Formulation and Evaluation of Conventional Metronidazole Tablets using Natural Gum Extracted from Grewia species

Aims: The pharmaceutical world has been paying increasing attention to the extraction, development and use of natural gums as binders in the formulation of solid dosage forms. The use of natural gums as binders is more advantageous than the use of synthetic ones due to availability, low cost, biodegradability and biocompatibility. In this study, gum extracted from Grewia species was compared with that fromAcacia in metronidazole tablets.

Study Design: Ten batches of metronidazole tablets were formulated with varied concentration of Grewiaspp gum and Acacia gum.

Place and Duration of Study: The study was carried out in Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Delta State University, Abraka, Nigeria; between January and December 2019.

Methodology: Five batches of metronidazole tablets containing 0.5, 0.75, 1.0, 1.25 and 1.5% w/w of Grewia gum were preparedby wet granulation. Resulting granules were characterised by measuring flow and packing properties. In other experiments, five batches of tablets were formulated using same concentration of gum, with Acacia gum substituted for Grewia gum. Both sets of granules were compressed into tablets using tableting machine at a load of 27 arbitrary units. Tablets so formed were evaluated for hardness, friability, disintegration time, drug content and drug release profiles. Drug – excipient interaction was investigated with FTIR.

Results: The resulting metronidazole tablets showed hardness of 5.46 kgF to 7.87 kgF (Grewiagum) and 6.06 kgF-8.20 kgF (Acacia gum). Friability percentages of all the batches were above 1% except for A3-A5 and B5 which are less than 1%. All formulations released more than 75 % of the drug content within 60 min. The FTIR analysis revealed no interaction between the metronidazole and Grewia species gum.

Conclusion: Metronidazole granules and tablets were successfully prepared using Grewiagum and showed comparable pre-compression and post-compression properties with those formulated with Acacia.