Chitin, one of the natural abundant polysaccharide, have some benifical medicinal and pharmaceutical applications, but is insoluble in common solvent: CM-chitin(6-Carboxymethylchitin) introducing carboxymethyl radical at C6 is water soluble chitin derivative with biocompatiblity and biodegradability.
The pharmaceutical applications of CM-chitin as a diluent, stabilizer, and vehicle for controlled release preparation was examined with letosteine. Letosteine, cyclic cysteine derivative, was a little solubility but little stability in water. So as to enhance the solubility of letosteine, letosteine was mixed with various quantities of CM-chitin. As the quantity of CM-chitin was increased, the solubility of letosteine was enhanced in pH 5. Experiment informed that CM-chitin was hygroscopic substance and absorbed about 90% moisture for 4 weeks at 98% relative humidity. Letosteine absorbed more moisture than letosteine only. And hygroscopicity of physcal mixtures of letosteine and CM-chitin was higher than tablets of them. The more amount of absorbed moisture was, the less content of letosteine was. In stability test of letosteine, CM-chitin had no influence on stablization of letosteine at 30 t;. But as the mixture ratio of CM-chitin was increased, degradation of letosteine was decreased at 50 *C, 70t. Also the dissolution rate of letosteine was decreased remarkably by CM-chitin. Letosteine was more quickly dissolved in phosphate buffer solution than in water. Accodingly CM-chitin was more effective to intestinal dissolved coating dosage form. CM-chitin is widely available in pharmaceutical applications such as increasing solubility, stablization, and controlled release of drug.
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