Enantioselective analysis is an essential requirement during the pharmaceutical development of chiral drug molecules. In pre-clinical and clinical studies, the Food and Drug Administration (FDA) mandates the assessment of “in vivo” inter-conversion of chiral drugs to determine their physiological effects. In-vivo analysis of the active pharmaceutical ingredient (API) and its potential metabolites could be quite challenging due to their low abundance (ng/mL levels) and matrix interferences. Therefore, highly selective and sensitive analytical techniques are required to separate the API and its metabolites from the matrix components and one another. Additionally, for chiral APIs, further analytical separation is required to resolve the API and its potential metabolites from their corresponding enantiomers.

In this work, we demonstrate the optimization of our previously designed two-dimensional liquid chromatography-supercritical fluid chromatography-mass spectrometry (2D-LC-SFC -MS) system to achieve 10 ng/mL detection limit [1]. The first LC dimension, used as a desalting step, could efficiently separate the API from its potential metabolites and matrix components. The API and its metabolites were then trapped/focused on small trapping columns and transferred onto the second SFC dimension for chiral separation. Detection can be achieved by ultra-violet (UV) or MS detection. Different system parameters such as column dimensions, transfer volumes, trapping column stationary phase, system tubing internal diameter (i.d.), and detection techniques, were optimized to enhance the sensitivity of the 2D-LC-SFC-MS system. The limit of detection was determined to be 10 ng/mL. An application is described where a mouse hepatocyte treated sample was analyzed using the optimized 2D-LC-SFC-MS system with successful assessment of the ratio of API to its metabolite (1D-LC), as well as the corresponding enantiomeric excess values (% e.e.) of each (2D-SFC).

对映选择性分析是手性药物分子药物开发过程中的基本要求。在临床前和临床研究中，美国食品药物管理局（FDA）要求评估手性药物的“体内”相互转化，以确定其生理作用。由于活性成分低（ng / mL水平）和基质干扰小，因此对活性药物成分（API）及其潜在代谢产物进行体内分析可能具有很大的挑战性。因此，需要高度选择性和灵敏的分析技术来将API及其代谢物与基质组分分离。另外，对于手性API，需要进一步的分析分离，以从相应的对映异构体中分离出API及其潜在的代谢物。

在这项工作中，我们证明了我们先前设计的二维液相色谱-超临界流体色谱-质谱（2D-LC-SFC -MS）系统的优化，可达到10 ng / mL的检测限[1]。用作脱盐步骤的第一个LC尺寸可以有效地将API与潜在的代谢物和基质成分分离。然后将API及其代谢物捕集/聚焦在小型捕集柱上，并转移到第二个SFC维上进行手性分离。可以通过紫外线（UV）或MS检测来实现检测。优化了不同的系统参数，例如色谱柱尺寸，传输体积，捕集柱固定相，系统管内径（id）和检测技术，以提高2D-LC-SFC-MS系统的灵敏度。检出限确定为10 ng / mL。描述了一种应用，其中使用优化的2D-LC-SFC-MS系统分析了小鼠肝细胞处理的样品，并成功评估了API与其代谢物的比例（1D-LC）以及相应的对映体过量值（％ ee）中的每个（2D-SFC）。