Potential drug delivery systems from chitosan-g-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogels



Biocompatible and biodegradable pH-responsive hydrogels based on acrylic acid and acrylamide onto chitosan were prepared for controlled drug delivery of the drug acyclovir (ACV), which can be used for treatment of Herpes simplex and Varicella Zoster. These interpolymeric hydrogels were synthesized by a free radical polymerization technique using ammonium persulfate (APS) as initiator and methylene bisacrylamide (MBA) as a crosslinker.The synthesized hydrogels were subjected to equilibrium swelling studies in simulated gastric and intestinal fluids (SGF and SIF). Hydrogels containing drug ACV, at different drug-to-polymer ratios, were prepared by direct adsorption method. The loading yield was found to depend on both the impregnation time and the amount of encapsulated drug. In vitro drug-release studies in different buffer solutions showed that the most important parameter affecting the drug-release behavior of hydrogels is the pH of the solution. More than 50% of the entrapped drugs were released in the first 2h at gastric pH and the rest of the drug release was slower.