A novel tanshinone IIA/chitosan solid dispersion: Preparation, characterization and cytotoxicity evaluation

The objective of this study was to develop and evaluate a novel tanshinone IIA (TA)/chitosan (CS) solid dispersion (TA-CS-SD) to improve the bioavailability. Solid dispersion of tanshinone IIA with chitosan was prepared by a pH inversion method via the pH-responsive dissolution property of chitosan matrix. The in vitro dissolution study confirmed dramatically elevated dissolution rate of TA by solid dispersion approach, and the release mechanism exhibited pH-responsive performance. The solid dispersion was characterized by x-ray diffractometry (XRD), differential scanning calorimetry (DSC), fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Our results showed that TA existed in the form of microcrystal or superfine crystal in solid dispersion, and the reduction of crystallinity was correlated with the content of CS matrix. In vitro cytotoxicity study was performed in human non-small cell lung cancer A549 cell line by CCK-8 assay. Significant improvement in antitumor activity of TA in TA-CS-SD was achieved compared to the crystalline drug. These results indicated that, compared with free TA, TA-CS-SD demonstrated higher dissolution rate and bioactivity.