The Synthesis Of 6-carboxymethyl Chitin And The Preparation And Applications Of Its Gel Materials.

Renewable resource polymers come from the biomass originated from solar energy. They are inexhaustible and renewable; the essential of the research and exploitation on natural polymers actually is the research, exploitation and conversion of ecologic resource and energy. Chitin, a (1→4)-linked N-acetamido-2-deoxy-β-D-glucan, one of the natural abundant polysaccharides present in the cuticles of Crustacea, has been reported to have some beneficial medicinal and pharmaceutical applications as its good biocompatibility and low toxicity. The recent progress on the structure and chemical modification of chitin and its derivative and their new materials were reviewed in this paper.6-carboxymethyl chitin (6-CMCH), the derivative of Carboxy- methylated chitin, it is a water-soluble and pH sensitive material while retained the excellent bio-characteristic, so it is a superexcellent material to prepare biogelatin. A series of gelatin materials based on chitin's derivative which were obtained by carboxymethylation, crosslinking due to ferric irons, blending with Alginate and grafting acrylic acid (AA). The materials which had sustained release characteristic had been studied as a carrier for the drug release. The main contents are as follows:Firstly, 6-CMCH with different degree of substitution from chitin was prepared. Meanwhile, the influence of reaction materials, times, and temperature on production also has been considered, the best reaction condition was found when the weight ratio of Chloroacetic acid and sodium hydroxide was 9:10, and adding 2%(wt) sodium dodecyl sulfate and little sodium borohydride. Then the 6-CMCH gelatin microsphere is prepared with the cross-link reagent of ferric chloride mixed with calcium chloride. At last the swelling behavior in buffer solution with different pH value and drug sustained release in vitro with the model drug Bovine Serum Albumin (BSA) were both been examined carefully. The microsphere was found reaching the max swelling degree (S.D) at pH3.0, for the more, S.D and release rate increased with the rising of time and concentration of cross-link reagent, and with the reducing of pH values.Secondly, the complex microsphere with materials of 6-CMCH, sodium alginate (ALG) and cross-link reagent of ferric chloride was prepared. After examining its swelling behavior and the release of 5-Aminosalicylic Acid (5-ASA), it was proved that the microsphere could be existed stablely both in acid and medium buffer solution.