Enhanced dissolution and oral bioavailability of tanshinone IIA base by solid dispersion system with low-molecular-weight chitosan

Abstract

Objectives: The aim of this study is to improve the dissolution and oral bioavailability of tanshinone IIA (TAN).

Methods: Solid dispersions of TAN with low-molecular-weight chitosan (LMC) were prepared and the in-vitro dissolution and in-vivo performance were evaluated.

Key findings: At 1 h, the extent of dissolution of TAN from the LMC-TAN system (weight ratio 9 : 1) increased about 368.2% compared with the pure drug. Increasing the LMC content from 9 : 1 to 12 : 1 in this system did not significantly increase the rate and the extent of dissolution. Differential scanning calorimetry, X-ray diffraction and scanning electron microscopy demonstrated the formation of amorphous tanshinone IIA and the absence of crystallinity in the solid dispersion. Fourier transform infrared spectroscopy revealed that there was no interaction between drug and carrier. In-vivo test showed that LMC-TAN solid dispersion system presented significantly larger AUC0-t , which was 0.67 times that of physical mixtures and 1.17 times that of TAN. Additionally, the solid dispersion generated obviously higher Cmax and shortened Tmax compared with TAN and physical mixtures.

Conclusions: In conclusion, the LMC -based solid dispersions could achieve complete dissolution, accelerated absorption rate and superior oral bioavailability.