Formulation Development and Evaluation of Directly Compressed Polyherbal Tablets Containing Plant Extracts

Abstract

Polyherbal formulations combine multiple medicinal plants to achieve synergistic therapeutic effects and improved efficacy. The present study aimed to formulate and evaluate polyherbal tablets containing extracts of Gymnema sylvestre, Vinca rosea, Cinnamomum zeylanicum, and Eugenia jambolana using the direct compression technique. Five formulations (PHF-1 to PHF-5) were prepared by varying the proportions of ethanolic and aqueous extracts of the selected medicinal plants. Microcrystalline cellulose, lactose, starch, polyvinylpyrrolidone (PVP K-30), talc, and magnesium stearate were used as excipients. The powder blends were evaluated for bulk density, tapped density, angle of repose, Carr’s index, and Hausner’s ratio. Compressed tablets were evaluated for weight variation, hardness, friability, and disintegration time according to pharmacopeial procedures. All powder blends exhibited satisfactory flow properties with angle of repose values below 30°, Carr’s index ranging from 11.8–16.0%, and Hausner’s ratio below 1.25. The compressed tablets complied with pharmacopeial specifications for weight variation. Tablet hardness ranged from 4.5–6.2 kg/cm², friability was below 1%, and disintegration time ranged from 9.8–13.5 minutes. Among all formulations, PHF-3 and PHF-4 demonstrated superior pre compression and post-compression characteristics. The direct compression method successfully produced polyherbal tablets with acceptable pharmaceutical properties. Formulations PHF-3 and PHF-4 showed optimum flowability, compressibility, mechanical strength, and disintegration behavior, making them suitable candidates for further pharmacological investigations.