Synthesis, characterization, and drug delivery property of 2-N-carboxymethyl-6-O-diethylaminoethyl-chitosan

A novel route is demonstrated for the synthesis of 2-N-carboxymethyl-6- O-diethylaminoethyl-chitosan (DEAE-CMC) by incorporation of carboxymethyl groups as hydrophilic moieties to the C2-NH2, and diethylaminoethyl groups as hydrophobic moieties to the C6-CH2OH of the structural unit of chitosan, via a protection-graft-deprotection procedure with benzaldehyde as protective agent. The structure, morphology, and thermal properties of the chitosan graft copolymers were characterized by means of FT-IR, 1H NMR, SEM, TGA and DSC. Chitosan and its derivatives were used as carrier of model drug-Vitamin B12 (VB12), and their controlled delivery behaviour in phosphate buffer solution (pH 7.4) were studied. The results show that the release rate of VB12 from the carrier of DEAE-CMC copolymer becomes much slower than that of chitosan in phosphate buffer solution