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British Journal of Clinical Pharmacology Mar 1985The pharmacokinetics and pharmacodynamics of atenolol and timolol were studied in six extensive and four poor metabolisers of debrisoquine. There was a significant... (Comparative Study)
Comparative Study
The pharmacokinetics and pharmacodynamics of atenolol and timolol were studied in six extensive and four poor metabolisers of debrisoquine. There was a significant correlation between the debrisoquine to 4-hydroxydebrisoquine ratio and the area under the plasma concentration time curve (AUC) for timolol (rs = 0.75, P less than 0.02). The mean of the AUC values for timolol was significantly greater in the poor metabolisers than in the extensive metabolisers (P less than 0.05). There was a significant correlation between the debrisoquine to 4-hydroxydebrisoquine ratio and beta-adrenoceptor blockade 24 h after dosing with timolol (rs = 0.66, P less than 0.05). The mean degree of beta-adrenoceptor blockade was significantly greater in the poor metabolisers than in the extensive metabolisers 24 h after dosing with timolol (P less than 0.01). There was no relation between the debrisoquine to 4-hydroxydebrisoquine ratio and the pharmacokinetics or pharmacodynamics of atenolol.
Topics: Adrenergic beta-Antagonists; Adult; Atenolol; Chromatography, High Pressure Liquid; Debrisoquin; Heart Rate; Humans; Kinetics; Male; Oxidation-Reduction; Phenotype; Physical Exertion; Spectrophotometry, Ultraviolet; Timolol
PubMed: 2859048
DOI: 10.1111/j.1365-2125.1985.tb02651.x -
ACS Medicinal Chemistry Letters Jun 2023The COVID-19 pandemic has highlighted the need for new antiviral approaches because many of the currently approved drugs have proven ineffective against mitigating...
The COVID-19 pandemic has highlighted the need for new antiviral approaches because many of the currently approved drugs have proven ineffective against mitigating SARS-CoV-2 infections. The host transmembrane serine protease TMPRSS2 is a promising antiviral target because it plays a role in priming the spike protein before viral entry occurs for the most virulent variants. Further, TMPRSS2 has no established physiological role, thereby increasing its attractiveness as a target for antiviral agents. Here, we utilize virtual screening to curate large libraries into a focused collection of potential inhibitors. Optimization of a recombinant expression and purification protocol for the TMPRSS2 peptidase domain facilitates subsequent biochemical screening and characterization of selected compounds from the curated collection in a kinetic assay. In doing so, we identify new noncovalent TMPRSS2 inhibitors that block SARS-CoV-2 infectivity in a cellular model. One such inhibitor, debrisoquine, has high ligand efficiency, and an initial structure-activity relationship study demonstrates that debrisoquine is a tractable hit compound for TMPRSS2.
PubMed: 37284689
DOI: 10.1021/acsmedchemlett.3c00035 -
Brazilian Journal of Medical and... May 2000We describe a new simple, selective and sensitive micromethod based on HPLC and fluorescence detection to measure debrisoquine (D) and 4-hydroxydebrisoquine (4-OHD) in...
We describe a new simple, selective and sensitive micromethod based on HPLC and fluorescence detection to measure debrisoquine (D) and 4-hydroxydebrisoquine (4-OHD) in urine for the investigation of xenobiotic metabolism by debrisoquine hydroxylase (CYP2D6). Four hundred microl of urine was required for the analysis of D and 4-OHD. Peaks were eluted at 8.3 min (4-OHD), 14.0 min (D) and 16.6 min for the internal standard, metoprolol (20 microg/ml). The 5-microm CN-reverse-phase column (Shimpack, 250 x 4.6 mm) was eluted with a mobile phase consisting of 0.25 M acetate buffer, pH 5.0, and acetonitrile (9:1, v/v) at 0.7 ml/min with detection at lambdaexcitation = 210 nm and lambdaemission = 290 nm. The method, validated on the basis of measurements of spiked urine, presented 3 ng/ml (D) and 6 ng/ml (4-OHD) sensitivity, 390-6240 ng/ml (D) and 750-12000 ng/ml (4-OHD) linearity, and 5.7/8.2% (D) and 5.3/8.2% (4-OHD) intra/interassay precision. The method was validated using urine of a healthy Caucasian volunteer who received one 10-mg tablet of Declinax(R), po, in the morning after an overnight fast. Urine samples (diuresis of 4 or 6 h) were collected from zero to 24 h. The urinary excretion of D and 4-OHD, Fel (0-24 h), i.e., fraction of dose administered and excreted into urine, was 6.4% and 31.9%, respectively. The hydroxylation capacity index reported as metabolic ratio was 0.18 (D/4-OHD) for the person investigated and can be compared to reference limits of >12.5 for poor metabolizers (PM) and <12.5 for extensive metabolizers (EM). In parallel, the recovery ratio (RR), another hydroxylation capacity index, was 0.85 (4-OHD: SigmaD + 4-OHD) versus reference limits of RR <0.12 for PM and RR >0. 12 for EM. The healthy volunteer was considered to be an extensive metabolizer on the basis of the debrisoquine test.
Topics: Chromatography, High Pressure Liquid; Cytochrome P-450 CYP2D6; Debrisoquin; Female; Fluorometry; Humans; Hydroxylation; Middle Aged; Phenotype; Sensitivity and Specificity; Xenobiotics
PubMed: 10775881
DOI: 10.1590/s0100-879x2000000500004 -
Proceedings of the National Academy of... Mar 1994
Review
Topics: Debrisoquin; Humans; Pharmacogenetics; Polymerase Chain Reaction; Polymorphism, Genetic; Racial Groups
PubMed: 8134334
DOI: 10.1073/pnas.91.6.1983 -
British Journal of Clinical Pharmacology Jun 19951. The pharmacokinetics of ethylmorphine after administration of a single dose of the cough mixture Cosylan were investigated in 10 healthy subjects. 2. The median...
1. The pharmacokinetics of ethylmorphine after administration of a single dose of the cough mixture Cosylan were investigated in 10 healthy subjects. 2. The median urinary recovery of ethylmorphine and measured metabolites was 77% over 48 h. The median tmax of unchanged ethylmorphine was 45 min, and the terminal elimination t1/2 was 2 h. Ethylmorphine-6-glucuronide was found to be the major metabolite. 3. Two subjects had significantly lower urinary recovery (0.48 h) of morphine and morphine-glucuronides than the remainder. Furthermore, these two had urinary metabolic ratios (MRO) and partial metabolic clearances (CLmO) for O-deethylation of ethylmorphine tentatively classifying them phenotypically as poor metabolisers of the debrisoquine/sparteine type. 4. Genotyping for cytochrome P450 (CYP) 2D6 alleles revealed five homozygote (wt/wt) and five heterozygote subjects. Two subjects phenotypically classified as poor metabolisers were genotypically CYP2D6A/wt and CYP2D6D/wt, respectively. 5. Serum and urine samples taken more than 8 and 24 h after administration of ethyl-morphine respectively, contained morphine and morphine-glucuronides, but no ethylmorphine, ethylmorphine-6-glucuronide or (serum only) norethylmorphine. Norethylmorphine could be detected after hydrolysis of urine samples in all subjects. The urinary recovery of the active metabolites morphine and morphine-6-glucuronide after administration of ethylmorphine varied by a factor of 9 between individuals. 6. The wide variation in recovery of morphine and morphine-glucuronides after oral administration of ethylmorphine could not be explained simply by a difference in CYP2D6 genotype. Constitutional variation in other enzymatic pathways involved in ethylmorphine metabolism is probably crucial. Ratios of morphine to parent drug cannot be used to distinguish the source of morphine after administration of ethylmorphine. Norethylmorphine should be included in urine assays for opiates in forensic toxicology, and no firm conclusions about the source of morphine are possible based on serum samples obtained more than 24 h after drug administration.
Topics: Adult; Biotransformation; Cytochrome P-450 Enzyme System; Drug Administration Schedule; Ethylmorphine; Genotype; Glucuronates; Humans; Male; Morphine
PubMed: 7654478
DOI: 10.1111/j.1365-2125.1995.tb05720.x -
Clinical Pharmacology and Therapeutics May 2005Phytochemical-mediated modulation of cytochrome P450 (CYP) activity may underlie many herb-drug interactions. Single-time point phenotypic metabolic ratios were used to... (Clinical Trial)
Clinical Trial Comparative Study Randomized Controlled Trial
OBJECTIVES
Phytochemical-mediated modulation of cytochrome P450 (CYP) activity may underlie many herb-drug interactions. Single-time point phenotypic metabolic ratios were used to determine whether long-term supplementation of goldenseal ( Hydrastis canadensis ), black cohosh ( Cimicifuga racemosa ), kava kava ( Piper methysticum ), or valerian ( Valeriana officinalis ) extracts affected CYP1A2, CYP2D6, CYP2E1, or CYP3A4/5 activity.
METHODS
Twelve healthy volunteers (6 women) were randomly assigned to receive goldenseal, black cohosh, kava kava, or valerian for 28 days. For each subject, a 30-day washout period was interposed between each supplementation phase. Probe drug cocktails of midazolam and caffeine, followed 24 hours later by chlorzoxazone and debrisoquin (INN, debrisoquine), were administered before (baseline) and at the end of supplementation. Presupplementation and postsupplementation phenotypic trait measurements were determined for CYP3A4/5, CYP1A2, CYP2E1, and CYP2D6 by use of 1-hydroxymidazolam/midazolam serum ratios (1-hour sample), paraxanthine/caffeine serum ratios (6-hour sample), 6-hydroxychlorzoxazone/chlorzoxazone serum ratios (2-hour sample), and debrisoquin urinary recovery ratios (8-hour collection), respectively. The content of purported "active" phytochemicals was determined for each supplement.
RESULTS
Comparisons of presupplementation and postsupplementation phenotypic ratio means revealed significant inhibition (approximately 40%) of CYP2D6 (difference, -0.228; 95% confidence interval [CI], -0.268 to -0.188) and CYP3A4/5 (difference, -1.501; 95% CI, -1.840 to -1.163) activity for goldenseal. Kava produced significant reductions (approximately 40%) in CYP2E1 only (difference, -0.192; 95% CI, -0.325 to -0.060). Black cohosh also exhibited statistically significant inhibition of CYP2D6 (difference, -0.046; 95% CI, -0.085 to -0.007), but the magnitude of the effect (approximately 7%) did not appear to be clinically relevant. No significant changes in phenotypic ratios were observed for valerian.
CONCLUSIONS
Botanical supplements containing goldenseal strongly inhibited CYP2D6 and CYP3A4/5 activity in vivo, whereas kava inhibited CYP2E1 and black cohosh weakly inhibited CYP2D6. Accordingly, serious adverse interactions may result from the concomitant ingestion of goldenseal supplements and drugs that are CYP2D6 and CYP3A4/5 substrates. Kava kava and black cohosh may interact with CYP2E1 and CYP2D6 substrates, respectively. Valerian appears to be less likely to produce CYP-mediated herb-drug interactions.
Topics: Adult; Aryl Hydrocarbon Hydroxylases; Caffeine; Capsules; Cimicifuga; Dietary Supplements; Drug Administration Schedule; Female; Herb-Drug Interactions; Humans; Hydrastis; Kava; Male; Midazolam; Patient Selection; Phenotype; Time Factors; Valerian
PubMed: 15900287
DOI: 10.1016/j.clpt.2005.01.009 -
British Journal of Clinical Pharmacology Oct 2003To investigate pharmacokinetics of the enantiomers of citalopram (CT) and its metabolites desmethylcitalopram (DCT) and didesmethylcitalopram (DDCT) in Swedish healthy...
AIMS
To investigate pharmacokinetics of the enantiomers of citalopram (CT) and its metabolites desmethylcitalopram (DCT) and didesmethylcitalopram (DDCT) in Swedish healthy volunteers in relation to CYP2C19 and CYP2D6 geno- and phenotypes.
METHODS
Racemic CT was given for seven days to panels with different genotypes and the following mephenytoin (Me) and debrisoquine (De) hydroxylation phenotypes: EMDe/EMMe, PMDe/EMMe, EMDe/PMMe (n = 6 in all groups), and one PMDe/PMMe subject. Blood sampling was carried out during day 7, and all urine was collected for 12 h after the last dose of CT.
RESULTS
The AUC of S-CT was significantly higher in the EMDe/PMMe panel compared to the EMDe/EMMe and PMDe/EMMe panels (P < 0.05), whereas the AUC of R-CT did not differ between the panels. Similar differences, although they did not reach statistical significance, were noted for S-DCT and R-DCT. The enantiomers of DDCT were not quantifiable in PMDe, and there was no difference in DDCT enantiomer concentrations between the other two panels. A PMDe/PMMe subject stopped taking CT after five days due to severe adverse effects. Based on two time points, this subject had a very long CT half-life of 95 h. The value of 1.0 for the S/R ratio of the CT trough in this subject was similar to the mean S/R CT trough ratio of the EMDe/PMMe panel, but higher than the S/R CT ratio of the EMDe/EMMe panel (0.56; 95% CI 0.49-0.63) and the PMDe/EMMe panel (0.44; 95% CI 0.31-0.57). Thus the latter two phenotypes eliminated S-CT more rapidly via CYP2C19. An adverse effect described as an 'alcohol hangover' feeling was reported by one subject from each of the three panels. These individuals had the highest concentrations of both CT enantiomers.
CONCLUSIONS
The AUC of S-, but not R-(CT) was found to be significantly higher in PM of mephenytoin compared to EMs, PMs may need a lower dosage of CT.
Topics: Adult; Antidepressive Agents; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Citalopram; Cytochrome P-450 CYP2C19; Cytochrome P-450 CYP2D6; Female; Genotype; Humans; Isomerism; Male; Mixed Function Oxygenases; Phenotype
PubMed: 12968986
DOI: 10.1046/j.1365-2125.2003.01874.x -
British Journal of Clinical Pharmacology Apr 19961. To determine whether dexfenfluramine is a substrate of cytochrome P450 2D6 (CYP2D6), its disposition has been studied in nine extensive (EM) and eight poor...
1. To determine whether dexfenfluramine is a substrate of cytochrome P450 2D6 (CYP2D6), its disposition has been studied in nine extensive (EM) and eight poor metabolizers (PM) of debrisoquine. 2. Following a 30 mg dose of dexfenfluramine hydrochloride, urine was collected in all subjects for 96 h post-dose and plasma samples were collected in 11 subjects (six EMs and five PMs). Dexfenfluramine and nordexfenfluramine were measured in urine by h.p.l.c. and in plasma by g.c. 3. Urinary recovery of dexfenfluramine was greater in PMs than EMs (4136 +/- 1509 micrograms vs 1986 +/- 792 micrograms; 95% CI of difference 926-3374; P < 0.05) whereas that of nordexfenfluramine was similar in both phenotypes (PM: 1753 +/- 411 micrograms vs 1626 +/- 444 micrograms). 4. Dexfenfluramine AUC was higher in PMs (677 +/- 348 micrograms l-1 h) than EMs 359 +/- 250 micrograms l-1 h). The apparent oral clearance of dexfenfluramine was greater in EMs than PMs (93.6 +/- 42.4 l h-1 vs 45.6 +/- 19.5 l h-1; 95% CI of difference 1.2-94.7; P < 0.05). The renal clearance was similar in both phenotypes (EMs: 5.88 +/- 2.83 l h-1; PMs 6.60 +/- 2.01 l h-1), indicating that the higher urinary recovery of dexfenfluramine in PMs reflects higher plasma concentrations, rather than phenotype differences in the renal handling, of dexfenfluramine. 5. The apparent nonrenal clearance of dexfenfluramine was substantially lower (P < 0.05; 95% CI of difference 3.0-94.1) in PMs (39.0 +/- 19.5 l h-1) than EMs (87.6 +/- 41.2 l h-1). 6. There was a significant inverse correlation (rs = 0.776 95% CI-0.31-0.94; n = 11; p = 0.005) between the debrisoquine metabolic ratio and the apparent nonrenal clearance of dexfenfluramine. 7. PMs had a higher incidence of adverse effects (nausea and vomiting) than EMs. 8. In conclusion, the metabolism of dexfenfluramine is impaired in PMs. Thus CYP2D6, the isoenzyme deficient in poor metabolizers of debrisoquine, must catalyse at least one pathway of dexfenfluramine biotransformation.
Topics: Adult; Appetite Depressants; Cytochrome P-450 CYP2D6; Cytochrome P-450 Enzyme System; Debrisoquin; Female; Fenfluramine; Humans; Isoenzymes; Male; Mixed Function Oxygenases; Phenotype; Polymorphism, Genetic
PubMed: 8730977
DOI: 10.1046/j.1365-2125.1996.03178.x -
American Journal of Veterinary Research Sep 2016OBJECTIVE To characterize polymorphisms of the gene for cytochrome P450 isozyme 2D50 (CYP2D50) and the disposition of 2 CYP2D50 probe drugs, dextromethorphan and...
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.
Topics: Animals; Cytochrome P-450 Enzyme System; Debrisoquin; Dextromethorphan; Female; Horses; Isoenzymes; Male; Polymorphism, Single Nucleotide
PubMed: 27580115
DOI: 10.2460/ajvr.77.9.1029 -
Neuropsychopharmacologia Hungarica : a... Sep 2010"Ecstasy", 3,4-methylenedioxymethamphetamine (MDMA), an amphetamine analogue is one of the most widely used recreational drugs. In spite of the fact that neurotoxic...
"Ecstasy", 3,4-methylenedioxymethamphetamine (MDMA), an amphetamine analogue is one of the most widely used recreational drugs. In spite of the fact that neurotoxic effects of MDMA has been found in several species from rodents to non-human primates, and results increasingly point to damage also in human MDMA users, data about the sensitivity of different brain areas and the recovery after neuronal damage are scarce. Serotonin transporter (5-HTT) mRNA in the raphe nuclei also has not been examined. Humans with genetic predisposition for the slow metabolism of MDMA, the so-called "poor metabolizers" of debrisoquin are at higher risk. Five- 9% of the Caucasian population is considered to carry this phenotype. These studies were carried out in Dark Agouti rats, a special strain that show decreased microsomal CYP2D1 isoenzyme activity, and thus may serve as a model of vulnerable human users. These works were designed to characterize MDMA-induced damage and recovery of the serotonergic system including sleep and morphological changes within 180 days. In our experiments we investigated the 5-HTT mRNA expression in the brainstem and medullary raphe nuclei, 5-HTT immunoreactive (IR) fibre densities in several brain areas, and 16 functional measures of sleep in response to a single dose of +/- MDMA (15mg\kg). Furthermore, behavioural experiments were performed 21 days after MDMA treatment. We found similar changes in 5-HTT mRNA expression in the examined raphe nuclei, namely transient increases 7 days after MDMA treatment followed by transient decreases at 21 days. Significant (20-40%), widespread reductions in 5-HTT-IR fibre density were detected in most brain areas at 7 and 21 days after MDMA administration. All cortical, but only some brainstem areas were damaged. Parallel to the neuronal damage we observed significant reductions in rapid eye movement (REM) sleep latency, increased fragmentation of sleep and increases in delta power spectra in non-REM sleep. At 180 days almost all functional changes in sleep were normalized together with 5-HTT mRNA expression in the examined raphe nuclei and the recovery of 5-HTT-IR fibre density in most brain areas. Our results also suggest that the acute MDMA administration abolished aggressive behaviour but MDMA pretreatment and the consequent depletion of serotonergic terminals did not affect aggression. Our findings concerning the changes detected in 5-HTT mRNA expression and fibre density indicate lasting impairment of the serotonergic system and suggest that a single use of MDMA may be associated with long-lasting cognitive, learning, memory and mood deficits and sleep disturbances particularly when a constellation of genetic vulnerability and certain environmental factors are present. Our data provide further evidence for the connection between altered serotonergic functions and sleep disturbance.
Topics: Aggression; Animals; Basal Metabolism; Brain; Gene Expression Regulation; Genetic Predisposition to Disease; Humans; Immunohistochemistry; In Situ Hybridization; Male; N-Methyl-3,4-methylenedioxyamphetamine; Neurons; RNA, Messenger; Raphe Nuclei; Rats; Risk Factors; Serotonin; Serotonin Plasma Membrane Transport Proteins; Sleep; Substance-Related Disorders; Time Factors; Wakefulness
PubMed: 20962361
DOI: No ID Found