Nimodipine is a dihydropyridine calcium channel blocker that exhibits higher selectivity toward cerebral blood vessels compared with other members of the same class. It has been shown to improve outcomes and prevent delayed cerebral ischemia in the setting of aneurysmal subarachnoid hemorrhage, a life‐threatening brain bleed. Nimodipine is a chiral compound and it is marketed as a racemic mixture of (+)‐R and (−)‐S enantiomers. (−)‐S‐Nimodipine is approximately twice as potent a vasorelaxant as the racemic mixture and is more rapidly eliminated than the (+)‐R counterpart following oral dosing. Few analytical procedures have been reported to determine nimodipine enantiomers in biological samples; however, the reported methods were time‐consuming, involved multistep extraction procedures and required large sample volumes. Herein, we present an LC–MS/MS method for quantifying nimodipine enantiomers in human plasma using a small sample volume (0.3 ml) and a single liquid–liquid extraction step. The peak area ratios were linear over the tested concentration ranges (1.5–75 ng/ml) with r² > 0.99. The intraday CV and percentage error were within ±14% while the interday values were within ±13%, making this analytical method feasible for research purposes and pharmacokinetic studies.

中文翻译：

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液相色谱-串联质谱法测定人血浆中尼莫地平的对映选择性

尼莫地平是一种二氢吡啶类钙通道阻滞剂，与同类的其他成员相比，对脑血管具有更高的选择性。在动脉瘤性蛛网膜下腔出血（威胁生命的脑出血）的情况下，已证明它可以改善预后并预防延迟的脑缺血。尼莫地平是一种手性化合物，以（+）- R和（-）- S对映异构体的外消旋混合物形式销售。（−）‐ S‐尼莫地平的强效血管舒张剂的效价约为外消旋混合物的两倍，且消除速度比（+）‐ R更迅速口服后服用。很少有分析方法可以测定生物样品中的尼莫地平对映体。但是，报告的方法耗时，涉及多步提取程序并且需要大量样品。在这里，我们提出了一种LC-MS / MS方法，使用少量样品（0.3 ml）和单个液-液萃取步骤来定量测定人血浆中的尼莫地平对映体。峰面积比在测试浓度范围（1.5–75 ng / ml）内呈线性，r ²  > 0.99。日内CV和百分比误差在±14％之内，而日间值在±13％之内，这使得该分析方法可用于研究目的和药代动力学研究。