Influence of vitamin E tocopherol polyethylene glycol succinate 1000 on intestinal absorption of icariside II

In the present study, the Caco-2 monolayer model and a four-site rat intestinal perfusion model were used to investigate the effects of vitamin E tocopherol polyethylene glycol succinate 1000 (TPGS) on the intestinal absorption of icariside II. Icariside II was analyzed by ultra-performance liquid chromatography (UPLC). After that its apparent permeability coefficients (Papp) and effective permeability (P*_eff ) were calculated. In the Caco-2 cell model, Papp values from the apical (AP) to the basolateral (BL) of icariside II were increased and its efflux ratios were markedly reduced in the presence of TPGS. However, either 0.25 mg/mL or 0.5 mg/mL of TPGS had no significant difference in promoting the absorption of icariside II. In four-site rat intestinal perfusion model, P*_eff of icariside II were significantly increased by 0.5 mg/mL of TPGS in ileum and colon. The results suggest that TPGS could promote the intestinal absorption of icariside II.