An original and sensitive ultraperformance liquid chromatography–tandem mass spectrometric (UPLC–MS/MS) method for the determination of pseudoprotodioscin (PPD) in rat plasma was developed and validated. Digitoxin was applied as an internal standard. Plasma samples were processed by acetonitrile-mediated plasma protein precipitation and chromatographed using a step gradient program on a C18 column (2.1 × 50 mm i.d., 1.7 μm). The mobile phase was comprised of acetonitrile and 0.1 mmol L⁻¹ aqueous lithium acetate mixed with 0.03% formic acid at the flow rate of 0.2 mL min⁻¹. Multiple reaction monitoring (MRM) transitions were performed for detection and lithium adduct ions were employed with a significant improvement of the response of the analytes in electrospray positive ionization mode. The concentration range of calibration curve was linear over the range 2–5000 ng mL⁻¹. The intra- and inter-day precisions were all less than 11.5% and accuracies were within the range of 94.1–103.5%, and the analytes exhibited no severe matrix effect. The validated method was successfully applied in the pharmacokinetics of PPD after intragastric (50 mg kg⁻¹) and intravenous (4 mg kg⁻¹) administration in rats. PPD showed rapid excretion and with bioavailability of simply about 5.7% in rats.

开发并验证了一种新颖而灵敏的超高效液相色谱-串联质谱法（UPLC-MS / MS）测定大鼠血浆中的伪原薯s素（PPD）。使用Digitoxin作为内标。血浆样品通过乙腈介导的血浆蛋白沉淀进行处理，并使用逐步梯度程序在C18色谱柱（2.1×50 mm内径，1.7μm）上进行色谱分离。流动相由乙腈和0.1 mmol L ^-1醋酸锂水溶液与0.03％甲酸混合而成，流速为0.2 mL min ^-1。进行了多反应监测（MRM）转换以进行检测，并采用了锂加成离子，从而显着改善了电喷雾正电离模式下分析物的响应。校准曲线的浓度范围在2–5000 ng mL ^-1范围内呈线性。日内和日间精度均小于11.5％，精度在94.1–103.5％的范围内，并且分析物没有表现出严重的基质作用。经验证的方法已成功应用于大鼠胃内（50 mg kg ^-1）和静脉内（4 mg kg ^-1）给药后的PPD药代动力学。PPD在大鼠中排泄迅速，生物利用度仅约5.7％。