Abstract:Objective: To prepare tanshinone microemulsion (Tan-ME) and investigate its properities and the absorption character in rat intestine in situ. Method: The microemulsions were prepared and characterized using Zetapals Zeta potential/particle size analysis and atomic force microscope. A HPLC method for determination of tanshinone ⅡA in the intestinal flux was established. Result: The Tan-ME was fine droplet with an average droplet size of (32.25±6.59) nm. The results of Tan-ME absorption in small intestinal indicated that Tan-ME could improve the absorption of tanshinone ⅡA in rat small intestine, but the absorption coefficient of Tan-ME, Ka was influenced by the ratio of water-phase in Tan-ME. Conclusion: Tan-ME could improve the absorption of tanshinone ⅡA in rat small intestine. Thus bioavailability of tanshinone was improved.