Formulation, characterization and physicochemical evaluation of amoxicillin effervescent tablets

BACKGROUND: Amoxicillin is a semisynthetic antibiotic, which is used as an antimicrobial drug. This study was designed to formulate amoxicillin effervescent tablets, aimed at improved patient compliance and increased drug stability. MATERIALS AND METHODS: In this study, nine effervescent tablet formulations were prepared from amoxicillin trihydrate. The effervescent base was comprised of various amounts of citric acid and sodium bicarbonate. Powders and granules were evaluated for their particle size, bulk density, tapped density, compressibility index, Hausner's ratio and angle of repose. The effervescent tablets were then prepared from powders and granules of acceptable quality by direct compression and fusion methods. The tablets were evaluated for weight variation, friability, pH of solution, carbon dioxide (CO(2)) content, hardness, effervescence time, thickness, assay, content uniformity, water content and equilibrium moisture content. RESULTS: The results indicated better flowability of granules prepared by fusion method as compared with the direct compression. The percent weight variations of tablets were within the acceptable limit of 0.5%. The friability was less than 1% in all formulations. The solution pH of tablets prepared by direct compression and fusion methods ranged from 4.55 to 5.74 and 4.74-5.84, respectively. The CO(2) amounts generated by of fusion method tablets were smaller as compared to the direct compression method. The hardness of tablets was 40.66-56 for direct compression method and 60.6-74.6 for fusion method. The tablets produced by the fusion method had a larger thickness and lower water content than tablets produced by direct compression method. CONCLUSION: Tablets prepared by the fusion method exhibited superior pre- and post-compression characteristics as compared to tablets prepared by direct compression method.