Improved in vitro and in vivo hepatoprotective effects of liposomal silymarin in alcohol-induced hepatotoxicity in Wistar rats

Background: Silymarin, a known hepatoprotectant, owing to its poor oral bioavailability, has limited pharmacological effects. The present study was designed to improve its in vitro and in vivo hepatoprotection and increase its oral bioavailability against alcohol intoxication by formulating it in four different liposomal formulations namely conventional, dicetyl phosphate, stearyl amine and PEGylated liposomes. Method: The liposomes were prepared using phosphatidylcholine, cholesterol, and silymarin in addition to dicetyl phosphate, stearyl amine and DSPE mPEG 2000 by film hydration method with 5% sucrose as a cryo-protectant. The optimized formulations were studied for their release profile at pH 1.2 and 6.8. Liposomes were studied for in vitro protection on Chang liver cells and efficacious liposomes were selected for in vivo hepatoprotection study. Further, conventional liposomes were studied for bioavailability in alcohol intoxicated Wistar rats. Results: The conventional liposomes increased in vitro release profile at pH 1.2 and 6.8 and also showed better in vitro protection compared to silymarin alone. Conventional and PEGylated liposomes showed better improvement in liver function, better efficacy in combating inflammatory conditions, better improvement in antioxidant levels and reversal of histological changes compared to silymarin alone. Conventional also showed an almost fourfold increase in area under the curve compared to silymarin suspension. Conclusion: Conventional and PEGylated liposomes of silymarin were found to be more efficacious as hepatoprotective against alcohol-induced hepatotoxicity by its free radical scavenging and anti-inflammatory effects. Conventional liposomes showed enhanced bioavailability compared to silymarin alone.