Polyacrylamide-chitosan hydrogels: in vitro biocompatibility and sustained antibiotic release studies

Controlled drug delivery is gaining importance over the conventional methods of drug administration because of its inherent benefits. Self-regulated release from the delivery vehicle may enhance drug potency with a sustained action. The present study describes a novel hydrogel blend of polyacrylamide with chitosan for controlled delivery of antibiotics. Hydrogel was synthesized by cross-linking acrylamide-chitosan mixture (8:2 v/v) with N,N' methylene bisacrylamide. Hydrogel was characterized for surface morphology, hydrophilicity, pH-dependent swelling properties, cytotoxicity, and control release properties. Scanning electron microscopy (SEM) revealed the macroporous surface morphology of the matrix with average pore size at 104 +/- 7.61 mu. Hydrogel was found to be highly hydrophilic as assessed by octane contact angle (154.5 + 0.572) measurement. Hydrogel showed no cytotoxic effects on NIH3T3 and HeLa cells up to 40% of extract concentrations as determined by MTT and neutral red assay. This showed hydrogel biocompatibility and thus absence of deleterious effects of the hydrogel on cell viability and functionality. Hydrogels did not show any pH-dependent swelling profile, and they swelled considerably to achieve a swelling ratio of approximately 16.0 at the end of 24 hr. Amoxicillin was incorporated in the hydrogel matrix as a candidate antibiotic for release studies. In vitro release studies of amoxicillin revealed the sustained nature of delivery and matrix released 56.47 + 1.12% and 77.096 + 1.72% of amoxicillin at the end of 24 and 75 hr, respectively. Although in vivo studies are awaited, the present study provides enough documentation to consider polyacrylamide-chiotsan hydrogel as a possible candidate for controlled delivery of antibiotics.