improvement of bioavailability and dissolution of tanshinone iia by encapsulating it with hydroxypropyl-β-cyclodextrin

Background: tanshinone iia(ta) could be used for the treatment of some diseases. however, the clinical application of ta was hindered by its poor water - solubility and low oral bioavailability, etc. the aim of this study was to improve its oral bioavailability and dissolution by encapsulating ta with hydroxypropyl–beta–cyclodextrin (hp-β-cd). methods: the encapsulation composite of hp-β-cd/ta was prepared through solution method with optimization of response surface test design by taking encapsulation efficiency and drug loading as the goals; the in-vitro dissolution and in-vivo metabolism of the composite in rats were evaluated. results: the optimal concentration of hp-β-cd in water was 0.4 g/ml; the optimal ratio of ta to hp-β-cd was 1:7 in weight for the encapsulating process at 50°c with stirring for 2h; the encapsulation efficiency and drug loading were 84.06% and 7.38%, respectively; the cumulative release of ta from hp–β -cd ta composite in vitro dissolution reached to 72% within 90 min, which was 3.78 times of that of the original ta substance; the area under the curves of auc(0-t) and auc(0-∞) of the hp–β –cd -ta inclusion composite were 3.71 and 3.42 times of the original ta substance under p<0.01, respectively. the apparent distribution volume vz/f and the clearance rate vlz/f of hp–β –cd -ta inclusion composite decreased by 7.71 and 3.48 times as compared with the original ta substance, respectively. conclusion: the improvements of bioavailability and dissolution by encapsulating ta with hp-β-cd were effective.