Cellulose Acetate Succinate as an Enteric Coating for Some Compressed Tablets

Abstract

The preparation and testing of compressed tablets of barium sulfate and sodium chloride coated with cellulose acetate succinate (CAS) are described, and the statistical evaluation of the data obtained is presented. The most satisfactory coatings were obtained when the test material, in an acetone-ethyl acetate solution, was applied by a modified “pan” method using talc as a dusting powder. Generally, CAS coatings which were stable for 3 1/2 hours in Simulated Gastric Fluid USP XVI dissolved sooner than control coatings of CAP applied and treated in the same manner. Disintegration times were slightly lower for most tablets placed directly into Simulated Intestinal Fluid, USP XVI than they were for tablets first treated with Simulated Gastric Fluid USP XVI for 31/2 hours and then tested in the former solution. None of the tablet coatings showed signs of cracks as a result of storage at −2 ± 2° for 21 days or 45 ± 2° for 10 days; however, some of these showed statistically significant differences in average disintegration time when compared with samples stored at room temperature. When test and control tablets were stored at 40 ± 2° and approximately 81% humidity, the majority of coatings were unsatisfactory. Tablets lost less than 3.56% tablet weight as a result of the simulated gastric fluid treatment. Preliminary in vivo tests with human subjects indicate that CAS has merit as an enteric coating. Pancreatin appears to have little effect on the disintegration times of the test coating.