In this paper,the effect of the chemically modified cyclodextrin [2-hydroxypropyl-&beta-cyclodextrin,(HP-&beta-CD)] on the dissolution rate,and intestinal permeability of the tanshinone IIA (TS) was investigated.The corresponding inclusion complex was obtained at the molar ratio of 1 ∶ 1 by lyophilization and characterized by differential scanning calorimetry and X-ray diffraction.The dissolution rate of the drug was significantly improved by complexation with HP-&beta-CD.The percentage of TS dissolved from free TS and the complex was 9.26% and 97.2%,respectively.Using the in situ intestinal perfusion technique,the absorption behaviors of TS and its inclusion complex were investigated.at a series of concentration in three segments of small intestine.It was demonstrated that the absorption of TS whether it was free or complexed was independent on the concentration and not intestinal site-dependent via the perfusion model.The permeability rates of TS across the intestinal epithelial membrane were enhanced about 7 times and the absorptive fraction was increased approximately 9-fold by the formation of inclusion complex with HP-&beta-CD at each intestinal segment.The results obtained suggested the potential use of HP-&beta-CD to improve the gastrointestinal tract absorption of TS.