Controlled release of antifungal drug terbinafine hydrochloride from poly(N-vinyl 2-pyrrolidone/itaconic acid) hydrogels.

Adsorption and controlled release of terbinafine hydrochloride (TER-HCl) to and from pH-sensitive poly(N-vinyl 2-pyrrolidone/itaconic acid) P(VP/IA) hydrogels were investigated. P(VP/IA) hydrogels were prepared by irradiating the ternary monomer mixtures of N-vinyl 2-pyrrolidone/itaconic acid/ethylene glycol dimethacrylate in aqueous solution by gamma-rays at ambient temperature. Hydrogels containing antifungal drug TER-HCl, at different drug-to-polymer ratios, were prepared by direct adsorption method. The influence of IA content in the gel on the adsorption capacities of hydrogels and the effect of pH on the releasing behavior of TER-HCl from the gel matrix were investigated. Terbinafine adsorption capacity of hydrogels was found to increase from 6 to 82 mg of TER-HCl per gram of dry gel with increasing drug concentration and amount of IA in the gel system. In-vitro drug-release studies in different buffer solutions showed that the basic parameters affecting the drug-release behavior of hydrogels are the pH of the solution and the IA content of the hydrogel.