Xiao Ya, Zhao Qiang, Wu Qian, Chang Jinhua, Xue Hefei, Liu Cuizhe, Liu Xigang
Hebei Key Laboratory of Research and Development for Chinese Medicine, Chengde Medical University Anyuan Road, Shuangqiao Chengde Hebei 067000 P. R. China
RSC Adv. 2018 Sep 5;8(54):30978-30985. doi: 10.1039/c8ra05941a. eCollection 2018 Aug 30.
Cucurbitacin B (CuB) is a highly oxygenated tetracyclic triterpene, and a Biopharmaceutics Classification System (BCS) class IV drug used for the treatment of persistent hepatitis, chronic hepatitis, and primary liver cancer. Nevertheless, CuB has low solubility and low permeability, and is present at low concentrations in the human body. The aim of this study was to develop a method for the determination of CuB in plasma using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) with estrone as an internal standard (IS), as well as to examine the pharmacokinetics and absolute bioavailability of CuB in rats. Plasma samples were processed by liquid-liquid extraction with ethyl acetate. Separation was achieved on a BEH C18 column (2.1 × 50 mm, 1.7 μm) at 35 °C using an isocratic mobile phase system with 0.1% formic acid-acetonitrile (50 : 50, v/v) at a flow rate of 0.3 mL min. The detection was performed using a multiple reaction monitoring mode a positive electrospray ionization interface. The calibration curves showed good linearity ( = 0.9998) within the tested concentration ranges. The lower limit of quantification for plasma was 0.05 ng mL; the matrix effect of CuB and IS was 94.19-99.42% and 100.83%, respectively. The mean extraction recoveries from plasma were 85.34-90.53%. The intra-day and inter-day accuracies and precision deviations were within ±15%, which was in line with the allowable range of accuracy. In addition, the stability of the method was also verified. The absolute bioavailability of orally administered CuB in rats was 1.37%. To sum up, the presented method was determined to be suitable for the quantitation of CuB in rat plasma. Also, the absolute bioavailability observed in the present study suggested that it was necessary to change the dosage form to improve bioavailability, or to improve this by other means.
葫芦素B（CuB）是一种高度氧化的四环三萜，属于生物药剂学分类系统（BCS）中的IV类药物，用于治疗持续性肝炎、慢性肝炎和原发性肝癌。然而，CuB溶解度低、渗透性差，在人体内的浓度较低。本研究的目的是建立一种以雌酮为内标（IS），采用超高效液相色谱-质谱联用（UPLC-MS/MS）测定血浆中CuB的方法，并研究CuB在大鼠体内的药代动力学和绝对生物利用度。血浆样品采用乙酸乙酯液-液萃取法处理。在35℃下，使用0.1%甲酸-乙腈（50∶50，v/v）等度流动相系统，流速为0.3 mL/min，在BEH C18柱（2.1×50 mm，1.7μm）上实现分离。采用多反应监测模式和正电喷雾电离接口进行检测。校准曲线在测试浓度范围内显示出良好的线性（r = 0.9998）。血浆定量下限为0.05 ng/mL；CuB和IS的基质效应分别为94.19 - 99.42%和100.83%。血浆中的平均提取回收率为85.34 - 90.53%。日内和日间准确度及精密度偏差均在±15%以内，符合准确度允许范围。此外，该方法的稳定性也得到了验证。大鼠口服CuB的绝对生物利用度为（1.37%）。综上所述，所建立的方法适用于大鼠血浆中CuB的定量分析。同时，本研究中观察到的绝对生物利用度表明，有必要改变剂型以提高生物利用度，或通过其他方式进行改进。
