Pharmacokinetic effects of metformin hydrochloride, food and alcohol on Ramulus Mori (Sangzhi) alkaloids

Ramulus Mori (Sangzhi) alkaloids (SZ-A) are a group of polyhydroxy alkaloids extracted and isolated from the traditional Chinese medicine mulberry twig, which is mainly used for the treatment of type 2 diabetes mellitus (T2DM). In addition to acting as a glycosidase inhibitor in the small intestine after oral administration, SZ-A can also be absorbed into blood and widely distributed to target organs related to diabetes, exerting multiple pharmacological effects. It is important to elucidate the possible pharmacokinetic influences of SZ-A for its clinical rational applications, such as drug interactions, the effects of food and alcohol on the absorption of SZ-A. However, studies in this area are limited. Therefore, the pharmacokinetic interactions between orally administrated SZ-A (50 mg·kg^-1) and metformin hydrochloride (Met, 200 mg·kg^-1) in Sprague-Dawley (SD) rats were examined. Then, the effect of food (standard feed) on the pharmacokinetics of SZ-A was investigated using fasting administration of SZ-A (50 mg·kg^-1) in rats as a control. Finally, we investigated the pharmacokinetic characteristics of SZ-A (50 mg·kg^-1) in different concentrations alcohol solutions using aqueous solution of SZ-A administered to rats as a control to evaluate the effect of alcohol on the bioabsorption of SZ-A. The results showed no significant pharmacokinetic interactions between SZ-A and Met after combination treatment. The standard feed had little effect on the pharmacokinetic profile of SZ-A. Alcohol retarded the absorption of SZ-A, resulting in a significant decrease in the C_max of SZ-A. The decrease was greater at higher alcohol concentrations; however, no significant difference was observed in the AUC_0-t. These results support the clinical rational applications of SZ-A. All animal protocols were approved by the Ethics Committee of Kangtai Medical Laboratory Service Hebei Co., Ltd. (Hebei, China) (No. MDL2022-01-17-1).