RESUMO
Objective: To investigate the intestinal absorption characteristics of Pulsatilla saponin D in rats. Methods: In situ single-pass intestinal perfusion model was used to inspect the absorption of Pulsatilla saponin D in the intestinal tract of rats. HPLC was used to determine the concentration of Pulsatilla saponin D in intestinal perfusion fluid samples. Absorption rate constant (Ka) and apparent permeability coefficient (Papp) were used as indexes to investigate the effects of absorption sites, drug concentration, different pH values, and P-glycoprotein (P-gp) inhibitor on Pulsatilla saponin D absorption. Results: There was the significant difference (Pileum>jejunum>duodenum. With the pH value increasing, the Ka and Papp values also increased and both of them had significant differences (P0.05); There was significant difference (P<0.05) in Ka and Papp values with and without P-gp inhibitor. Conclusion: Pulsatilla saponin D could be well absorbed in whole intestinal segments of rats, and the best intestinal absorption site is colon; The drug concentration in a certain range has no effect on Ka and Papp values, which preliminarily comfirms that the obsorption mechanism of Pulsatilla saponin D could be passive diffusion; Pulsatilla saponin D may be a substrate of P-gp and possess the saturation phenomenon of transporters.