Effects of Long‐Term Administration and Multicomponent Formulation on the Disposition of Calycosin From Danggui Buxue Decoction: A Pharmacokinetic, Tissue Distribution, and Metabolism Study

Calycosin is an active compound of Danggui Buxue Decoction (DBD) with various pharmacological effects including anti‐inflammatory and immunomodulatory activities. However, it remains unclear whether long‐term administration and the multi component of DBD influence the disposition of calycosin. This study aimed to investigate the absorption, distribution, and metabolism of calycosin following long‐term oral administration of DBD. SD rats were divided into six groups. Plasma was collected at 0.083–24 h after the last administration and separated for the determination of calycosin. For the tissue distribution study, rats were sacrificed 1 h after the last dose and tissues were collected. The concentrations of analytes were determined after sample preparation. Plasma collected within 1 h was used for metabolite identification of calycosin. Pharmacokinetic results indicated that the SH group exhibited the highest plasma exposure of calycosin. Calycosin accumulation was detected in the liver of six groups with levels ranking as MH > SH > ML > SL > MD > SD group. Metabolism studies revealed that the MD group had the highest number of calycosin metabolites. Both long‐term administration and the complex composition influence the absorption, distribution, and metabolism of calycosin in rats after oral administration of DBD. Therefore, this study provides a theoretical basis for the rational clinical use of DBD and calycosin.