FORMULATION AND EVALUATION OF METFORMIN HYDROCHLORIDE SUSTAINED-RELEASE ORAL MATRIX TABLETS

Objective: The aim of this investigation was to develop and optimize metformin hydrochloride matrix tablets for sustained release application. The sustained release matrix tablet of metformin hydrochloride was prepared by wet granulation technique using chitosan, xanthan gum, and hydroxypropyl methylcellulose at varying concentrations. Material and Methods: Extended release of metformin hydrochloride matrix tablets was prepared by wet granulation method. The influence of varying the polymer ratios was evaluated. The excipients used in this study did not alter physicochemical properties of the drug. Results: All the batches were evaluated for thickness, weight variation, hardness, and drug content uniformity. The in vitro drug dissolution study was carried out using USP apparatus Type II, paddle method, and the release mechanisms were explored. Mean dissolution time is used to characterize drug release rate from a dosage form and indicates the drug release is retarding efficiency of the polymer. This study revealed that as the concentration of matrix material increased, drug release from matrices decreased. This may be due to slower penetration of the dissolution medium into the matrices. Conclusion: Formulation with chitosan MS1 drug release was 86%, xanthan gum MS489%, and finally MS7 with hydroxypropyl methyl cellulose which exhibited the highest drug release retardation also had the lowest matrix concentration. Hence, lower concentration of polymers is suitable to prepare metformin hydrochloride tablets compared to higher concentrations.