Free-radical copolymerization of glycidyl methaerylate (GMA) with N-vinylpyrrolidone (VPD) was carried out at 50 degreesC using 3.0 mol (.) L (1) of N,N'-dimethylformamide solution and 9.0 (.) 10(-3) mol (.) L-1 of 2,2'-azobisisobutyronitrile as an initiator. The modification reaction of GMA-VPD copolymers with a model bioactive carboxylic acid, 6-methoxy-alpha-methyl-2-naphthaleneacetic acid (naproxen), was studied in the homogeneous phase using basic catalysts. The influence of the type of catalyst and the GMA content was evaluated.