目的 建立简单、快速的测定K-H缓冲液中知母皂苷B2含量的LC-MS方法，检验特定剂量知母皂苷B2在大鼠离体肝灌流模型中的肝脏提取率。方法将SD大鼠离体肝灌流给予知母皂苷B2，取出不同时间点肝灌流液，LC-MS法测定肝灌流液中知母皂苷B2的浓度。色谱条件 :ACE C18色谱柱(100 mm × 2.1 mm， 1 μm)，流动相为乙腈-0.05 %甲酸水溶液(V/V)，采用梯度洗脱。结果知母皂苷B2在0.125 ~ 2 μg/mL范围内线性良好(r2=0.999)，日间和日内变异系数(RSD) ＜ 10 %，基质效应RSD ＜ 15 %，符合生物样品分析的方法学要求。结论该方法准确、灵敏、快速、高效，适用于知母皂苷B2在离体灌流液中的定量分析。获得了1.6 μg/mL的知母皂苷B2样品大鼠离体肝灌流状态下的肝提取率和肝清除率曲线。

Objective To develop a LC-MS method to determine timosaponin B2 in K-H buffer quickly and effectively，and by using this method to study the metabolism of timosaponin B2 in isolated perfused rat liver model. Methods The isolated SD rat liver was perfused with K-H buffer containing timosaponin B2，and then the perfusate was taken out at different time for the determination of timosaponin B2 concentration by LC-MS method. The chromatographic condition was as follows:ACE C18 column(100 mm×2.1 mm，1 μm)，mobile phase consisting of acetonitrile -0.05 ％ formic acid V/V)，gradient elution. Results The linear ranges of timosaponin B2 was 0.125~2 μg/mL(r2=0.999). The intra-day and inter-day coefficient of differentiation was less than 10%，and the coefficient of differentiation for matrix effect was less than 15 %，which fit the standard. Conclusion The method is effective，rapid and accurate for the determination of timosaponin B2 in K-H buffer，and the hepatic extraction rate and a liver clearance curve of timosaponin B2 at 1.6 μg/mL have beengot in isolated perfused rat liver.

R285.5

国家科技重大专项《重大新药创制》课题(2012ZX09301001-001)。