Characterization and in vitro drug release behavior of (2-hydroxyethyl methacrylate)-co-(2-acrylamido-2-methyl-1-propanesulfonic acid) crosslinked hydrogels prepared by ionizing radiation

A series of copolymer hydrogels of 2-hydroxyethyl methacrylate (HEMA)/2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) were prepared by solution free radical polymerization using gamma irradiation. Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy techniques were used to characterize the HEMA/AMPS hydrogels. The swelling behavior of the prepared hydrogels was determined by investigating the time and pH-dependent swelling of the HEMA/AMPS hydrogels of different AMPS content. The drug loading and controlled release behaviors of the hydrogel were evaluated using hydrocortisone acetate as drug model. The results indicated that the release rate of the drug from the hydrogel showed good pH-response.