DESIGN AND EVALUATION OF CHITOSAN-BASED MICROPARTICLES AS MODELS OF PROTEIN DELIVERY SYSTEMS

Controlled release systems for protein and peptide vaccines based polymers have been considered for many applications in medical therapies. Chitosan is non-toxic and easily absorbed biopolymers and is often used in many researches to sustained release drugs and proteic vaccines. This study investigates the kinetics of release in vitro of bovine serum albumin (BSA) from chitosan microparticles and the effect of the preparation process of the microparticles in the release rate. Chitosan microparticles were design by a coacervation / precipitation method under different time’s sonication and different protein / chitosan ratio were used (0, 5 to 2 g. g^-1). To the in vitro study of the protein release, the microparticles were resuspended in PBS pH 7.4 at 37 °C under stirring and the samples in different intervals were aliquoted to dosage of BSA release. The morphology of the chitosan microparticles was examined with Electron Microscopy, which showed particle size between 10 – 30 µm and porous structures. Studies were conducted to investigate the BSA stability during the process of BSA loaded, no BSA degradation, through electrophoresis in polyacrylamide gel, were observed the microparticles prepared with 20 minutes of sonication had a higher speed BSA release, in relation to the other sonication times, being 0.86 µg/mL^-1/ min^-1, with BSA/chitosan ratio of 1, 5g. g^-1. These data showed that the preparation process is an important factor in controlling release of protein from chitosan microparticles, and this can become a potential for carrier vaccines in mucosal delivery systems.