Controlled release of terbinafine hydrochloride from pH sensitive poly(acrylamide/maleic acid) hydrogels

Adsorption and controlled release of terbinafine hydrochloride (TER-HCl) to and from pH sensitive poly(acrylamide/maleic acid) (P(AAm/MA)) hydrogels were investigated. P(AAm/MA) hydrogels were prepared by irradiating the ternary mixtures of AAm/MA/and water by gamma-rays at ambient temperature. Antifungal drug, TER-HCl containing hydrogels, at different drug to polymer ratios, was prepared by direct adsorption method. The influence of MA content in the gel on the adsorption capacities of hydrogel and the effect of pH on the releasing behavior of TER-HCl from gel matrix were investigated. Terbinafine adsorption capacity of hydrogels are found to increase from 2 to 38 mg TER-HCl per g dry gel with increasing amount of MA in the gel system. In vitro drug release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and MA content of hydrogel.