A simple, highly sensitive ultra-performance liquid chromatography- electrospray ionization-mass spectrometry (LC-ESI-MS) method has been developed to quantify of withanolide B and obakunone (IS) in guinea pig plasma and tissues, and to compare the pharmacokinetics and tissue distribution of withanolide B in normal and psoriasis guinea pigs. After mixing with IS, plasma and tissues were pretreated by protein precipitation with methanol. Chromatographic separation was performed on a C18 column using aqueous (0.1% formic acid) and acetonitrile (0.1% formic acid) solutions at 0.4 mL/min as the mobile phase. The gradient program was selected (0–4.0 min, 2–98% B; 4.0–4.5 min, 98–2% B; and 4.5–5 min, 2% B). Detection was performed on a 4000 QTRAP UPLC–ESI-MS/MS system from AB Sciex in the multiple reaction monitoring (MRM) mode. Withanolide B and obakunone (IS) were monitored under positive ionization conditions. The optimized mass transition ion-pairs (m/z) for quantitation were 455.1/109.4 for withanolide B and 455.1/161.1 for obakunone.

已经开发了一种简单，高度灵敏的超高效液相色谱-电喷雾电离质谱（LC-ESI-MS）方法，用于定量测定豚鼠血浆和组织中的withanolide B和obakunone（IS），并比较其药代动力学和正常和牛皮癣豚鼠体内withanolide B的组织分布。与IS混合后，血浆和组织通过用甲醇进行蛋白质沉淀进行预处理。在C18色谱柱上进行色谱分离，使用0.4 mL / min的水溶液（0.1％甲酸）和乙腈（0.1％甲酸）溶液作为流动相。选择了梯度程序（0–4.0分钟，2–98％B； 4.0–4.5分钟，98–2％B； 4.5–5分钟，2％B）。在AB Sciex的4000 QTRAP UPLC-ESI-MS / MS系统上以多反应监测（MRM）模式进行检测。在正电离条件下监测Withanolide B和obakunone（IS）。优化的质量转移离子对（m / z）的抗氧化剂A的含量为455.1 / 109.4，奥巴酮的测定值为455.1 / 161.1。