Preparation of polysaccharide composite films using cyclodextrin-conjugated chitosan for sustained release of hydrophobic drugs.

Cyclodextrin-conjugated polysaccharides are often used as functional materials for biological applications, such as drug carriers, because the hydrophobic cavity of the cyclodextrin moiety can encapsulate molecules. Herein, β-cyclodextrin (β-CD)-conjugated chitosan (CD-CHI) for loading and sustained-release of low-molecular-weight hydrophobic drugs was synthesized, and polysaccharide composite films containing β-CD units were prepared from polyion complexes consisting of chondroitin sulfate C and CD-CHI by hot press techniques. β-CD units of the obtained CD-CHI were modified by 9.2% of the amino groups in CHI units. The synthesized CD-CHI was used as a raw material for polysaccharide composite films. The mechanical strength and swelling ratio of the obtained films were comparable to those of films without β-CD. Furthermore, thiabendazole (TBZ) was loaded into the polysaccharide composite films, and it was suggested that the loaded TBZ formed inclusion complexes with the β-CD units in CD-CHI. The loaded TBZ showed sustained-release ability, and the release mechanism from the films was analyzed and described using two kinetic models. Based on these results, polysaccharide composite films using CD-CHI are expected to be used as sustained-release carriers for hydrophobic drugs.