LC-MS/MS Method for Quantification of Liquiritigenin in Rat Plasma: Application to Pharmacokinetic Study of Liquiritin

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 C-18 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/z 255.0 -> 119.0 for LG and m/z 271.0 -> 151.0 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 analysis 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.