Formulation and Evaluation of Metformin Controlled Release Tablets Using Tamarind Seed Gum Powder as a Natural Polymer

Abstract

Aim: This research aims to develop controlled-release tablets of metformin using tamarind seed gum powder as the matrix-forming agent.

Methods: Tamarind seeds were thoroughly cleaned, boiled and dehulled manually to remove the seed coat. The dehulled seeds were then dried, ground into a fine powder and sieved using a 60-mesh screen. The resulting gum powder was purified and subjected to drying under controlled conditions to ensure its suitability for use as a polymer. Controlled-release tablets were prepared through direct compression. Tamarind seed gum powder was incorporated at varying concentrations (5%-20% w/w) to optimize the drug release profile. The evaluation of the tablets included both pre-compression and post-compression parameters.

Results: The drug release profile of metformin from the tablets showed sustained release over a 12-hour period. Increasing the concentration of tamarind seed gum in the formulations led to a slower release rate, which can be attributed to the gum's ability to swell and form a gel-like matrix, thereby controlling the drug release. The optimized formulation best fit the Higuchi model, suggesting that diffusion was the predominant mechanism governing the release of metformin from the tablets. As the concentration of tamarind seed gum increases (from 5% to 20%), the rate of drug release decreases, showing a slower release over the 12-hour period. This can be explained by the enhanced gel formation and swelling capacity of tamarind seed gum, which restricts the diffusion of the drug. Tablets stored at 40°C/75% RH for three months showed no significant changes in drug release or physicochemical properties, confirming the stability of the formulation.

Conclusion: Tamarind seed gum powder exhibits significant potential as a natural polymer for controlled-release formulations of metformin hydrochloride. This study underscores its ability to achieve sustained drug release, maintaining consistent pharmacokinetic profiles. The results support the development of cost-effective, biocompatible drug delivery systems that harness the benefits of natural resources, offering a sustainable alternative to synthetic polymers in pharmaceutical applications.