Objective A simple, sensitive, and rapid LC-MS/MS method has been established and validated for the determination of liquiritigenin （LG） in rat plasma. Methods Naringenin was chosen as internal standard （IS）. LG and IS were separated on a Diamonsil C18 analytical column with a mobile phase of methanol-10% methanol in water containing 0.5 mmol/L ammonium formate and 0.2% formic acid （55：45） at the isocratic flow rate of 0.6 mL/min for 10 min. The multiple reaction monitoring （MRM） was performed on a mass spectrometer in the negative ion mode with electro-spray ionization （ESI） source and the transition from precursor ion to product ion was m/z255.0~119.0 for LG and m/z 271.04151.0 for IS, respectively. Results The linearity was acceptable in the range of 5-5000 ng/mL （r= 0.9973）. The inter-day and intra-day accuracies were in the ranges of -0.09%-3.25% and -5.02%-9.21%, respectively. The precision was in the ranges of 3.60%-12.4% and 0.909%-6.89%, respectively. LG was stable in the course of anarysis and storage. Conclusion The LC-MS/MS method was successfully applied to the pharmacokinetic study for the first time in rats after ig and iv administration of liquiritin （LQ）, a glycoside of LG, at pharmacologically effective levels.
Shi-qi DongHui-rong FanQuan-sheng LiGuang-li WeiYa-zhuo LiChang-xiao LiuDuan-yun Si
