Preparation of Tanshinone II A solid dispersion by spray freeze drying and its characterization

OBJECTIVE: To prepare tanshinone II A solid dispersion using spray freeze drying (SFD) method. METHODS: Dissolution profiles of tanshinone II A from different solid dispersions prepared with various excipients were plotted. Based on the dissolution rate, F68 was selected as the excipient. The optimized formula was characterized in terms of morphology, surface area and crystallinity. RESULTS: Compared to raw material, the specific surface of tanshinone II A solid dispersion prepared by SFD method with drug-F68 ratio of 1:9 (w/w) increased by 3 folds. The majority of the tanshinone II A in the solid dispersion transformed from crystalline form to amorphous state. As a result, the dissolution rate of Tanshinone II A significantly enhanced, and 70% of tanshinone II A in the solid dispersion were dissolved in 10 min. CONCLUSION: SFD method has been successfully utilized to prepare solid dispersion of tanshinone II A with enhanced dissolution rate than that of the raw material, which is a prerequisite for increasing its oral bioavailability in vivo.