Clopidogrel acyl--d-glucuronide is a mechanism-based inhibitor of cytochrome P450 2C8 in human liver microsomes (HLMs). However, time-dependent inactivation (TDI) of CYP2C8 could not be detected in an earlier study in human recombinant CYP2C8 (Supersomes). Here, we investigate whether different enzyme sources exhibit differences in detection of CYP2C8 TDI under identical experimental conditions. Inactivation of CYP2C8 by amiodarone (100 M), clopidogrel acyl--d-glucuronide (100 M), gemfibrozil 1-glucuronide (100 M), and phenelzine (100 M) was investigated in HLMs and three recombinant human CYP2C8 preparations (Supersomes, Bactosomes, and EasyCYP Bactosomes) using amodiaquine -deethylation as the marker reaction. Furthermore, the inactivation kinetics of CYP2C8 by clopidogrel glucuronide (5-250 M) was determined in Supersomes and Bactosomes. Amiodarone caused weak TDI in all enzyme preparations tested, while the extent of inactivation by clopidogrel glucuronide, gemfibrozil glucuronide, and phenelzine varied markedly between preparations, and even different Supersome lots. Both glucuronides caused strong inactivation of CYP2C8 in HLMs, Bactosomes and in one Supersome lot (>50% inhibition), but significant inactivation could not be reliably detected in other Supersome lots or EasyCYP Bactosomes. In Bactosomes, the concentration producing half of k (K) and maximal inactivation rate (k) of clopidogrel glucuronide (14 M and 0.054 minute) were similar to those determined previously in HLMs. Phenelzine caused strong inactivation of CYP2C8 in one Supersome lot (91% inhibition) but not in HLMs or other recombinant CYP2C8 preparations. In conclusion, different enzyme sources and different lots of the same recombinant enzyme preparation are not equally sensitive to detect inactivation of CYP2C8, suggesting that recombinant CYPs should be avoided when identifying mechanism-based inhibitors.
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http://dx.doi.org/10.1124/dmd.118.085498 | DOI Listing |
Chem Res Toxicol
September 2023
Clinical Pharmacology Research Center, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
Genipin (GP) is the reactive aglycone of geniposide, the main component of traditional Chinese medicine (GF). The covalent binding of GP to cellular proteins is suspected to be responsible for GF-induced hepatotoxicity and inhibits drug-metabolizing enzyme activity, although the mechanisms remain to be clarified. In this study, the mechanisms of GP-induced human hepatic P450 inactivation were systemically investigated.
View Article and Find Full Text PDFBiomolecules
September 2022
Albany College of Pharmacy and Health Sciences, 106 New Scotland Ave, BRB104C, Albany, NY 12208, USA.
The lipid-regulating drug gemfibrozil is a useful medication for reducing high cholesterol and triglycerides in the blood. In addition to oxidation, it undergoes extensive glucuronidation to produce gemfibrozil acyl glucuronide, which is a known mechanism-based inactivator of cytochrome P450 (CYP) 2C8. Such selective and time-dependent inhibition results in clinically important drug-drug interactions (DDI) with the drugs metabolized by CYP2C8.
View Article and Find Full Text PDFPharmaceutics
April 2022
Department of Clinical Pharmacy, Saarland University, 66123 Saarbrücken, Germany.
Drug Metab Dispos
April 2022
Department of Pharmaceutics, University of Washington, Seattle, Washington (S.B., J.D.U.); Department of Pharmaceutical Sciences, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington (M.F.P.); and Center of Excellence for Natural Product Drug Interaction Research, Spokane, Washington (M.F.P., J.D.U.)
We previously reported the unbound reversible (IC) and time-dependent (K) inhibition potencies of cannabidiol (CBD), delta-9-tetrahydrocannabinol (THC), and THC metabolites 11-hydroxy THC (11-OH THC) and 11-nor-9-carboxy-delta-9-THC (11-COOH THC) against the major cytochrome P450 (P450) enzymes (1A2, 2C9, 2C19, 2D6, and 3A). Here, using human liver microsomes, we determined the CYP2A6, 2B6, and 2C8 IC values of the aforementioned cannabinoids and the IC and K of the circulating CBD metabolites 7-hydroxy CBD (7-OH CBD) and 7-carboxy CBD (7-COOH CBD), against all the P450s listed above. The IC of CBD, 7-OH CBD, THC, and 11-OH THC against CYP2B6 was 0.
View Article and Find Full Text PDFChem Biol Interact
January 2022
Department of Pharmacy, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China. Electronic address:
Vicagrel, an antiplatelet drug candidate targeting platelet P2Y receptor and has finished its phase II clinical trial. The inhibition of six major cytochrome P450 enzymes (P450) (CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) and six UDP-glucuronosyltransferases (UGT) (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, and UGT2B7) by vicagrel was evaluated using pooled human liver microsomes and specific probe substrates. Physiology-based pharmacokinetic (PBPK) simulation was further applied to predict the in vivo drug-drug interaction (DDI) potential between vicagrel and bupropion as well as S-mephenytoin.
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