Investigation of metabolic kinetics and reaction phenotyping of ligustrazin by using liver microsomes and recombinant human enzymes

• Published in: Yao hsüeh hsüeh pao Vol. 49; no. 3; p. 374
• Main Authors: Tan, Yan, Zhuang, Xiao-Mei, Shen, Guo-Lin, Li, Hua, Gao, Yue
• Format: Journal Article
• Language: Chinese
• Published: China 01.03.2014
• Subjects: Animals; Cytochrome P-450 CYP1A2 - metabolism; Cytochrome P-450 CYP2C9 - metabolism; Cytochrome P-450 CYP3A - metabolism; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System - metabolism; Drug Interactions; Glucuronosyltransferase - metabolism; Humans; Ligusticum - chemistry; Microsomes, Liver - enzymology; NADP - metabolism; NADP - pharmacology; Pyrazines - metabolism; Pyrazines - pharmacokinetics; Rats; Uridine Diphosphate Glucuronic Acid - metabolism; Uridine Diphosphate Glucuronic Acid - pharmacology
• ISSN: 0513-4870

The metabolic characteristics of ligustrazin (TMPz) in liver microsomes were investigated in the present study. The reaction phenotyping of TMPz metabolism was also identified by in vitro assessment using recombinant human cytochrome P450 enzymes (CYP) and UDP glucuronosyltransferases (UGT). TMPz was incubated at 37 degrees C with human (HLM) and rat liver microsomes (RLM) in the presence of different co-factors. The metabolic stability and enzyme kinetics of TMPz were studied by determining its remaining concentrations with a LC-MS/MS method. TMPz was only metabolically eliminated in the microsomes with NADPH or NADPH+UDPGA. In the HLM and RLM with NADPH+UDPGA, t1/2, K(m) and V(max) of TMPz were 94.24 +/- 4.53 and 105.07 +/- 9.44 min, 22.74 +/- 1.89 and 33.09 +/- 2.74 micromol x L(-1), 253.50 +/- 10.06 and 190.40 +/- 8.35 nmol x min(-1) x mg(-1) (protein), respectively. TMPz showed a slightly higher metabolic rate in HLM than that in RLM. Its primary oxidative metabolites, 2-hydroxymethyl-3, 5, 6-trimethylpy