Determination of the enantiomers of omeprazole in blood plasma by normal-phase liquid chromatography and detection by atmospheric pressure ionization tandem mass spectromtry

摘要

An enantioselective assay of meprazole in blood plasma using normal-phase liquid chromatography on a Chiralpak AD column and detection by mass spectrometry is described. Omeprazole is extracted by a mixture of dichloromethane and hexane and,after evaporation,redissolution and injection,separated into its enantiomers on the chiral stationary phase. Detection is made by a triple quadrupole mass spectrometer,using deuterated analogues as internal standards. The method enables determination in plasma down to 10 nmol/1 (LOQ) and shows excellent consistency suited for pharmacokinetic studies in man.