Free radical copolymerization of acryloxyethyltrimethylammonium chloride with 2hydroxyethyl methacrylate using sodium persulfate as initiator was carried out at 60 degrees C and of its electrostatic interaction with sodium alginate (NaAlg) allowed obtaining polymeric microparticles by complex coacervation. The solute transport in this swellable matrix was investigated to check the effect of cross-linking and simulated physiological condition over release process. Cefazolin Sodium loaded microparticles were prepared by incorporation of drug directly in the reaction mixture and their ability of releasing resulted in more extensive in enzyme-free simulated intestinal medium. The polymeric microparticles prepared in this study were characterized by scanning electron microscopy showing irregular spherical form and rough structure. Particles showed unimodal distribution and the size distribution ranged from 1.1 to 1.8 mm (n = 100). (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013