Studies on Forsythin Uptake Kinetics by Everted Rat Gut Sac Model

摘要

Purpose. Our aim was to investigate the uptake kinetics of forsythin in the small intestine and analyze the factors that affect absorption. Methods. A simple and convenient method was established by HPLC to detect forsythin. To characterize forsythin uptake kinetics in different sacs, three different forsythin concentrations, P-glycoprotein inhibitor verapamil hydrochloride and Tween-80 were assayed by the everted rat gut sac model. Results. Forsythin could be absorbed in the whole intestine, the data had concentration and time dependence, and k_a had no significant differences (P>0.05) at three concentrations (10, 20, and 40ug*mL~(-1)). The results showed linear correlation between the forsythin absorption in sac contents and the incubation time from 0~90min. Forsythin absorbed dose order in rat small intestine is ileum>jejunum>duodenum. The permeability increased when forsythin was perfused with Tween-80, but P-gp inhibitor verapamil hydrochloride didn't has this effect. Conclusion. The absorption of forsythin in the small intestine is first-order process. The absorption mechanism is inferred the passive diffusion. Forsythin is not the substrate of P-gp.