title: [A limited sampling strategy of phenotyping probe midazolam to predict inhibited activities of hepatic CYP3A in rats].
abstract: The present study was to evaluate feasibility of a limited sampling strategy (LSS) in the prediction of inhibited hepatic CYP3A activity with systemic clearance of midazolam (MDZ), a hepatic CYP3A activity phenotyping probe. Rats were pretreated with a serial doses of ketoconazole, a selective inhibitor on CYP3A. Blood samples were collected and detected for MDZ at specified time points after intravenous injection of MDZ. Stepwise regression analysis and a Jack-knife validation procedures were performed in one group of rats as training set to establish the most informative LSS model for accurately estimating the clearance of MDZ. Another group of rats with same treatment was used as validation set to estimate the individual clearance based on predictive equations derived from the training set. Bland-Altman plots showed a good agreement between the systemic clearance calculated from DAS (CLobs) and corresponding parameter that was derived from three LSS models (CLest). LSS models derived from two or three sampling time points, including 60, 90 min, 30, 60, 90 min and 30, 60, 120 min, exhibited a good accuracy and acceptable error for estimating the CLobs of MDZ to evaluate hepatic CYP3A activity, especially the 60, 90 min LSS model is most accurate and convenient. The results supported that limited plasma sampling to predict the systemic clearance of MDZ is easier than the usual method for estimating CYP3A phenotyping when the hepatic activity of CYP3A is reduced in the rat. The present study provided theoretical basis and laboratory evidence for LSS to clinically evaluate metabolizing function of liver and
authors.affiliation: Basic Medical College, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Xue-hui
authors.initials: XH
authors.lastname: Zhu
authors.forename: Jian-jie
authors.initials: JJ
authors.lastname: Jiao
authors.forename: Cai-li
authors.initials: CL
authors.lastname: Zhang
authors.forename: Jian-shi
authors.initials: JS
authors.lastname: Lou
authors.forename: Chang-xiao
authors.initials: CX
authors.lastname: Liu
mesh_terms: D000818:Animals; D019540:Area Under Curve; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A / Q000235:genetics / Q000378:metabolism*; D065692:Cytochrome P-450 CYP3A Inhibitors; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007275:Injections, Intravenous; D007654:Ketoconazole / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008657:Metabolic Clearance Rate; D008874:Midazolam / Q000097:blood / Q000493:pharmacokinetics*; D010641:Phenotype; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D065692:Cytochrome P-450 CYP3A Inhibitors; D004791:Enzyme Inhibitors; D001189:Aryl Hydrocarbon Hydroxylases; C465138:Cyp3a23-3a1 protein, rat; D051544:Cytochrome P-450 CYP3A; D008874:Midazolam; D007654:Ketoconazole