Controlled Release of Biomolecules from pH-Sensitive Hydrogels Prepared by Radiation Polymerization

Abstract

Copolymers of 2-hydroxyethyl methacrylate and methacrylic acid based hydrogels were studied as hydrogel drug delivery systems. Radiation copolymerization of 2-hydroxyethyl methacrylate and methacrylic acid (mixed with 3,3'-azobis(6-hydroxy benzoic acid)(ABHB) as an azo derivative of 5-aminosalicylic acid were carried out with various amounts of methacryloyloxyethyl esters of terephthalic acid for crosslinking. The polymer structures were characterized by FTIR, 1H NMR, 13C NMR spectroscopy and glass transition temperature (Tg). The hydrolysis of the drug–polymer conjugates were carried out in dialysis bags containing aqueous buffer solutions (pH 1 and 7.4) at 37°C. The drug-release profiles indicate that the amount of drug release depended on the degree of swelling and crosslinking.