High-performance liquid chromatographic assay for the simultaneous determination of lansoprazole enantiomers and metabolites in human liver microsomes

In this study, a simple, sensitive and enantioselective HPLC method was developed for the simultaneous determination of lansoprazole enantiomers: a proton pump inhibitor, and its major metabolites: 5-hydroxylansoprazole and lansoprazole sulfone in human liver microsomes. After extraction from the microsomal incubation mixture with a diethyl ether–dichloromethane (7:3, v/v) mixture, analytes were measured by reversed-phase HPLC on a Chiralcel® OD-R column. Detection was made using an ultraviolet absorbance detector set at a wavelength of 285 nm. The mobile phase consisted of a methanol–water (75:25, v/v) mixture. At a flow-rate of 0.5 ml/min, the total run time was 35 min. The limit of quantification for both lansoprazole enantiomers was 0.25 μM and for the metabolites 0.13 μM. The method is suitable for the analysis of lansoprazole enantiomers and its metabolites from human microsomal liver incubations.