Enhanced oral bioavailability of Wurenchun (Fructus Schisandrae Chinensis extracts) by self-emulsifying drug delivery systems.

Wurenchun is the alcohol extract from Fructus Schisandrae Chinensis, which has good efficiency in lowering abnormal serum glutamic pyruvic transaminase (SGPT) level of patients suffering from acute or chronic hepatitis. The main purpose of this work is to prepare self-emulsifying drug delivery systems (SEDDS) for enhancing the solubility, dissolution rate, and oral bioavailability of poorly water-soluble traditional Chinese medicines, Wurenchun. Pseudoternary phase diagrams were used to evaluate the efficient self-emulsification domains, and particle size distributions of resultant emulsions were determined. The dissolution test was performed according to the second method of Chinese Pharmacopoeia dissolution procedure. The pharmacokinetic study in rats for the optimized formulation was performed and compared to commercial capsules. The optimized formulation for bioavailability assessment consisted of 20% oleic acid, 65% Tween 20, and 15% Transcutol P. The mean droplet size distribution of the optimized SEDDS was approximately 240 nm when diluted with 1000-fold volume of the distilled water. The in vitro dissolution rates of the active components of Wurenchun SEDDS were significantly higher than those of the commercial capsules. SEDDS have significantly increased the C(max) and area under the curve) (AUC) of Wurenchun compared to reference capsules (P < 0.05). And the relative bioavailability of SEDDS for schisandrin and schisandrin B was 292.2% and 205.8% compared to the commercial capsules, respectively. The results suggest the potential use of SEDDS to improve oral absorption of the sparingly soluble drugs or traditional Chinese medicine, such as Wurenchun.