Superporous hydrogels based on blends of chitosan and polyvinyl alcohol as a carrier for enhanced gastric delivery of resveratrol

Resveratrol exhibits a number of pharmacological properties, notably antioxidant, anti-inflammatory and anti-cancer activities which are beneficial for the treatment of gastric diseases. However, the poor aqueous solubility and rapid metabolism are the important limitations in clinical uses. Superporous hydrogels (SPHs) based on chitosan/PVA blends were developed as a carrier for resveratrol solid dispersion (Res_SD) to increase the solubility and achieve sustained drug release in the stomach. The SPHs were prepared by gas forming method using glyoxal and sodium bicarbonate as cross-linking agent and gas generator, respectively. The solid dispersions of resveratrol with PVP-K30 were prepared by solvent evaporation and incorporated into the superporous hydrogels. All formulations showed rapid absorption of simulated gastric fluid and reached the equilibrium swollen state within a few minutes. The water absorption ratio and mechanical strength of SPHs were predominantly affected by the chitosan content, with maximum values at 1400 % and 375 g/cm², respectively.The Res_SD-loaded SPHs exhibited good floating properties and SEM micrographs revealed a highly interconnected pores structure with size around 150 μm. Resveratrol was efficiently entrapped within the SPHs at levels between 64 and 90 % w/w and efficient drug release was sustained over 12 h dependent on the concentration of chitosan and PVA. The Res_SD-loaded SPHs exhibited slightly less cytotoxic efffect towards AGS cells than pure resveratrol. Furthermore, the formulation showed similar anti-inflammatory activity against RAW 264.7 cells compared with indomethacin.