FORMULATION AND EVALUATION OF GASTRORETENTIVE METRONIDAZOLE TABLETS USING BRACHYSTEGIA EURYCOMA GUM

This study was conducted to evaluate gastroretentive metronidazole tablets formulated using Brachystegia eurycoma gum as a matrix. The gum was isolated from powdered dried Brachystegia eurycoma seeds. Gastroretentive metronidazole tablets were produced by direct compression technique using Brachystegia eurycoma gum, sodium carboxymethylcellulose, or their combination as the matrix. Sodium bicarbonate was used as a gas generating agent. The tablets were evaluated based on hardness, friability, weight uniformity, drug content, swelling studies, buoyancy lag time, and total buoyancy time. Hardness ranged from 4.57 ± 0.053 to 11.81 ± 0.90 Kgf. None of the tablets deviated from the mean tablet weight by more than ± 5%. The friability of the tablets was within 0.28 to 1.00% except for formulation MF1 that was 1.93%. Drug content was between 91.51% and 109.53%. The buoyancy lag time was between 2.35 and 20.15 min, and tablets from all the formulations maintained a total buoyancy time of above 12 h. Eighty percent (80%) of metronidazole was released from formulations MF1 to MF5 after 6, 9, 7, 5, and 12 h, respectively. The kinetics of release was by first order and Higuchi model, whereas the mechanism of release was by diffusion for formulations MF1 to MF3 and by non Fickian diffusion for formulations MF5 to MF6. Tablets from the optimized formulation, MF2 was stable after storage for one year at room temperature. Gastroretentive metronidazole tablets formulated using Brachystegia eurycoma gum as matrix showed good post compression properties on evaluation, especially buoyancy lag time, total buoyancy time, and in-vitro release.