Study Of Chitosan Derivates (Chitosan-g-(PCL-b-MPEG) And Chitosan/Alginate Complexes

Chitosan is a well-known abundant natural polymer with good biodegradability, biocompatibility and bioactivity. Chitosan-g-(PCL-b-MPEG) copolymers of various compositions were successful synthesized via a protection-graft-deprotection procedure. The reactions were used a new method with phthaloyl-protected chitosan (PHCS) as an intermediate. The products were biodegradable. The chemical structures of the grafted copolymers were characterized by Fourier transform infrared and NMR spectroscopy. After deprotection, the phthaloyl group was removed and the amino group was regenerated. Thus the obtain Chitosan-g-(PCL-b-MPEG) was amphoteric hybrid with unique free amino groups and amphiphilic MPEG-PCL side chain. Crystallinity and behavior of aggregation were also investigated. Then Norcantharidin (NCTD) was used as a model drug to investigate the drug-loaded and drug-released properties of Chitosan-g-(PCL-b-MPEG).Chitosan and alginate solution can self-assemble to form polyelectrolyte complexes. The complexes were characterized by FTIR and element analyse, and the crystallization, moisture-absorption ability and disintegration after pressing to tablet were also investigated. The results showed that chitosan-alginate complexes presented amorphous state, and their moisture-absorption abilities were better than the original chitosan and alginate. Especially, the complexes had great moisture-absorption abilities when prepared from the solution of pH 5.0. The complexes exhibited excellent disintegration effect in the lactose tablet.