In vivo and in vitro metabolism study of traditional Chinese medicine formula Dingkun Dan in rats by using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry

Dingkun Dan (DKD), a reputable traditional Chinese medicine formula, has been used to treat gynecological diseases and showed significant clinical effects since ancient times. However, the application and development of DKD are seriously hampered by the unclear active substances. Structural characterization of compounds absorbed in vivo and their corresponding metabolites is significant for clarifying the pharmacodynamic material basis. In this study, an integrated strategy using ultra-performance liquid chromatography, coupled with quadrupole time-of-flight mass spectrometry and UNIFI™ software, was used to identify prototypes and metabolites after oral administration of DKD in rats. As a result, a total of 261 compounds, including 140 prototypes and 121 metabolites, were tentatively characterized in rat plasma, urine, and feces. The metabolic pathways of prototypes have been studied to clarify their possible transformation process in vivo. Moreover, an in vitro metabolism study was applied for verifying the metabolites under simulating the metabolic environment in vivo. This first systematic metabolic study of DKD is important for elucidating the metabolites and metabolic pathways and could provide a scientific basis for explaining the integrative mechanism in further pharmacology study.