THE RELATIONSHIP BETWEEN PHYSICOCHEMICAL PROPERTIES AND ENTERIC DISSOLUTION OF SHELLAC AND ITS MODIFICATION

Six commercial shellac samples were used for the preparation of enteric coating material. Its iodine value, saponification value, acid value and alcohol-insoluble substance have been determined. The results indicated the relation between enteric disintegration properties of shellac and its physical-chemical data. The material with iodine value of 8～10 and alcohol-insoluble substance below 10% were suitable for enteric coating. Soft soap can modify enteric disintegration properties of shellac. Significant differences were found between the modified and non-modified shellac coating formulation. Shellac incorporated with soft soap can decrease the disintegration time of shellac enteric coating in pH6.8～7.5 medium and increase its stability.