelly and Lieberman 2014). If replicated, there is some reason to think that the administration of other agents with DM, such as lithium or D-cycloserine, might prolong the duration of the rapid-antidepressant effect. PMID:27738380

  11. Dextromethorphan provides neuroprotection via anti-inflammatory and anti-excitotoxicity effects in the cortex following traumatic brain injury.

    PubMed

    Pu, Benfang; Xue, Yonghua; Wang, Qingming; Hua, Chunhui; Li, Xinyuan

    2015-09-01

    Traumatic brain injury (TBI) is caused by primary and secondary injury mechanisms. TBI induces a certain amount of inflammatory responses and glutamate excitotoxicity that are believed to participate in the pathogenesis of secondary injury. The non‑narcotic anti‑tussive drug dextromethorphan (DM) has been reported to have a high safety profile in humans and its neuroprotective against a variety of disorders, including cerebral ischemia, epilepsy and acute brain injury. However, few studies have explored the underlying mechanisms of the neuroprotective effects of DM in animals in the setting of TBI. The aim of the present study was to investigate the neuroprotective effects of DM on TBI and to determine the underlying mechanisms. Rats were subjected to a controlled cortical impact (CCI) injury and randomly divided into three groups: Sham‑operated, TBI and DM treatment groups. The DM treatment group was administered DM (30 mg/kg of body weight, intraperitoneally) immediately after injury. It was identified that DM treatment following TBI significantly reduced brain edema and neurological deficits, as well as increased neuronal survival. These effects correlated with a decrease of tumor necrosis factor α, interleukin‑1β (IL‑1β) and IL‑6 protein expression and an increase of glutamate/aspartate transporter and glutamate transporter‑1 in the cortex of the brain. These results provided in vivo evidence that DM exerts neuroprotective effects via reducing inflammation and excitotoxicity induced following TBI. The present study has shed light on the potential use of DM as a neuroprotective agent in the treatment of cerebral injuries.

  12. Effect of polysulfonate resins and direct compression fillers on multiple-unit sustained-release dextromethorphan resinate tablets.

    PubMed

    Pongjanyakul, Thaned; Priprem, Aroonsri; Chitropas, Padungkwan; Puttipipatkhachorn, Satit

    2005-09-30

    The purpose of this work was to investigate the effect of different polysulfonate resins and direct compression fillers on physical properties of multiple-unit sustained-release dextromethorphan (DMP) tablets. DMP resinates were formed by a complexation of DMP and strong cation exchange resins, Dowex 50 W and Amberlite IRP69. The tablets consisted of the DMP resinates and direct compression fillers, such as microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), and spray-dried rice starch (SDRS). Physical properties of tablets, such as hardness, disintegration time, and in vitro release, were investigated. A good performance of the tablets was obtained when MCC or SDRS was used. The use of rod-like and plate-like particles of Amberlite IRP69 caused a statistical decrease in tablet hardness, whereas good tablet hardness was obtained when spherical particle of Dowex 50 W was used. The plastic deformation of the fillers, such as MCC and SDRS, caused a little change in the release of DMP. A higher release rate constant was found in the tablets containing DCP and Dowex 50 W, indicating the fracture of the resinates under compression, which was attributable to the fragmentation of DCP. However, the release of DMP from the tablets using Amberlite IRP69 was not significantly changed because of the higher degree of cross-linking of the resinates, which exhibited more resistance to deformation under compression. In conclusion, the properties of polysulfonate resin, such as particle shape and degree of cross-linking, and the deformation under compaction of fillers affect the physical properties and the drug release of the resinate tablets.

  13. 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.

  14. Binding of bufuralol, dextromethorphan, and 3,4-methylenedioxymethylamphetamine to wild-type and F120A mutant cytochrome P450 2D6 studied by resonance Raman spectroscopy

    SciTech Connect

    Bonifacio, Alois . E-mail: zwan@few.vu.nl

    2006-05-12

    Cytochrome P450 2D6 (CYP2D6) is one of the most important drug-metabolizing enzymes in humans. Resonance Raman data, reported for First time for CYP2D6, show that the CYP2D6 heme is found to be in a six-coordinated low-spin state in the absence of substrates, and it is perturbed to different extents by bufuralol, dextromethorphan, and 3,4-methylenedioxymethylamphetamine (MDMA). Dextromethorphan and MDMA induce in CYP2D6 a significant amount of five-coordinated high-spin heme species and reduce the polarity of its heme-pocket, whereas bufuralol does not. Spectra of the F120A mutant CYP2D6 suggest that Phe{sup 12} is involved in substrate-binding of dextromethorphan and MDMA, being responsible for the spectral differences observed between these two compounds and bufuralol. These differences could be explained postulating a different substrate mobility for each compound in the CYP2D6 active site, consistently with the role previously suggested for Phe{sup 12} in binding dextromethorphan and MDMA.

  15. Effect of Curcuma longa on CYP2D6- and CYP3A4-mediated metabolism of dextromethorphan in human liver microsomes and healthy human subjects.

    PubMed

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

    2015-03-01

    Effect of Curcuma longa rhizome powder and its ethanolic extract on CYP2D6 and CYP3A4 metabolic activity was investigated in vitro using human liver microsomes and clinically in healthy human subjects. Dextromethorphan (DEX) was used as common probe for CYP2D6 and CYP3A4 enzymes. Metabolic activity of CYP2D6 and CYP3A4 was evaluated through in vitro study; where microsomes were incubated with NADPH in presence and absence of Curcuma extract. In clinical study phase-I, six healthy human subjects received a single dose (30 mg) of DEX syrup, and in phase-II DEX syrup was administered with Curcuma powder. The enzyme CYP2D6 and CYP3A4 mediated O- and N-demethylation of dextromethorphan into dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Curcuma extract significantly inhibited the formation of DOR and 3-MM, in a dose-dependent and linear fashion. The 100 μg/ml dose of curcuma extract produced highest inhibition, which was about 70 % for DOR and 80 % for 3-MM. Curcuma significantly increases the urine metabolic ratio of DEX/DOR but the change in DEX/3-MM ratio was statistically insignificant. Present findings suggested that curcuma significantly inhibits the activity of CYP2D6 in in vitro as well as in vivo; which indicates that curcuma has potential to interact with CYP2D6 substrates.

  16. 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

  17. 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.

  18. 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 Central

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

    2016-01-01

    Abstract 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

  19. 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 ...

  20. 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

  1. 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

  2. Role of hypothermia in the mechanism of protection against serotonergic toxicity. II. Experiments with methamphetamine, p-chloroamphetamine, fenfluramine, dizocilpine and dextromethorphan.

    PubMed

    Farfel, G M; Seiden, L S

    1995-02-01

    Several amphetamine analogs, when administered in high-dose regimens, have been shown to cause long-lasting depletions of central serotonin (5-HT), which are indicative of neuronal toxicity. These depletions and the resulting toxicity can be attenuated pharmacologically or by lowering ambient temperature. The noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (DZ) blocks depletion of 5-HT induced by methamphetamine (METH) and p-chloroamphetamine (PCA), but not fenfluramine (FEN). This study investigated whether the effects of DZ and another calcium channel antagonist, dextromethorphan (DEX), are due to induction of hypothermia. Male Sprague-Dawley rats were injected with either saline (SAL), DZ (1 or 2 injections of 2.5 mg/kg), or DEX (75.0 mg/kg) followed by either SAL, METH (4 injections of 10.0 mg/kg), PCA (1 injection of 10.0 mg/kg) or FEN (2 or 4 injections of 12.5 mg/kg). Core body temperature (TEMP) was monitored for 4 h or longer with radiotelemetry. Base-line TEMP was between 37.0 and 37.6 degrees C. SAL/METH caused a significant increase in TEMP which peaked at 40.8 +/- 0.50 degrees C after the last injection. Coadministration of DZ with METH caused TEMP to decrease to 33.8 +/- 0.30 degrees C within 2 h of the first injection and lasting more than 3 h, and protected against depletion of 5-HT. SAL/PCA caused a small increase in TEMP to 37.7 +/- 0.36 degrees C, whereas coadministration of DZ with PCA decreased TEMP to 35.2 +/- 0.50 degrees C, lasting 2 h, in a dose regimen which has been shown to be neuroprotective.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. The common antitussive agent dextromethorphan protects against hyperoxia-induced cell death in established in vivo and in vitro models of neonatal brain injury.

    PubMed

    Posod, A; Pinzer, K; Urbanek, M; Wegleiter, K; Keller, M; Kiechl-Kohlendorfer, U; Griesmaier, E

    2014-08-22

    Preterm infants are prematurely subjected to relatively high oxygen concentrations, even when supplemental oxygen is not administered. There is increasing evidence to show that an excess of oxygen is toxic to the developing brain. Dextromethorphan (DM), a frequently used antitussive agent with pleiotropic mechanisms of action, has been shown to be neuroprotective in various models of central nervous system pathology. Due to its numerous beneficial properties, it might also be able to counteract detrimental effects of a neonatal oxygen insult. The aim of the current study was to evaluate its therapeutic potential in established cell culture and rodent models of hyperoxia-induced neonatal brain injury. For in vitro studies pre- and immature oligodendroglial (OLN-93) cells were subjected to hyperoxic conditions for 48 h after pre-treatment with increasing doses of DM. For in vivo studies 6-day-old Wistar rat pups received a single intraperitoneal injection of DM in two different dosages prior to being exposed to hyperoxia for 24h. Cell viability and caspase-3 activation were assessed as outcome parameters at the end of exposure. DM significantly increased cell viability in immature oligodendroglial cells subjected to hyperoxia. In pre-oligodendroglial cells cell viability was not significantly affected by DM treatment. In vivo caspase-3 activation induced by hyperoxic exposure was significantly lower after administration of DM in gray and white matter areas. In control animals kept under normoxic conditions DM did not significantly influence caspase-3-dependent apoptosis. The present results indicate that DM is a promising and safe treatment strategy for neonatal hyperoxia-induced brain injury that merits further investigation.

  4. 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

  5. Multivariate optimization and validation of a capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromur, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate in a pharmaceutical preparation using response surface methodology.

    PubMed

    Palabiyik, I Murat; Onur, Feyyaz

    2010-01-01

    A fast, accurate, precise and sensitive capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromide, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate has been developed. Response surface methodology with a central composite design was used for optimization of the concentration of the buffer, pH of the buffer and applied voltage. Therefore, working with Na(2)HPO(4) buffer (pH 8.00, 0.01 M) at 20 kV as an applied voltage in the capillary electrophoresis method were found to be suitable; under these optimal conditions, these four active ingredients were separated in about 7 min. This developed method was validated and successfully applied to a pharmaceutical preparation, sugar-coated tablet, and the results were compared with a high-performance liquid chromatographic method developed by us.

  6. 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.

  7. 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

  8. In silico description of differential enantioselectivity in methoxychlor O-demethylation by CYP2C enzymes.

    PubMed

    Bikádi, Zsolt; Hazai, Eszter

    2008-09-01

    Methoxychlor undergoes metabolism by cytochrome P450 (CYP) enzymes forming a chiral mono-phenolic derivative (Mono-OH-M) as main metabolite. In the current study, members of the CYP2C family were examined for their chiral preference in Mono-OH-M formation. CYP2C9 and CYP2C19 possessed high enantioselectivity favoring the formation of S-Mono-OH-M; CYP2C3 showed no enantioselectivity, whereas CYP2C5 slightly favored the formation of R-Mono-OH-M. Molecular modeling calculations were utilized in order to explain the observed differences in chiral preference of CYP2C enzymes. Molecular docking calculations could describe neither the existence of chiral preference in metabolism, nor the enantiomer which is preferentially formed. Molecular dynamic calculations were also carried out and were found to be useful for accurate description of chiral preference in biotransformation of methoxychlor by CYP2C enzymes. An in silico model capable of predicting chiral preference in cytochrome P450 enzymes in general can be developed based on the analysis of the stability and rigidity parameters of interacting partners during molecular dynamic simulation.

  9. Inhibition of human cytochrome P450 2D6 (CYP2D6) by methadone.

    PubMed Central

    Wu, D; Otton, S V; Sproule, B A; Busto, U; Inaba, T; Kalow, W; Sellers, E M

    1993-01-01

    1. In microsomes prepared from three human livers, methadone competitively inhibited the O-demethylation of dextromethorphan, a marker substrate for CYP2D6. The apparent Ki value of methadone ranged from 2.5 to 5 microM. 2. Two hundred and fifty-two (252) white Caucasians, including 210 unrelated healthy volunteers and 42 opiate abusers undergoing treatment with methadone were phenotyped using dextromethorphan as the marker drug. Although the frequency of poor metabolizers was similar in both groups, the extensive metabolizers among the opiate abusers tended to have higher O-demethylation metabolic ratios and to excrete less of the dose as dextromethorphan metabolites than control extensive metabolizer subjects. These data suggest inhibition of CYP2D6 by methadone in vivo as well. 3. Because methadone is widely used in the treatment of opiate abuse, inhibition of CYP2D6 activity in these patients might contribute to exaggerated response or unexpected toxicity from drugs that are substrates of this enzyme. PMID:8448065

  10. 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

    2015-07-08

    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.

  11. Effect of protein-calorie malnutrition on cytochromes P450 and glutathione S-transferase.

    PubMed

    Zhang, W; Parentau, H; Greenly, R L; Metz, C A; Aggarwal, S; Wainer, I W; Tracy, T S

    1999-01-01

    Protein-calorie malnutrition (PCM) can develop both from inadequate food intake and as a consequence of diseases such as cancer and AIDS. Several studies have shown that PCM can alter drug clearance but little information is available on the effect of PCM on individual cytochrome P450 isoforms and phase II conjugation enzymes. The aim of the present study was to begin a systematic evaluation of the effect of PCM on the activity of individual drug metabolizing enzymes in a rat model of PCM. Control and PCM rats received isocaloric diets which contained either 21% or 5% (deficient) protein. After 3 weeks, the animals were sacrificed and microsomal and cytosolic fractions prepared. Ethoxyresorufin O-deethylation (EROD), chlorzoxazone 6-hydroxylation, dextromethorphan N- and O-demethylation and 1-chloro-2,4-dinitrobenzene (CDNB) conjugation were used as measures of CYP1A, CYP2E1, CYP3A2, CYP2D1 and glutathione S-transferase (GST) activity, respectively. Additionally, NADPH-cytochrome P450 reductase activity was measured in the liver microsomes. PCM significantly reduced the maximum velocity (Vmax) of all model reactions studied. However, differential effects were observed with respect to K(m) values of the reactions. The K(m) values for EROD and dextromethorphan N-demethylation were significantly increased in PCM animals, whereas the K(m) values for chlorzoxazone 6-hydroxylation and dextromethorphan O-demethylation were decreased. In contrast, the K(m) value for CDNB conjugation was unchanged. When NADPH-cytochrome P450 reductase activity was compared, a 29% reduction in reductase activity was noted in PCM animals as compared to controls. Thus, it appears that PCM decreases the overall activity of certain phase I and phase II metabolism enzymes in rat liver while exhibiting differential effects on K(m). Furthermore, this reduction in activity may be due in part to diminished activity of cytochrome P450 reductase.

  12. The potential for CYP2D6 inhibition screening using a novel scintillation proximity assay-based approach.

    PubMed

    Delaporte, E; Slaughter, D E; Egan, M A; Gatto, G J; Santos, A; Shelley, J; Price, E; Howells, L; Dean, D C; Rodrigues, A D

    2001-08-01

    High throughput inhibition screens for human cytochrome P450s (CYPs) are being used in preclinical drug metabolism to support drug discovery programs. The versatility of scintillation proximity assay (SPA) technology has enabled the development of a homogeneous high throughput assay for cytochrome P450 2D6 (CYP2D6) inhibition screen using [O-methyl-(14)C]dextromethorphan as substrate. The basis of the assay was the trapping of the O-demethylation product, [(14)C]HCHO, on SPA beads. Enzyme kinetics parameters V(max) and apparent K(m), determined using pooled human liver microsomes and microsomes from baculovirus cells coexpressing human CYP2D6 and NADPH-cytochrome P450 reductase, were 245 pmol [(14)C]HCHO/min/mg protein and 11 microM, and 27 pmol [(14)C]HCHO/min/pmol and 1.6 microM, respectively. In incubations containing either pooled microsomes or recombinant CYP2D6, [(14)C]dextromethorphan O-demethylase activity was inhibited in the presence of quinidine (IC(50) = 1.0 microM and 20 nM, respectively). By comparison, inhibitors selective for other CYP isoforms were relatively weak (IC(50) > 25 microM). In agreement, a selective CYP2D6 inhibitory monoclonal antibody caused greater than 90% inhibition of [(14)C]dextromethorphan O-demethylase activity in human liver microsomes, whereas CYP2C9/19- and CYP3A4/5-selective antibodies elicited a minimal inhibitory effect. SPA-based [(14)C]dextromethorphan O-demethylase activity was also shown to correlate (r(2) = 0.6) with dextromethorphan O-demethylase measured by high-performance liquid chromatography in a bank of human liver microsomes (N = 15 different organ donors). In a series of known CYP2D6 inhibitors/substrates, the SPA-based assay resolved potent inhibitors (IC(50) < 2 microM) from weak inhibitors (IC(50) >or= 20 microM). It is concluded that the SPA-based assay described herein is suitable for CYP2D6 inhibition screening using either native human liver microsomes or cDNA-expressed CYP2D6. PMID:11689122

  13. 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

  14. The extent and determinants of changes in CYP2D6 and CYP1A2 activities with therapeutic doses of sertraline.

    PubMed

    Ozdemir, V; Naranjo, C A; Herrmann, N; Shulman, R W; Sellers, E M; Reed, K; Kalow, W

    1998-02-01

    The extent of changes in CYP2D6 and CYP1A2 activities with higher therapeutic dosages (>50 mg/day) of sertraline is not well established in vivo. This study assessed the extent and determinants of changes in CYP2D6 and CYP1A2 isozyme activities after treatment with clinically relevant doses of sertraline. Patients and healthy volunteers aged 19 to 85 years (N = 21) were treated with sertraline for 5 to 55 days. The dosage of sertraline ranged from 25 to 150 mg/day (93.5+/-26.4 mg/day; mean +/- SD). All subjects had an extensive metabolizer phenotype for CYP2D6 and received a single oral dose of dextromethorphan (30 mg) and caffeine (100 mg) before and after sertraline treatment. The log O-demethylation ratio (ODMR) of dextromethorphan and the caffeine metabolic ratio (CMR) in overnight urine were used as in vivo indices of the CYP2D6 and CYP1A2 isozyme activities, respectively. Concurrent medications and lifestyle habits (e.g., smoking and diet) were monitored during the study. Baseline log ODMR (-2.33+/-0.45) but not CMR (5.1+/-1.9) (mean +/- SD) significantly changed after sertraline treatment (-2.19+/-0.62; 4.5+/-1.6, respectively) (p: ODMR = 0.04, CMR = 0.10). There was no significant effect of age, dose, duration of treatment, gender, sertraline and/or desmethylsertraline plasma concentration, subject type (patient or volunteer), and weight on the extent of changes in log ODMR or CMR (p > 0.05). In conclusion, sertraline treatment at a mean daily dosage of 94.0 mg did not significantly change CYP1A2 activity and resulted in a modest inhibition of CYP2D6 activity.

  15. Mechanism-based inhibition of human liver microsomal cytochrome P450 2D6 (CYP2D6) by alkamides of Piper nigrum.

    PubMed

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

    2006-05-01

    Nineteen alkamides isolated from Piper nigrum L. were tested for their mechanism-based inhibition on human liver microsomal dextromethorphan O-demethylation activity, a prototype marker for cytochrome P450 2D6 (CYP2D6). All compounds increased their inhibitory activity with increasing preincubation time. Among them, 15 and 17 showed more than 50 % decrease of the CYP2D6 residual activity after 20 min preincubation. Further investigations on 15 and 17 showed that the characteristic time- and concentration-dependent inhibition, which required a catalytic step with NADPH, was not protected by nucleophiles, and was decreased by the presence of a competitive inhibitor. The kinetic parameters for inactivation (kinact and KI) were 0.028 min-1 and 0.23 microM for 15 and 0.064 min-1 and 0.71 microM for 17, respectively, which were stronger than the known mechanism-based inhibitor, paroxetine (a positive control). Thus, 15 and 17 are potent mechanism-based inhibitors of CYP2D6.

  16. 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.

  17. 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…

  18. 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

  19. 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…

  20. Guaifenesin

    MedlinePlus

    Leader Adult Tussin® ... Leader Mucus Relief® ... Leader Adult Tussin DM® (as a combination product containing Dextromethorphan, Guaifenesin) ... Leader Childrens Mucus Relief Cough® (as a combination product containing Dextromethorphan, Guaifenesin)

  1. Dual Therapeutic Effects of C-10068, a Dextromethorphan Derivative, Against Post-Traumatic Nonconvulsive Seizures and Neuroinflammation in a Rat Model of Penetrating Ballistic-Like Brain Injury.

    PubMed

    Lu, Xi-Chun May; Shear, Deborah A; Graham, Philip B; Bridson, Gary W; Uttamsingh, Vinita; Chen, Zhiyong; Leung, Lai Yee; Tortella, Frank C

    2015-10-15

    Post-traumatic seizures can exacerbate injurious outcomes of severe brain trauma, yet effective treatments are limited owing to the complexity of the pathology underlying the concomitant occurrence of both events. In this study, we tested C-10068, a novel deuterium-containing analog of (+)-N-methyl-3-ethoxymorphinan, in a rat model of penetrating ballistic-like brain injury (PBBI) and evaluated the effects of C-10068 on PBBI-induced nonconvulsive seizures (NCS), acute neuroinflammation, and neurofunctional outcomes. NCS were detected by electroencephalographic monitoring. Neuroinflammation was evaluated by immunohistochemical markers, for example, glial fibrillary acidic protein and major histocompatibility complex class I, for activation of astrocytes and microglia, respectively. Neurofunction was tested using rotarod and Morris water maze tasks. Three infusion doses of C-10068 (1.0, 2.5, and 5.0 mg/kg/h × 72 h) were tested in the antiseizure study. Neuroinflammation and neurofunction were evaluated in animals treated with 5.0 mg/kg/h × 72 h C-10068. Compared to vehicle treatment, C-10068 dose dependently reduced PBBI-induced NCS incidence (40-50%), frequency (20-70%), and duration (30-82%). The most effective antiseizure dose of C-10068 (5.0 mg/kg/h × 72 h) also significantly attenuated hippocampal astrocyte activation and perilesional microglial reactivity post-PBBI. Within C-10068-treated animals, a positive correlation was observed in reduction in NCS frequency and reduction in hippocampal astrocyte activation. Further, C-10068 treatment significantly attenuated astrocyte activation in seizure-free animals. However, C-10068 failed to improve PBBI-induced motor and cognitive functions with the dosing regimen used in this study. Overall, the results indicating that C-10068 exerts both potent antiseizure and antiinflammatory effects are promising and warrant further investigation.

  2. 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)

  3. Biotransformation of selamectin with Streptomyces lydicus SX-1298 using a novel static agar fermentation system with Reemay mesh.

    PubMed

    Pacey, M S; Barnes, M M; Monday, R A; Ritzau, M; Wellington, E M

    2001-05-01

    A novel approach to biotransformation is described using a solid medium matrix and Reemay mesh that gives efficient biotransformation of compounds with minimal matrices in the ensuing gum solids. Using this approach with a newly isolated biotransforming organism, Streptomyces lydicus SX1298, a series of hydroxylations and an O-demethylation is described for selamectin the first endectocide for cats and dogs.

  4. Three New Tazettine-Type Alkaloids from Galanthus gracilis and Galanthus plicatus Subsp. byzantinus.

    PubMed

    Unver, N; Noyan, S; Gözler, T; Onür, M A; Gözler, B; Hesse, M

    1999-05-01

    Three new tazettine-type alkaloids were isolated from two different GALANTHUS species of Turkish origin. (+)-Isotazettinol and (+)-3- O-demethylmacronine are obtained from G. GRACILIS, while (+)-3- O-demethyl-3-epimacronine is found in G. PLICATUS subsp. BYZANTINUS. The known base, trispheridine, is reported for the first time in GALANTHUS genus.

  5. 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

  6. 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 ...

  7. 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, ...

  8. Transformation of (sup14)C-Lignin-Labeled Cell Walls of Wheat by Syntrophococcus sucromutans, Eubacterium oxidoreducens, and Neocallimastix frontalis

    PubMed Central

    Bernard-Vailhe, M. A.; Besle, J. M.; Dore, J.

    1995-01-01

    Wheat cell walls, saponified or not, labeled with [U-(sup14)C]phenylalanine or [O-methyl-(sup14)C]sinapate were fermented by Neocallimastix frontalis or Syntrophococcus sucromutans plus Eubacterium oxidoreducens or a mixed culture. Phenolics were less solubilized but more transformed by bacteria than by the fungus, and mineralization was slight. S. sucromutans O-demethylated [O-methyl-(sup14)C]syringyl lignins, yielding labeled acetate. PMID:16534916

  9. Abuse of nutmeg (Myristica fragrans Houtt.): studies on the metabolism and the toxicologic detection of its ingredients elemicin, myristicin, and safrole in rat and human urine using gas chromatography/mass spectrometry.

    PubMed

    Beyer, Jochen; Ehlers, Dorothea; Maurer, Hans H

    2006-08-01

    Seeds of nutmeg are used as spice, but they are also abused because of psychotropic effects described after ingestion of large doses. It was postulated that these effects could be attributable to metabolic formation of amphetamine derivatives from the main nutmeg ingredients elemicin (EL), myristicin (MY), and safrole (SA). In a case of a suspected nutmeg abuse, neither such amphetamine derivatives nor the main nutmeg ingredients could be detected in urine. The metabolites of EL, MY, and SA were identified using gas chromatography-mass spectrometry in rat urine and their presence in human urine of the nutmeg abuser was confirmed. The identified metabolites indicated that EL, MY, and SA were once and twice hydroxylated at the side chain. In addition, EL was O-demethylated at 2 positions followed by side chain hydroxylation. MY and SA were demethylenated and subsequently methylated. In the human urine sample, the following metabolites could be identified: O-demethyl elemicin, O-demethyl dihydroxy elemicin, demethylenyl myristicin, dihydroxy myristicin, and demethylenyl safrole. As in the human urine sample, neither amphetamine derivatives nor the main nutmeg ingredients could be detected in the rat urine samples. Finally, toxicologic detection of nutmeg abuse was possible by identification of the described metabolites of the EL, MY, and SA in urine applying the authors' systematic toxicologic analysis procedure using full-scan gas chromatography-mass spectrometry after acid hydrolysis, liquid-liquid extraction of analytes, and microwave-assisted acetylation of extracted analytes.

  10. 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.

  11. 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

  12. Interactions between CYP2C9 and CYP2C19 in reconstituted binary systems influence their catalytic activity: possible rationale for the inability of CYP2C19 to catalyze methoxychlor demethylation in human liver microsomes.

    PubMed

    Hazai, Eszter; Kupfer, David

    2005-01-01

    Previous studies in our laboratory showed that among cDNA-expressed human cytochrome P450 (P450) supersomes, CYP2C19 was the most active in methoxychlor-O-demethylation. However, based on the lack of inhibition of methoxychlor-O-demethylation by monoclonal anti-CYP2C19 antibodies in human liver microsomes (HLM), CYP2C19 did not seem to catalyze that reaction in HLM. By contrast, CYP2C9, much less active than CYP2C19 in supersomes, was the most active in HLM. The current study examines whether the lack of methoxychlor-O-demethylation by CYP2C19 in HLM was due to CYP2C19 exhibiting inferior competition for the NADPH-cytochrome P450 reductase (CPR) versus CYP2C9 and explores the interactions between CYP2C9 and CYP2C19 in a singular and binary complex of a reconstituted system. When reconstituted with CPR, cytochrome b(5), and lipid, purified CYP2C19 and CYP2C9 catalyzed methoxychlor-O-demethylation. However, whereas equimolar CPR to CYP2C9 supported maximal rates of methoxychlor demethylation and diclofenac hydroxylation, the rate of methoxychlor demethylation by CYP2C19 was not fully saturated, even with a 9-fold molar excess of CPR over CYP2C19. This behavior of CYP2C19 was also observed with S-mephenytoin as the substrate. When a binary reconstitution system was prepared by mixing CYP2C9 and CYP2C19 enzymes, methoxychlor-O-demethylation and S-mephenytoin hydroxylation by CYP2C19 were dramatically inhibited. Inhibition depended on the amount of CPR and substrate used. By contrast, in the incubation containing CYP2C9, diclofenac hydroxylation was activated by the presence of CYP2C19. These results show that interactions among P450 enzymes can modulate their catalytic rates, which depend on the substrate undergoing metabolism.

  13. CYP2C subfamily, primarily CYP2C9, catalyses the enantioselective demethylation of the endocrine disruptor pesticide methoxychlor in human liver microsomes: use of inhibitory monoclonal antibodies in P450 identification.

    PubMed

    Hu, Y; Krausz, K; Gelboin, H V; Kupfer, D

    2004-02-01

    1. The endocrine disruptor pesticide methoxychlor undergoes O-demethylation by mammalian liver microsomes forming chiral mono-phenolic (1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane, i.e. mono-OH-M) and achiral bis-phenolic oestrogenic metabolites. Human liver microsomes (HLM) generated primarily the S-mono-OH-M. 2. Inhibitory monoclonal antibodies (MAb) identified those P450s catalysing the enantioselective O-demethylation of methoxychlor. In HLM, O-demethylation was inhibited by MAb anti-2C9 (30-40%), diminishing the per cent of S-mono-OH-M from about 80 to 55-60%. MAb anti-CYP1A2, 2A6, 2B6, 2C8, 2C19, 2D6 and 3A4 did not affect the demethylation rate in HLM. Nevertheless, MAb anti-CYP1A2 decreased the formation of R-mono-OH-M from 21-23 to 10-17%, indicating that CYP1A2 exhibits a role in generating the R-enantiomer. 3. Among cDNA-expressed human P450s (supersomes), CYP2C19 was the most active in demethylation, but in HLM, CYP2C19 appeared inactive (no inhibition by MAb anti-CYP2C19). There was a substantial difference in the per cent inhibition of demethylation by MAb anti-CYP2C9 and anti-rat CYP2C (MAb inhibiting all human CYP2C forms) and in altering the enantioselectivity, suggesting that demethylation by combined CYP2C8, 2C18 and 2C19 was significant (20-30%). 4. Polymorphism of methoxychlor demethylation was examined with supersomes and HLM-expressing CYP2C9 allelic variants. CYP2C9*1 and 2C9*2 were highly active; however, CYP2C9*3 appeared inactive.

  14. In vitro immunosuppressive activity of tacrolimus dihydrodiol precursors obtained by chemical oxidation and identification of a new metabolite of SDZ-RAD by electrospray and electrospray-linked scan mass spectrometry.

    PubMed

    Lhoëst, G; Hertsens, R; Verbeeck, R K; Maton, N; Wallemacq, P; Dehoux, J P; Latinne, D

    2001-08-01

    Different tacrolimus epoxides and dihydrodiol epoxides arising from the chemical oxidation of the parent drug are described. Open-chain tautomeric forms involving the lactone function were identified for the tacrolimus epoxides. Moreover, the identification by electrospray and electrospray linked scan mass spectrometry of an SDZ-RAD C16-C27 O-demethyl 17, 18-19, 20-21, 22 tris-epoxide new metabolite isolated from pig liver microsomes is reported. The in vitro immunosuppressive activity, using mixed lymphocyte reactions of the two macrolide reported oxidation compounds are discussed. PMID:11523088

  15. (-)-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.

  16. (-)-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

  17. 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.

  18. Inhibitory effects of beryllium chloride on rat liver microsomal enzymes.

    PubMed

    Teixeira, C F; Yasaka, W J; Silva, L F; Oshiro, T T; Oga, S

    1990-04-30

    A single i.v. dose (0.1 mmol Be2+/kg) of beryllium chloride prolonged the duration of pentobarbital-induced sleep and zoxazolamine-induced paralysis, in rats. The effects are correlated with changes of the pharmacokinetic parameters and with the in vitro inhibition of both aliphatic and aromatic hydroxylation of pentobarbital and zoxazolamine. In vitro N-demethylation of meperidine and aminopyrine was partially inhibited while O-demethylation of quinidine was unaffected by liver microsomes of rats pretreated with beryllium salt. The findings give clues that beryllium chloride inhibits some forms of cytochrome P-450, especially those responsible for hydroxylation of substrates, like pentobarbital and zoxazolamine.

  19. 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

  20. 75 FR 23782 - Drug Safety and Risk Management Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... HUMAN SERVICES Food and Drug Administration Drug Safety and Risk Management Advisory Committee; Notice... be open to the public. Name of Committee: Drug Safety and Risk Management Advisory Committee. General... risks of dextromethorphan use as a cough suppressant in prescription and nonprescription drug...

  1. 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

  2. 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

  3. Physiologically Based Pharmacokinetic Predictions of Tramadol Exposure Throughout Pediatric Life: an Analysis of the Different Clearance Contributors with Emphasis on CYP2D6 Maturation.

    PubMed

    T'jollyn, Huybrecht; Snoeys, Jan; Vermeulen, An; Michelet, Robin; Cuyckens, Filip; Mannens, Geert; Van Peer, Achiel; Annaert, Pieter; Allegaert, Karel; Van Bocxlaer, Jan; Boussery, Koen

    2015-11-01

    This paper focuses on the retrospective evaluation of physiologically based pharmacokinetic (PBPK) techniques used to mechanistically predict clearance throughout pediatric life. An intravenous tramadol retrograde PBPK model was set up in Simcyp® using adult clearance values, qualified for CYP2D6, CYP3A4, CYP2B6, and renal contributions. Subsequently, the model was evaluated for mechanistic prediction of total, CYP2D6-related, and renal clearance predictions in very early life. In two in vitro pediatric human liver microsomal (HLM) batches (1 and 3 months), O-desmethyltramadol and N-desmethyltramadol formation rates were compared with CYP2D6 and CYP3A4 activity, respectively. O-desmethyltramadol formation was mediated only by CYP2D6, while N-desmethyltramadol was mediated in part by CYP3A4. Additionally, the clearance maturation of the PBPK model predictions was compared to two in vivo maturation models (Hill and exponential) based on plasma concentration data, and to clearance estimations from a WinNonlin® fit of plasma concentration and urinary excretion data. Maturation of renal and CYP2D6 clearance is captured well in the PBPK model predictions, but total tramadol clearance is underpredicted. The most pronounced underprediction of total and CYP2D6-mediated clearance was observed in the age range of 2-13 years. In conclusion, the PBPK technique showed to be a powerful mechanistic tool capable of predicting maturation of CYP2D6 and renal tramadol clearance in early infancy, although some underprediction occurs between 2 and 13 years for total and CYP2D6-mediated tramadol clearance. PMID:26209290

  4. In Vivo Information-Guided Prediction Approach for Assessing the Risks of Drug-Drug Interactions Associated with Circulating Inhibitory Metabolites

    PubMed Central

    Parker, Robert B.; Laizure, S. Casey

    2012-01-01

    The in vivo drug-drug interaction (DDI) risks associated with cytochrome P450 inhibitors that have circulating inhibitory metabolites cannot be accurately predicted by conventional in vitro-based methods. A novel approach, in vivo information-guided prediction (IVIP), was recently introduced for CYP3A- and CYP2D6-mediated DDIs. This technique should be applicable to the prediction of DDIs involving other important cytochrome P450 metabolic pathways. Therefore, the aims of this study were to extend the IVIP approach to CYP2C9-mediated DDIs and evaluate the IVIP approach for predicting DDIs associated with inhibitory metabolites. The analysis was based on data from reported DDIs in the literature. The IVIP approach was modified and extended to CYP2C9-mediated DDIs. Thereafter, the IVIP approach was evaluated for predicting the DDI risks of various inhibitors with inhibitory metabolites. Although the data on CYP2C9-mediated DDIs were limited compared with those for CYP3A- and CYP2D6-mediated DDIs, the modified IVIP approach successfully predicted CYP2C9-mediated DDIs. For the external validation set, the prediction accuracy for area under the plasma concentration-time curve (AUC) ratios ranged from 70 to 125%. The accuracy (75–128%) of the IVIP approach in predicting DDI risks of inhibitors with circulating inhibitory metabolites was more accurate than in vitro-based methods (28–805%). The IVIP model accommodates important confounding factors in the prediction of DDIs, which are difficult to handle using in vitro-based methods. In conclusion, the IVIP approach could be used to predict CYP2C9-mediated DDIs and is easily modified to incorporate the additive effect of circulating inhibitory metabolites. PMID:22563046

  5. 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

  6. 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

  7. Metabolism of one-carbon compounds by the ruminal acetogan syntrophococcus sucromutans

    SciTech Connect

    Dore, J.; Bryant, M.P. )

    1990-04-01

    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 (Woods) 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-{sup 14}C) pyruvate, and chemically synthesized O-(methyl-{sup 14}C) vanillate were used to further investigate the catabolism of one-carbon (C{sub 1}) 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 CO{sub 2} was detected, but labeled formate predominantly labeled the methyl group of acetate. Labeled CO{sub 2} readily exchanged with the carboxyl group of pyruvate but not with formate, and both labeled CO{sub 2} and pyruvate predominantly labeled the carboxyl group acetate. No CO{sub 2} 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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

  13. Characterization of the active site properties of CYP4F12.

    PubMed

    Eksterowicz, John; Rock, Dan A; Rock, Brooke M; Wienkers, Larry C; Foti, Robert S

    2014-10-01

    Cytochrome P450 4F12 is a drug-metabolizing enzyme that is primarily expressed in the liver, kidney, colon, small intestine, and heart. The properties of CYP4F12 that may impart an increased catalytic selectivity (decreased promiscuity) were explored through in vitro metabolite elucidation, kinetic isotope effect experiments, and computational modeling of the CYP4F12 active site. By using astemizole as a probe substrate for CYP4F12 and CYP3A4, it was observed that although CYP4F12 favored astemizole O-demethylation as the primary route of metabolism, CYP3A4 was capable of metabolizing astemizole at multiple sites on the molecule. Deuteration of astemizole at the site of O-demethylation resulted in an isotope effect of 7.1 as well as an 8.3-fold decrease in the rate of clearance for astemizole by CYP4F12. Conversely, although an isotope effect of 3.8 was observed for the formation of the O-desmethyl metabolite when deuterated astemizole was metabolized by CYP3A4, there was no decrease in the clearance of astemizole. Development of a homology model of CYP4F12 based on the crystal structure of cytochrome P450 BM3 predicted an active site volume for CYP4F12 that was approximately 76% of the active site volume of CYP3A4. As predicted, multiple favorable binding orientations were available for astemizole docked into the active site of CYP3A4, but only a single binding orientation with the site of O-demethylation oriented toward the heme was identified for CYP4F12. Overall, it appears that although CYP4F12 may be capable of binding similar ligands to other cytochrome P450 enzymes such as CYP3A4, the ability to achieve catalytically favorable orientations may be inherently more difficult because of the increased steric constraints of the CYP4F12 active site. PMID:25074871

  14. 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

  15. A role of Bradyrhizobium elkanii and closely related strains in the degradation of methoxychlor in soil and surface water environments.

    PubMed

    Satsuma, Koji; Masuda, Minoru; Sato, Kiyoshi

    2013-01-01

    We have reported that a leguminous bacterial strain, Bradyrhizobium sp. strain 17-4, isolated from river sediment, phylogenetically very close to Bradyrhizobium elkanii, degraded methoxychlor through O-demethylation and oxidative dechlorination. In the present investigation, we found that B. elkanii (USDA94), a standard species deposited in the Culture Collection, degraded methoxychlor. Furthermore, Bradyrhizobium sp. strain 4-1, also very close to B. elkanii, isolated from Japanese paddy field soil, degraded methoxychlor. These B. elkanii and closely related strains degraded methoxychlor through almost identical metabolic pathways, and cleaved the phenyl ring and mineralized. In contrast, another representative Bradyrhizobium species, B. japonicum (USDA110), did not degrade methoxychlor at all. Based on these findings, B. elkanii and closely related strains are likely to play an important role not only in providing the readily biodegradable substrates but also in completely degrading (mineralizing) methoxychlor by themselves in the soil and surface water environment.

  16. 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.

  17. 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.

  18. Mescaline-induced changes of brain-cortex ribosomes. Mescaline demethylase activity of brain-cortex soluble supernatant.

    PubMed

    Datta, R K; Ghosh, J J

    1977-02-01

    Brain-cortex slices demethylate mescaline and p-methoxyacetanilide, a reference O-demethylating substrate, though the rate of demethylation of mescaline is about one third that of the reference substrate. The demethylase activity is localized mostly in the soluble supernatant (105 000 x g). It is purified 47-fold with respect to the demethylation of mescaline by ammonium sulfate precipitation and DEAE cellulose chromatography. The partially purified demethylase, which is stable for 3-5 days at -5 degrees C in the presence of dithiothreitol and glutathione and is inhibited by p-chloromercuribenzoate, has maximal activity at pH between 7.2 and 8.0. It demethylates mescaline into 3,4-dimethoxy-5-hydroxyphenethylamine and 3,5-dimethoxy-4-hydroxyphenethylamine and some unidentified derivatives.

  19. 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

  20. 4-Nitrocatechol production from rho-nitrophenol by rat liver.

    PubMed

    Chrastil, J; Wilson, J T

    1975-05-01

    Time course studies of rho-nitroanisole O-demethylation revealed formaldehyde production in excess of rho-nitrophenol (PNP) and 4-nitrocatechol (NTC) formation by rat liver microsomes. This indicated that these products (PNP, NTC) were metabolised further. The hydroxylation reaction PNP yields NTC showed substrate and product inhibition and a requirement for reduced nicotinamide adenine dinucleotide phosphate and O2 and was localized in liver microsomes. It was strongly activated by ascorbic acid, cysteine, adenosine triphosphate or hydroxylamine in vitro and enhanced by phenobarbital treatment in vivo. Mercapturic derivatives were metabolized to the corresponding hydroxy compounds with the same speed as their parent compounds. Both PNP and NTC were metabolized to the corresponding glucuronide and sulfate conjugates. On the other hand, the PNP or NTC glucuronides and sulfates were metabolized with liver microsomes to PNP and NTC.

  1. 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

  2. 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).

  3. 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.

  4. Methane production from coal by a single methanogen

    NASA Astrophysics Data System (ADS)

    Mayumi, Daisuke; Mochimaru, Hanako; Tamaki, Hideyuki; Yamamoto, Kyosuke; Yoshioka, Hideyoshi; Suzuki, Yuichiro; Kamagata, Yoichi; Sakata, Susumu

    2016-10-01

    Coal-bed methane is one of the largest unconventional natural gas resources. Although microbial activity may greatly contribute to coal-bed methane formation, it is unclear whether the complex aromatic organic compounds present in coal can be used for methanogenesis. We show that deep subsurface–derived Methermicoccus methanogens can produce methane from more than 30 types of methoxylated aromatic compounds (MACs) as well as from coals containing MACs. In contrast to known methanogenesis pathways involving one- and two-carbon compounds, this “methoxydotrophic” mode of methanogenesis couples O-demethylation, CO2 reduction, and possibly acetyl–coenzyme A metabolism. Because MACs derived from lignin may occur widely in subsurface sediments, methoxydotrophic methanogenesis would play an important role in the formation of natural gas not limited to coal-bed methane and in the global carbon cycle.

  5. 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

  6. 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

  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.

  8. Low resolution and high resolution MS for studies on the metabolism and toxicological detection of the new psychoactive substance methoxypiperamide (MeOP).

    PubMed

    Meyer, Markus R; Holderbaum, Anna; Kavanagh, Pierce; Maurer, Hans H

    2015-10-01

    In 2013, the new psychoactive substance methoxypiperamide (MeOP) was first reported to the European Monitoring Centre for Drug and Drug Addiction. Its structural similarity to already controlled piperazine designer drugs might have contributed to the decision to offer MeOP for online purchase. The aims of this work were to identify the phase I/II metabolites of MeOP in rat urine and the human cytochrome P450 (CYP) isoenzymes responsible for the initial metabolic steps. Finally, the detectability of MeOP in rat urine by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled with multistage mass spectrometry (LC-MS(n)) standard urine screening approaches (SUSAs) was evaluated. After sample preparation by cleavage of conjugates followed by extraction for elucidating phase I metabolites, the analytes were separated and identified by GC-MS as well as liquid chromatography-high resolution-tandem mass spectrometry (LC-HR-MS/MS). For detection of phase II metabolites, the analytes were separated and identified after urine precipitation followed by LC-HR-MS/MS. The following metabolic steps could be postulated: hydrolysis of the amide, N-oxide formation, N- and/or O-demethylation, oxidation of the piperazine ring to the corresponding keto-piperazine, piperazine ring opening followed by oxidation of a methylene group to the corresponding imide, and hydroxylation of the phenyl group. Furthermore, N-acetylation, glucuronidation and sulfation were observed. Using human CYPs, CYP1A2, CYP2C19, CYP2D6, and/or CYP3A4 were found to catalyze N-oxide formation and N-, O-demethylation and/or oxidation. Mostly MeOP and N-oxide-MeOP but to a minor degree also other metabolites could be detected in the GC-MS and LC-MS(n) SUSAs. PMID:26456786

  9. 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.

  10. FK506 maturation involves a cytochrome p450 protein-catalyzed four-electron C-9 oxidation in parallel with a C-31 O-methylation.

    PubMed

    Chen, Dandan; Zhang, Lihan; Pang, Bo; Chen, Jing; Xu, Zhinan; Abe, Ikuro; Liu, Wen

    2013-05-01

    FK506, structurally similar to FK520 and rapamycin, is an α-keto amide bonding-containing, macrolide natural product that exhibits potent immunosuppressive activity and moderate antifungal activity. FK506 biosynthesis requires a hybrid polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) system to construct the skeleton of the macrolide. The mechanism for tailoring this macrolide to furnish FK506 remains poorly understood. In this study, we report a maturation paradigm common for FK506, FK520, and rapamycin, by characterizing two conserved regiospecific, post-PKS-NRPS modifications in an FK506-producing Streptomyces tsukubaensis strain. A cytochrome P450 protein, FkbD, catalyzes a less common, four-electron oxidation at C-9 to give a rarely found α-keto amide group, whereas a methyltransferase, FkbM, is responsible for O-methylation at C-31 to afford a methoxy group. Both FkbD and FkbM are highly tolerant in their substrate choice; therefore, the order of FkbD- and FkbM-catalyzed reactions is interchangeable in the FK506 biosynthetic pathway. Inactivation of fkbD produced a new intermediate, 9-deoxo-FK506, which displayed antifungal activity lower than that of FK506. Taking previously reported bioassay results regarding the intermediates 9-deoxo-31-O-demethyl-FK506 and 31-O-demethyl-FK506 into account, it is clear that the modifications catalyzed by FkbD and FkbM are of importance to reach the full biological activity of FK506 by forming a key structure motif that is necessary for interaction of the molecule with the receptor and, subsequently, the downstream intracellular responses. PMID:23435975

  11. 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

  12. 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.

  13. Identifying a selective substrate and inhibitor pair for the evaluation of CYP2J2 activity.

    PubMed

    Lee, Caroline A; Jones, J P; Katayama, Jonathan; Kaspera, Rüdiger; Jiang, Ying; Freiwald, Sascha; Smith, Evan; Walker, Gregory S; Totah, Rheem A

    2012-05-01

    CYP2J2, an arachidonic acid epoxygenase, is recognized for its role in the first-pass metabolism of astemizole and ebastine. To fully assess the role of CYP2J2 in drug metabolism, a selective substrate and potent specific chemical inhibitor are essential. In this study, we report amiodarone 4-hydoxylation as a specific CYP2J2-catalyzed reaction with no CYP3A4, or other drug-metabolizing enzyme, involvement. Amiodarone 4-hydroxylation enabled the determination of liver relative activity factor and intersystem extrapolation factor for CYP2J2. Amiodarone 4-hydroxylation correlated with astemizole O-demethylation but not with CYP2J2 protein content in a sample of human liver microsomes. To identify a specific CYP2J2 inhibitor, 138 drugs were screened using terfenadine and astemizole as probe substrates with recombinant CYP2J2. Forty-two drugs inhibited CYP2J2 activity by ≥50% at 30 μM, but inhibition was substrate-dependent. Of these, danazol was a potent inhibitor of both hydroxylation of terfenadine (IC(50) = 77 nM) and O-demethylation of astemizole (K(i) = 20 nM), and inhibition was mostly competitive. Danazol inhibited CYP2C9, CYP2C8, and CYP2D6 with IC(50) values of 1.44, 1.95, and 2.74 μM, respectively. Amiodarone or astemizole were included in a seven-probe cocktail for cytochrome P450 (P450) drug-interaction screening potential, and astemizole demonstrated a better profile because it did not appreciably interact with other P450 probes. Thus, danazol, amiodarone, and astemizole will facilitate the ability to determine the metabolic role of CYP2J2 in hepatic and extrahepatic tissues. PMID:22328583

  14. 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

  15. Effect of penicillin-based antibiotics, amoxicillin, ampicillin, and piperacillin, on drug-metabolizing activities of human hepatic cytochromes P450.

    PubMed

    Niwa, Toshiro; Morimoto, Mari; Hirai, Takako; Hata, Tomomi; Hayashi, Misato; Imagawa, Yurie

    2016-02-01

    The effects of three kinds of penicillin-based antibiotics, amoxicillin, ampicillin, and piperacillin, on drug-metabolizing activity of human hepatic cytochrome P450 (P450 or CYP) were investigated. Metabolic activities of P450s expressed in recombinant Escherichia coli at substrate concentrations around the Michaelis constant were compared in the presence or absence of the antibiotics. Amoxicillin, ampicillin, and piperacillin at 0.5 or 1 mM concentrations neither inhibited nor stimulated CYP2C9-mediated tolbutamide methylhydroxylation, CYP2D6-mediated dopamine formation from p-tyramine, or CYP3A4- or CYP3A5-mediated testosterone 6β-hydroxylation. However, amoxicillin and piperacillin inhibited CYP2C8-mediated aminopyrine N-demethylation at 50% inhibitory concentration of 0.83 and 1.14 mM, respectively. These results suggest that piperacillin might inhibit CYP2C8 clinically, although the interactions between these three penicillin-based antibiotics and other drugs that are metabolized by P450s investigated would not be clinically significant.

  16. Effect of cefixime and cefdinir, oral cephalosporins, on cytochrome P450 activities in human hepatic microsomes.

    PubMed

    Niwa, Toshiro; Shiraga, Toshifumi; Hashimoto, Tomoko; Kagayama, Akira

    2004-01-01

    The effects of two kinds of oral cephalosporins, cefixime and cefdinir, on cytochrome P450 (CYP) activities in human hepatic microsomes were investigated. Both cefixime and cefdinir at 2 mM concentration neither inhibited nor stimulated CYP1A1/2-mediated 7-ethoxyresorufin O-deethylation, CYP2A6-mediated coumarin 7-hydroxylation, CYP2B6-mediated 7-benzyloxyresorufin O-debenzylation, CYP2C8/9-mediated tolbutamide methylhydroxylation, CYP2C19-mediated S-mephenytoin 4'-hydroxylation, CYP2D6-mediated bufuralol 1'-hydroxylation, CYP2E1-mediated chlorzoxazone 6-hydroxylation, CYP3A4-mediated nifedipine oxidation, or CYP3A4-mediated testosterone 6beta-hydroxylation. The free fractions of cefixime and cefdinir in the incubation mixture, which were measured by ultracentrifugation, were 86.1-93.8% and 94.1-97.8%, respectively. These results suggest that both cefixime and cefdinir would not cause clinically significant interactions with other drugs, which are metabolized by CYPs, via the inhibition of metabolism.

  17. Activity levels of tamoxifen metabolites at the estrogen receptor and the impact of genetic polymorphisms of phase I and II enzymes on their concentration levels in plasma.

    PubMed

    Mürdter, T E; Schroth, W; Bacchus-Gerybadze, L; Winter, S; Heinkele, G; Simon, W; Fasching, P A; Fehm, T; Eichelbaum, M; Schwab, M; Brauch, H

    2011-05-01

    The therapeutic effect of tamoxifen depends on active metabolites, e.g., cytochrome P450 2D6 (CYP2D6) mediated formation of endoxifen. To test for additional relationships, 236 breast cancer patients were genotyped for CYP2D6, CYP2C9, CYP2B6, CYP2C19, CYP3A5, UGT1A4, UGT2B7, and UGT2B15; also, plasma concentrations of tamoxifen and 22 of its metabolites, including the (E)-, (Z)-, 3-, and 4'-hydroxymetabolites as well as their glucuronides, were quantified using liquid chromatography-tandem mass spectrometry (MS). The activity levels of the metabolites were measured using an estrogen response element reporter assay; the strongest estrogen receptor inhibition was found for (Z)-endoxifen and (Z)-4-hydroxytamoxifen (inhibitory concentration 50 (IC50) 3 and 7 nmol/l, respectively). CYP2D6 genotypes explained 39 and 9% of the variability of steady-state concentrations of (Z)-endoxifen and (Z)-4-hydroxytamoxifen, respectively. Among the poor metabolizers, 93% had (Z)-endoxifen levels below IC90 values, underscoring the role of CYP2D6 deficiency in compromised tamoxifen bioactivation. For other enzymes tested, carriers of reduced-function CYP2C9 (*2, *3) alleles had lower plasma concentrations of active metabolites (P < 0.004), pointing to the role of additional pathways.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. Nanosilver particle effects on drug metabolism in vitro.

    PubMed

    Lamb, John G; Hathaway, Laura B; Munger, Mark A; Raucy, Judy L; Franklin, Michael R

    2010-12-01

    Nanosilver particles are present in consumer and health care products. Their effects on human microsomal cytochrome P450 (P450) activities and induction in luciferase reporter-engineered Caco-2 (MDR1.C) and HepG2 (DPX2 and 1A2DRE) cells have been investigated. The LD(50) values were ∼ 4 μg silver/ml for HepG2 and 5 μg/ml for Caco-2 cells. At silver concentrations that showed no decreased cell viability (<1 μg silver/ml), the pregnane X receptor (PXR)-driven 4.5-fold induction response of MDR1.C cells to 50 μM omeprazole was unaffected. In DPX2 cells, the PXR-driven 5.5- and 6.5-fold induction responses to omeprazole and 10 μM rifampicin were attenuated to 4- and 3.5-fold, respectively. Nanosilver particles alone showed no induction. In 1A2DRE cells, the aryl hydrocarbon receptor-driven 5.5-fold induction response to omeprazole was attenuated to 4-fold. In 1A2DRE cells, nanosilver alone elicited slight induction at 1 μg/ml. The inhibition of human P450-selective activities by nanosilver particles in vitro was proportional to the silver/microsomal protein ratio. At a fixed (0.5 mg/ml) protein concentration, P450-selective activities differed in sensitivity (IC(50) value). Coumarin 7-hydroxylation and 7-ethoxy-4-trifluoromethylcoumarin O-deethylation exhibited the highest IC(50) values (33.5 and 31.9 μM, respectively) and S-mephenytoin 4-hydroxylation exhibited the lowest (6.4 μM). Other IC(50) values were, in ascending order, 8.0 to 9.3 μM (testosterone 6β-hydroxylation, 7-benzyloxyquinoline debenzylation, and diclofenac 4-hydroxylation), 16.0 μM (chlorzoxazone 6-hydroxylation), 21.2 μM [7-methoxy-4-(aminomethyl)-coumarin O-demethylation], and 24.4 μM (7-methoxyresorufin O-demethylation). An investigation of 70 μM nanosilver particles showed that microsomal NADPH cytochrome c reductase activities were inhibited <12%. From our in vitro observations, we extrapolated that nanosilver particles reaching the liver may be a potential source of drug

  4. 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

  5. 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

  6. Inhibitory effects of kale ingestion on metabolism by cytochrome P450 enzymes in rats.

    PubMed

    Yamasaki, Izumi; Yamada, Masayoshi; Uotsu, Nobuo; Teramoto, Sachiyuki; Takayanagi, Risa; Yamada, Yasuhiko

    2012-01-01

    Kale (Brassica oleracea L. var acephala DC) is a leafy green vegetable belonging to the cabbage family (Brassicaceae) that contains a large amount of health-promoting phytochemicals. There are any reports about the effects of kale ingestion on the chemoprevention function and mechanism, but the interactions between kale and drugs have not been researched. We investigated the effects of kale intake on cytochrome P450 (CYP) metabolism by using cocktail probe drugs, including midazolam (for CYP3A4), caffeine (for CYP1A2), dextromethorphan (for CYP2D6), tolbutamide (for CYP2C9), omeprazole (for CYP2C19), and chlorzoxazone (for CYP2E1). Cocktail drugs were administered into rats treated with kale and cabbage (2000 mg/kg) for a week. The results showed that kale intake induced a significant increase in plasma levels and the AUC of midazolam, caffeine, and dextromethorphan. In addition, the plasma concentration and AUC of omeprazole tended to increase. Additionally, no almost differences in the mRNA expression levels of CYP enzymes in the liver were observed. In conclusion, kale ingestion was considered to have an inhibitory effect on the activities of CYP3A4, 1A2, 2D6, and 2C19 for a reason competitive inhibition than inhibitory changes in the mRNA expressions.

  7. 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

  8. Human plasma concentrations of cytochrome P450 probes extrapolated from pharmacokinetics in cynomolgus monkeys using physiologically based pharmacokinetic modeling.

    PubMed

    Shida, Satomi; Utoh, Masahiro; Murayama, Norie; Shimizu, Makiko; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-01-01

    1. Cynomolgus monkeys are widely used in preclinical studies as non-human primate species. Pharmacokinetics of human cytochrome P450 probes determined in cynomolgus monkeys after single oral or intravenous administrations were extrapolated to give human plasma concentrations. 2. Plasma concentrations of slowly eliminated caffeine and R-/S-warfarin and rapidly eliminated omeprazole and midazolam previously observed in cynomolgus monkeys were scaled to human oral biomonitoring equivalents using known species allometric scaling factors and in vitro metabolic clearance data with a simple physiologically based pharmacokinetic (PBPK) model. Results of the simplified human PBPK models were consistent with reported experimental PK data in humans or with values simulated by a fully constructed population-based simulator (Simcyp). 3. Oral administrations of metoprolol and dextromethorphan (human P450 2D probes) in monkeys reportedly yielded plasma concentrations similar to their quantitative detection limits. Consequently, ratios of in vitro hepatic intrinsic clearances of metoprolol and dextromethorphan determined in monkeys and humans were used with simplified PBPK models to extrapolate intravenous PK in monkeys to oral PK in humans. 4. These results suggest that cynomolgus monkeys, despite their rapid clearance of some human P450 substrates, could be a suitable model for humans, especially when used in conjunction with simple PBPK models.

  9. Effects of methadone on human cigarette smoking and subjective ratings.

    PubMed

    Chait, L D; Griffiths, R R

    1984-06-01

    In order to study possible interactions between opioids and cigarette smoking, we examined the effects of oral methadone administration on the smoking behavior of five male methadone-maintenance patients. Isolated subjects smoked their regular brand of cigarettes ad libitum in a naturalistic laboratory environment while reading or watching television. Ninety minutes before each daily 2-hr smoking session subjects received either placebo, dextromethorphan (a taste blind) or one of three doses of methadone, 0.5, 1.0 or 2.0 times their regular maintenance dose (40-60 mg). Each subject received each treatment five times, in a mixed order across days. Methadone pretreatment resulted in a dose-related increase in the number of cigarettes smoked per session (from a mean of 2.8 after placebo to 5.6 after the high dose of methadone). The total time spent puffing during the session increased from a mean of 27 sec after placebo to 74 sec after the high dose of methadone. CO levels in expired air (a measure of actual smoke inhalation) showed corresponding dose-related increases. Methadone administration also resulted in dose-related decreases in pupil diameter and increases in subjective ratings of smoking satisfaction and dose-strength. Dextromethorphan had no significant effects on any measure of smoking behavior or subjective response. The results demonstrate that methadone can produce substantial increases in cigarette smoking and may have implications regarding the proposed role of endogenous opioids in the smoking process.

  10. 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

  11. An assessment of drug-drug interactions: the effect of desvenlafaxine and duloxetine on the pharmacokinetics of the CYP2D6 probe desipramine in healthy subjects.

    PubMed

    Patroneva, Albena; Connolly, Sandra M; Fatato, Penny; Pedersen, Ron; Jiang, Qin; Paul, Jeffrey; Guico-Pabia, Christine; Isler, Jennifer A; Burczynski, Michael E; Nichols, Alice I

    2008-12-01

    A number of antidepressants inhibit the activity of the cytochrome P450 2D6 enzyme system, which can lead to drug-drug interactions. Based on its metabolic profile, desvenlafaxine, administered as desvenlafaxine succinate, a new serotonin-norepinephrine reuptake inhibitor, is not expected to have an impact on activity of CYP2D6. This single-center, randomized, open-label, four-period, crossover study was undertaken to evaluate the effect of multiple doses of desvenlafaxine (100 mg/day, twice the recommended therapeutic dose for major depressive disorder in the United States) and duloxetine (30 mg b.i.d.) on the pharmacokinetics (PK) of a single dose of desipramine (50 mg). A single dose of desipramine was given first to assess its PK. Desvenlafaxine or duloxetine was then administered, in a crossover design, so that steady-state levels were achieved; a single dose of desipramine was then coadministered. The geometric least-square mean ratios (coadministration versus desipramine alone) for area under the plasma concentration versus time curve (AUC) and peak plasma concentrations (C(max)) of desipramine and 2-hydroxydesipramine were compared using analysis of variance. Relative to desipramine alone, increases in AUC and C(max) of desipramine associated with duloxetine administration (122 and 63%, respectively) were significantly greater than those associated with desvenlafaxine (22 and 19%, respectively; P < 0.001). Duloxetine coadministered with desipramine was also associated with a decrease in 2-hydroxydesipramine C(max) that was significant compared with the small increase seen with desvenlafaxine and desipramine (-24 versus 9%; P < 0.001); the difference between changes in 2-hydroxydesipramine AUC did not reach statistical significance (P = 0.054). Overall, desvenlafaxine had a minimal impact on the PK of desipramine compared with duloxetine, suggesting a lower risk for CYP2D6-mediated drug interactions.

  12. 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.

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

    PubMed Central

    Pan, Xian; Lee, Yoon-Kwang

    2015-01-01

    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

  14. Liquid chromatography/tandem mass spectrometry method for simultaneous evaluation of activities of five cytochrome P450s using a five-drug cocktail and application to cytochrome P450 phenotyping studies in rats.

    PubMed

    Zhang, Shaoyu; Song, Naining; Li, Quansheng; Fan, Huirong; Liu, Changxiao

    2008-08-01

    A reliable liquid chromatography/tandem mass spectrometry has been developed for simultaneous evaluation of the activities of five cytochrome P450s (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A) in rat plasma and urine. The five-specific probe substrates/metabolites include phenacetin/paracetamol (CYP1A2), tolbutamide/4-hydroxytolbutamide and carboxytolbutamide (CYP2C9), mephenytoin/4'-hydroxymephenytoin (CYP2C19), dextromethorphan/dextrorphan (CYP2D6), and midazolam/1'-hydroxymidazolam (CYP3A). Internal standards were brodimoprim (for phenacetin, paracetamol, midazolam and 1'-hydroxymidazolam), ofloxacin (for 4'-hydroxymephenytoin, dextromethorphan and dextrorphan) and meloxicam (for tolbutamide, 4-hydroxytolbutamide and carboxytolbutamide). Sample preparation was conducted with solid-phase extraction using Oasis HLB cartridges. The chromatography was performed using a C(18) column with mobile phase consisting of methanol/0.1% formic acid in 20 mM ammonium formate (75:25). The triple-quadrupole mass spectrometric detection was operated in both positive mode (for phenacetin, paracetamol, midazolam, 1'-hydroxymidazolam, brodimoprim, 4'-hydroxymephenytoin, dextromethorphan, dextrorphan and ofloxacin) and negative mode (for tolbutamide, 4-hydroxytolbutamide, carboxytolbutamide and meloxicam). Multiple reaction monitoring mode was used for data acquisition. Calibration ranges in plasma were 2.5-2500 ng/mL for phenacetin, 2.5-2500 ng/mL for paracetamol, 5-500 ng/mL for midazolam, and 0.5-500 ng/mL for 1'-hydroxymidazolam. In urine calibration ranges were 5-1000 ng/mL for dextromethorphan, 0.05-10 microg/mL for dextrorphan and 4'-hydroxymephenytoin, 5-2000 ng/mL for tolbutamide, 0.05-20 microg/mL for 4-hydroxytolbutamide and 0.025-10 microg/mL for carboxytolbutamide. The intra- and inter-day precision were 4.3-12.4% and 1.5-14.8%, respectively for all of the above analytes. The intra- and inter-day accuracy ranged from -9.1 to 8.3% and -10 to 9.2%, respectively for all of

  15. 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

  16. 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

  17. 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

  18. The penetration of misonidazole into spontaneous canine tumours.

    PubMed Central

    White, R. A.; Workman, P.; Owen, L. N.; Bleehen, N. M.

    1979-01-01

    The hypoxic cell-radiosensitizing drug misonidazole (1-(2-nitroimidazol-1-yl)-3-methoxypropan -2 -ol, Ro 07-0582, MIS) was administered at a dose of 150 mg/kg i.v. to 6 dogs bearing spontaneous tumours, and the resulting tumour concentrations were measured to HPLC analysis. In 4 dogs it was possible to obtain serial biopsy specimens up to 5 h. With the exception of a brain tumour, the tumour concentrations ranged between 47% and 95% of the plasma concentration, most of the values falling within the range 50--70%. Concentrations in the brain tumour were markedly lower. Barbiturate anaesthesia was necessary for the removal of the serial biopsy specimens, and the effects of sodium pentobarbitone anaesthesia on the pharmacokinetics of MIS were investigated in 2 dogs. After barbiturate anaesthesia peak plasma concontrations were raised and the availability of MIS was increased, although the biological half-life remained unaltered. The metabolism of MIS to the O-demethylated metabolite, Ro 05-9963, was delayed initially. The concentrations of MIS AND Ro 05-9963 in cerebrospinal fluid were also recorded in these dogs; MIS concentrations were found to approach those of the plasma, whereas the metabolite concentrations were considerably lower (0--58% of the plasma concentration). PMID:289406

  19. In vitro metabolism of [14C]methoxychlor in rat, mouse, Japanese quail and rainbow trout in precision-cut liver slices.

    PubMed

    Ohyama, K; Maki, S; Sato, K; Kato, Y

    2004-08-01

    1. The in vitro metabolism of [14C]methoxychlor (MXC) has been studied using precision-cut liver slices from the Sprague-Dawley male rat, CD-1 male mouse, WE strain male Japanese quail and juvenile rainbow trout (Oncorhynchus mykiss). The results demonstrated integrated phase I and II metabolism of MXC and species differences in the metabolic profiles were observed. 2. In rat liver slice preparations, MXC was rapidly metabolized to bis-OH-MXC by sequential O-demethylation followed by subsequent O-glucuronidation forming bis-OH-MXC glucuronide. No mono-OH-MXC glucuronide was detected. The doubly conjugated metabolite, bis-OH-MXC 4-O-sulphate 4'-O-glucuronide, was also detected as a rat-specific metabolite. 3. Formation of mono-OH-MXC and its glucuronide was the main metabolic pathway in the mouse and Japanese quail. In contrast to the rat, only minor amounts of bis-OH-MXC glucuronide were detected. A reductively dehalogenated metabolite, dechlorinated mono-OH-MXC glucuronide, was observed only in mouse preparations. 4. In rainbow trout, comparative amounts of both mono- and bis-OH-MXC glucuronide were formed as the major metabolites. Unconjugated forms of these metabolites were detected only as minor products. 5. The different metabolic profiles of MXC observed in the four animal species are possibly due to substrate specificity of contributing CYP450 monooxgenase enzyme(s) in different animal species.

  20. An environmental fate study of methoxychlor using water-sediment model system.

    PubMed

    Masuda, Minoru; Satsuma, Koji; Sato, Kiyoshi

    2012-01-01

    Agricultural waste water containing pesticides can reach the sea via rivers and estuaries, including brackish lakes. We studied the metabolic fate of methoxychlor [MXC; 1,1,1-trichloro-2,2-bis(4-methoxyphenyl)ethane] in a model system consisting of sediment and associated water collected from two sampling sites: a brackish lake and a freshwater river. MXC degraded rapidly and was finally mineralized in both sediment systems. The first step of degradation was dechlorination to yield 1,1-dichloro-2,2-bis(4-methoxyphenyl)ethane [de-Cl-MXC] or CN-replacement to yield 2,2-bis(4-methoxyphenyl)acetonitrile [MXC-CN], followed by O-demethylation. Although the metabolites were common to the two sediments, the dynamics of the metabolites over time were clearly distinct. In the brackish lake sediment, de-Cl-MXC accumulated transiently, whereas in the river sediment, it was rapidly converted to its demethylated metabolite. We also found that dechlorination and CN-replacement proceeded in autoclave-sterilized river sediment. In the river sediment, the abiotic reaction mediated by abundant humic acid and low oxygen level also appeared to contribute to the overall MXC metabolism.

  1. Reductive dechlorination of methoxychlor and DDT by human intestinal bacterium Eubacterium limosum under anaerobic conditions.

    PubMed

    Yim, You-Jin; Seo, Jiyoung; Kang, Su-Il; Ahn, Joong-Hoon; Hur, Hor-Gil

    2008-04-01

    Methoxychlor [1,1,1-trichloro-2,2-bis(p-methoxyphenyl)ethane], a substitute for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), is a compound of environmental concern because of potential long-term health risks related to its endocrine-disrupting and carcinogenic potency. In order to determine the metabolic fate of methoxychlor and DDT in the human intestinal gut, Eubacterium limosum (ATCC 8486), a strict anaerobe isolated from the human intestine that is capable of O-demethylation toward O-methylated isoflavones, was used as a model intestinal microbial organism. Under anaerobic incubation conditions, E. limosum completely transformed methoxychlor and DDT in 16 days. Based on gas chromatography-mass chromatography analyses, the metabolites produced from methoxychlor and DDT by E. limosum were confirmed to be 1,1-dichloro-2,2-bis(p-methoxyphenyl)ethane (methoxydichlor) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), respectively. This study suggests that E. limosum in the human intestinal gut might be a participant in the reductive dechlorination of methoxychlor to the more antiandrogenic active methoxydichlor.

  2. Comparative in vitro metabolism of the suspected pro-oestrogenic compound, methoxychlor in precision-cut liver slices from male and female rats.

    PubMed

    Ohyama, K; Maki, S; Sato, K; Kato, Y

    2005-04-01

    The in vitro metabolism of [14C]methoxychlor (MXC), a suspected pro-oestrogenic compound, by male and female Fischer rats (F344) was compared in precision-cut liver slices. The results demonstrated time-dependent metabolism of MXC with integrated phase I and II reactions, and the sex differences were detected in the metabolic profiles. In liver slices from male rats, MXC was metabolized to bis-demethylated MXC (bis-OH-MXC) by sequential O-demethylation followed by subsequent O-glucuronidation. The doubly conjugated metabolite, bis-OH-MXC 4-O-sulphate 4'-O-glucuronide was additionally produced. In the case of the female rat, the glucuronides of both mono- and bis-OH-MXC were formed as the main metabolites, and the mono-OH-MXC glucuronide appeared to be specific to the female rat. The ratios of bis-/mono-demethylated metabolite, which include the amounts of corresponding conjugates, were approximately 95/5 for the male rats and 40/60 for the female. These results imply that demethylation to the intermediate metabolite, (S)-mono-OH-MXC, is a key step for the sex-dependent metabolism of MXC in the rats. The phase I metabolites produced were extensively conjugated with D-glucuronic acid in both male and female rats.

  3. Update on hydrocodone metabolites in rats and dogs aided with a semi-automatic software for metabolite identification Mass-MetaSite.

    PubMed

    Li, Austin C; Chovan, James P; Yu, Erya; Zamora, Ismael

    2013-04-01

    1. There has been a lack of in vivo metabolite profiling update of hydrocodone since the original report on species differences was published in 1978. As such, the mechanism for its analgesic activity in different species has been ambiguous. To address safety concern from regulatory agencies, hydrocodone metabolite profiles in rats and dogs are updated herein aided by a newly developed software, Mass-MetaSite. 2. Samples collected from rats and dogs dosed orally with hydrocodone were analyzed with reversed phase liquid chromatography coupled with LTQ-Orbitrap. The exact mass measurement data collected with data-dependent acquisition methodology were analyzed both traditionally, using Xcalibur Qual Browser and MetWorks, and by Mass-MetaSite. 3. Profiling of hydrocodone metabolites in rat and dog plasma reflected previously reported species differences in circulating metabolites. While hydrocodone mainly underwent O-demethylation and ketone reduction in rats forming hydromorphone and reduced hydromorphone, which were then subsequently cleared via glucuronide conjugation, hydrocodone in dogs was cleared predominantly by N-demethylation and N-oxidation. 4. Given the success ratio of metabolite detection offered by Mass-MetaSite, the software will be able to aid chemists in early identification of drug metabolites from complex biomatrices.

  4. 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

  5. The effects of flubendazole and mebendazole on cytochromes P4501A in pheasant hepatocytes.

    PubMed

    Savlík, M; Polásková, P; Szotáková, B; Lamka, J; Skálová, L

    2005-10-01

    Many benzimidazoles are known inducers of cytochromes P4501A (CYP1A) in laboratory animals and cell lines. As flubendazole and mebendazole are benzimidazole anthelmintics often used in a pheasant, in the present study an effect of these drugs in primary cultures of pheasant (Phasianus colchicus) hepatocytes was investigated. After 48 h incubation of the hepatocytes with the benzimidazoles (0.2-5 microM), CYP1A activities -- ethoxyresorufin O-deethylation (EROD) and methoxyresorufin O-demethylation (MROD) activities were measured and the CYP1A protein levels were determined by Western blotting. None of the tested benzimidazoles influenced the CYP1A protein content. No pharmacologically significant enhancement of CYP1A after exposure of the hepatocytes to flubendazole and mebendazole was found. Inhibition of the EROD/MROD activities caused by both tested substances was observed only at the highest concentration (5 microM). From a point of view of CYP1A induction or inhibition, the treatment of pheasants by both anthelmintics tested seems to be safe. Our study demonstrates the inter-species differences in CYP1A inducibility and the importance of induction/inhibition studies on target animals.

  6. Structural Transformation of 8-5-Coupled Dehydrodiferulates by Human Intestinal Microbiota.

    PubMed

    Schendel, Rachel R; Karrer, Cecile; Bunzel, Diana; Huch, Melanie; Hildebrand, Andreas A; Kulling, Sabine E; Bunzel, Mirko

    2015-09-16

    Ingested dehydrodiferulates (DFAs) are partially released from cereal dietary fiber by human colonic microbiota, but little research has explored the further microbial metabolism of 8-5-coupled DFAs. This study investigated the in vitro microbial metabolism and elucidated major metabolites of free 8-5-DFAs (benzofuran and open forms) and an esterified analogue, 8-5-DFA diethyl ester (benzofuran). Synthesized standard compounds were incubated with fresh human fecal suspensions. Metabolites were isolated and structurally elucidated using high-resolution-LC-time-of-flight-(ToF)-MS, GC-MS, and NMR. Nine metabolite structures were unambiguously characterized with NMR, and four additional metabolites were tentatively identified to reveal structural conversion motifs: propenyl side chain hydrogenation (all substrates), O-demethylation and reductive ring-opening (8-5-DFA diethyl ester and free 8-5-DFA [benzofuran]), and de-esterification (8-5-DFA diethyl ester). A pathway of microbial 8-5-DFA metabolism was proposed based on metabolite formation kinetics. Importantly, de-esterification of the 8-5-DFA diethyl ester occurred primarily after and/or concurrently with other metabolism steps. Cleavage to monomers was not observed. PMID:26287944

  7. Is maternal opioid use hazardous to breast-fed infants?

    PubMed

    Hendrickson, Robert G; McKeown, Nathanael J

    2012-01-01

    Over the last few decades, the rate of breastfeeding has increased steadily in the developed countries of the world. During this time, opioid use in the general population has steadily increased as well. Despite this, clinicians remain unclear whether opioid use is safe during breastfeeding. While the vast majority of medications used during breastfeeding occur without incident, case reports and studies have reported possible opioid toxicity in breast-fed infants. Multiple enzymes are involved in the metabolism of opioids. CYP2D6 catabolizes O-demethylation of codeine, tramadol, oxycodone, and hydrocodone to more potent metabolites. CYP3A4 inactivates methadone, meperidine, and buprenorphine. Glucoronide conjugation by the UGT enzyme family inactivates morphine and hydromorphone. Genetic polymorphisms and interfering medications affect the maternal metabolism, which in turn determines the exposure and risk to the breast-fed neonate. We review the production of breast milk, the transfer of xenobiotics from blood to milk, the characteristics that alter xenobiotic breast-milk concentrations, and we review the evidence of specific common opioids and infant toxicity. The short-term maternal use of prescription opioids is usually safe and infrequently presents a hazard to the newborn.

  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.

  9. 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

  10. Peroxidase-catalyzed metabolism of etoposide (VP-16-213) and covalent binding of reactive intermediates to cellular macromolecules

    SciTech Connect

    Haim, N.; Nemec, J.; Roman, J.; Sinha, B.K.

    1987-11-15

    The horseradish peroxidase- and prostaglandin synthetase-catalyzed oxidative metabolism of the highly active anticancer drug, etoposide (VP-16-213), has been studied in vitro. This oxidation of VP-16 resulted in the formation of VP-16 quinone, an aromatic VP-16 derivative and the corresponding aromatic VP-16 quinone. This oxidative metabolism of VP-16 also resulted in the formation of reactive species that covalently bound to exogenously added DNA and heat-inactivated microsomal proteins. The peroxidase-catalyzed binding was time dependent and required the presence of cofactors (hydrogen peroxide or arachidonic acid). The prostaglandin synthetase/arachidonic acid-catalyzed metabolism and binding of VP-16 were inhibited by indomethacin, an inhibitor of the cyclooxygenase, and were shown to involve the peroxidative arm of prostaglandin synthetase. Our studies show that the protein covalent binding species were formed as a result of O-demethylation of the drug as shown by the loss of specifically labeled (O-/sup 14/CH/sub 3/) radioactivity from O-methoxy group and by incubating proteins with VP-16 quinones. In contrast, the covalent binding intermediates for DNA appeared to be different and VP-16-derived quinone methides are suggested as DNA binding species. Co-oxidation of VP-16 and the related drug, VM-26, during prostaglandin biosynthesis may be an important pathway for the metabolism of these agents and may play a role in their cytotoxic properties.

  11. 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.

  12. 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

  13. 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

  14. UPLC-ESI-Q-TOF-MS(E) identification of urinary metabolites of the emerging sport nutrition supplement methoxyisoflavone in human subjects.

    PubMed

    Lecompte, Yannick; Rosset, Martine; Richeval, Camille; Humbert, Luc; Arpino, Patrick

    2014-08-01

    Methoxyisoflavone (5-methyl-7-methoxyisoflavone) is a synthetic isoflavone used by bodybuilders for its ergogenic properties. A recent study demonstrated that methoxyisoflavone metabolites can induce false-positive results in urinary immunoassay screening tests for cannabinoids, and only one metabolite has been identified. To improve the knowledge on the metabolic pathways of methoxyisoflavone, ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF) was applied. Urine samples were obtained from methoxyisoflavone regular users. After enzymatic hydrolysis and liquid-liquid extraction, the samples were analyzed by UPLC-Q-TOF fitted with an electrospray ionization source (ESI) operating under positive ion mode. Mass data were acquired with the MS(E) method. Five metabolites were identified. Those were divided into two metabolic pathways, depending on whether the B ring hydroxylation was preceded or not by the O-demethylation of the methoxy group. The MS(E) mass spectra of methoxyisoflavone and its metabolites are specific of isoflavones structures and revealed 1,3 retro Diels-Alder fragmentation and double CO loss. Losses of small neutral molecules CO and H2O, and radical CH3, typical of flavonoids, were also observed. This study illustrates the capacity of the sensitive UPLC-Q-TOF analytical system, combined with the MS(E) method of collection of fragmentation data, to rapidly elucidate the unknown xenobiotics metabolism. PMID:24742771

  15. 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

  16. Potential of decursin to inhibit the human cytochrome P450 2J2 isoform.

    PubMed

    Lee, Boram; Wu, Zhexue; Sung, Sang Hyun; Lee, Taeho; Song, Kyung-Sik; Lee, Min Young; Liu, Kwang-Hyeon

    2014-08-01

    CYP2J2 enzyme is highly expressed in human tumors and carcinoma cell lines, and epoxyeicosatrienoic acids, CYP2J2-mediated metabolites, have been implicated in the pathologic development of human cancers. To identify a CYP2J2 inhibitor, 50 natural products obtained from plants were screened using astemizole as a CYP2J2 probe substrate in human liver microsomes. Of these, decursin noncompetitively inhibited CYP2J2-mediated astemizole O-demethylation and terfenadine hydroxylation activities with Ki values of 8.34 and 15.8μM, respectively. It also showed cytotoxic effects against human hepatoma HepG2 cells in a dose-dependent manner while it did not show cytotoxicity against mouse hepatocytes. The present data suggest that decursin is a potential candidate for further evaluation for its CYP2J2 targeting anti-cancer activities. Studies are currently underway to test decursin as a potential therapeutic agent for cancer. PMID:24788058

  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. 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

  19. 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

  20. 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.

  1. Microbial cycling of volatile organic sulfur compounds.

    PubMed

    Lomans, B P; van der Drift, C; Pol, A; Op den Camp, H J M

    2002-04-01

    Microbial cycling of volatile organic sulfur compounds (VOSCs), especially dimethyl sulfide (DMS) and methanethiol (MT), is intensively studied because these compounds play an important role in the processes of global warming, acid precipitation, and the global sulfur cycle. VOSC concentrations in freshwater sediments are low due to the balance between the formation and degradation of these compounds. These reactions occur for the greater part at the oxic/anoxic interphase of sediment and water column. In contrast to marine ecosystems, where dimethylsulfoniopropionate is the main precursor of MT and DMS, in freshwater ecosystems, VOSCs are formed mainly by methylation of sulfide and to a lesser extent from the degradation of S-containing amino acids. One of the major routes for DMS and MT formation through sulfide methylation is anaerobic O-demethylation of methoxylated aromatic compounds. Inhibition studies have revealed that the major part of the endogenously produced MT and DMS is degraded anaerobically by methanogens. The major bacterial groups involved in formation and consumption of VOSCs are described. PMID:12022467

  2. CYP1A1 and CYP1B1-mediated biotransformation of the antitrypanosomal methamidoxime prodrug DB844 forms novel metabolites through intramolecular rearrangement

    PubMed Central

    Ju, Wujian; Yang, Sihyung; Ansede, John H.; Stephens, Chad E.; Bridges, Arlene S.; Voyksner, Robert D.; Ismail, Mohamed A.; Boykin, David W.; Tidwell, Richard R.; Hall, James Edwin; Wang, Michael Zhuo

    2013-01-01

    DB844 (CPD-594-12), N-methoxy-6-{5-[4-(N-methoxyamidino)phenyl]-furan-2-yl}-nicotinamidine, is an oral prodrug that has shown promising efficacy in both mouse and monkey models of second stage human African trypanosomiasis. However, gastrointestinal (GI) toxicity was observed with high doses in a vervet monkey safety study. In the current study, we compared the metabolism of DB844 by hepatic and extrahepatic cytochrome P450s to determine if differences in metabolite formation underlie the observed GI toxicity. DB844 undergoes sequential O-demethylation and N-dehydroxylation in the liver to form the active compound DB820 (CPD-593-12). However, extrahepatic CYP1A1 and CYP1B1 produced two new metabolites, MX and MY. Accurate mass and collision-induced dissociation mass spectrometry analyses of the metabolites supported proposed structures of MX and MY. In addition, MY was confirmed with a synthetic standard and detection of nitric oxide release when DB844 was incubated with CYP1A1. Taken altogether, we propose that MX is formed by insertion of an oxygen into the amidine C=N to form an oxaziridine, which is followed by intramolecular rearrangement of the adjacent O-methyl group and subsequent release of nitric oxide. The resulting imine ester, MX, is further hydrolyzed to form MY. These findings may contribute to furthering the understanding of toxicities associated with benzamidoxime- and benzmethamidoxime-containing molecules. PMID:24186380

  3. (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.

  4. 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.

  5. 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

  6. Highly antiplasmodial non-natural oxidative products of dioncophylline A: synthesis, absolute configuration, and conformational stability.

    PubMed

    Hemberger, Yasmin; Zhang, Guoliang; Brun, Reto; Kaiser, Marcel; Bringmann, Gerhard

    2015-10-01

    Four new compounds, the monomeric dioncotetralones A (6 a) and B (6 b) and the dimeric compounds jozimine A3 (7) and jozimine A4 (9), were semi-synthesized from the natural product dioncophylline A (4) and its 5'-O-demethylated derivative (5), respectively, under phenol oxidative reaction conditions. Dioncotetralones A (6 a) and B (6 b) possess an unprecedented Z-configured double bond, in contrast to the classic biaryl axis that is present in the precursor dioncophylline A (4), and an additional stereogenic center at the C2' atom was generated due to the dearomatization. The resulting steric repulsion forced the expected planar double bond into a helical distorted conformation. The homocoupling of 5 yielded compounds 7 and 9, the latter of which is the first sp(3) -sp(2) coupled product of a monomeric naphthylisoquinoline with a reduced one and, thus, contains a newly generated stereogenic center. The full stereostructures of 6 a, 6 b, 7, and 9 were successfully elucidated by the interplay of spectroscopic methods (1D/2D NMR and electronic circular-dichroism spectroscopy) in combination with quantum-chemical calculations. In addition, compounds 6 a and 7 exhibited high antiplasmodial activities with excellent half-maximal inhibitory concentration values.

  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. [Recent advances in Sphingobium sp. SYK-6 for lignin aromatic compounds degradation--a review].

    PubMed

    Zhang, Xiaoyan; Peng, Xue; Masai, Eiji

    2014-08-01

    Lignin is complex heteropolymer produced from hydroxycinnamyl alcohols through radical coupling. In nature, white-rot fungi are assumed initially to attack native lignin and release lignin-derived-low-molecular-weight compounds, and soil bacteria play an importent role for completely degradation of these compounds. Study on the soil bacteria degrading lignin-derived-low-molecular-weight compounds will give way to understand how aromatic compounds recycle in nature, and to utilize lignin compounds as the renewable materials for valuable materials production. Sphingobium sp. SYK-6 that grows on lignin biphenyl (5,5'-dehydrodivanillate) had been isolated from pulp effluent in 1987. We have researched this bacterium more than 25 years, a serious aromatic metabolic pathway has been determined, and related genes have been isolated. As the complete genome sequence of SYK-6 has been opened to the public in 2012, the entire aromatic compounds degradation mechanisms become more clear. Main contents in our review cover: (1) genome information; (2) aryl metabolism; (3) biphenyl metabolism; (4) ferulate metabolism; (5) tetrahydrofolate-dependent O-demethylation system for lignin compound degrdation; (6) protocatechuate 4,5-cleavage pathway; (7) multiple pathways for 3-O-methylgallate metabolism.

  9. 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.

  10. 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

  11. Genotoxic mechanisms for the carcinogenicity of the environmental pollutants and carcinogens o-anisidine and 2-nitroanisole follow from adducts generated by their metabolite N-(2-methoxyphenyl)-hydroxylamine with deoxyguanosine in DNA

    PubMed Central

    Stiborová, Marie; Naiman, Karel; Martínková, Markéta; Martínek, Václav; Svobodová, Martina; Schmeiser, Heinz H.; Frei, Eva

    2009-01-01

    An aromatic amine, o-anisidine (2-methoxyaniline) and its oxidative counterpart, 2-nitroanisole (2-methoxynitrobenzene), are the industrial and environmental pollutants causing tumors of the urinary bladder in rats and mice. Both carcinogens are activated to the same proximate carcinogenic metabolite, N-(2-methoxyphenyl)hydroxylamine, which spontaneously decomposes to nitrenium and/or carbenium ions responsible for formation of deoxyguanosine adducts in DNA in vitro and in vivo. In other words, generation of N-(2-methoxyphenyl)hydroxylamine is responsible for the genotoxic mechanisms of the o-anisidine and 2-nitroanisole carcinogenicity. Analogous enzymes of human and rat livers are capable of activating these carcinogens. Namely, human and rat cytochorme P4502E1 is the major enzyme oxidizing o-anisidine to N-(2-methoxyphenyl)hydroxylamine, while xanthine oxidase of both species reduces 2-nitroanisole to this metabolite. Likewise, O-demethylation of 2-nitroanisole, which is the detoxication pathway of its metabolism, is also catalyzed by the same human and rat enzyme, cytochorme P450 2E1. The results demonstrate that the rat is a suitable animal model mimicking the fate of both carcinogens in humans and suggest that both compounds are potential carcinogens also for humans. PMID:21217841

  12. 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

  13. Total Synthesis of 7′-Desmethylkealiiquinone, 4′-Desmethoxykealiiquinone, and 2-Deoxykealiiquinone

    PubMed Central

    2015-01-01

    Synthetic approaches to the imidazonaphthoquinone core of kealiiquinone and related Leucetta-derived alkaloids are described. The polysubstituted benzimidazole framework can be constructed through intramolecular Diels–Alder reactions of propiolate-derived enynes followed by oxidation. Adjustment of the oxidation state of the thus formed lactone allows introduction of the 2,3-dihydroxybenzoquinone moiety through a presumed benzoin-like condensation between a phthaldehyde derivative and a masked glyoxal equivalent catalyzed by a cyanide ion. Oxidation of the C2-position can be accomplished through application of an operationally simple treatment of an imidazolium salt with bleach, thus producing the corresponding 2-imidazolone. Debenzylation of a late stage intermediate en route to kealiiquinone was compromised by concomitant O-demethylation upon treatment with triflic acid resulting in the formation of non-natural 7′-desmethylkealiiquinone. Other endgame strategies were evaluated; however, these efforts did not lead to completion of a synthesis of kealiiquinone but did provide access to other closely related analogues. PMID:24533685

  14. Recent trends of drug abuse and drug-associated deaths in Korea.

    PubMed

    Chung, Heesun; Park, Meejung; Hahn, Eunyoung; Choi, Haeyoung; Choi, Hwakyung; Lim, Miae

    2004-10-01

    Methamphetamine is the most abused drug in Korea followed by cannabis and opiates. Recent characteristics of the drug problem in Korea include increased drug smuggling from abroad, drug trafficking by organized gangs, varieties of drug smuggling, foreigners engaged in drug smuggling, and spread among drug abusers and areas. New drugs such as MDMA, Yaba, and LSD are found in greater proportion in the seizure records, indicating diversification of smuggled drugs in Korea. In addition, there is a growing tendency for the abuse of common medicines among young people in Korea because they are easily available. Methamphetamine is so seriously abused that fatalities from its overdose have occurred; since 1985, 20 such fatalities have been reported. Many deaths from the abuse of noncontrolled substances, especially dextromethorphan, zipeprol, and carisoprodol, which are taken for their hallucinogenic effects, were also reported. Recently, there was even a fatality related to smuggling of cocaine by body-packing.

  15. N-methyl-D-aspartate promotes the survival of cerebellar granule cells: pharmacological characterization.

    PubMed

    Balázs, R; Hack, N; Jørgensen, O S; Cotman, C W

    1989-07-01

    The survival of cerebellar granule cells in culture is promoted by chronic exposure to N-methyl-D-aspartate (NMDA). The effect is due to the stimulation of 'conventional' NMDA receptor-ionophore complex: it is concentration dependent, voltage dependent and blocked by the selective antagonists D-2-amino-5-phosphonovalerate, D-2-amino-7-phosphonoheptanoate, dextromethorphan and (+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imin emaleate (MK 801). The most potent antagonist tested was MK-801. In contrast, non-selective antagonists, including kynurenate, were much less effective. Further, the trophic effect of NMDA is not reproduced by ibotenate or quinolinate at the concentration range tested. It could also be shown that glutamate released into the culture medium is responsible for limited cell survival in the absence of NMDA.

  16. 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.

  17. 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

  18. A categorical review on electroanalytical determination of non-narcotic over-the-counter abused antitussive drugs.

    PubMed

    Thapliyal, Neeta; Patel, Harun; Karpoormath, Rajshekhar; Goyal, Rajendra N; Patel, Rajkumar

    2015-09-01

    Dextromethorphan (DXM) and diphenhydramine (DPH) are two commonly used over-the-counter non-narcotic antitussive drugs. Recent reports reveal the widespread abuse of DXM and DPH due to their euphoric and alcohol-like effects. Due to their medicinal importance as well as the apparent increase in their use as abused drugs, it has become critical to determine them in samples of biological, clinical and pharmaceutical interest. The electrochemical techniques for drug analysis have gathered considerable attention due to their pronounced selectivity, sensitivity and simplicity. The given review presents a compilation of published voltammetric and potentiometric methods developed for determination of DXM and DPH. It critically highlights the analytical performances, revealing the recent trends and progress in the specified approach for their analysis. The review forms a basis for further progress in this field and development of improved electrochemical sensors to determine the drug.

  19. 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.

  20. 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

  1. Analysis of pharmaceutical preparations containing antihistamine drugs by micellar liquid chromatography.

    PubMed

    Martínez-Algaba, C; Bermúdez-Saldaña, J M; Villanueva-Camañas, R M; Sagrado, S; Medina-Hernández, M J

    2006-02-13

    Rapid chromatographic procedures for analytical quality control of pharmaceutical preparations containing antihistamine drugs, alone or together with other kind of compounds are proposed. The method uses C18 stationary phases and micellar mobile phases of cetyltrimethylammonium bromide (CTAB) with either 1-propanol or 1-butanol as organic modifier. The proposed procedures allow the determination of the antihistamines: brompheniramine, chlorcyclizine, chlorpheniramine, diphenhydramine, doxylamine, flunarizine, hydroxyzine, promethazine, terfenadine, tripelennamine and triprolidine, in addition to caffeine, dextromethorphan, guaifenesin, paracetamol and pyridoxine in different pharmaceutical presentations (tablets, capsules, suppositories, syrups and ointments). The methods require minimum handling sample and are rapid (between 3 and 12 min at 1 mLmin(-1) flow rate) and reproducible (R.S.D. values<5%). Limits of detection are lower than 1 microgmL(-1) and the recoveries of the analytes in the pharmaceutical preparations are in the range 100+/-10%.

  2. Modular microfluidic system for emulation of human phase I/phase II metabolism.

    PubMed

    Kampe, Thomas; König, Anna; Schroeder, Hendrik; Hengstler, Jan G; Niemeyer, Christof M

    2014-03-18

    We present a microfluidic device for coupled phase I/phase II metabolic reactions in vitro. The chip consists of microchannels, which are used as packed bed reactor compartments, filled with superparamagnetic microparticles bearing recombinant microsomal phase I cytochrome P450 or phase II conjugating enzymes (UDP-glucuronosyltransferase). Online coupling of the microfluidic device with LC/MS enabled the quantitative assessment of coupled phase I/phase II transformations, as demonstrated for two different substrates, 7-benzyloxy-4-trifluoromethylcoumarin (BFC) and dextromethorphan (DEX). In contrast, conventional sequential one-pot incubations did not generate measurable amounts of phase II metabolites. Because the microfluidic device is readily assembled from standard parts and can be equipped with a variety of recombinant enzymes, it provides a modular platform to emulate and investigate hepatic metabolism processes, with particular potential for targeted small-scale synthesis and identification of metabolites formed by sequential action of specific enzymes. PMID:24597510

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. Initial characterization and autoradiographic localization of a novel sigma/opioid binding site in immune tissues.

    PubMed

    Whitlock, B B; Liu, Y; Chang, S; Saini, P; Ha, B K; Barrett, T W; Wolfe, S A

    1996-07-01

    High concentrations of novel, haloperidol- and DTG-inaccessible (+)-[3H]-3-PPP binding sites were found in human peripheral blood leukocytes rat spleen and splenocytes, but not in rat brain. Splenic sites were localized in a course punctate pattern in the marginal zones and red pulp. The pharmacology of the splenic sites was: (-)-SKF 10,047 > or = naltrexone = (-)-pentazocine > (+)-pentazocine = (-)-3-PPP = (+)-SKF 10,047 > or = (+)-3-PPP > or = dextrorphan > dextromethorphan > PCP > clorgyline. DTG, haloperidol, TCP, (-)-deprenyl and SKF 525-A did not complete. Binding activity was destroyed by heating and phospholipase C, but not by proteases or glycosidases. These sites may be involved in immunomodulation by opiate and sigma receptor agonists.

  8. 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.

  9. Physiologically based pharmacokinetic modeling to predict drug-drug interactions involving inhibitory metabolite: a case study of amiodarone.

    PubMed

    Chen, Yuan; Mao, Jialin; Hop, Cornelis E C A

    2015-02-01

    Evaluation of drug-drug interaction (DDI) involving circulating inhibitory metabolites of perpetrator drugs has recently drawn more attention from regulatory agencies and pharmaceutical companies. Here, using amiodarone (AMIO) as an example, we demonstrate the use of physiologically based pharmacokinetic (PBPK) modeling to assess how a potential inhibitory metabolite can contribute to clinically significant DDIs. Amiodarone was reported to increase the exposure of simvastatin, dextromethorphan, and warfarin by 1.2- to 2-fold, which was not expected based on its weak inhibition observed in vitro. The major circulating metabolite, mono-desethyl-amiodarone (MDEA), was later identified to have a more potent inhibitory effect. Using a combined "bottom-up" and "top-down" approach, a PBPK model was built to successfully simulate the pharmacokinetic profile of AMIO and MDEA, particularly their accumulation in plasma and liver after a long-term treatment. The clinical AMIO DDIs were predicted using the verified PBPK model with incorporation of cytochrome P450 inhibition from both AMIO and MDEA. The closest prediction was obtained for CYP3A (simvastatin) DDI when the competitive inhibition from both AMIO and MDEA was considered, for CYP2D6 (dextromethorphan) DDI when the competitive inhibition from AMIO and the competitive plus time-dependent inhibition from MDEA were incorporated, and for CYP2C9 (warfarin) DDI when the competitive plus time-dependent inhibition from AMIO and the competitive inhibition from MDEA were considered. The PBPK model with the ability to simulate DDI by considering dynamic change and accumulation of inhibitor (parent and metabolite) concentration in plasma and liver provides advantages in understanding the possible mechanism of clinical DDIs involving inhibitory metabolites.

  10. 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.

  11. 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

  12. 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.

  13. [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

  14. 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

  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. 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

  18. 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

  19. High-sensitivity liquid chromatography-tandem mass spectrometry for the simultaneous determination of five drugs and their cytochrome P450-specific probe metabolites in human plasma.

    PubMed

    Oh, Kyung-Suk; Park, Su-Jin; Shinde, Dhananjay D; Shin, Jae-Gook; Kim, Dong-Hyun

    2012-05-01

    A sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method with electrospray ionization was developed for the simultaneous quantitation of five probe drugs and their metabolites in human plasma for assessing the in vivo activities of cytochrome P450 (CYP). CYP isoform specific substrates and their metabolites of CYP1A2 (caffeine), CYP2C9 (losartan), CYP2C19 (omeprazole), CYP2D6 (dextromethorphan) and CYP3A (midazolam) were all simultaneously analyzed using LC-MS/MS after administration of a mixture of five drugs (i.e., a "cocktail approach") to healthy volunteers. The assay uses propranolol as an internal standard; dual liquid extraction; a Xbridge MS C(18) (100 mm × 2.1mm, 3.5 μm) column; a gradient mobile phase of 0.1% formic acid/acetonitrile (7/3→3/7); mass spectrometric detection in positive ion mode. The method was validated from 5 to 500 ng/mL for caffeine and paraxanthine, 0.1-40 ng/mL for losartan and EXP3174, 0.05-20 ng/mL for omeprazole and 5-hydroxyomeprazole, 0.008-0.8 ng/mL for dextromethorphan and dextrorphan, 0.01-1.0 ng/mL for midazolam, and 0.04-4 ng/mL for 1'-hydroxymidazolam. The intra- and inter-day precision over the concentration ranges for all analytes were lower than 12.5% and 13.8% (relative standard deviation, %RSD), and accuracy was between 86.5% and 108.4% and between 87.0% and 107.0%, respectively. This highly sensitive and quantitative method allowed a pharmacokinetic study in subjects receiving doses 10-100 times lower than typical therapeutic doses.

  20. Fate of the nonsteroidal anti-inflammatory drug naproxen in agricultural soil receiving liquid municipal biosolids.

    PubMed

    Topp, Edward; Hendel, John G; Lapen, David R; Chapman, Ralph

    2008-10-01

    Naproxen (2-(6-methoxy-2-naphthyl) propionic acid) is widely used for the treatment of pain and swelling associated with arthritis, gout, and other inflammatory conditions. Naproxen has been detected in municipal sewage outflows and in surface waters and could reach agricultural land through the application of municipal biosolids or reclaimed water. The persistence characteristics of naproxen in three agricultural soils were investigated. In laboratory microcosms of moist soil incubated at 30 degrees C, [O-14CH3]naproxen was rapidly and thoroughly mineralized to 14CO2 with comparable kinetics in a sandy loam soil, a loam soil, and a silt loam soil. Naproxen mineralization was responsive to soil temperature and soil moisture content, consistent with the primary mechanism of dissipation being biodegradation. Mineralization of naproxen was hastened by the addition of liquid municipal biosolids (LMBs) from a municipal sewage treatment plant that aerated this material. Naproxen was stable in autoclaved soils with or without addition of autoclaved LMBs, whereas naproxen was rapidly mineralized in sterile soil supplemented with nonsterile LMBs. An enrichment culture was obtained from aerobically digested LMBs in a mineral salts medium with naproxen as the sole source of carbon. The culture converted the parent compound to the corresponding naphthol, O-desmethyl naproxen. In summary, naproxen was rapidly removed from soil, with mesophilic aerobic biodegradation being the primary mechanism of dissipation. Microorganisms carried in biosolids enhanced naproxen dissipation in soil, with the initial mechanism of attack likely being O-demethylation. We conclude on this basis that naproxen in soils receiving biosolids would be readily biodegradable and, in the absence of preferential flow or runoff, pose little risk for contamination of adjacent water or crops. PMID:18419173

  1. 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

  2. O-demethylase from Acetobacterium dehalogenans--cloning, sequencing, and active expression of the gene encoding the corrinoid protein.

    PubMed

    Kaufmann, F; Wohlfarth, G; Diekert, G

    1998-10-15

    The ether-cleaving O-demethylase from the strictly anaerobic homoacetogen Acetobacterium dehalogenans catalyses the methyltransfer from 4-hydroxy-3-methoxy-benzoate (vanillate) to tetrahydrofolate. In the first step a vanillate :corrinoid protein methyltransferase (methyltransferase I) mediates the methylation of a 25-kDa corrinoid protein with the cofactor reduced to cob(I)alamin. The methyl group is then transferred to tetrahydrofolate by the action of a methylcorrinoid protein:tetrahydrofolate methyltransferase (methyltransferase II). Using primers derived from the amino-terminal sequences of the corrinoid protein and the vanillate:corrinoid protein methyltransferase (methyltransferase I), a 723-bp fragment was amplified by PCR, which contained the gene odmA encoding the corrinoid protein of O-demethylase. Downstream of odmA, part of the odmB gene encoding methyltransferase I was identified. The amino acid sequence deduced from odmA showed about 60% similarity to the cobalamin-binding domain of methionine synthase from Escherichia coli (MetH) and to corrinoid proteins of methyltransferase systems involved in methanogenesis from methanol and methylamines. The sequence contained the DXHXXG consensus sequence typical for displacement of the dimethylbenzimidazole base of the corrinoid cofactor by a histidine from the protein. Heterologous expression of odmA in E. coli yielded a colourless, oxygen-insensitive apoprotein, which was able to bind one mol cobalamin or methylcobalamin/mol protein. Both of these reconstituted forms of the protein were active in the overall O-demethylation reaction. OdmA reconstituted with hydroxocobalamin and reduced by titanium(III) citrate to the cob(I)alamin form was methylated with vanillate by methyltransferase I in an irreversible reaction. Methylcobalamin carrying OdmA served as methyl group donor for the methylation of tetrahydrofolate by methyltransferase II. This reaction was found to be reversible, since methyltranSferase II

  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. Bioactivation of the citrus flavonoid nobiletin by CYP1 enzymes in MCF7 breast adenocarcinoma cells.

    PubMed

    Surichan, Somchaiya; Androutsopoulos, Vasilis P; Sifakis, Stavros; Koutala, Eleni; Tsatsakis, Aristidis; Arroo, Randolph R J; Boarder, Michael R

    2012-09-01

    Recent studies have demonstrated cytochrome P450 CYP1-mediated metabolism and CYP1-enzyme induction by naturally occurring flavonoids in cancer cell line models. The arising metabolites often exhibit higher activity than the parent compound. In the present study we investigated the CYP1-mediated metabolism of the citrus polymethoxyflavone nobiletin by recombinant CYP1 enzymes and MCF7 breast adenocarcinoma cells. Incubation of nobiletin in MCF7 cells produced one main metabolite (NM1) resulting from O-demethylation in either A or B rings of the flavone moiety. Among the three CYP1 isoforms, CYP1A1 exhibited the highest rate of metabolism of nobiletin in recombinant CYP microsomal enzymes. The intracellular CYP1-mediated bioconversion of the flavone was reduced in the presence of the CYP1A1 and CYP1B1-selective inhibitors α-napthoflavone and acacetin. In addition nobiletin induced CYP1 enzyme activity, CYP1A1 protein and CYP1B1 mRNA levels in MCF7 cells at a concentration dependent manner. MTT assays in MCF7 cells further revealed that nobiletin exhibited significantly lower IC50 (44 μM) compared to cells treated with nobiletin and CYP1A1 inhibitor (69 μM). FACS analysis demonstrated cell a cycle block at G1 phase that was attenuated in the presence of CYP1A1 inhibitor. Taken together the data suggests that the dietary flavonoid nobiletin induces its own metabolism and in turn enhances its cytostatic effect in MCF7 breast adenocarcinoma cells, via CYP1A1 and CYP1B1 upregulation.

  5. 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

  6. A Unified Strategy toward the Synthesis of Acerogenin-Type Macrocycles: Total Syntheses of Acerogenins A, B, C, and L and Aceroside IV.

    PubMed

    Gonzalez, Gabriela Islas; Zhu, Jieping

    1999-02-01

    A general strategy for the synthesis of acerogenin-type diarylheptanoids containing an endocyclic biaryl ether bond has been developed, and convergent total syntheses of acerogenin A, B, C, and L and aceroside IV have been accomplished. Cycloetherification of the linear diarylheptanoid 1-(4-fluoro-3-nitrophenyl)-7-(3-hydroxy-4-methoxyphenyl)heptan-3-one (18) under mild conditions (CsF, DMF, 0.01 M, rt, 5 h) gave the macrocycle 4-methoxy-17-nitro-2-oxatricyclo[13.2.2(3,7)]eicosa-1(18),3,5,7(20),15(19),16-hexaen-12-one (19) in 95% yield. Removal of the nitro group followed by O-demethylation gave acerogenin C (2), whose reduction afforded acerogenin A (1). Glucosidation of 2 with 2,3,4,6-alpha-D-tetrabenzoylglucopyranosyl bromide followed by saponification gave aceroside IV (3) in excellent overall yield. Acerogenins B (4) and L (5) were synthesized in a similar fashion featuring a key intramolecular S(N)Ar reaction of linear compound 29. The entropy driving force resulting from the preorganization of cyclization precursors in favor of the bent conformation was proposed to contribute significantly to the efficiency of this cyclization. Both computational studies and spectroscopic data (NOE) supported this hypothesis. Experimentally, it was observed that even at high concentration (1 M of 18 in DMF) the analytically pure macrocycle 19 could still be obtained in 45-50% isolated yield. Furthermore, when the cyclization of 18 was carried out in the presence of an external nucleophile (4-methoxyphenol, 33) or an electrophile (4-fluoro-3-nitrotoluene, 34), only the 15-membered cyclophane 19 was isolable. This provides experimental evidence that compound 18 is indeed preorganized in such a way that intramolecular reaction was highly competitive with the alternative intermolecular process.

  7. 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.

  8. 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.

  9. 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

  10. Molecular modeling and metabolic studies of the interaction of catechol-O-methyltransferase and a new nitrocatechol inhibitor.

    PubMed

    Palma, P N; Bonifácio, M J; Loureiro, A I; Wright, L C; Learmonth, D A; Soares-da-Silva, P

    2003-03-01

    Catechol-O-methyltransferase (COMT, EC 2.1.1.6) plays a central role in the metabolic inactivation of neurotransmitters and neuroactive xenobiotics possessing a catechol motif. 1-(3,4-Dihydroxy-5-nitrophenyl)-2-phenyl-ethanone (BIA 3-202) is a novel nitrocatechol-type inhibitor of COMT, the potential clinical benefit of which is currently being evaluated in the treatment of Parkinson's disease. In the present work we characterize the molecular interactions of BIA 3-202 within the active site of COMT and discuss their implication on the regioselectivity of metabolic O-methylation. Unrestrained flexible-docking simulations suggest that the solution structure of this complex is better described as an ensemble of alternative binding modes, in contrast to the well defined bound configuration revealed by the X-ray structures of related nitrocatechol inhibitors, co-crystallized with COMT. The docking results wherein presented are well supported by experimental evidence, where the pattern of in vitro enzymatic O-methylation and O-demethylation reactions are analyzed. We propose a plausible explanation for the paradoxical in vivo regioselectivity of O-methylation of BIA 3-202, as well as of its related COMT inhibitor tolcapone. Both compounds undergo in vivo O-methylation by COMT at either meta or para catechol hydroxyl groups. However, results herein presented suggest that, in a subsequent step, the p-O-methyl derivatives are selectively demethylated by a microsomal enzyme system. The overall balance is the accumulation of the m-O-methylated metabolites over the para-regioisomers. The implications for the general recognition of nitrocatechol-type inhibitors by COMT and the regioselectivity of their metabolic O-methylation are discussed.

  11. Structural diversity and defensive properties of norditerpenoid alkaloids.

    PubMed

    González-Coloma, Azucena; Reina, Matías; Medinaveitia, Alberto; Guadaño, Ana; Santana, Omar; Martínez-Díaz, Rafael; Ruiz-Mesía, Lastenia; Alva, Allenger; Grandez, Maritza; Díaz, Rafael; Gavín, José A; De la Fuente, Gabriel

    2004-07-01

    We have tested the insect antifeedant and toxic activity of 43 norditerpenoid alkaloids on Spodoptera littoralis and Leptinotarsa decemlineata including eserine (physostigmine), anabasine, and atropine. Antifeedant effects of the test compounds were structure- and species-dependent. The most active antifeedants to L. decemlineata were 1,14-diacetylcardiopetaline (9) and 18-hydroxy- 14-O-methylgadesine (33), followed by 8-O-methylconsolarine (12), 14-O-acetyldelectinine (27), karakoline (7), cardiopetaline (8), 18-O-demethylpubescenine (13), 14-O-acetyldeltatsine (18), takaosamine (21), ajadine (24), and 8-O-methylcolumbianine (6) (EC50 < 1 microg/cm2). This insect showed a moderate response to atropine. S. littoralis had the strongest antifeedant response to 24, 18, 14-O-acetyldelcosine (19), and delphatine (29) (EC50 < 3 microg/cm2). None of the model substances affected the feeding behavior of this insect. The most toxic compound to L. decemlineata was aconitine (1), followed by cardiopetalidine (10) (% mortality > 60), 14-deacetylpubescenine (14), 18-O-benzoyl-18-O-demethyl-14-O-deacetylpubescenine (17), 14-O-acetyldelcosine (19), 14-deacetylajadine (25) and methyllycaconitine (30) (% mortality > 45). Orally injected S. littoralis larvae were negatively affected by 1, cardiopetaline (8), 10, 1,14-O-acetylcardiopetalidina (11), 12, 14, 1,18-O-diacetyl-19-oxo-gigactonine (41), olivimine (43), and eserine in varying degrees. Their antifeedant or insecticidal potencies did not parallel their reported nAChR binding activity, but did correlate with the agonist/antagonist insecticidal/antifeedant model proposed for nicotininc insecticides. A few compounds [14, tuguaconitine (38), 14-demethyldelboxine (40), 19, dehydrodelsoline (36), 18-O-demethylpubescenine (13), 41, 9, and delcosine (23)] had selective cytotoxic effects to ward insect-derived Sf9 cells. None were cytotoxic to mammalian CHO cells and none increased Trypanosoma cruzi mortality. The selective cytotoxic

  12. 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

  13. Ibogaine: complex pharmacokinetics, concerns for safety, and preliminary efficacy measures.

    PubMed

    Mash, D C; Kovera, C A; Pablo, J; Tyndale, R F; Ervin, F D; Williams, I C; Singleton, E G; Mayor, M

    2000-09-01

    Ibogaine is an indole alkaloid found in the roots of Tabernanthe Iboga (Apocynaceae family), a rain forest shrub that is native to western Africa. Ibogaine is used by indigenous peoples in low doses to combat fatigue, hunger and thirst, and in higher doses as a sacrament in religious rituals. Members of American and European addict self-help groups have claimed that ibogaine promotes long-term drug abstinence from addictive substances, including psychostimulants and opiates. Anecdotal reports attest that a single dose of ibogaine eliminates opiate withdrawal symptoms and reduces drug craving for extended periods of time. The purported efficacy of ibogaine for the treatment of drug dependence may be due in part to an active metabolite. The majority of ibogaine biotransformation proceeds via CYP2D6, including the O-demethylation of ibogaine to 12-hydroxyibogamine (noribogaine). Blood concentration-time effect profiles of ibogaine and noribogaine obtained for individual subjects after single oral dose administrations demonstrate complex pharmacokinetic profiles. Ibogaine has shown preliminary efficacy for opiate detoxification and for short-term stabilization of drug-dependent persons as they prepare to enter substance abuse treatment. We report here that ibogaine significantly decreased craving for cocaine and heroin during inpatient detoxification. Self-reports of depressive symptoms were also significantly lower after ibogaine treatment and at 30 days after program discharge. Because ibogaine is cleared rapidly from the blood, the beneficial aftereffects of the drug on craving and depressed mood may be related to the effects of noribogaine on the central nervous system.

  14. Forensic drug testing for opiates. VI. Urine testing for hydromorphone, hydrocodone, oxymorphone, and oxycodone with commercial opiate immunoassays and gas chromatography-mass spectrometry.

    PubMed

    Smith, M L; Hughes, R O; Levine, B; Dickerson, S; Darwin, W D; Cone, E J

    1995-01-01

    Opiate testing for morphine and codeine is performed routinely in forensic urine drug-testing laboratories in an effort to identify illicit opiate abusers. In addition to heroin, the 6-keto-opioids, including hydromorphone, hydrocodone, oxymorphone, and oxycodone, have high abuse liability and are self-administered by opiate abusers, but only limited information is available on detection of these compounds by current immunoassay and gas chromatographic-mass spectrometric (GC-MS) methods. In this study, single doses of hydromorphone, hydrocodone, oxymorphone, and oxycodone were administered to human subjects, and urine samples were collected before and periodically after dosing. Opiate levels were determined in a quantitative mode with four commercial immunoassays, TDx opiates (TDx), Abuscreen radioimmunoassay (ABUS), Coat-A-Count morphine in urine (CAC), and EMIT d.a.u. opiate assay (EMIT), and by GC-MS. GC-MS assay results indicated that hydromorphone, hydrocodone, oxymorphone, and oxycodone administration resulted in rapid excretion of parent drug and O-demethylated metabolites in urine. Peak concentrations occurred within 8 h after drug administration and declined below 300 ng/mL within 24-48 h. Immunoassay testing indicated that hydromorphone, hydrocodone, and oxycodone, but not oxymorphone, were detectable in urine by TDx and EMIT (300-ng/mL cutoff) for 6-24 h. ABUS detected only hydrocodone, and CAC failed to detect any of the four 6-keto-opioid analgesics. Generally, immunoassays for opiates in urine displayed substantially lower sensitivities for 6-keto-opioids compared with GC-MS. Consequently, urine samples containing low to moderate concentrations of hydromorphone, hydrocodone, oxymorphone, and oxycodone will likely go undetected when tested by conventional immunoassays.

  15. 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

  16. Danazol Inhibits Cytochrome P450 2J2 Activity in a Substrate-independent Manner.

    PubMed

    Lee, Eunyoung; Wu, Zhexue; Shon, Jong Cheol; Liu, Kwang-Hyeon

    2015-08-01

    Cytochrome P450 2J2 (CYP2J2) is an enzyme responsible for the metabolism of endogenous substrates including arachidonic acid, as well as therapeutic drugs such as albendazole, astemizole, ebastine, and terfenadine. Selective inhibitors of CYP2J2 are essential for P450 reaction phenotyping studies. To find representative CYP2J2 index inhibitors, we evaluated the inhibitory potential of danazol, hydroxyebastine, telmisartan, and terfenadone against CYP2J2 activity for four representative CYP2J2 substrates (albendazole, astemizole, ebastine, and terfenadine) using recombinant CYP2J2. Of these four CYP2J2 inhibitors, danazol strongly inhibited CYP2J2-mediated albendazole, astemizole, ebastine, and terfenadine metabolism in a substrate-independent manner, with IC50 values of 0.05, 0.07, 0.18, and 0.34 μM, respectively. Danazol noncompetitively inhibited CYP2J2-mediated astemizole O-demethylation activities with a Ki value of 0.06 μM. Terfenadone strongly inhibited CYP2J2-mediated albendazole, astemizole, and terfenadine metabolism (IC50 < 0.21 μM), whereas it showed weak inhibition against CYP2J2-catalyzed ebastine hydroxylase activity (IC50 = 6.04 μM). Telmisartan had no inhibitory effect on CYP2J2-mediated ebastine and terfenadine hydroxylation (IC50 > 20 μM). Taken together, these data suggest that danazol may be used as a CYP2J2 index inhibitor in reaction phenotyping studies. PMID:26048912

  17. 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

  18. Inhibition of cytochrome P450 2J2 by tanshinone IIA induces apoptotic cell death in hepatocellular carcinoma HepG2 cells.

    PubMed

    Jeon, Yu Jin; Kim, Joong Sun; Hwang, Geun Hye; Wu, Zhexue; Han, Ho Jae; Park, Soo Hyun; Chang, Woochul; Kim, Lark Kyun; Lee, You-Mie; Liu, Kwang-Hyeon; Lee, Min Young

    2015-10-01

    Cytochrome P450 2J2 (CYP2J2) is highly expressed in human tumors and carcinoma cell lines, and has been implicated in the pathogenesis of human cancers. The aim of this study was to identify a compound that could inhibit the activity of CYP2J2, and to examine its anticancer activity. To identify CYP2J2 inhibitors, 10 terpenoids obtained from plants were screened using astemizole as a CYP2J2 probe substrate in human liver microsomes (HLMs). Of these, tanshinone IIA dose-dependently and non-competitively inhibited CYP2J2-mediated astemizole O-demethylation activity. Tanshinone IIA significantly decreased viability of human hepatoma HepG2 cells and SiHa cervical cancer cells; however, it was not cytotoxic against mouse hepatocytes. Furthermore, treatment of cells with tanshinone IIA significantly increased apoptotic cell death rate, as shown by the increase in Annexin V-stained cell populations, Bcl-2 associated X protein (Bax)/B-cell lymphoma 2 (Bcl-2) ratio, and poly (ADP-ribose) polymerase 1 (PARP-1) cleavage in HepG2 cells. Furthermore, the results of this study showed that tanshinone IIA significantly decreased HepG2 cell-based tumor growth in nude mice in a dose-dependent manner. On the other hand, the tanshinone IIA-induced apoptotic cell death rate was significantly attenuated by enhanced up-regulation of CYP2J2 expression. Thus, our data strongly suggest that tanshinone IIA exerts its anticancer effect by inhibiting CYP2J2 activity. PMID:26209360

  19. Simultaneous stereoselective analysis by capillary electrophoresis of tramadol enantiomers and their main phase I metabolites in urine.

    PubMed

    Rudaz, S; Veuthey, J L; Desiderio, C; Fanali, S

    1999-06-18

    Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol and its six phase I metabolites using carboxymethylated beta-cyclodextrin (CMB) added to the background electrolyte (BGE). Baseline resolution of tramadol and its metabolites was obtained in less than 30 min using a 50 mM phosphate buffer (pH 2.5) containing 5 mM of CMB. Chiral determinations of tramadol and its main three metabolites, O-demethyltramadol (M1), N-demethyltramadol (M2) and O-demethyl-N-demethyltramadol (M5), were performed in urine after a simple double liquid-liquid extraction of 200 microliters of biological material. In the tested concentration range (0.5-20 micrograms/ml, except for M2: 0.5-10 micrograms/ml) coefficients of correlation superior than 0.994 were obtained. Within-day variation determined on three different concentrations for each enantiomers showed accuracies ranging from 95.4% to 103.2%. The relative standard deviation (RSD) of these assays was determined to be less than 10.0%. Day-to-day variation presented accuracies ranging from 96.3% to 106.5% with a RSD less than 9.0%. After oral administration of 100 mg of tramadol hydrochloride to an healthy volunteer, the urinary excretion was monitored during 30 h. About 15% of the dose was excreted as unchanged tramadol. The enantiomeric ratios of all the excreted analytes, T, M1, M2 and M5, were found to be very different to 1.0, showing that a stereoselective metabolism of tramadol clearly occurred.

  20. 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.

  1. Investigation of the in vitro metabolism of the emerging drug candidate S107 for doping-preventive purposes.

    PubMed

    Beuck, S; Schänzer, W; Thevis, M

    2011-02-01

    The metabolic fate of the emerging drug candidate S107, possessing the potential for misuse as performance-enhancing agent in sports, was investigated by in vitro phase I and II experiments with human microsomal and S9 liver enzymes. The metabolites were identified by liquid chromatography-mass spectrometry with electrospray ionisation in positive mode (LC-ESI-MS/MS). Their collision-induced dissociation behaviour was studied by high-resolution/high accuracy Orbitrap MS(n) analysis, supported by stable isotope labelling, H/D-exchange experiments and density functional theory calculations. Monooxygenation accounted for the main phase I metabolic transformation due to N- and S-oxidation of the 1,4-benzothiazepine core, as substantiated by chemical synthesis, selective reduction methods and characteristic APCI in source fragmentation behaviour of the metabolites. Another dominant metabolic pathway was demethylation, yielding the N- and O-demethylated metabolite, respectively. The latter was further conjugated by glucuronidation as well as sulfonation in subsequent phase II metabolic reactions, whereas the N-demethylated metabolite was not amenable to conjugation. The active drug molecule itself was converted to two glucuronic acid conjugates, which are proposed to consist of two quaternary S107-N(+)-glucuronide isomers. All glucuronides were susceptible to enzymatic hydrolysis with β-glucuronidase (Escherichia coli). A comprehensive LC-ESI-MS(/MS)-based detection method for urine was developed and its fitness for purpose was assessed. The assay can serve as a potential screening and/or confirmation method for S107 in clinical drug testing and doping control analysis in the future. PMID:21254313

  2. In vitro metabolism of a new cardioprotective agent, KR-32570, in human liver microsomes.

    PubMed

    Kim, Hyojin; Kang, Suil; Kim, Hyunmi; Yoon, Yune-Jung; Cha, Eun-Young; Lee, Hye Suk; Kim, Jeong-Han; Yea, Sung Su; Lee, Sang-Seop; Shin, Jae-Gook; Liu, Kwang-Hyeon

    2006-01-01

    KR-32570 (5-(2-methoxy-5-chlorophenyl)furan-2-ylcarbonyl)guanidine) is a new reversible Na+/H+ exchanger inhibitor for preventing ischemia-reperfusion injury. This study was performed to identify the metabolic pathway of KR-32570 in human liver microsomes. Human liver microsomal incubation of KR-32570 in the presence of NADPH and UDPGA resulted in the formation of six metabolites, M1-M6. M1 was identified as O-desmethyl-KR-32570, on the basis of liquid chromatography/tandem mass spectrometric (LC/MS/MS) analysis with the synthesized authentic standard. M2 and M3 were suggested to be hydroxy-KR-32570 and hydroxy-O-desmethyl-KR-32570, respectively. M1, M2, and M3 were further metabolized to their glucuronide conjugates, M4, M5, and M6, respectively. In addition, the specific P450 isoforms responsible for KR-32570 oxidation to two major metabolites, O-desmethyl-KR-32570 and hydroxy-KR-32570, were identified using a combination of correlation analysis, chemical inhibition in human liver microsomes and metabolism by expressed recombinant P450 isoforms. The inhibitory potency of KR-32570 on clinically major P450s was investigated in human liver microsomes. The results show that CYP3A4 contributes to the oxidation of KR-32570 to hydroxy-KR-32570, and CYP1A2 play the predominant role in O-demethylation of KR-32570. KR-32570 was found to inhibit moderately the metabolism of CYP2C8 substrates.

  3. Exploration of the nicotinamide-binding site of the tankyrases, identifying 3-arylisoquinolin-1-ones as potent and selective inhibitors in vitro.

    PubMed

    Paine, Helen A; Nathubhai, Amit; Woon, Esther C Y; Sunderland, Peter T; Wood, Pauline J; Mahon, Mary F; Lloyd, Matthew D; Thompson, Andrew S; Haikarainen, Teemu; Narwal, Mohit; Lehtiö, Lari; Threadgill, Michael D

    2015-09-01

    Tankyrases-1 and -2 (TNKS-1 and TNKS-2) have three cellular roles which make them important targets in cancer. Using NAD(+) as a substrate, they poly(ADP-ribosyl)ate TRF1 (regulating lengths of telomeres), NuMA (facilitating mitosis) and axin (in wnt/β-catenin signalling). Using molecular modelling and the structure of the weak inhibitor 5-aminoiso quinolin-1-one, 3-aryl-5-substituted-isoquinolin-1-ones were designed as inhibitors to explore the structure-activity relationships (SARs) for binding and to define the shape of a hydrophobic cavity in the active site. 5-Amino-3-arylisoquinolinones were synthesised by Suzuki-Miyaura coupling of arylboronic acids to 3-bromo-1-methoxy-5-nitro-isoquinoline, reduction and O-demethylation. 3-Aryl-5-methylisoquinolin-1-ones, 3-aryl-5-fluoroisoquinolin-1-ones and 3-aryl-5-methoxyisoquinolin-1-ones were accessed by deprotonation of 3-substituted-N,N,2-trimethylbenzamides and quench with an appropriate benzonitrile. SAR around the isoquinolinone core showed that aryl was required at the 3-position, optimally with a para-substituent. Small meta-substituents were tolerated but groups in the ortho-positions reduced or abolished activity. This was not due to lack of coplanarity of the rings, as shown by the potency of 4,5-dimethyl-3-phenylisoquinolin-1-one. Methyl and methoxy were optimal at the 5-position. SAR was rationalised by modelling and by crystal structures of examples with TNKS-2. The 3-aryl unit was located in a large hydrophobic cavity and the para-substituents projected into a tunnel leading to the exterior. Potency against TNKS-1 paralleled potency against TNKS-2. Most inhibitors were highly selective for TNKSs over PARP-1 and PARP-2. A range of highly potent and selective inhibitors is now available for cellular studies. PMID:26189030

  4. Activation of proestrogens from hops (Humulus lupulus L.) by intestinal microbiota; conversion of isoxanthohumol into 8-prenylnaringenin.

    PubMed

    Possemiers, Sam; Heyerick, Arne; Robbens, Veerle; De Keukeleire, Denis; Verstraete, Willy

    2005-08-10

    Hop, an essential ingredient in most beers, contains a number of prenylflavonoids, among which 8-prenylnaringenin (8-PN) would be the most potent phytoestrogen currently known. Although a number of health effects are attributed to these compounds, only a few reports are available about the bioavailability of prenylflavonoids and the transformation potency of the intestinal microbial community. To test these transformations, four fecal samples were incubated with xanthohumol, isoxanthohumol (IX), and 8-PN. Upon incubation with IX, present in strong ales up to 4 mg/L, 36% was converted into 8-PN in one fecal sample and the estrogenic properties of the sample drastically increased. In an experiment with 12 fecal cultures, this conversion was observed in one-third of the samples, indicating the importance of interindividual variability in the intestinal microbial community. Eubacterium limosum was identified to be capable of this conversion (O-demethylation) of IX into 8-PN, and after strain selection, a conversion efficiency of 90% was achieved. Finally, strain supplementation to a nonconverting fecal sample led to rapid and high 8-PN production at only 1% (v/v) addition. Up to now, the concentration of 8-PN in beer was considered too low to affect human health. However, these results show that the activity of the intestinal microbial community could more than 10-fold increase the exposure concentration. Because prenylflavonoids are present in many beers with IX being the major constituent, the results raise the question whether moderate beer consumption might contribute to increased in vivo levels of 8-PN and even influence human health.

  5. 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

  6. Isolation and characterization of two new homoacetogenic hydrogen-utilizing bacteria from the human intestinal tract that are closely related to Clostridium coccoides.

    PubMed Central

    Kamlage, B; Gruhl, B; Blaut, M

    1997-01-01

    Two gram-positive, strictly anoxic, coccoid- to rod-shaped strains of bacteria, Clostridium coccoides 1410 and C. coccoides 3110, were isolated from human feces on the typical homoacetogenic substrates formate plus H2 plus CO2 (strain 1410) and vanillate plus H2 plus CO2 (strain 3110) in the presence of 2-bromoethanesulfonate to inhibit methanogenesis. On the basis of 16S rRNA sequencing, DNA-DNA hybridization, and physiological and morphological parameters, both isolates are closely related to C. coccoides DSM 935T. The G+C contents of the DNA were 46.1 and 46.2 mol% for C. coccoides 1410 and C. coccoides 3110, respectively. Cytochromes could not be detected. Formate was degraded exclusively to acetate, whereas vanillate was O-demethylated, resulting in acetate and 3,4-dihydroxybenzoate, the latter being further decarboxylated to catechol. In the presence of organic substrates, H2 was cometabolized to acetate, but both strains failed to grow autotrophically. Lactose, lactulose, sorbitol, glucose, and various other carbohydrates supported growth as well. Untypical of homoacetogens, glucose and sorbitol were fermented not exclusively to acetate; instead, considerable amounts of succinate and D-lactate were produced. H2 was evolved from carbohydrates only in negligible traces. Acetogenesis from formate plus H2 plus CO2 or vanillate plus H2 plus CO2 was constitutive, whereas utilization of carbohydrates was inducible. Hydrogenase, CO dehydrogenase, formate dehydrogenase, and all of the tetrahydrofolic acid-dependent, C1 compound-converting enzymes of the acetyl-coenzyme A pathway of homoacetogenesis were present in cell extracts. PMID:9143110

  7. Metabolism and excretion of anacetrapib, a novel inhibitor of the cholesteryl ester transfer protein, in humans.

    PubMed

    Kumar, Sanjeev; Tan, Eugene Y; Hartmann, Georgy; Biddle, Zachary; Bergman, Arthur J; Dru, James; Ho, Jonathan Z; Jones, Allen N; Staskiewicz, Steve J; Braun, Matthew P; Karanam, Bindhu; Dean, Dennis C; Gendrano, Isaias Noel; Graves, Mark W; Wagner, John A; Krishna, Rajesh

    2010-03-01

    Anacetrapib is a novel cholesteryl ester transfer protein inhibitor being developed for the treatment of primary hypercholesterolemia and mixed dyslipidemia. The absorption, distribution, metabolism, and excretion of anacetrapib were investigated in an open-label study in which six healthy male subjects received a single oral dose of 150 mg and 165 microCi of [(14)C]anacetrapib. Plasma, urine, and fecal samples were collected at predetermined times for up to 14 days postdose and were analyzed for total radioactivity, the parent compound, and metabolites. The majority of the administered radioactivity (87%) was eliminated by fecal excretion, with negligible amounts present in urine (0.1%). The peak level of radioactivity in plasma (approximately 2 microM equivalents of [(14)C]anacetrapib) was achieved approximately 4 h postdose. The parent compound was the major radioactive component (79-94% of total radioactivity) in both plasma and feces. Three oxidative metabolites, M1, M2, and M3, were detected in plasma and feces and were identified as the O-demethylated species (M1) and two secondary hydroxylated derivatives of M1 (M2 and M3). Each metabolite was detected at low levels, representing

  8. Application of physiologically based pharmacokinetic modeling in predicting drug–drug interactions for sarpogrelate hydrochloride in humans

    PubMed Central

    Min, Jee Sun; Kim, Doyun; Park, Jung Bae; Heo, Hyunjin; Bae, Soo Hyeon; Seo, Jae Hong; Oh, Euichaul; Bae, Soo Kyung

    2016-01-01

    Background Evaluating the potential risk of metabolic drug–drug interactions (DDIs) is clinically important. Objective To develop a physiologically based pharmacokinetic (PBPK) model for sarpogrelate hydrochloride and its active metabolite, (R,S)-1-{2-[2-(3-methoxyphenyl)ethyl]-phenoxy}-3-(dimethylamino)-2-propanol (M-1), in order to predict DDIs between sarpogrelate and the clinically relevant cytochrome P450 (CYP) 2D6 substrates, metoprolol, desipramine, dextromethorphan, imipramine, and tolterodine. Methods The PBPK model was developed, incorporating the physicochemical and pharmacokinetic properties of sarpogrelate hydrochloride, and M-1 based on the findings from in vitro and in vivo studies. Subsequently, the model was verified by comparing the predicted concentration-time profiles and pharmacokinetic parameters of sarpogrelate and M-1 to the observed clinical data. Finally, the verified model was used to simulate clinical DDIs between sarpogrelate hydrochloride and sensitive CYP2D6 substrates. The predictive performance of the model was assessed by comparing predicted results to observed data after coadministering sarpogrelate hydrochloride and metoprolol. Results The developed PBPK model accurately predicted sarpogrelate and M-1 plasma concentration profiles after single or multiple doses of sarpogrelate hydrochloride. The simulated ratios of area under the curve and maximum plasma concentration of metoprolol in the presence of sarpogrelate hydrochloride to baseline were in good agreement with the observed ratios. The predicted fold-increases in the area under the curve ratios of metoprolol, desipramine, imipramine, dextromethorphan, and tolterodine following single and multiple sarpogrelate hydrochloride oral doses were within the range of ≥1.25, but <2-fold, indicating that sarpogrelate hydrochloride is a weak inhibitor of CYP2D6 in vivo. Collectively, the predicted low DDIs suggest that sarpogrelate hydrochloride has limited potential for causing

  9. Simultaneous Screening of Activities of Five Cytochrome P450 and Four Uridine 5'-Diphospho-glucuronosyltransferase Enzymes in Human Liver Microsomes Using Cocktail Incubation and Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Lee, Boram; Ji, Hyeon-Kyeong; Lee, Taeho; Liu, Kwang-Hyeon

    2015-07-01

    Cytochrome P450 (P450) and uridine 5'-diphospho-glucuronosyltransferase (UGT) are major metabolizing enzymes in the biotransformation of most drugs. Altered P450 and UGT activities are a potential cause of adverse drug-drug interaction. A method for the simultaneous evaluation of the activities of five P450s (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A) and four UGTs (UGT1A1, UGT1A4, UGT1A9, and UGT2B7) was developed using in vitro cocktail incubation and tandem mass spectrometry. The nine probe substrates used in this assay were phenacetin (CYP1A2), diclofenac (CYP2C9), S-mephenytoin (CYP2C19), dextromethorphan (CYP2D6), midazolam (CYP3A), 7-ethyl-10-hydroxy-camptothecin (SN-38) (UGT1A1), trifluoperazine (UGT1A4), mycophenolic acid (UGT1A9), and naloxone (UGT2B7). This new method involves incubation of two cocktail doses and single cassette analysis. The two cocktail doses and the concentration of each probe substrate in vitro were determined to minimize mutual drug interactions among substrates. Cocktail A comprised phenacetin, diclofenac, S-mephenytoin, dextromethorphan, and midazolam, whereas cocktail B comprised SN-38, trifluoperazine, mycophenolic acid, and naloxone. In the incubation study of these cocktails, the reaction mixtures were pooled and simultaneously analyzed using liquid chromatography-tandem mass spectrometry. The method was validated by comparing inhibition data obtained from the incubation of each probe substrate alone with data from the cocktail method. The IC50 values obtained in both cocktail and individual incubations were in agreement with values previously reported in the literature. This cocktail method offers a rapid and robust way to simultaneously evaluate phase I and II enzyme inhibition profiles of many new chemical entities. This new method will also be useful in the drug discovery process and for advancing the mechanistic understanding of drug interactions. PMID:25904760

  10. 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

  11. 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.

  12. Immunochemical detection of cytochrome P450 enzymes in liver microsomes of 27 cynomolgus monkeys.

    PubMed

    Uehara, Shotaro; Murayama, Norie; Nakanishi, Yasuharu; Zeldin, Darryl C; Yamazaki, Hiroshi; Uno, Yasuhiro

    2011-11-01

    The cynomolgus monkey is widely used as a primate model in preclinical studies because of its evolutionary closeness to humans. Despite their importance in drug metabolism, the content of each cytochrome P450 (P450) enzyme has not been systematically determined in cynomolgus monkey livers. In this study, liver microsomes of 27 cynomolgus monkeys were analyzed by immunoblotting using selective P450 antibodies. The specificity of each antibody was confirmed by analyzing the cross-reactivity against 19 CYP1-3 subfamily enzymes using recombinant proteins. CYP2A, CYP2B6, CYP2C9/19, CYP2C76, CYP2D, CYP2E, CYP3A4, and CYP3A5 were detected in all 27 animals. In contrast, CYP1A, CYP1D, and CYP2J were below detectable levels in all liver samples. The average content of each P450 showed that among the P450s analyzed CYP3A (3A4 and 3A5) was the most abundant (40% of total immunoquantified P450), followed by CYP2A (25%), CYP2C (14%), CYP2B6 (13%), CYP2E1 (11%), and CYP2D (3%). No apparent sex differences were found for any P450. Interanimal variations ranged from 2.6-fold (CYP3A) to 11-fold (CYP2C9/19), and most P450s (CYP2A, CYP2D, CYP2E, CYP3A4, and CYP3A5) varied 3- to 4-fold. To examine the correlations of P450 content with enzyme activities, metabolic assays were performed in 27 cynomolgus monkey livers using 7-ethoxyresorufin, coumarin, pentoxyresorufin, flurbiprofen, bufuralol, dextromethorphan, and midazolam. CYP2D and CYP3A4 contents were significantly correlated with typical reactions of human CYP2D (bufuralol 1'-hydroxylation and dextromethorphan O-deethylation) and CYP3A (midazolam 1'-hydroxylation and 4-hydroxylation). The results presented in this study provide useful information for drug metabolism studies using cynomolgus monkeys.

  13. Application of physiologically based pharmacokinetic modeling in predicting drug–drug interactions for sarpogrelate hydrochloride in humans

    PubMed Central

    Min, Jee Sun; Kim, Doyun; Park, Jung Bae; Heo, Hyunjin; Bae, Soo Hyeon; Seo, Jae Hong; Oh, Euichaul; Bae, Soo Kyung

    2016-01-01

    Background Evaluating the potential risk of metabolic drug–drug interactions (DDIs) is clinically important. Objective To develop a physiologically based pharmacokinetic (PBPK) model for sarpogrelate hydrochloride and its active metabolite, (R,S)-1-{2-[2-(3-methoxyphenyl)ethyl]-phenoxy}-3-(dimethylamino)-2-propanol (M-1), in order to predict DDIs between sarpogrelate and the clinically relevant cytochrome P450 (CYP) 2D6 substrates, metoprolol, desipramine, dextromethorphan, imipramine, and tolterodine. Methods The PBPK model was developed, incorporating the physicochemical and pharmacokinetic properties of sarpogrelate hydrochloride, and M-1 based on the findings from in vitro and in vivo studies. Subsequently, the model was verified by comparing the predicted concentration-time profiles and pharmacokinetic parameters of sarpogrelate and M-1 to the observed clinical data. Finally, the verified model was used to simulate clinical DDIs between sarpogrelate hydrochloride and sensitive CYP2D6 substrates. The predictive performance of the model was assessed by comparing predicted results to observed data after coadministering sarpogrelate hydrochloride and metoprolol. Results The developed PBPK model accurately predicted sarpogrelate and M-1 plasma concentration profiles after single or multiple doses of sarpogrelate hydrochloride. The simulated ratios of area under the curve and maximum plasma concentration of metoprolol in the presence of sarpogrelate hydrochloride to baseline were in good agreement with the observed ratios. The predicted fold-increases in the area under the curve ratios of metoprolol, desipramine, imipramine, dextromethorphan, and tolterodine following single and multiple sarpogrelate hydrochloride oral doses were within the range of ≥1.25, but <2-fold, indicating that sarpogrelate hydrochloride is a weak inhibitor of CYP2D6 in vivo. Collectively, the predicted low DDIs suggest that sarpogrelate hydrochloride has limited potential for causing

  14. 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

  15. 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

  16. 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

  17. 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.

  18. Involvement of multiple cytochrome P450 and UDP-glucuronosyltransferase enzymes in the in vitro metabolism of muraglitazar.

    PubMed

    Zhang, Donglu; Wang, Lifei; Chandrasena, Gamini; Ma, Li; Zhu, Mingshe; Zhang, Hongjian; Davis, Carl D; Humphreys, W Griffith

    2007-01-01

    Muraglitazar (Pargluva), a dual alpha/gamma peroxisome proliferator-activated receptor activator, has both glucose- and lipid-lowering effects in animal models and in patients with diabetes. The human major primary metabolic pathways of muraglitazar include acylglucuronidation, aliphatic/aryl hydroxylation, and O-demethylation. This study describes the identification of human cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) enzymes involved in the in vitro metabolism of muraglitazar. [(14)C]Muraglitazar was metabolized by cDNA-expressed CYP2C8, 2C9, 2C19, 2D6, and 3A4, but to a very minimal extent by CYP1A2, 2A6, 2B6, 2C18, 2E1, and 3A5. Inhibition of the in vitro metabolism of muraglitazar in human liver microsomes, at a clinically efficacious concentration, by chemical inhibitors and monoclonal antibodies further supported involvement of CYP2C8, 2C9, 2C19, 2D6, and 3A4 in its oxidation. A combination of intrinsic clearance (V(max)/K(m)) and relative concentrations of each P450 enzyme in the human liver was used to predict the contribution of CYP2C8, 2C9, 2C19, 2D6, and 3A4 to the formation of each primary oxidative metabolite and to the overall oxidative metabolism of muraglitazar. Glucuronidation of [(14)C]muraglitazar was catalyzed by cDNA-expressed UGT1A1, 1A3, and 1A9, but not by UGT1A6, 1A8, 1A10, 2B4, 2B7, and 2B15. The K(m) values for muraglitazar glucuronidation by the three active UGT enzymes were similar (2-4 muM). In summary, muraglitazar was metabolized by multiple P450 and UGT enzymes to form multiple metabolites. This characteristic predicts a low potential for the alteration of the pharmacokinetic parameters of muraglitazar via polymorphic drug metabolism enzymes responsible for clearance of the compound or by coadministration of drugs that inhibit or induce relevant metabolic enzymes. PMID:17062778

  19. In vitro characterization of the metabolic pathways and cytochrome P450 inhibition and induction potential of BMS-690514, an ErbB/vascular endothelial growth factor receptor inhibitor.

    PubMed

    Hong, Haizheng; Su, Hong; Ma, Li; Yao, Ming; Iyer, Ramaswamy A; Humphreys, W Griffith; Christopher, Lisa J

    2011-09-01

    (3R,4R)-4-Amino-1-((4-((3-methoxyphenyl)amino)pyrrolo[2,1-f][1,2,4]triazin-5-yl)methyl)-3-piperidinol (BMS-690514) is a potent inhibitor of ErbB human epidermal growth factor receptors (HER1, 2, and 4) and vascular endothelial growth factor receptors 1 to 3 that has been under clinical development for solid tumor malignancies. BMS-690514 is primarily cleared by metabolism with the primary metabolic pathways being direct glucuronidation (M6), hydroxylation (M1, M2, and M37), and O-demethylation (M3). In the current investigation, the metabolic drug-drug interaction potential of BMS-690514 was evaluated in a series of in vitro studies. Reaction phenotyping experiments with cDNA-expressed human cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) enzymes and human liver microsomes (HLM) in the presence of P450 or UGT inhibitors suggested that CYP3A4, CYP2D6, and CYP2C9 were the major enzymes responsible for the oxidative metabolism of BMS-690514, whereas both UGT2B4 and UGT2B7 were responsible for the formation of M6. BMS-690514 did not cause direct or time-dependent inhibition of P450 enzymes (IC(50) values ≥40 μM) in incubations with HLM and probe substrates of CYP1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, or 3A4. The compound also did not substantially induce CYP1A1, CYP1A2, CYP2B6, CYP3A4, or UGT1A1 at concentrations up to 10 μM in cultured human hepatocytes. Considering the submicromolar plasma C(max) concentration at the anticipated clinical dose of 200 mg, BMS-690514 is unlikely to cause clinically relevant drug-drug interactions when coadministered with other medications. In addition, because multiple enzymatic clearance pathways are available for the compound, inhibition of an individual metabolic pathway either via coadministered drugs or gene polymorphisms is not expected to cause pronounced (>2-fold) increases in BMS-690514 exposure. PMID:21673131

  20. A tetrahydrofolate-dependent O-demethylase, LigM, is crucial for catabolism of vanillate and syringate in Sphingomonas paucimobilis SYK-6.

    PubMed

    Abe, Tomokuni; Masai, Eiji; Miyauchi, Keisuke; Katayama, Yoshihiro; Fukuda, Masao

    2005-03-01

    Vanillate and syringate are converted into protocatechuate (PCA) and 3-O-methylgallate (3MGA), respectively, by O-demethylases in Sphingomonas paucimobilis SYK-6. PCA is further degraded via the PCA 4,5-cleavage pathway, while 3MGA is degraded through multiple pathways in which PCA 4,5-dioxygenase (LigAB), 3MGA 3,4-dioxygenase (DesZ), and an unidentified 3MGA O-demethylase and gallate dioxygenase are participants. For this study, we isolated a 4.7-kb SmaI fragment that conferred on Escherichia coli the activity required for the conversion of vanillate to PCA. The nucleotide sequence of this fragment revealed an open reading frame of 1,413 bp (ligM), the deduced amino acid sequence of which showed 49% identity with that of the tetrahydrofolate (H4folate)-dependent syringate O-demethylase gene (desA). The metF and ligH genes, which are thought to be involved in H4folate-mediated C1 metabolism, were located just downstream of ligM. The crude LigM enzyme expressed in E. coli converted vanillate and 3MGA to PCA and gallate, respectively, with similar specific activities, and only in the presence of H4folate; however, syringate was not a substrate for LigM. The disruption of ligM led to significant growth retardation on both vanillate and syringate, indicating that ligM is involved in the catabolism of these substrates. The ability of the ligM mutant to transform vanillate was markedly decreased, and this mutant completely lost the 3MGA O-demethylase activity. A ligM desA double mutant completely lost the ability to transform vanillate, thus indicating that desA also contributes to vanillate degradation. All of these results indicate that ligM encodes vanillate/3MGA O-demethylase and plays an important role in the O demethylation of vanillate and 3MGA, respectively.

  1. Characterization of the gallate dioxygenase gene: three distinct ring cleavage dioxygenases are involved in syringate degradation by Sphingomonas paucimobilis SYK-6.

    PubMed

    Kasai, Daisuke; Masai, Eiji; Miyauchi, Keisuke; Katayama, Yoshihiro; Fukuda, Masao

    2005-08-01

    Sphingomonas paucimobilis SYK-6 converts vanillate and syringate to protocatechuate (PCA) and 3-O-methylgallate (3MGA) in reactions with the tetrahydrofolate-dependent O-demethylases LigM and DesA, respectively. PCA is further degraded via the PCA 4,5-cleavage pathway, whereas 3MGA is metabolized via three distinct pathways in which PCA 4,5-dioxygenase (LigAB), 3MGA 3,4-dioxygenase (DesZ), and 3MGA O-demethylase (LigM) are involved. In the 3MGA O-demethylation pathway, LigM converts 3MGA to gallate, and the resulting gallate appears to be degraded by a dioxygenase other than LigAB or DesZ. Here, we isolated the gallate dioxygenase gene, desB, which encodes a 418-amino-acid protein with a molecular mass of 46,843 Da. The amino acid sequences of the N-terminal region (residues 1 to 285) and the C-terminal region (residues 286 to 418) of DesB exhibited ca. 40% and 27% identity with the sequences of the PCA 4,5-dioxygenase beta and alpha subunits, respectively. DesB produced in Escherichia coli was purified and was estimated to be a homodimer (86 kDa). DesB specifically attacked gallate to generate 4-oxalomesaconate as the reaction product. The K(m) for gallate and the V(max) were determined to be 66.9 +/- 9.3 microM and 42.7 +/- 2.4 U/mg, respectively. On the basis of the analysis of various SYK-6 mutants lacking the genes involved in syringate degradation, we concluded that (i) all of the three-ring cleavage dioxygenases are involved in syringate catabolism, (ii) the pathway involving LigM and DesB plays an especially important role in the growth of SYK-6 on syringate, and (iii) DesB and LigAB are involved in gallate degradation.

  2. 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).

  3. 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.

  4. Surface-enhanced resonance Raman scattering of cytochrome P450-2D6 on coated silver hydrosols.

    PubMed

    Bonifacio, Alois; Keizers, Peter H J; Vermeulen, Nico P E; Commandeur, Jan N M; Gooijer, Cees; van der Zwan, Gert

    2007-02-13

    Surface-enhanced resonance Raman scattering (SERRS) from dilute solutions (down to nanomolar concentrations) of human mono-oxygenase CYP2D6 is observed using aqueous dispersions of Ag nanoparticles (hydrosol) coated with self-assembled monolayers (SAMs) of mercaptoalkanoic acids of two different lengths. From a direct comparison with its resonance Raman spectrum in solution, CYP2D6 appears to fully retain its native structure upon adsorption on coated hydrosol through electrostatic interaction, while a structural change in the active site is observed when uncoated citrate-reduced hydrosol is used. Using SERRS on these biocompatible coated hydrosols, the effects of dextromethorphan on the enzyme's active site can be observed, demonstrating that CYP2D6 ability of binding substrates is preserved. Moreover, by tuning the wavelength of the exciting laser away from the main absorption band of the heme, the vibrational bands of the SAM coating are observed and analyzed to see how the presence of the protein affects the SAM structure.

  5. 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

  6. Transcranial random noise stimulation-induced plasticity is NMDA-receptor independent but sodium-channel blocker and benzodiazepines sensitive

    PubMed Central

    Chaieb, Leila; Antal, Andrea; Paulus, Walter

    2015-01-01

    Background: Application of transcranial random noise stimulation (tRNS) between 0.1 and 640 Hz of the primary motor cortex (M1) for 10 min induces a persistent excitability increase lasting for at least 60 min. However, the mechanism of tRNS-induced cortical excitability alterations is not yet fully understood. Objective: The main aim of this study was to get first efficacy data with regard to the possible neuronal effect of tRNS. Methods: Single-pulse transcranial magnetic stimulation (TMS) was used to measure levels of cortical excitability before and after combined application of tRNS at an intensity of 1 mA for 10 min stimulation duration and a pharmacological agent (or sham) on eight healthy male participants. Results: The sodium channel blocker carbamazepine showed a tendency toward inhibiting MEPs 5–60 min poststimulation. The GABAA agonist lorazepam suppressed tRNS-induced cortical excitability increases at 0–20 and 60 min time points. The partial NMDA receptor agonist D-cycloserine, the NMDA receptor antagonist dextromethorphan and the D2/D3 receptor agonist ropinirole had no significant effects on the excitability increases seen with tRNS. Conclusions: In contrast to transcranial direct current stimulation (tDCS), aftereffects of tRNS are seem to be not NMDA receptor dependent and can be suppressed by benzodiazepines suggesting that tDCS and tRNS depend upon different mechanisms. PMID:25914617

  7. 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

  8. Neuroprotective effects of psychotropic drugs in Huntington's disease.

    PubMed

    Lauterbach, Edward C

    2013-11-15

    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.

  9. Neuroprotective Activity of Pongamia pinnata in Monosodium Glutamate-induced Neurotoxicity in Rats

    PubMed Central

    Swamy, A. H. M. VISWANATHA; Patel, N. L.; Gadad, P. C.; Koti, B. C.; Patel, U. M.; Thippeswamy, A. H. M.; Manjula, D. V.

    2013-01-01

    This study was designed to evaluate the neuroprotective activity of ethanol extract of Pongamia pinnata stem bark in monosodium glutamate-induced neurotoxicity in rats. Neurotoxicity was induced by intraperitoneal injection of monosodium glutamate 2 g per kg body weight daily for 7 days. Ethanol extract of Pongamia pinnata stem bark (200 and 400 mg/kg) was administered orally after 1 h of monosodium glutamate treatment. Dextromethorphan (30 mg/kg, p.o.) was used as standard drug for the comparison. The degree of protection was determined by various behavioural, locomotor, muscle grip activity, lipid peroxidation and measurement of antioxidant status of glutathione, catalase and superoxide dismutase. Estimation of calcium, sodium and potassium ions in brain tissue and gamma aminobutyric acid level in serum was carried out. The histopathological study of brain tissue was also carried out. Treatment with Pongamia pinnata significantly improved monosodium glutamate-induced alteration in behavioural and locomotor activity and muscle strength. Significant decrease in lipid peroxidation and increase in glutathione, superoxide dismutase and catalase was observed in Pongamia pinnata treated group. Further, Pongamia pinnata also significantly reduced the monosodium glutamate-induced excitotoxicity by decreasing the level of Ca+2 and Na+ with concomitant increase in the level of K+. Serum gamma aminobutyric acid level was also increased in Pongamia pinnata treated animals. Further, the histopathological evidence supports the neuroprotective activity of Pongamia pinnata. In conclusion, the present study suggests that the ethanol extract of stem bark of Pongamia pinnata possesses significant neuroprotective activity in albino rats. PMID:24591740

  10. Neuroprotective Activity of Pongamia pinnata in Monosodium Glutamate-induced Neurotoxicity in Rats.

    PubMed

    Swamy, A H M Viswanatha; Patel, N L; Gadad, P C; Koti, B C; Patel, U M; Thippeswamy, A H M; Manjula, D V

    2013-11-01

    This study was designed to evaluate the neuroprotective activity of ethanol extract of Pongamia pinnata stem bark in monosodium glutamate-induced neurotoxicity in rats. Neurotoxicity was induced by intraperitoneal injection of monosodium glutamate 2 g per kg body weight daily for 7 days. Ethanol extract of Pongamia pinnata stem bark (200 and 400 mg/kg) was administered orally after 1 h of monosodium glutamate treatment. Dextromethorphan (30 mg/kg, p.o.) was used as standard drug for the comparison. The degree of protection was determined by various behavioural, locomotor, muscle grip activity, lipid peroxidation and measurement of antioxidant status of glutathione, catalase and superoxide dismutase. Estimation of calcium, sodium and potassium ions in brain tissue and gamma aminobutyric acid level in serum was carried out. The histopathological study of brain tissue was also carried out. Treatment with Pongamia pinnata significantly improved monosodium glutamate-induced alteration in behavioural and locomotor activity and muscle strength. Significant decrease in lipid peroxidation and increase in glutathione, superoxide dismutase and catalase was observed in Pongamia pinnata treated group. Further, Pongamia pinnata also significantly reduced the monosodium glutamate-induced excitotoxicity by decreasing the level of Ca(+2) and Na(+) with concomitant increase in the level of K(+). Serum gamma aminobutyric acid level was also increased in Pongamia pinnata treated animals. Further, the histopathological evidence supports the neuroprotective activity of Pongamia pinnata. In conclusion, the present study suggests that the ethanol extract of stem bark of Pongamia pinnata possesses significant neuroprotective activity in albino rats.

  11. [Emergent drugs (II): the Pharming phenomenon].

    PubMed

    Burillo-Putze, G; Aldea-Perona, A; Rodríguez-Jiménez, C; García-Sáiz, M M; Climent, B; Dueñas, A; Munné, P; Nogué, S; Hoffman, R S

    2013-01-01

    The use of medicines, with or without medical prescription, for recreational ends by the young population has received little attention from doctors. In the USA, one in five adolescents has used medicines for recreational purposes, and consultations in Emergency Departments for medicine abuse have exceeded those for illegal drugs. Although few data are available in Spain, such consumption is situated between 3.1 and 8.6% according to surveys. The medicines most used are dextromethorphan and methylphenidate. The former, on sale without prescription, presents a varied symptomatology, dosage and dependent metabolic action, ranging from euphoria to hallucinations. Methylphenidate, taken orally, nasally or intravenously, is used as a stimulant in substitution for cocaine and is one of the medicines most diverted onto the illicit market at the world level. In principle, other substances like modafinil and propofol present a limited incidence of non-medical use, but they have a probable abuse potential that should be borne in mind, above all in the health context. Finally, opiates like fentanyl, oxycodone and buprenorphine, with new pharmaceutical presentations, have recently become generalized in the therapeutic arsenal of many medical specialities; they are giving rise to phenomena of abuse, dependence and diversion towards the illicit market. Demands for detoxification treatment, their mixture with illegal substances, and cases of death should alert us to the abuse of these medicines.

  12. Cocktail approach for in vivo phenotyping of 5 major CYP450 isoenzymes: development of an effective sampling, extraction, and analytical procedure and pilot study with comparative genotyping.

    PubMed

    Wohlfarth, Ariane; Naue, Jana; Lutz-Bonengel, Sabine; Dresen, Sebastian; Auwärter, Volker

    2012-08-01

    In this study, the authors developed a phenotyping method for CYP1A2, 2C9, 2C19, 2D6, and 3A4 using a cocktail of 100 mg caffeine, 125 mg tolbutamide, 20 mg omeprazole, 30 mg dextromethorphan, and 2 mg midazolam. A simple sampling scheme was established collecting 3 blood samples at 0, 4, and 24 hours followed by solid-phase extraction and liquid chromatography/tandem mass spectrometry analysis. After addition of 8 deuterated internal standards and extraction, the analytes were separated using gradient elution with ammonium acetate and methanol. Data acquisition was performed on a triple quadrupole linear ion trap mass spectrometer in multiple-reaction monitoring mode with positive electrospray ionization. The assay was validated according to international guidelines: limits of quantification (LOQs) were between 0.25 and 1.0 ng/mL for all analytes, except for paraxanthine and caffeine (20 ng/mL). Extraction efficiencies ranged between 77% and 103% and matrix effects between 23% and 95%; precision and accuracy data fulfilled accepted criteria. Calibration curves from LOQ to 1000 ng/mL were established for undiluted and 1:10 diluted plasma (r > 0.998). The method was tested in a pilot study with 14 volunteers. Additional genotyping of the probands generally demonstrated good accordance with the measured phenotyping indices but also disclosed certain contradictory results.

  13. Pharmacological treatment of opioid-induced hyperalgesia: a review of the evidence.

    PubMed

    Ramasubbu, Chitra; Gupta, Anita

    2011-01-01

    Opioids are commonly used to treat moderate to severe pain. Opioid-induced hyperalgesia is a paradoxical response to opioid agonists resulting in an increased perception of pain rather than an antinociceptive effect. Even though there is a debate regarding its clinical relevance, it is becoming a challenge in both acute and chronic pain settings. The study of opioid-induced hyperalgesia is an emerging field with multiple challenges faced by investigators with regard to defining the diagnosis and characterizing the findings. The objective of this study was to review the preliminary evidence related to the treatment and management of opioid-induced hyperalgesia. Lack of data, small patient numbers, short-term follow-up, and variations in study design limited the review. With the literature on this subject being sparse, this study attempts to provide a preliminary look at the available data and to set the stage for an eventual meta-analysis. Case reports in the literature have shown success with various pharmacological interventions. Possible treatment regimens include ketamine, dextromethorphan, and nonsteroidal anti-inflammatory drugs (NSAIDs), opioid switching, amantadine, buprenorphine, α(2) agonists, and methadone. These agents are briefly discussed in this paper. Further well-designed, placebo-controlled trials are needed to assess the effectiveness of the interventions investigated in this review.

  14. Potential inhibitory effect of herbal medicines on rat hepatic cytochrome P450 2D gene expression and metabolic activity.

    PubMed

    Al-Jenoobi, F I; Korashy, H M; Ahad, A; Raish, M; Al-Mohizea, A M; Alam, M A; Al-Suwayeh, S A; Alkharfy, K M

    2014-11-01

    The aim of current study was to investigate the effect of some commonly used medicinal herbs on the regulation of rat CYP2D gene expression and its metabolic activity. Wistar albino rats were treated for seven consecutive days with selected doses of five commonly used herbs (Trigonella foenum-graecum, Ferula asafoetida, Nigella sativa, Commiphora myrrha and Lepidium sativum). Thereafter, rat livers were harvested and CYP2D mRNA levels were determined by RT-PCR. The metabolic activity of CYP2D was performed on rat hepatic microsomes using dextromethorphan as specific substrate. All investigated herbs produced inhibition of CYP2D mRNA expression and metabolic activity. The inhibitory potential of investigated herbs on rat CYP2D mRNA was in the following order: Commiphora myrrha > Nigella sativa > Lepidium sativum > Trigonella foenum-graecum > Ferula asafoetida. Whereas, the inhibitory potential of investigated herbs on CYP2D mediated enzyme metabolic activity was found in following order: Nigella sativa > Lepidium sativum > Trigonella foenum-graecum > Commiphora myrrha > Ferula asafoetida. The current study shows that only used herbs reduce CYP2D activity in rat liver microsomes at the transcriptional levels. Such effects could lead to undesirable pharmacological effects of clinically used low therapeutic index CYP2D substrate drugs.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Antitussive and toxicological evaluation of Vitex negundo.

    PubMed

    Haq, Rizwan-ul; Shah, Azhar-ul-Haq Ali; Khan, Arif-ullah; Ullah, Zahoor; Khan, Habib-ullah; Khan, Rafeeq Alam; Malik, Abdul

    2012-01-01

    Vitex negundo Linn. (Verbenaceae) is used in traditional medical system for respiratory disorders. This study was carried out to investigate its cough-relieving potential. The antitussive effect of the butanolic extract of V. negundo (Vn) on sulphur dioxide (SO(2))-induced cough was examined in mice. Safety profile of Vn was carried out by observing acute neurotoxicity, median lethal dose (LD(50)) and behavioural signs. Vn dose-dependently (250-1000 mg kg(-1)) inhibited the cough provoked by SO(2) gas in mice and exhibited maximum protection after 60 min of administration. At 1000 mg kg(-1), Vn caused maximum cough-suppressive effects i.e. cough inhibition at 60 min was 67.4%, as compared to codeine (10 mg kg(-1)), dextromethorphan (10 mg kg(-1)) and saline having cough-inhibitory potential 75.7%, 74.7% and 0%, respectively. LD(50) value of V. negundo was found to be greater than 5000 mg kg(-1). In toxicity tests, no signs of neural impairment and acute behavioural toxicity were observed at antitussive doses and extract has been well tolerated at higher doses. These results indicate that V. negundo exhibits antitussive effect and it was found devoid of toxicity.

  20. Where are the new cough treatments: a debriefing of recent clinical proof-of-concept trials with the NOP agonist SCH 486757.

    PubMed

    McLeod, Robbie L; Tulshian, Deen B; Sadeh, Jonathan

    2011-01-01

    Cough continues to be one of the top reasons why patients seek medical attention from health care providers. The prescription antitussive market is dominated by opioids, such as codeine that produces inconsistent efficacy and is often accompanied by significant side effect liabilities. Consequently, cough represents an unmet medical need and an underserved market. Yet, against the backdrop of increasing cough research, the development of novel treatments has been exceptionally challenging with dextromethorphan being the last US drug approved for cough almost a half century ago. We support the position that an unambiguous and actionable 'road map' that clearly delineates the pathway forward for new cough suppressants from basic research to and beyond clinical proof-of-concept studies will be an important aspect for future success of this pharmacological class of drug. Pivotal to the establishment of such a road map will be the review of lessons learned from antitussive agents that have been recently progressed to proof-of-concept trials. In the present commentary, we briefly discuss observations and challenges pertaining to SCH 486757, a selective orally active NOP agonist that has recently advanced to human antitussive testing.

  1. 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.

  2. NMDA Receptors as Potential Therapeutic Targets in Diabetic Nephropathy: Increased Renal NMDA Receptor Subunit Expression in Akita Mice and Reduced Nephropathy Following Sustained Treatment With Memantine or MK-801.

    PubMed

    Roshanravan, Hila; Kim, Eun Young; Dryer, Stuart E

    2016-10-01

    N-methyl-d-aspartate (NMDA) receptors are expressed throughout the kidney, and the abundance of these receptors and some of their endogenous agonists are increased in diabetes. Moreover, sustained activation of podocyte NMDA receptors induces Ca(2+) influx, oxidative stress, loss of slit diaphragm proteins, and apoptosis. We observed that NMDA receptor subunits and their transcripts are increased in podocytes and mesangial cells cultured in elevated glucose compared with controls. A similar increase in NMDA subunits, especially NR1, NR2A, and NR2C, was observed in glomeruli and tubules of Akita mice. Sustained continuous treatment with the strong NMDA receptor antagonist dizocilpine (MK-801) for 28 days starting at 8 weeks of age reduced 24-h albumin excretion and mesangial matrix expansion and improved glomerular ultrastructure in Akita mice. MK-801 did not alleviate reduced Akita mouse body weight and had no effect on kidney histology or ultrastructure in DBA/2J controls. The structurally dissimilar NMDA antagonist memantine also reduced diabetic nephropathy, although it was less effective than MK-801. Inhibition of NMDA receptors may represent a valid therapeutic approach to reduce renal complications of diabetes, and it is possible to develop well-tolerated agents with minimal central nervous system effects. Two such agents, memantine and dextromethorphan, are already in widespread clinical use.

  3. 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

  4. 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

  5. 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

  6. 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

  7. [Emergent drugs (II): the Pharming phenomenon].

    PubMed

    Burillo-Putze, G; Aldea-Perona, A; Rodríguez-Jiménez, C; García-Sáiz, M M; Climent, B; Dueñas, A; Munné, P; Nogué, S; Hoffman, R S

    2013-01-01

    The use of medicines, with or without medical prescription, for recreational ends by the young population has received little attention from doctors. In the USA, one in five adolescents has used medicines for recreational purposes, and consultations in Emergency Departments for medicine abuse have exceeded those for illegal drugs. Although few data are available in Spain, such consumption is situated between 3.1 and 8.6% according to surveys. The medicines most used are dextromethorphan and methylphenidate. The former, on sale without prescription, presents a varied symptomatology, dosage and dependent metabolic action, ranging from euphoria to hallucinations. Methylphenidate, taken orally, nasally or intravenously, is used as a stimulant in substitution for cocaine and is one of the medicines most diverted onto the illicit market at the world level. In principle, other substances like modafinil and propofol present a limited incidence of non-medical use, but they have a probable abuse potential that should be borne in mind, above all in the health context. Finally, opiates like fentanyl, oxycodone and buprenorphine, with new pharmaceutical presentations, have recently become generalized in the therapeutic arsenal of many medical specialities; they are giving rise to phenomena of abuse, dependence and diversion towards the illicit market. Demands for detoxification treatment, their mixture with illegal substances, and cases of death should alert us to the abuse of these medicines. PMID:23648497

  8. 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.

  9. 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

  10. 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

  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. 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

  13. 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

  14. A simplified analytical method for a phenotyping cocktail of major CYP450 biotransformation routes.

    PubMed

    Jerdi, Mallorie Clement; Daali, Youssef; Oestreicher, Mitsuko Kondo; Cherkaoui, Samir; Dayer, Pierre

    2004-09-01

    An efficient, fast and reliable analytical method was developed for the simultaneous evaluation of the activities of five major human drug metabolising cytochrome P450 (1A2, 2C9, 2C19, 2D6 and 3A4) with a cocktail approach including five probe substances, namely caffeine, flurbiprofen, omeprazole, dextromethorphan and midazolam. All substances were administered simultaneously and a single plasma sample was obtained 2h after the administration. Plasma samples were handled by liquid-liquid extraction and analysed by gradient high performance liquid chromatography (HPLC) coupled to UV and fluorescence detectors. The chromatographic separation was achieved using a Discovery semi-micro HS C18 HPLC column (5 microm particle size, 150 mm x 2.1 mm i.d.) protected by a guard column (5 microm particle size, 20 mm x 2.1 mm i.d.) The mobile phase was constituted of a methanol, acetonitrile and 20mM ammonium acetate (pH 4.5) with 0.1% triethylamine mixture and was delivered at a flow rate of 0.3 mL min(-1). All substances were separated simultaneously in a single run lasting less than 22 min. The HPLC method was formally validated and showed good performances in terms of linearity, sensitivity, precision and accuracy. Finally, the method was found suitable for the screening of these compounds in plasma samples.

  15. 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.

  16. Geneva Cocktail for Cytochrome P450 and P-Glycoprotein Activity Assessment Using Dried Blood Spots

    PubMed Central

    Bosilkovska, M; Samer, C F; Déglon, J; Rebsamen, M; Staub, C; Dayer, P; Walder, B; Desmeules, J A; Daali, Y

    2014-01-01

    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

  17. 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.

  18. Bitter taste receptor T2R1 activities were compatible with behavioral sensitivity to bitterness in chickens.

    PubMed

    Hirose, Nozomi; Kawabata, Yuko; Kawabata, Fuminori; Nishimura, Shotaro; Tabata, Shoji

    2015-05-01

    Clarification of the mechanism of the sense of taste in chickens will provide information useful for creating and improving new feedstuffs for chickens, because the character of the taste receptors in oral tissues affects feeding behavior in animals. In this study, we focused on the sensitivity to bitterness in chickens. We cloned one of the bitter taste receptors, T2R1, from the chicken palate, constructed several biosensor-cells expressing chicken T2R1 (cT2R1), and determined a highly sensitive biosensor of cT2R1 among them. By using Ca(2+) imaging methods, we identified two agonists of cT2R1, dextromethorphan (Dex) and diphenidol (Dip). Dex was a new agonist of cT2R1 that was more potent than Dip. In a behavioral drinking study, the intake volumes of solutions of these compounds were significantly lower than that of water in chickens. These aversive concentrations were identical to the concentrations that could activate cT2R1 in a cell-based assay. These results suggest that the cT2R1 activities induced by these agonists are linked to behavioral sensitivity to bitterness in chickens.

  19. Simplified reversed-phase HPLC method with spectrophotometric detection for the assay of verapamil in rat plasma.

    PubMed

    Lau-Cam, C A; Piemontese, D

    1998-02-01

    A high-performance liquid chromatographic (HPLC) method was developed for the assay of verapamil in rat plasma. After deproteinization of the plasma sample with an acetonitrile-perchloric acid (8:2) mixture containing dextromethorphan, the internal standard, an aliquot of the supernatant was directly analyzed on a cyanopropylsilane column with methanol-acetonitrile-triethylamine acetate buffer (10:30:60) as the mobile phase and detection at 235 mm. At a flow rate of 1.5 ml min-1, a complete analysis was completed in less than 6 min. The method was linear for verapamil concentrations in the range 0.5-10 micrograms ml-1 (r = 0.9999). Recoveries for the same drug concentrations from spiked rat plasma ranged from 85.6-93.0% (n = 8). The mean RSD values for intraday and interday assay reproducibility (n = 3) were, in both cases, less than 0.9%. The limit of detectability was about 0.1 microgram ml-1. The method was found useful to monitor the plasma levels of verapamil in rats that had received this drug by the nasal, oral and intravenous routes of administration.

  20. 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

  1. Desorption electrospray ionization (DESI) with atmospheric pressure ion mobility spectrometry for drug detection.

    PubMed

    Roscioli, Kristyn M; Tufariello, Jessica A; Zhang, Xing; Li, Shelly X; Goetz, Gilles H; Cheng, Guilong; Siems, William F; Hill, Herbert H

    2014-04-01

    Desorption electrospray ionization (DESI) was coupled to an ambient pressure drift tube ion mobility time-of-flight mass spectrometer (IM-TOFMS) for the direct analysis of active ingredients in pharmaceutical samples. The DESI source was also coupled with a standalone IMS demonstrating potential of portable and inexpensive drug-quality testing platforms. The DESI-IMS required no sample pretreatment as ions were generated directly from tablets and cream formulations. The analysis of a range of over-the-counter and prescription tablet formations was demonstrated for amphetamine (methylphenidate), antidepressant (venlafaxine), barbiturate (Barbituric acid), depressant (alprazolam), narcotic (3-methylmorphine) and sympatholytic (propranolol) drugs. Active ingredients from soft and liquid formulations, such as Icy Hot cream (methyl salicylate) and Nyquil cold medicine (acetaminophen, dextromethorphan, doxylamine) were also detected. Increased sensitivity for selective drug responses was demonstrated through the formation of sodiated adduct ions by introducing small quantities of NaCl into the DESI solvent. Of the drugs and pharmaceuticals tested in this study, 68% (22 total samples) provided a clear ion mobility response at characteristic mobilities either as (M + H)(+), (M - H)(-), or (M + Na)(+) ions.

  2. 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

  3. 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

  4. Over the counter drugs (and dietary supplement) exercise: a team-based introduction to biochemistry for health professional students.

    PubMed

    Phadtare, Sangita; Abali, Emine; Brodsky, Barbara

    2013-01-01

    For successful delivery of basic science topics for health-professional students, it is critical to reduce apprehension and illustrate relevance to clinical settings and everyday life. At the beginning of the Biochemistry course for Physician Assistants, a team-based assignment was designed to develop an understanding of the mechanism of action, effectiveness, and toxicity of five common over the counter (OTC) drugs and dietary supplements, and place these familiar medicines in a political and historical context. The objectives of this exercise were to stimulate interest in biochemistry; to provide basic information on enzymes and enzyme inhibitors related to these drugs to be expanded upon later in the course; and to encourage active and interactive learning. Teams of five students were formed, and each student was given an information sheet on aspirin, alpha-galactosidase, orlistat, dextromethorphan, or simvastatin, a low dose statin, which was previously available without prescription at pharmacies in the UK. After each member of the team acquired information on one OTC drug/dietary supplement by reading an assigned information sheet, the team was asked to go through a series of questions, and then submit answers to a quiz as a group. A high rate of success on the quiz, an overwhelmingly positive response on formal course evaluations, and enthusiastic exchanges during class suggested this team-based session accomplished its goals.

  5. Drugs that antagonize limb flick behavior induced by D-lysergic acid diethylamide (LSD) in cats.

    PubMed

    Haigler, H J; Spring, D D

    1979-06-28

    In cats observed in their home cages limb flicks (LF) are a sensitive measure of the behavioral effects of LSD. LF induced by LSD (50 microgram/kg) were blocked by dextrorphan (0.6 mg/kg), dextromethorphan (0.6 mg/kg), and imipramine (5 mg/kg) at doses that did not produce ataxia or sleep. Levorphanol (0.6 mg/kg), a narcotic that is a congener of dextrorphan, did not block LF induced by LSD possibly because it produced an excitatory effect when given alone. Pentobarbital at low doses (2 and 4 mg/kg) increased the number of LF induced by LSD but at a high dose (8 mg/kg) decreased LF induced by LSD either by producing ataxia, so the cats tended to remain immobile, or by producing sleep. Chlorpromazine (CPZ) at three doses (2, 4, and 8 mg/kg) attenuated the effects of LSD on LF, but did not block LF as completely as the above three blocking drugs, and produced ataxia and sleep.

  6. 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.

  7. Role of calcium, glutamate and NMDA in major depression and therapeutic application.

    PubMed

    Deutschenbaur, Lorenz; Beck, Johannes; Kiyhankhadiv, Anna; Mühlhauser, Markus; Borgwardt, Stefan; Walter, Marc; Hasler, Gregor; Sollberger, Daniel; Lang, Undine E

    2016-01-01

    Major depression is a common, recurrent mental illness that affects millions of people worldwide. Recently, a unique fast neuroprotective and antidepressant treatment effect has been observed by ketamine, which acts via the glutamatergic system. Hence, a steady accumulation of evidence supporting a role for the excitatory amino acid neurotransmitter (EAA) glutamate in the treatment of depression has been observed in the last years. Emerging evidence indicates that N-methyl-D-aspartate (NMDA), group 1 metabotropic glutamate receptor antagonists and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) agonists have antidepressant properties. Indeed, treatment with NMDA receptor antagonists has shown the ability to sprout new synaptic connections and reverse stress-induced neuronal changes. Based on glutamatergic signaling, a number of therapeutic drugs might gain interest in the future. Several compounds such as ketamine, memantine, amantadine, tianeptine, pioglitazone, riluzole, lamotrigine, AZD6765, magnesium, zinc, guanosine, adenosine aniracetam, traxoprodil (CP-101,606), MK-0657, GLYX-13, NRX-1047, Ro25-6981, LY392098, LY341495, D-cycloserine, D-serine, dextromethorphan, sarcosine, scopolamine, pomaglumetad methionil, LY2140023, LY404039, MGS0039, MPEP, 1-aminocyclopropanecarboxylic acid, all of which target this system, have already been brought up, some of them recently. Drugs targeting the glutamatergic system might open up a promising new territory for the development of drugs to meet the needs of patients with major depression. PMID:25747801

  8. Current drugs for the treatment of dry cough.

    PubMed

    Padma, L

    2013-05-01

    Cough is one of the commonest symptoms of respiratory tract infections and is a frequent problem encountered in general practice as well as in hospital practice. A wide range of disease processes may present with cough and definitive treatment depends on identifying the cause and diagnosis. Specific treatment of the cause should control the cough, but this may not occur in all cases and in a sizeable proportion of patients, no associated cause can be found. An increased sensitivity of the cough reflex can be observed in patients with dry cough. Symptomatic relief must be considered when the cough interferes with the patient's daily activities and this is effectively treated with antitussive preparations which are available as combinations of codeine or dextromethorphan with antihistamines, decongestants and expectorants Antitussives are used for effective symptomatic relief of dry or non-productive cough. First generation antihistamines like chlorpheniramine and centrally acting opioid derivatives like codeine are often used alone or in combination in the management of nonspecific cough. Sedation caused by these is valuable, particularly if the cough is disturbing the sleep. Although there is extensive experimental data on single agent antitussives and antitussive combinations, there is a major paucity of published literature on these combinations in nonspecific cough. Treatment of dry cough remains a challenge in some patients and this article reviews the scope of the current drugs and combination of Codeine and Chlorpheniramine in the effective management of dry cough.

  9. [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.

  10. 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

  11. Acute encephalomyelitis complicated with severe neurological sequelae after intrathecal administration of methotrexate in a patient with acute lymphoblastic leukemia.

    PubMed

    Nishikawa, Takuro; Okamoto, Yasuhiro; Maruyama, Shinsuke; Tanabe, Takayuki; Kurauchi, Koichiro; Kodama, Yuichi; Nakagawa, Shunsuke; Shinkoda, Yuichi; Kawano, Yoshifumi

    2014-11-01

    A four-year-old girl on maintenance therapy for acute lymphoblastic leukemia (ALL) complained of a headache and low back pain on the day she received her 21st intrathecal methotrexate (it-MTX) administration, and the next day experienced numbness and pain in her foot. This numbness gradually spread to her hand. She thereafter developed a fever and was hospitalized on day 8. After antibiotic therapy, the fever disappeared. However, her lower limbs became paralyzed, and she also developed urinary retention. On day 12, her paralysis progressed upwards, and she also developed paralysis of the upper limbs. Finally, she experienced convulsions with an impairment of consciousness. A magnetic resonance imaging study of the brain and spinal cord showed abnormal signals in the brain cortex and anterior horn. Accordingly, we diagnosed acute encephalomyelitis associated with it-MTX. High-dose intravenous immunoglobulin, steroid pulse therapy, plasma exchange, and dextromethorphan administration were initiated, while she received mechanical ventilation. Despite this intensive treatment, she suffered severe neurological damage and had to be maintained on mechanical ventilation due to persistent flaccid quadriplegia one year after the onset. When patients have symptoms of ascending paralysis during it-MTX treatment, clinicians should carefully consider the possibility of acute encephalomyelitis due to it-MTX. PMID:25501412

  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. 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

  15. Studies on the potency of various antitussive agents.

    PubMed

    Wang, S C; Chou, D T; Wallenstein, M C

    1977-09-01

    Several antitussive agents were assessed for their cough-suppressant activity. Cough responses were obtained by electrically stimulating the lower brainstem, in cats lightly anesthetized with sodium pentobarbital or in unanesthetized midcollicular decerebrate preparations. Cough sounds were recorded with the aid of a microphone. The cough reactive region was concentrated in an area dorsomedial to the trigeminal tract and nucleus. The potency of these antitussive agents (dextromethorphan, RO 21-4790-001, codeine, clonazepam, diazepam and caramiphen) were determined by studying their effect on the centrally induced cough responses. Each of these agents was administered in graded doses intravenously to determine the minimal effective doses for suppressing the cough responses. They are 0.57, 2.55, 1.71, 0.048, 0.28 and 3.18 mg/kg for the above listed drugs. The results indicate that clonazepam was found to be the most potent antitussive among these agents, the mean effective dose being about 1/35 of that of codeine. The antitussive potency of benzodiazepines is not well correlated with their muscle relaxant activity. For instance, clonazepam and diazepam have the same potency in depressing polysynaptic spinal reflexes, whereas the former is six times more potent than diazepam as an antitussive. This finding indicates that clonazepam has a high specificity as an antitussive.

  16. Ion mobility spectrometry for the rapid analysis of over-the-counter drugs and beverages.

    PubMed

    Fernández-Maestre, Roberto; Hill, Herbert H

    2009-08-01

    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.

  17. 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

  18. 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

  19. 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

  20. 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.

  1. Labeling by ( sup 3 H)1,3-di(2-tolyl)guanidine of two high affinity binding sites in guinea pig brain: Evidence for allosteric regulation by calcium channel antagonists and pseudoallosteric modulation by sigma ligands

    SciTech Connect

    Rothman, R.B.; Reid, A.; Mahboubi, A.; Kim, C.H.; De Costa, B.R.; Jacobson, A.E.; Rice, K.C. )

    1991-02-01

    Equilibrium binding studies with the sigma receptor ligand ({sup 3}H)1,3-di(2-tolyl)guanidine (({sup 3}H)DTG) demonstrated two high affinity binding sites in membranes prepared from guinea pig brain. The apparent Kd values of DTG for sites 1 and 2 were 11.9 and 37.6 nM, respectively. The corresponding Bmax values were 1045 and 1423 fmol/mg of protein. Site 1 had high affinity for (+)-pentazocine, haloperidol, (R)-(+)-PPP, carbepentane, and other sigma ligands, suggesting a similarity with the dextromethorphan/sigma 1 binding site described by Musacchio et al. (Life Sci. 45:1721-1732 (1989)). Site 2 had high affinity for DTG and haloperidol (Ki = 36.1 nM) and low affinity for most other sigma ligands. Kinetic experiments demonstrated that ({sup 3}H)DTG dissociated in a biphasic manner from both site 1 and site 2. DTG and haloperidol increased the dissociation rate of ({sup 3}H)DTG from site 1 and site 2, demonstrating the presence of pseudoallosteric interactions. Inorganic calcium channel blockers such as Cd2+ selectively increased the dissociation rate of ({sup 3}H)DTG from site 2, suggesting an association of this binding site with calcium channels.

  2. 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.

  3. 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

  4. Prediction of Drug Clearance and Drug-Drug Interactions in Microscale Cultures of Human Hepatocytes.

    PubMed

    Lin, Christine; Shi, Julianne; Moore, Amanda; Khetani, Salman R

    2016-01-01

    Accurate prediction of in vivo hepatic drug clearance using in vitro assays is important to properly estimate clinical dosing regimens. Clearance of low-turnover compounds is especially difficult to predict using short-lived suspensions of unpooled primary human hepatocytes (PHHs) and functionally declining PHH monolayers. Micropatterned cocultures (MPCCs) of PHHs and 3T3-J2 fibroblasts have been shown previously to display major liver functions for several weeks in vitro. In this study, we first characterized long-term activities of major cytochrome P450 enzymes in MPCCs created from unpooled cryopreserved PHH donors. MPCCs were then used to predict the clearance of 26 drugs that exhibit a wide range of turnover rates in vivo (0.05-19.5 ml/min per kilogram). MPCCs predicted 73, 92, and 96% of drug clearance values for all tested drugs within 2-fold, 3-fold, and 4-fold of in vivo values, respectively. There was good correlation (R(2) = 0.94, slope = 1.05) of predictions between the two PHH donors. On the other hand, suspension hepatocytes and conventional monolayers created from the same donor had significantly reduced predictive capacity (i.e., 30-50% clearance values within 4-fold of in vivo), and were not able to metabolize several drugs. Finally, we modulated drug clearance in MPCCs by inducing or inhibiting P450s. Rifampin-mediated CYP3A4 induction increased midazolam clearance by 73%, while CYP3A4 inhibition with ritonavir decreased midazolam clearance by 79%. Similarly, quinidine-mediated CYP2D6 inhibition reduced clearance of dextromethorphan and desipramine by 71 and 22%, respectively. In conclusion, MPCCs created using cryopreserved unpooled PHHs can be used for drug clearance predictions and to model drug-drug interactions. PMID:26452722

  5. The effects of milk thistle (Silybum marianum) on human cytochrome P450 activity.

    PubMed

    Kawaguchi-Suzuki, Marina; Frye, Reginald F; Zhu, Hao-Jie; Brinda, Bryan J; Chavin, Kenneth D; Bernstein, Hilary J; Markowitz, John S

    2014-10-01

    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.

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Effects of Seijo-bofu-to, a traditional Japanese herbal medicine containing furanocoumarin derivatives, on the drug-metabolizing enzyme activities in healthy male volunteers.

    PubMed

    Saruwatari, Junji; Takashima, Ayaka; Yoshida, Kousuke; Soraoka, Hiromi; Ding, Tong-Bin; Uchiyashiki, Yoshihiro; Tsuda, Yoshiyuki; Imamura, Motoki; Oniki, Kentaro; Miyata, Keishi; Nakagawa, Kazuko

    2014-10-01

    Seijo-bofu-to, a traditional medicine used to treat acne in Asian countries, contains twelve herbal components, including Angelica dahurica root, a source of furanocoumarin derivatives. In this study, we investigated potential herb-drug interactions of seijo-bofu-to in healthy male volunteers. Thirty-two young, healthy, non-smoking males were assessed for the baseline activity of cytochrome P450 (CYP) 1A2, CYP3A, CYP2D6, N-acetyltransferase 2 and xanthine oxidase according to the urinary metabolic indices of 8-hr urine samples collected after the administration of a 150-mg dose of caffeine and a 30-mg dose of dextromethorphan, and the ratio of urinary excretion of 6β-hydroxycortisol to cortisol. Thereafter, the volunteers received 3.75 g of seijo-bofu-to twice daily for 7 days and underwent the same tests on post-dose day 7. The geometric mean ratio of the CYP1A2 activity on day 7 to that observed at baseline was 0.66 (95% CI, 0.55-0.79, p = 0.001). The geometric mean phenotypic indices for CYP3A, CYP2D6, N-acetyltransferase 2 and xanthine oxidase on day 7 did not differ from the baseline values. The findings of the present study suggest that seijo-bofu-to may inhibit the activity of CYP1A2, whereas it is unlikely to participate in herb-drug interactions involving medications predominantly metabolized by CYP3A, CYP2D6, N-acetyltransferase 2 or xanthine oxidase.

  12. 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.

  13. Antitussive activity of sigma-1 receptor agonists in the guinea-pig.

    PubMed

    Brown, Claire; Fezoui, Malika; Selig, William M; Schwartz, Carl E; Ellis, James L

    2004-01-01

    1. 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. 2. 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. 3. 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)). 4. 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.

  14. 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

  15. 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

  16. 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

  17. 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

  18. Contribution of the activities of CYP3A, CYP2D6, CYP1A2 and other potential covariates to the disposition of methadone in patients undergoing methadone maintenance treatment

    PubMed Central

    Shiran, Mohammad-Reza; Lennard, Martin S; Iqbal, Mohammad-Zafar; Lagundoye, Oldwale; Seivewright, Nicholas; Tucker, Geoffrey T; Rostami-Hodjegan, Amin

    2009-01-01

    AIMS To investigate the influence of different cytochrome P450 (CYP) activities and other potential covariates on the disposition of methadone in patients on methadone maintenance therapy (MMT). METHODS Eighty-eight patients (58 male; 21–55 years; 84 White) on MMT were studied. CYP2D6 activity [3 h plasma metabolic ratio of dextromethorphan (DEX) to dextrorphan (DOR)] was determined in 44 patients (29 male; 24–55 years), CYP1A2 activity (salivary caffeine elimination half-life) in 44 patients (21 male; 24–55 years) and CYP3A activity (oral clearance of midazolam) in 49 patients (33 male; 23–55 years). Data on all three CYPs were obtained from 32 subjects. Total plasma concentrations of (RS)-methadone and total and unbound plasma concentrations of both enantiomers were measured by LC/MS. Population pharmacokinetics and subsequent multiple regression analysis were used to calculate methadone oral clearance and to identify its covariates. RESULTS Between 61 and 68% of the overall variation in total plasma trough concentrations of (RS)-, (R)- and (S)-methadone was explained by methadone dose, duration of addiction before starting MMT, CYP3A activity and illicit morphine use. CYP3A activity explained 22, 16, 15 and 23% of the variation in unbound (R)-, unbound (S)-, total (RS)- and total (S)-methadone clearances, respectively. Neither CYP2D6 nor CYP1A2 activity was related to methadone disposition. CONCLUSIONS CYP3A activity has a modest influence on methadone disposition. Inhibitors and inducers of this enzyme should be monitored in patients taking methadone. PMID:19133059

  19. 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

  20. 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.

  1. Resveratrol modulates drug- and carcinogen-metabolizing enzymes in a healthy volunteer study.

    PubMed

    Chow, H-H Sherry; Garland, Linda L; Hsu, Chiu-Hsieh; Vining, Donna R; Chew, Wade M; Miller, Jessica A; Perloff, Marjorie; Crowell, James A; Alberts, David S

    2010-09-01

    Resveratrol has been shown to exhibit cancer-preventive activities in preclinical studies. We conducted a clinical study to determine the effect of pharmacologic doses of resveratrol on drug- and carcinogen-metabolizing enzymes. Forty-two healthy volunteers underwent baseline assessment of cytochrome P450 (CYP) and phase II detoxification enzymes. CYP1A2, CYP2D6, CYP2C9, and CYP3A4 enzyme activities were measured by the metabolism of caffeine, dextromethorphan, losartan, and buspirone, respectively. Blood lymphocyte glutathione S-transferase (GST) activity and GST-pi level and serum total and direct bilirubin, a surrogate for UDP-glucuronosyl transferase (UGT) 1A1 activity, were measured to assess phase II enzymes. After the baseline evaluation, study participants took 1 g of resveratrol once daily for 4 weeks. Enzyme assessment was repeated upon intervention completion. Resveratrol intervention was found to inhibit the phenotypic indices of CYP3A4, CYP2D6, and CYP2C9 and to induce the phenotypic index of 1A2. Overall, GST and UGT1A1 activities were minimally affected by the intervention, although an induction of GST-pi level and UGT1A1 activity was observed in individuals with low baseline enzyme level/activity. We conclude that resveratrol can modulate enzyme systems involved in carcinogen activation and detoxification, which may be one mechanism by which resveratrol inhibits carcinogenesis. However, pharmacologic doses of resveratrol could potentially lead to increased adverse drug reactions or altered drug efficacy due to inhibition or induction of certain CYPs. Further clinical development of resveratrol for cancer prevention should consider evaluation of lower doses of resveratrol to minimize adverse metabolic drug interactions. PMID:20716633

  2. 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.

  3. 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

  4. “Is This a Drug?” Answers From Medical Students in a Tertiary Care Teaching Hospital in Eastern India

    PubMed Central

    Kundu, Tania Sur; Sengupta, Parama; Ghosh, Arijit; Das, Nina

    2016-01-01

    Introduction World Health Organization (WHO) defines what is drug and what is not. Second year MBBS students learn the principles of Pharmacology that they use in their later clinical practice life. The aim of the survey was to determine how medical students classify a range of preparations they might encounter in their professional lives and whether a brand name or a commercial preparation of a drug would influence their decision in the categorization of the preparation as a ‘drug’ or ‘not a drug’. Aim To assess the knowledge of medical students, if a substance or product is a drug. Materials and Methods We surveyed 2 concurrent years of medical students to classify 60 candidate medicinal preparations into “drug” and “not-drug” from a validated questionnaire. The candidate preparations were named either in generic or in their commercially available forms and they were all essential drugs as per WHO definition. Results The two groups of students, A and B, included 192 and 215 students respectively. Demographically there was little difference in the two groups. Agents like Aspirin, Paracetamol, Amphetamine, Salbutamol, Atropine, Dextromethorphan, Codeine, Diazepam, Ciprofloxacin ear drops, Levonorgestrol, Neosporin eye ointment, Furosemide, Metronidazole, Penicillin, Sorbitrate, Lignocaine, Methotrexate, Penicillin, Zolpidem and Thalidomide received almost unanimous votes as drugs. Arsenic trioxide, Fentanyl and petroleum jelly were considered to be “non-drugs” by most participants. The two groups did not differ significantly in their responses. Conclusion Some major lacunae were noted in the knowledge of the participating students despite book teaching on the definition of a drug. Drugs used for prophylaxis and those used in physiological conditions or topically, were often missed. These gaps need to be filled by more emphasis on definition of a drug and its clinical applicability based on example and case based studies. PMID:27656461

  5. 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

  6. 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

  7. 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

  8. An evaluation of the CYP2D6 and CYP3A4 inhibition potential of metoprolol metabolites and their contribution to drug-drug and drug-herb interaction by LC-ESI/MS/MS.

    PubMed

    Borkar, Roshan M; Bhandi, Murali Mohan; Dubey, Ajay P; Ganga Reddy, V; Komirishetty, Prashanth; Nandekar, Prajwal P; Sangamwar, Abhay T; Kamal, Ahmed; Banerjee, Sanjay K; Srinivas, R

    2016-10-01

    The aim of the present study was to evaluate the contribution of metabolites to drug-drug interaction and drug-herb interaction using the inhibition of CYP2D6 and CYP3A4 by metoprolol (MET) and its metabolites. The peak concentrations of unbound plasma concentration of MET, α-hydroxy metoprolol (HM), O-desmethyl metoprolol (ODM) and N-desisopropyl metoprolol (DIM) were 90.37 ± 2.69, 33.32 ± 1.92, 16.93 ± 1.70 and 7.96 ± 0.94 ng/mL, respectively. The metabolites identified, HM and ODM, had a ratio of metabolic area under the concentration-time curve (AUC) to parent AUC of ≥0.25 when either total or unbound concentration of metabolite was considered. In vitro CYP2D6 and CYP3A4 inhibition by MET, HM and ODM study revealed that MET, HM and ODM were not inhibitors of CYP3A4-catalyzed midazolam metabolism and CYP2D6-catalyzed dextromethorphan metabolism. However, DIM only met the criteria of >10% of the total drug related material and <25% of the parent using unbound concentrations. If CYP inhibition testing is solely based on metabolite exposure, DIM metabolite would probably not be considered. However, the present study has demonstrated that DIM contributes significantly to in vitro drug-drug interaction. Copyright © 2016 John Wiley & Sons, Ltd.

  9. N-acyl-2-substituted-1,3-thiazolidines, a new class of non-narcotic antitussive agents: studies leading to the discovery of ethyl 2-[(2-methoxyphenoxy)methyl]-beta-oxothiazolidine-3-propanoate.

    PubMed

    Gandolfi, C A; Di Domenico, R; Spinelli, S; Gallico, L; Fiocchi, L; Lotto, A; Menta, E; Borghi, A; Dalla Rosa, C; Tognella, S

    1995-02-01

    The synthesis of a novel class of antitussive agents is described. The compounds were examined for antitussive activity in guinea pig after cough induction by electrical or chemical stimulation. Ethyl 2-[(2-methoxyphenoxy)methyl]-beta-oxothiazolidine-3-propanoate (BBR 2173, moguisteine, 7) and other structurally related compounds showed a significant level of activity, comparable to that of codeine and dextromethorphan. The compounds presented in this paper are characterized by the N-acyl-2-substituted-1,3-thiazolidine moiety, which is a novel entry in the field of antitussive agents. The serendipitous discovery of the role played by the thiazolidine moiety in determining the antitussive effect promoted extensive investigations on these structures. This optimization process on N-acyl-2-substituted-1,3-thiazolidines led to the initial identification of 2-[(2-methoxypheoxy)methyl]-3-[2-(acetylthio)acetyl]- 1,3-thiazolidine (18a) as an interesting lead compound. The careful study of the rapid and very complicated metabolism of 18a provided further insights for the design of newer related derivatives. The observation that the metabolic oxidation on the lateral chain's sulfur of 18a to sulfoxide maintained the antitussive properties suggested the introduction of isosteric functional groups with respect to the sulfoxide moiety. Subsequent structural modifications showed that hydrolyzable malonic residues in the 3-position of the thiazolidine ring were able to assure high antitussive activity. This optimization ultimately led to the selection of moguisteine (7) as the most effective and safest representative of the series. Moguisteine is completely devoid of unwanted side effects (such as sedation and addiction), and its activity was demonstrated also in clinical studies.

  10. 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

  11. 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

  12. 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

  13. Insights into drug metabolism by cytochromes P450 from modelling studies of CYP2D6-drug interactions.

    PubMed

    Maréchal, J-D; Kemp, C A; Roberts, G C K; Paine, M J I; Wolf, C R; Sutcliffe, M J

    2008-03-01

    The cytochromes P450 (CYPs) comprise a vast superfamily of enzymes found in virtually all life forms. In mammals, xenobiotic metabolizing CYPs provide crucial protection from the effects of exposure to a wide variety of chemicals, including environmental toxins and therapeutic drugs. Ideally, the information on the possible metabolism by CYPs required during drug development would be obtained from crystal structures of all the CYPs of interest. For some years only crystal structures of distantly related bacterial CYPs were available and homology modelling techniques were used to bridge the gap and produce structural models of human CYPs, and thereby obtain useful functional information. A significant step forward in the reliability of these models came seven years ago with the first crystal structure of a mammalian CYP, rabbit CYP2C5, followed by the structures of six human enzymes, CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2D6 and CYP3A4, and a second rabbit enzyme, CYP2B4. In this review we describe as a case study the evolution of a CYP2D6 model, leading to the validation of the model as an in silico tool for predicting binding and metabolism. This work has led directly to the successful design of CYP2D6 mutants with novel activity-including creating a testosterone hydroxylase, converting quinidine from inhibitor to substrate, creating a diclofenac hydroxylase and creating a dextromethorphan O-demethylase. Our modelling-derived hypothesis-driven integrated interdisciplinary studies have given key insight into the molecular determinants of CYP2D6 and other important drug metabolizing enzymes. PMID:18026129

  14. Enantioselective metabolism of the endocrine disruptor pesticide methoxychlor by human cytochromes P450 (P450s): major differences in selective enantiomer formation by various P450 isoforms.

    PubMed

    Hu, Yiding; Kupfer, David

    2002-12-01

    Methoxychlor, a currently used pesticide that in mammals elicits proestrogenic/estrogenic activity and reproductive toxicity, has been classified as a prototype endocrine disruptor. Methoxychlor is prochiral, and its metabolites 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane (mono-OH-M); 1,1,1-trichloro- 2-(4-methoxyphenyl)-2-(3, 4-dihydroxyphenyl)ethane (catechol-M); and 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(3, 4-dihydroxyphenyl)ethane (tris-OH-M) are chiral; whereas 1,1,1-trichloro-2, 2-bis(4-hydroxyphenyl)ethane (bis-OH-M) is achiral. These metabolites are formed during methoxychlor incubation with liver microsomes or recombinant cytochrome p450s (rp450s). Since methoxychlor-metabolite enantiomers may have different estrogenic/antiestrogenic/antiandrogenic activities than corresponding racemates, the possibility that p450s preferentially generate or use R or S enantiomers, was examined. Indeed, rCYP1A2 and r2A6 mono-demethylated methoxychlor primarily into (R)-mono-OH-M at 91 and 75%, respectively, whereas rCYP1A1, 2B6, 2C8, 2C9, 2C19, and 2D6 formed the (S)-enantiomer at 69, 66, 75, 95, 96, and 80%, respectively. However, rCYP3A4, 3A5, and 2B1(rat) weakly demethylated methoxychlor without enantioselectivity. Human liver microsomes generated (S)-mono-OH-M (77-87%), suggesting that CYP1A2 and 2A6 display only minor catalytic contribution. P450 inhibitors demonstrated that CYP2C9 and possibly 2C19 are major hepatic catalysts forming (S)-mono-OH-M, and CYP1A2 is primarily involved in forming the (R)-mono-OH-M. Demethylation rate of (S)-mono-OH-M versus (R)-mono-OH-M forming achiral bis-OH-M by rCYP1A2 was 97/3, compared with 15/85 and 17/83 for rCYP2C9 and 2C19, respectively, indicating opposite substrate enantioselectivity of rCYP1A2 versus 2C9 and 2C19. Also, rCYP1A2 preferentially O-demethylated (R)-catechol-M into (R)-tris-OH-M (at 80%), contrasting r2C9 and r2C19 that yielded (S)-tris-OH-M at 80 and 77%, respectively. Ortho-hydroxylation of

  15. 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.

  16. 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

  17. [Inhibitory effect of imperatorin and isoimperatorin on activity of cytochrome P450 enzyme in human and rat liver microsomes].

    PubMed

    Cao, Yan; Zhong, Yu-Huan; Yuan, Mei; Li, Hua; Zhao, Chun-Jie

    2013-04-01

    Imperatorin (IM) and isoimperatorin (ISOIM) are major active components of common herbal medicines from Umbelliferae plants, and widely used in clinic. This article studies the inhibitory effect of IM and ISOIM on the activity of cytochrome P450 (CYP) enzyme, and assesses their potential drug-drug interaction. IM and ISOIM were incubated separately with human or rat liver microsomes for 30 min, with phenacetin, bupropion, tolbutamide, S-mephenytoin, dextromethorphan and midazolam as probe substrates. Metabolites of the CYP probe substrates were determined by LC-MS/MS, and IC50 values were calculated to assess the inhibitory effect of the two drugs on human CYP1A2, 2B6, 2C9, 2C19, 2D6 and 3A4 enzymes, as well as on rat CYP1A2, 2B6, 2D2 and 3A1/2, and grade their inhibitory intensity. In human liver microsomes, IM and ISOIM showed different inhibitory effects on all of the six CYP isoenzymes. They were strong inhibitors for 1A2 and 2B6. The IC50 values were 0.05 and 0.20 micromol x L(-1) for 1A2, and 0.18 and 1.07 micromol x L(-1) for 2B6, respectively. They also showed moderate inhibitory effect on 2C19, and weak effect on 2C9, 2D6 and 3A4. In rat liver microsomes, IM and ISOIM were identified as moderate inhibitors for 1A2, with IC50 values of 1.95 and 2.98 micromol x L(-1). They were moderate and weak inhibitors for 2B6, with IC50 values of 6.22 and 21.71 micromol x L(-1), respectively. They also had weaker inhibitory effect on 2D2 and 3A1/2. The results indicated that IM and ISOIM had extensive inhibitory effects on human CYP enzymes. They are strong inhibitors of CYP1 A2 and 2B6 enzymes. However, it is worth noting the interaction arising from the inhibitory effect of CYP enzymes in clinic.

  18. Classification of compounds for prevention of NMDLA-induced seizures/mortality, or maximal electroshock and pentylenetetrazol seizures in mice and antagonism of MK801 binding in vitro.

    PubMed

    Palmer, G C; Harris, E W; Ray, R; Stagnitto, M L; Schmiesing, R J

    1992-01-01

    Intravenous injection of N-methyl-D,L-aspartic acid (NMDLA) into mice produces characteristic convulsions followed by death. The present study was designed to determine the degree of blockade of these seizures/mortality by compounds acting at various subsites on the N-methyl-D-aspartic acid (NMDA) receptor complex (competitive and noncompetitive antagonists, as well as inhibitors of the strychnine-insensitive glycine subsite, and Zn++ subsite agonists), and also calcium channel blockers, clinically used anticonvulsants, plus selected compounds with activities or structures similar to specific agents chosen. Activity among compounds was correlated to in vitro potency regarding inhibition of binding of MK801 to the ionic channel subsite associated with the NMDA receptor. Furthermore, all compounds were examined for antiseizure properties with respect to tonic hindlimb extension elicited by maximal electroshock (MES) and clonus induced by pentylenetetrazol (PTZ). Drugs were subsequently classified according to their spectra of efficacy in these tests. The following characteristics emerged: 1) agents active at all 3 NMDA mechanisms (convulsions/mortality/MK801 binding) plus MES and PTZ, were MK801 and CPP [3-(2-carboxypiperazin-4-yl) propyl-1-phosphonic acid]; 2) active at all the NMDA mechanisms and MES were ketamine and dextromethorphan; 3) active against NMDLA-induced convulsions/mortality, MES and PTZ, but not MK801 binding, were doxepin, desipramine and diazepam; 4) active against NMDLA-induced convulsions/mortality and MES were des-Me-doxepin, flunarizine and remacemide; 5) active against NMDLA-induced convulsions/mortality and PTZ was nisoldipine; 6) active against only NMDLA-induced convulsions/mortality were chlorpheniramine and iproniazid; 7) active in the MES and PTZ tests were phenobarbital, pentobarbital and valproate; 8) active in the MES test alone were phenytoin and carbamazepine; 9) active against PTZ only was ethosuximide; 10) active only in the in

  19. Chronic Apocynin Treatment Attenuates Beta Amyloid Plaque Size and Microglial Number in hAPP(751)SL Mice

    PubMed Central

    Lull, Melinda E.; Levesque, Shannon; Surace, Michael J.; Block, Michelle L.

    2011-01-01

    Background NADPH oxidase is implicated in neurotoxic microglial activation and the progressive nature of Alzheimer's Disease (AD). Here, we test the ability of two NADPH oxidase inhibitors, apocynin and dextromethorphan (DM), to reduce learning deficits and neuropathology in transgenic mice overexpressing human amyloid precursor protein with the Swedish and London mutations (hAPP(751)SL). Methods Four month old hAPP(751)SL mice were treated daily with saline, 15 mg/kg DM, 7.5 mg/kg DM, or 10 mg/kg apocynin by gavage for four months. Results Only hAPP(751)SL mice treated with apocynin showed reduced plaque size and a reduction in the number of cortical microglia, when compared to the saline treated group. Analysis of whole brain homogenates from all treatments tested (saline, DM, and apocynin) demonstrated low levels of TNFα, protein nitration, lipid peroxidation, and NADPH oxidase activation, indicating a low level of neuroinflammation and oxidative stress in hAPP(751)SL mice at 8 months of age that was not significantly affected by any drug treatment. Despite in vitro analyses demonstrating that apocynin and DM ameliorate Aβ-induced extracellular superoxide production and neurotoxicity, both DM and apocynin failed to significantly affect learning and memory tasks or synaptic density in hAPP(751)SL mice. To discern how apocynin was affecting plaque levels (plaque load) and microglial number in vivo, in vitro analysis of microglia was performed, revealing no apocynin effects on beta-amyloid (Aβ) phagocytosis, microglial proliferation, or microglial survival. Conclusions Together, this study suggests that while hAPP(751)SL mice show increases in microglial number and plaque load, they fail to exhibit elevated markers of neuroinflammation consistent with AD at 8 months of age, which may be a limitation of this animal model. Despite absence of clear neuroinflammation, apocynin was still able to reduce both plaque size and microglial number, suggesting that apocynin

  20. 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

  1. 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

  2. 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

  3. Effects of Radix Astragali and Radix Rehmanniae, the components of an anti-diabetic foot ulcer herbal formula, on metabolism of model CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4 probe substrates in pooled human liver microsomes and specific CYP isoforms.

    PubMed

    Or, Penelope M Y; Lam, Francis F Y; Kwan, Y W; Cho, C H; Lau, C P; Yu, H; Lin, G; Lau, Clara B S; Fung, K P; Leung, P C; Yeung, John H K

    2012-04-15

    The present study investigated the effects of Radix Astragali (RA) and Radix Rehmanniae (RR), the major components of an anti-diabetic foot ulcer herbal formula (NF3), on the metabolism of model probe substrates of human CYP isoforms, CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4, which are important in the metabolism of a variety of xenobiotics. The effects of RA or RR on human CYP1A2 (phenacetin O-deethylase), CYP2C9 (tolbutamide 4-hydroxylase), CYP2D6 (dextromethorphan O-demethylase), CYP2E1 (chlorzoxazone 6-hydroxylase) and CYP3A4 (testosterone 6β-hydroxylase) activities were investigated using pooled human liver microsomes. NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.98mg/ml) and CYP3A4 (IC(50)=0.76mg/ml), with K(i) of 0.67 and 1.0mg/ml, respectively. With specific human CYP2C9 and CYP3A4 isoforms, NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.86mg/ml) and CYP3A4 (IC(50)=0.88mg/ml), with K(i) of 0.57 and 1.6mg/ml, respectively. Studies on RA or RR individually showed that RR was more important in the metabolic interaction with the model CYP probe substrates. RR dose-dependently inhibited the testosterone 6β-hydroxylation (K(i)=0.33mg/ml) while RA showed only minimal metabolic interaction potential with the model CYP probe substrates studied. This study showed that RR and the NF3 formula are metabolized mainly by CYP2C9 and/or CYP3A4, but weakly by CYP1A2, CYP2D6 and CYP2E1. The relatively high K(i) values of NF3 (for CYP2C9 and CYP3A4 metabolism) and RR (for CYP3A4 metabolism) would suggest a low potential for NF3 to cause herb-drug interaction involving these CYP isoforms.

  4. 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