On an effective approach to improve the properties and the drug release of chitosan-based microparticles.

The work investigated the possibility to develop an easy scalable treatment capable of modifying only the surface of chitosan-based materials, limiting the degradation of the bulk and the burst release of a drug, without compromising the properties of the polymeric matrix. To this aim, microparticles of CHI were superficially coated with poly-(styrene-co-maleic anhydride) (PSMA), taking advantage of the potential reactivity of chitosan amino groups and maleic functionalities of PSMA. The specific reactions/interactions occurring between the two polymers were studied by IR measurements, while FE-SEM analysis evidenced the modification of the morphology of the particles contacted with PSMA. Contact angle measurements demonstrated the change of wettability in the modified systems and TGA analysis allowed to estimate the amount of the deposited PSMA. The above treatment turned out to improve the particle stability both in an acidic environment and in an enzymatic system. The release properties of the treated and of the untreated particles, over a period of 10 h, were tested using, as model drug, the protein Bovine Serum Albumin (BSA). Finally, the cytocompatibility of the developed composite microparticles was assessed on MCF-7 human breast cancer cells, which measurements demonstrated the non-toxicity of the treatment.