Oil based nanocarrier for improved oral delivery of silymarin: In vitro and in vivo studies

Silymarin, obtained from Silybum marianum is used for hepatoprotection and having poor aqueous solubility and low bioavailability. Therefore, it was thought to incorporate the drug into oil-in-water (o/w) based nanocarrier to increase its oral bioavailability. In the present study, o/w nanocarrier was prepared by titration method and was characterized for droplet size, viscosity, etc. In vitro drug release was carried out by dialysis membrane method. A pharmacokinetic study was performed to determine maximum plasma concentration (Cmax), area under the curve (AUC), etc. and hepatoprotective activity was evaluated in terms of serum enzyme estimation. The optimized nanoemulsion formulation consisted of sefsol-218 as oil, tween 80 as a surfactant and ethanol as a co-surfactant having nano-droplet size and low viscosity. In vitro dissolution studies showed higher drug release from nanoemulsion as compared to bulk drug suspension. The AUC and Cmax of nanoemulsion after oral administration were 4-fold and 6-fold higher than those of drug suspension of silymarin. The results of pharmacokinetic studies showed better effects of developed nanoemulsion than drug suspension and marketed formulation. The present study showed that the nanoemulsion being a versatile technology has the potential to improve the biopharmaceutics properties of silymarin.

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