Drug loading and release behaviors of freestanding polysaccharide composite films

We developed freestanding, water-insoluble thin films made of polyion complexes (PICs) that consist of glycosaminoglycans such as chondroitin sulfate C (CS) and chitosan (CHI) by utilizing hot press techniques. In this study, material loading and release abilities of CS/CHI composite films were spectroscopically examined using small dye molecules; cationic methylene blue (MB) and anionic carboxyfluorescein (CF) were used as model drugs. The dye-loading films were prepared using pre- and post-loading methods. Microscopic film morphologies were not affected by the dye loadings. The mechanical strengths of the dye-loaded CS/CHI films were almost identical to those of the unloaded films. The dye release behaviors of the films in various aqueous solutions were examined, and the results demonstrated that the CS/CHI films exhibited media-responsive dye release abilities. The experimental results obtained under different conditions were compared and discussed based on the chemical structures of the polysaccharides used to generate the film components and the dye molecules. The present results demonstrate that these polysaccharide composite films are promising materials for use in applications that require sustained drug release under physiological conditions.