HPLC-ESI/MS analysis of stachydrine and its metabolites in rat urine

AimTo identify the main metabolites of stachydrine in rat. MethodsThe ionization, cleavage and chromatographic characteristics of stachydrine were studied by using high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry (HPLC-ESI/MS) for the first time. These characteristics of stachydrine were used as the basis for the analyses of metabolites in rat urine. The 0-24 h urine samples of rats after ig 25 mg·kg^-1 stachydrine were collected and purified by using C₁₈ solid-phase extraction cartridge, and then analyzed by HPLC-ESI/MS to identify stachydrine and its metabolites. ResultsThe parent drug (stachydrine), 6 phase I metabolites (N-demethyl, dehydrogenation, ring-oxidation) and 2 phase II metabolites (glycine conjugates of 2 ring-oxidation products) were identified existing in rat urine. ConclusionThe presented method was proved to be sensitive, rapid, high selective and specific for the identification of stachydrine and its metabolites in rat urine.