Identification of key metabolites of tectorigenin in rat urine by HPLC‐MS n

This is a report about the identification of key metabolites of tectorigenin in rat urine using high‐performance liquid chromatography–electrospray ionization ion trap tandem mass spectrometric method (HPLC‐ESI‐MS n ). Six healthy rats were administered a single dose (80 mg/kg) of tectorigenin by oral gavage. Urine was sampled for 0–24 h and centrifuged at 12,000 rpm for 10 min to obtain the supernatants, then the supernatants were purified by solid‐phase extraction with a C 18 cartridge. The chromatographic separation was carried out on a reversed‐phase C 18 column with a gradient elution program whereas acetonitrile–0.1% formic acid water was used as mobile phase. Mass spectra were acquired in negative ionization mode and a data‐dependant scan was used for the identification of the key metabolites of tectorigenin in the urine samples. As a result, four phase II metabolites and the parent drug tectorigenin were found and identified in rat urine for the first time. Copyright © 2008 John Wiley & Sons, Ltd.