Validation of a simple liquid chromatography–tandem mass spectrometric method for the determination of propiverine hydrochloride and its N-oxide metabolite in human plasma

A simple high-performance liquid chromatography (HPLC)–tandem mass spectrometric method has been developed for determination of propiverine hydrochloride and its metabolite, propiverine N-oxide (M-1) in human plasma using stable isotopes, propiverine hydrochloride-d10 and M-1-d10, as internal standards. The analytes were extracted with dichloromethane from 0.2 ml of plasma in neutral condition (pH 7.0) and separated by HPLC on a C18 reversed-phase column using methanol–1% acetic acid (50:50) as a mobile phase, and detected using positive electrospray ionization in selected reaction monitoring (SRM) mode. The method was validated over a concentration range of 2–500 ng/ml for propiverine hydrochloride and 4–1000 ng/ml for M-1 using 0.2 ml of human plasma per assay. The method developed was successfully applied to analysis of propiverine hydrochloride and M-1 in clinical studies.