Significance and challenges of stereoselectivity assessing methods in drug metabolism

Stereoselectivity in drug metabolism can not only influence the pharmacological activities, tolerability, safety, and bioavailability of drugs directly, but also cause different kinds of drug-drug interactions. Thus, assessing stereoselectivity in drug metabolism is of great significance for pharmaceutical research and development （R＆D） and rational use in clinic. Although there are various methods available for assessing stereoselectivity in drug metabolism, many of them have shortcomings. The indirect method of chro- matographic methods can only be applicable to specific samples with functional groups to be derivatized or form complex with a chiral selector, while the direct method achieved by chiral stationary phases （CSPs） is expensive. As a detector of chromatographic methods, mass spectrometry （MS） is highly sen- sitive and specific, whereas the matrix interference is still a challenge to overcome. In addition, the use of nuclear magnetic resonance （NMR） and immunoassay in chiral analysis are worth noting. This review presents several typical examples of drug stereoselective metabolism and provides a literature-based evaluation on current chiral analytical techniques to show the significance and challenges of stereo- selectivity assessing methods in drug metabolism.