Radiation synthesis of poly(N-vinyl 2-pyrrolidone/itaconic acid) hydrogelsand their controlled release behaviours

N-vinyl 2-pyrrolidone/itaconic acid copolymeric hydrogels were prepared by irradiating the ternary mixtures of N-vinyl 2-pyrrolidone/itaconic acid/wat er by gamma-rays at ambient temperature. For the characterization of networ k structure of these hydrogels, swelling properties in phosphate buffer sol utions and molecular weight between crosslinks were investigated. Methylene Blue was used as a model drug for the investigation of controlled release behaviour of hydrogels. Specific Methylene Blue adsorption capacity of hydr ogels are found to increase from 0.36 to 47.7 (mg MB/g gel) with increasing amount of itaconic acid in the gel system. The influence of molecular weig ht between cross-links, the concentration of ionizable groups, ionization a nd concentration of MB in the hydrogel were examined. The release studies s how that one of the basic parameters affecting the drug release behaviour o f hydrogels is the pH of the solution. (C) 1999 Elsevier Science Ltd. All r ights reserved.