A sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method was established for the quantification of total and unbound concentrations of LY3214996, an extracellular signal-regulated kinase inhibitor; abemaciclib, a cyclin-dependent kinase 4/6 inhibitor; and abemaciclib active metabolites, M2 and M20, in human plasma, brain tumor, and cerebrospinal fluid samples. The method was validated over a concentration range of 0.2–500 nM within a total run time of 3.8 min using isocratic elution on a Kinetex™ F₅ column. Detection was performed on a Sciex QTRAP 6500+ mass spectrometer employing multiple reaction monitoring mode under positive electrospray ionization. The intra- and inter-batch accuracy as well as the precision of the method for all matrices was within ±20% and ≤20% at the lower limit of quantification, and within ±15% and ≤15% for other quality control levels for all analytes. The unbound fractions of drugs and metabolites in spiked and patient samples were determined using an optimized equilibrium dialysis. The validated method was successfully applied in a phase 0/2 clinical trial to assess the central nervous system penetration of LY3214996 and abemaciclib.

建立了一种灵敏、快速的液相色谱串联质谱 (LC-MS/MS) 方法，用于定量细胞外信号调节激酶抑制剂 LY3214996 的总浓度和未结合浓度；abemaciclib，一种细胞周期蛋白依赖性激酶 4/6 抑制剂；和 abemaciclib 活性代谢物 M2 和 M20，在人血浆、脑肿瘤和脑脊液样本中。该方法在 0.2–500 nM 的浓度范围内使用 Kinetex™ F _{5上的等度洗脱在 3.8 分钟的总运行时间内进行了验证}柱子。在 Sciex QTRAP 6500+ 质谱仪上进行检测，采用正电喷雾电离下的多反应监测模式。所有基质的批内和批间准确度以及该方法的精密度在定量下限均在±20% 和≤20% 范围内，对于其他质量控制水平在±15% 和≤15% 范围内所有分析物。使用优化的平衡透析测定加标样品和患者样品中未结合的药物和代谢物部分。经验证的方法成功应用于 0/2 期临床试验，以评估 LY3214996 和 abemaciclib 的中枢神经系统渗透。