To investigate the clinical pharmacokinetics of CA4P, a high-throughput high-performance liquid chromatography–tandem mass spectrometry assay with an identical positive electrospray ionization (ESI) mode was developed for the simultaneous determination of CA4P, its active metabolite CA4, and CA4 glucuronide in human plasma. CA4P and CA4 were easier to protonate in positive ESI mode, whereas CA4G was reported to produce deprotonated ion in negative ESI mode. Because the baseline separation of CA4P and CA4G could not be achieved, using MS positive/negative ion switching is not feasible. In this study, an abundant ammonium adduct ion of CA4G in ESI+ was observed as an ideal precursor ion. The final precursor/product transition pairs chosen for CA4P, CA4, and CA4G were at m/z 397/350, 317/286, and 510/317, respectively. To the best of our knowledge, it is the first report on the simultaneous quantification of CA4P, CA4, and CA4G in biological samples. The proposed method was validated, which showed a wide linear dynamic range, high selectivity and sensitivity, good repeatability, and a short run time. Compared with the literatures, the lower limits of quantification were five- and two-fold more sensitive for CA4G and CA4, respectively. Therefore, this method was successfully applied to the pharmacokinetic study of CA4P in phase I clinical trial.

中文翻译：

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使用 HPLC-MS/MS 高通量同时测定人血浆中的考布他汀 A-4 磷酸盐及其代谢物：在临床药代动力学研究中的应用

为了研究 CA4P 的临床药代动力学，开发了一种具有相同正电喷雾电离 (ESI) 模式的高通量高效液相色谱-串联质谱法，用于同时测定 CA4P、其活性代谢物 CA4 和 CA4 葡萄糖醛酸苷。人血浆。CA4P 和 CA4 在正 ESI 模式下更容易质子化，而据报道 CA4G 在负 ESI 模式下产生去质子化的离子。由于无法实现 CA4P 和 CA4G 的基线分离，因此使用 MS 正/负离子切换是不可行的。在本研究中，ESI+ 中丰富的 CA4G 铵加合离子被观察到作为理想的母离子。为 CA4P、CA4 和 CA4G 选择的最终母体/产物过渡对处于m/z分别为 397/350、317/286 和 510/317。据我们所知，这是关于同时定量生物样品中 CA4P、CA4 和 CA4G 的第一份报告。所提出的方法经过验证，显示出较宽的线性动态范围、高选择性和灵敏度、良好的重复性和较短的运行时间。与文献相比，定量下限对 CA4G 和 CA4 的敏感性分别高出五倍和两倍。因此，该方法成功应用于CA4P的I期临床药代动力学研究。