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https://www.readbyqxmd.com/read/29136681/assessment-of-multiple-cytochrome-p450-activities-in-metabolically-inactivated-human-liver-microsomes-and-roles-of-p450-2c-isoforms-in-reaction-phenotyping-studies
#1
Norie Murayama, Kanako Yajima, Mikiko Hikawa, Kanami Shimura, Yu Ishii, Masaki Takada, Yasuhiro Uno, Masahiro Utoh, Kazuhide Iwasaki, Hiroshi Yamazaki
The fraction of substrate metabolized (fm ) can be used to estimate drug interactions and can be determined by comparison of the intrinsic clearances (CLint ) of victim drugs obtained from inhibited and uninhibited hepatic enzymes. Commercially available human liver microsomes were recently developed in which one cytochrome P450 (P450) isoform is selectively inactivated. These inactivated liver microsomes were used to evaluate the roles of P450 2C isoforms in the depletion and oxidation of probe substrates...
November 14, 2017: Biopharmaceutics & Drug Disposition
https://www.readbyqxmd.com/read/29133569/efficacy-of-tilorone-dihydrochloride-against-ebola-virus-infection
#2
Sean Ekins, Mary A Lingerfelt, Jason E Comer, Alexander N Freiberg, Jon C Mirsalis, Kathleen O'Loughlin, Anush Harutyunyan, Claire McFarlane, Carol E Green, Peter B Madrid
Tilorone dihydrochloride (tilorone) is a small-molecule, orally bioavailable drug that is used clinically as an antiviral outside of the US. A machine learning model trained on anti-Ebola virus (EBOV) screening data previously identified tilorone as a potent in vitro EBOV inhibitor, making it a candidate for the treatment of Ebola virus disease (EVD). In the present study, a series of in vitro ADMET (absorption, distribution, metabolism, excretion, toxicity) assays demonstrated the drug has excellent solubility, high Caco-2 permeability, was not a P-glycoprotein substrate and had no inhibitory activity against five human CYP450 enzymes (3A4, 2D6, 2C19, 2C9 and 1A2)...
November 13, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29121650/flavin-containing-monooxygenase-3-fmo3-role-in-busulphan-metabolic-pathway
#3
Ibrahim El-Serafi, Ylva Terelius, Manuchehr Abedi-Valugerdi, Seán Naughton, Maryam Saghafian, Ali Moshfegh, Jonas Mattsson, Zuzana Potácová, Moustapha Hassan
Busulphan (Bu) is an alkylating agent used in the conditioning regimen prior to hematopoietic stem cell transplantation (HSCT). Bu is extensively metabolized in the liver via conjugations with glutathione to form the intermediate metabolite (sulfonium ion) which subsequently is degraded to tetrahydrothiophene (THT). THT was reported to be oxidized forming THT-1-oxide that is further oxidized to sulfolane and finally 3-hydroxysulfolane. However, the underlying mechanisms for the formation of these metabolites remain poorly understood...
2017: PloS One
https://www.readbyqxmd.com/read/29120380/in-vitro-phase-i-metabolism-of-crv431-a-novel-oral-drug-candidate-for-chronic-hepatitis-b
#4
Daniel J Trepanier, Daren R Ure, Robert T Foster
The cytochrome P450-mediated Phase I in vitro metabolism of CRV431 was studied using selective chemical inhibition and recombinant human enzymes. Additionally, the metabolic profile of CRV431 in human, rat, and monkey liver microsomes was investigated. Liver microsomes were incubated for 0-80 min with CRV431, and the metabolite profile was assessed by electrospray ionization liquid chromatography mass spectrometry (ESI-LCMS). CRV431 was extensively metabolized through oxidation to produce various hydroxylated and demethylated species...
November 9, 2017: Pharmaceutics
https://www.readbyqxmd.com/read/29102810/role-of-cytochrome-p450-2c19-polymorphisms-and-body-mass-index-in-endometriosis-a-case-control-study
#5
Jéssica Vilarinho Cardoso, Maurício Simões Abrão, Plínio Tostes Berardo, Renato Ferrari, Luiz Eurico Nasciutti, Daniel Escorsim Machado, Jamila Alessandra Perini
OBJECTIVE: To investigate the contribution of CYP2C19 polymorphisms and body mass index (BMI) in the development of endometriosis. STUDY DESIGN: This is a case-control study that includes 356 women (187 cases and 169 controls) recruited from two hospitals in the Brazilian public health system. The genotyping analyses of the CYP2C19*2 and CYP2C19*17 polymorphisms were performed using TaqMan allelic discrimination assays, and the association of the studied polymorphisms with endometriosis was evaluated by multivariate logistic regression...
December 2017: European Journal of Obstetrics, Gynecology, and Reproductive Biology
https://www.readbyqxmd.com/read/29098786/functional-characterization-of-cyp2c19-variants-in-nebivolol-4-hydroxlation-in-vitro
#6
Xiao-Yang Zhou, Xiao-Xia Hu, Meng-Fang Li, Hao Wang, Li-Qun Zhang, Guo-Xin Hu, Jian-Ping Cai
Cytochrome P450 2C19 (CYP2C19) allelic variants are thought to play an important part in inter-individual variability in drug metabolism. We evaluated the in vitro hydroxylation of nebivolol by 31 CYP2C19 alleles identified in a Chinese Han population recently. Wild-type CYP2C19*1B and 30 isoforms were highly expressed in insect cells, and the enzymatic activities of CYP2C19 variants towards nebivolol hydroxylation were characterized. Among the 30 CYP2C19 alleles, most of the recombinant CYP2C19 variants exhibited no or significantly low activity compared with CYP2C19*1B...
November 3, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/29054967/prediction-of-cytochrome-p450-mediated-drug-clearance-in-humans-based-on-the-measured-activities-of-selected-cyps
#7
Jie Gao, Jie Wang, Na Gao, Xin Tian, Jun Zhou, Yan Fang, Hai-Feng Zhang, Qiang Wen, Lin-Jing Jia, Dan Zou, Hai-Ling Qiao
Determining drug-metabolizing enzyme activities on an individual basis is an important component of personalized medicine, and cytochrome P450 enzymes (CYPs) play a principal role in hepatic drug metabolism. Herein, a simple method for predicting the major CYP-mediated drug clearance in vitro and in vivo is presented. Ten CYP-mediated drug metabolic activities in human liver microsomes (HLMs) from 105 normal liver samples were determined. The descriptive models for predicting the activities of these CYPs in HLMs were developed solely on the basis of the measured activities of a smaller number of more readily assayed CYPs...
October 20, 2017: Bioscience Reports
https://www.readbyqxmd.com/read/29052493/impaired-liver-cytochrome-p450-2c11-activity-after-dual-antiplatelet-therapy-with-aspirin-and-clopidogrel-in-rats
#8
Chenyu Qian, Xi Luo, Mengbi Yang, Jing Jin, Zhong Zuo
1. Aspirin (ASA) and clopidogrel (CLP) are used in combination as dual antiplatelet therapy (DAPT) for acute coronary syndrome based on their complementary mechanisms for platelet aggregation inhibition. However, the pharmacokinetics of such drug combination usage has not been thoroughly investigated. 2. In the current study, an LC-MS/MS method was developed to simultaneously determine the plasma concentrations of ASA and its metabolite salicylic acid (SA) with CLP and its metabolites, clopidogrel carboxylic acid (CLPM) and clopidogrel active metabolite derivative (CAMD)...
October 20, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/29037010/effects-of-triflusal-and-clopidogrel-on-the-secondary-prevention-of-stroke-based-on-cytochrome-p450-2c19-genotyping
#9
Sang Won Han, Yong-Jae Kim, Seong Hwan Ahn, Woo-Keun Seo, Sungwook Yu, Seung-Hun Oh, Hyo Suk Nam, Hye-Yeon Choi, Sung Sang Yoon, Seo Hyun Kim, Jong Yun Lee, Jun Hong Lee, Yang-Ha Hwang, Kee Ook Lee, Yo Han Jung, Jun Lee, Sung-Il Sohn, Youn Nam Kim, Kyung-A Lee, Cheryl D Bushnell, Kyung-Yul Lee
BACKGROUND AND PURPOSE: To compare the efficacy and safety of antiplatelet agents for the secondary prevention of ischemic stroke based on cytochrome P450 2C19 (CYP2C19) polymorphisms. METHODS: This study was a prospective, multicenter, randomized, parallel-group, open-label, blind genotype trial. First time non-cardiogenic ischemic stroke patients were enrolled and screened within 30 days. Participants were randomized to receive either triflusal or clopidogrel for secondary stroke prevention...
September 2017: Journal of Stroke
https://www.readbyqxmd.com/read/29034770/association-with-polymorphic-marmoset-cytochrome-p450-2c19-of-in-vivo-hepatic-clearances-of-chirally-separated-r-omeprazole-and-s-warfarin-using-individual-marmoset-physiologically-based-pharmacokinetic-models
#10
Takashi Kusama, Akiko Toda, Makiko Shimizu, Shotaro Uehara, Takashi Inoue, Yasuhiro Uno, Masahiro Utoh, Erika Sasaki, Hiroshi Yamazaki
1. Simulated clearances of R-warfarin and efavirenz were recently reported for individual cynomolgus monkeys genotyped for cytochrome P450 2C19 and 2C9, respectively. To expand and verify this modeling procedure, simulations of R/S-omeprazole and R/S-warfarin clearances after oral administrations in individual marmosets were performed using individual simplified physiologically based pharmacokinetic (PBPK) modeling consisting of gut, liver, and central compartments. 2. Pharmacokinetics of R/S-omeprazole were chirally determined using the previously reported plasma microsamples in this study...
October 16, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/29026425/effect-of-cytochrome-p450-2c19-17-allelic-variant-on-cardiovascular-and-cerebrovascular-outcomes-in-clopidogrel-treated-patients-a-systematic-review-and-meta-analysis
#11
REVIEW
Bo Huang, De-Jun Cui, Ying Ren, Bin Han, Da-Ping Yang, Xun Zhao
BACKGROUND: We aimed to evaluate the associations of gain-of-function allele of CYP2C19*17 and risk of clinical events in clopidogrel-treated patients with cardiovascular and cerebrovascular diseases (CCVDs). MATERIALS AND METHODS: Literature search was conducted in PubMed, EMBASE, and Cochrane Library. Odds ratio (OR) combined with 95% confidence interval (CI) was the pooled statistics. Subgroup analysis was performed by disease type, bleeding events, and race...
2017: Journal of Research in Medical Sciences: the Official Journal of Isfahan University of Medical Sciences
https://www.readbyqxmd.com/read/28994497/effects-of-vernonia-cinerea-compounds-on-drug-metabolizing-cytochrome-p450s-in-human-liver-microsomes
#12
Phisit Pouyfung, Songklod Sarapusit, Pornpimol Rongnoparut
Vernonia cinerea has been widely used in traditional medicines for various diseases and shown to aid in smoking abstinence and has anticancer properties. V. cinerea bioactive compounds, including flavonoids and hirsutinolide-type sesquiterpene lactones, have shown an inhibition effect on the nicotine-metabolizing cytochrome P450 2A6 (CYP2A6) enzyme and hirsutinolides reported suppressing cancer growth. In this study, V. cinerea ethanol extract and its bioactive compounds, including four flavonoids and four hirsutinolides, were investigated for an inhibitory effect on human liver microsomal CYPs 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4 using cocktail inhibition assays combined with LC-MS/MS analysis...
October 10, 2017: Phytotherapy Research: PTR
https://www.readbyqxmd.com/read/28960401/prediction-of-drug-drug-interactions-using-physiologically-based-pharmacokinetic-models-of-cyp450-modulators-included-in-simcyp-software
#13
Niloufar Marsousi, Jules A Desmeules, Serge Rudaz, Youssef Daali
In recent years, Physiologically-Based PharmacoKinetic (PBPK) modeling has received growing interest as a useful tool for assessment of drug PK. It has demonstrated to be informative and helpful to quantify the modification in drug exposure due to specific physio-pathological conditions, age, genetic polymorphisms, ethnicity and particularly drug-drug interactions (DDIs). In this paper, the prediction success of DDIs involving various cytochrome P450 isoenzyme (CYP) modulators namely ketoconazole (a competitive inhibitor of CYP3A), itraconazole (a competitive inhibitor of CYP3A), clarithromycin (a mechanism-based inhibitor of CYP3A), quinidine (a competitive inhibitor of CYP2D6), paroxetine (a mechanism-based inhibitor of CYP2D6), ciprofloxacin (a competitive inhibitor of CYP1A2), fluconazole (a competitive inhibitor of CYP2C9/2C19) and rifampicin (an inducer of CYP3A) were assessed using Simcyp® software...
September 28, 2017: Biopharmaceutics & Drug Disposition
https://www.readbyqxmd.com/read/28934153/inhibitory-effect-of-selaginellins-from-selaginella-tamariscina-beauv-spring-against-cytochrome-p450-and-uridine-5-diphosphoglucuronosyltransferase-isoforms-on-human-liver-microsomes
#14
Jae-Kyung Heo, Phi-Hung Nguyen, Won Cheol Kim, Nguyen Minh Phuc, Kwang-Hyeon Liu
Selaginella tamariscina (Beauv.) has been used for traditional herbal medicine for treatment of cancer, hepatitis, and diabetes in the Orient. Numerous bioactive compounds including alkaloids, flavonoids, lignans, and selaginellins have been identified in this medicinal plant. Among them, selaginellins having a quinone methide unit and an alkylphenol moiety have been known to possess anticancer, antidiabetic, and neuroprotective activity. Although there have been studies on the biological activities of selaginellins, their modulatory potential of cytochrome P450 (P450) and uridine 5'-diphosphoglucuronosyltransferase (UGT) activities have not been previously evaluated...
September 21, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28920579/point-of-care-companion-diagnostic-tests-for-personalizing-psychiatric-medications-fulfilling-an-unmet-clinical-need
#15
Anil S Modak
Over the last decade stable isotope labeled substrates have been used as probes for rapid, point of care, non invasive and user friendly phenotype breath tests to evaluate activity of drug metabolizing enzymes. These diagnostic breath tests can be potentially used as Companion diagnostics (CDx) by physicians to personalize medications especially psychiatric drugs with narrow therapeutic windows, to monitor the progress of disease severity, medication efficacy and to study in vivo the pharmacokinetics of xenobiotics, Several genotype tests have been approved by the FDA over the last 15 years, however, they have not been cleared for use in personalizing medications since they fall woefully short in identifying all non responders to drugs especially for the CYP450 enzymes...
September 18, 2017: Journal of Breath Research
https://www.readbyqxmd.com/read/28866861/effects-of-the-proton-pump-inhibitors-omeprazole-and-pantoprazole-on-the-cytochrome-p450-mediated-metabolism-of-venlafaxine
#16
Maxim Kuzin, Georgios Schoretsanitis, Ekkehard Haen, Benedikt Stegmann, Christoph Hiemke, Gerhard Gründer, Michael Paulzen
BACKGROUND AND OBJECTIVE: An increasing trend in prescribing proton pump inhibitors (PPIs) inevitably increases the risk of unwanted drug-drug interactions (DDIs). The aim of this study was to uncover pharmacokinetic interactions between two PPIs-omeprazole and pantoprazole-and venlafaxine. METHODS: A therapeutic drug monitoring database contained plasma concentrations of venlafaxine and its active metabolite O-desmethylvenlafaxine. We considered three groups: a group of patients who received venlafaxine without confounding medications (non-PPI group, n = 906); a group of patients who were comedicated with omeprazole (n = 40); and a group of patients comedicated with pantoprazole (n = 40)...
September 2, 2017: Clinical Pharmacokinetics
https://www.readbyqxmd.com/read/28834279/the-cytochrome-p450-enzyme-responsible-for-the-production-of-z-norendoxifen-in-vitro
#17
Dabei Tang, Zhong Chu, Jessica Bo Li Lu, Jinzhong Liu, Qingyuan Zhang
BACKGROUND: Norendoxifen, an active metabolite of tamoxifen, is a potent aromatase inhibitor. Little information is available regarding production of norendoxifen in vitro. Here, we conducted a series of kinetic and inhibition studies in human liver microsomes (HLMs) and expressed P450s to study the metabolic disposition of norendoxifen. METHODS: To validate that norendoxifen was the metabolite of endoxifen, metabolites in HLMs incubates of endoxifen were measured using a HPLC/MS/MS method...
August 17, 2017: Chemistry & Biodiversity
https://www.readbyqxmd.com/read/28762864/progesterone-hydroxylation-by-cytochromes-p450-2c-and-3a-enzymes-in-marmoset-liver-microsomes
#18
Kazuyuki Nakanishi, Shotaro Uehara, Yasuhiro Uno, Takashi Inoue, Erika Sasaki, Hiroshi Yamazaki
1. Common marmosets (Callithrix jacchus) are potentially useful nonhuman primate models for preclinical drug metabolism studies. However, the roles of marmoset cytochrome P450 (P450) isoforms in the oxidation of endobiotic progesterone have not been fully investigated. In this study, the roles of marmoset P450 isoforms in progesterone hydroxylation were extensively determined. 2. The activities of liver microsomes from individual marmosets with respect to progesterone 21/17α- and 16α/6β-hydroxylation were significantly correlated with those for flurbiprofen 4-hydroxylation and midazolam 1'-hydroxylation, respectively, as similar correlations have been found in humans...
August 1, 2017: Xenobiotica; the Fate of Foreign Compounds in Biological Systems
https://www.readbyqxmd.com/read/28741150/eslicarbazepine-acetate-a-new-improvement-on-a-classic-drug-family-for-the-treatment-of-partial-onset-seizures
#19
REVIEW
Graciana L Galiana, Angela C Gauthier, Richard H Mattson
Eslicarbazepine acetate is a new anti-epileptic drug belonging to the dibenzazepine carboxamide family that is currently approved as adjunctive therapy and monotherapy for partial-onset (focal) seizures. The drug enhances slow inactivation of voltage-gated sodium channels and subsequently reduces the activity of rapidly firing neurons. Eslicarbazepine acetate has few, but some, drug-drug interactions. It is a weak enzyme inducer and it inhibits cytochrome P450 2C19, but it affects a smaller assortment of enzymes than carbamazepine...
September 2017: Drugs in R&D
https://www.readbyqxmd.com/read/28726718/inhibitory-effects-of-trapping-agents-of-sulfur-drug-reactive-intermediates-against-major-human-cytochrome-p450-isoforms
#20
Jasleen K Sodhi, Erlie Marie Delarosa, Jason S Halladay, James P Driscoll, Teresa Mulder, Patrick M Dansette, S Cyrus Khojasteh
In some cases, the formation of reactive species from the metabolism of xenobiotics has been linked to toxicity and therefore it is imperative to detect potential bioactivation for candidate drugs during drug discovery. Reactive species can covalently bind to trapping agents in in vitro incubations of compound with human liver microsomes (HLM) fortified with β-nicotinamide adenine dinucleotide phosphate (NADPH), resulting in a stable conjugate of trapping agent and reactive species, thereby facilitating analytical detection and providing evidence of short-lived reactive metabolites...
July 20, 2017: International Journal of Molecular Sciences
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