Enzyme Kinetics of Omeprazole Metabolism in Rat Liver Microsomes

OBJECTIVE: To study the enzyme kinetics of omeprazole(OPZ) metabolism in rat liver microsomes. METHODS: HPLC method was employed to quantify omeprazole and its major metabolite: hydroxyomeprazole (OH-OPZ), and Eadie-Hofstee graphic method was used to calculate the maximum reaction rate(Vmax)and Km of enzyme kinetic. RESULTS : The enzyme kinetics parameters were found as follows: Vmax=2 010nmol/(min·mg protein),Km=50.3μmol/L.CONCLUSI_ON: The method is shown to meet the requirement of methodological verification, which can yield the accurate in vitro constant and be suitable for the in vitro metabolism research of omeprazole.