Evaluation of Dissolution and Stability of Acid-resistance of Futraful Enteric Coated Preparations

The acid-resistance of enteric coated films and dissolution patterns of Futraful enteric coated granules and tablet were monitored with U. S. P. dissolution tester in pH shift test solution, in consideration of pH values of gastrointestinal tract, that is pH of the medium was designed to change gradually 2.3 to 3.7 in the first 150 min, rapidly from 3.7 to 6.2 in the following 30 min, and gradually up to 6.9 after 300 min. For granules, coated films showed satisfactory acidresistance and dissolution, because the rate of dissolution measured 210 min after the onset of the test was less than 10%. Furthermore, the rate of dissolution in the following 50 min was increased rapidly when pH of dissolution medium exceeded 6.5, while the time required to achieve 100% dissolution rate was 270 min after the onset of the test. For tablet, coated films also showed satisfactory acid resistance and dissolution, because the rate of disssolution measured 240 min after the onset of the test was 0%, and the rate of dissolution in the following 40 min was increased rapidly when pH of dissolution medium exceeded 6.7. The times for the 100% dissolution rate was 285 min.