RESEARCH ON THE PREPARATION OF AMLODIPINE 5MG IMMEDIATE-RELEASE FILM-COATED TABLETS TO IMPROVE ACTIVE INGREDIENT’S STABILITY

Background: Amlodipine is a representative active ingredient of calcium channel blockers. In addition to the general advantages of calcium channel blockers in treating hypertension, amlodipine also effectively controls blood pressure for 24 hours and has no or just a little effect on neurohormonal activation, so it does not cause high blood pressure at the last dose. However, amlodipine has a plasma half-life of between 30 and 40 hours, slowing the drug's action duration. Besides, amlodipine is very hygroscopic, causing instability during storage and leading to loss of drug efficacy. Objectives: To design and optimize the formula of amlodipine 5 mg immediate-release film-coated tablets and formulate a film coating for amlodipine 5 mg immediate-release film-coated tablets. Methods: The immediate-release tablet was formulated by direct compression method and designed by Design-Expert software with different types and numbers of super disintegrants. Evaluation of the solubility of each formula to determine the most optimal one; Formulation of the protective coating to help to stabilize the tablet. Results: Preparation of immediate-release filmcoated tablets containing amlodipine 5 mg with a 30-minute release of 96.76% of the active ingredient; formulation on the protective coating including titanium dioxide, PEG 6000, talc, HPMC E6, colorant, alcohol 96%, and distilled water. Conclusion: The research showed that the content of the amlodipine coating tablet released at 30 min in a pH 1.2 medium was near the maximum level and did not change significantly during 6 months of storage.