Enhanced dissolution and stability of Tanshinone IIA base by solid dispersion system with nano-hydroxyapatite

Tanshinone IIA (TSIIA) exhibits a variety of cardiovascular effects; however, it has low solubility in water. The preparation of poorly soluble drugs for oral delivery is one of the greatest challenges in the field of formulation research. Among the approaches available, solid dispersion (SD) technique has proven to be one of the most commonly used these methods for improving dissolution and bioavailability of drugs, because of its relative simplicity and economy in terms of both preparation and evaluation.

This study was aimed at investigating the dissolution behavior and physical stability of SDs of TSIIA by employing nano-hydroxyapatite (n-HAp).

The TSIIA SDs was prepared to use a spray-drying method. First, an in vitro dissolution test was performed to assess dissolution characteristics. Next, a set of complementary techniques (differential scanning calorimetry, scanning electron microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy) was used to monitor the physicochemical properties of the SDs. The SDs was stored at 40°C/75% relative humidity for 6 months, after which their stability was assessed.

TSIIA dissolution remarkably improved because of the formulation of the SDs with n-HAp particles. Comparisons with the corresponding physical mixtures revealed changes in the SDs and explained the formation of the amorphous phase. In the stability test, virtually no time-dependent decrease was observed in either in vitro drug dissolution or drug content.

SD formulation with n-HAp may be a promising approach for enhancing the dissolution and stability of TSIIA.