Hydrogels of Poly(acrylamide-co-acrylic acid): In-vitro Study on Release of Gentamicin Sulfate

Poly(acrylamide-co-acrylic acid) hydrogels, poly(AAm-co-AAc), were synthesized by free radical polymerization in solution using N,N’-methylenebisacrylamide (MBAAm) as the crosslinker. The structural parameters and the swelling behavior of the synthesized hydrogels were investigated for varying nominal crosslinking ratio and composition of the hydrogels. The use of hydrogels for drug release was investigated with gentamicin sulfate (GS) as the model drug. The drug release from hydrogels was investigated as a function of hydrogel composition, nominal crosslinking ratio (X) and drug loading. The observed drug release data was fitted to a power law model and the power law exponent (n) suggested that the drug release mechanism from these hydrogels was sensitive to hydrogel composition and was swelling-controlled for low concentrations of AAc and showed Fickian diffusion for high concentrations of AAc in the hydrogels. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies were performed on control hydrogel samples and drug loaded hydrogels to understand the chemical interactions between the drug and the polymer. Specific drug interactions were observed in these hydrogels.