pH- and temperature-sensitive semi-interpenetrating network hydrogels composed of poly(acrylamide) and poly(γ-glutamic acid) as amoxicillin controlled-release system

Hydrogels of semi-interpenetrating networks composed of poly(acrylamide) (PAAm) and poly(γ-glutamic acid) (γ-PGA) with different proportions were studied as potential amoxicillin controlled-release devices. The effects of the hydrogels composition, pH, and temperature on the kinetics and final release of amoxicillin were determined in batch experiments. The release kinetic tests were conducted using a buffer solution as the release medium under pH conditions of 3 and 7.2, and temperature of 25, 37, and 45 °C. The final percentage of amoxicillin released from the hydrogels was found to increase with temperature, pH, and the amount of γ-PGA in the hydrogels formulation. Overall, equilibrium conditions in the kinetics experiments were achieved within 240 min of hydrogel–solution contact. The overall rate of amoxicillin release was represented with a two-parameter empirical model as a function of time.