Formulation and Evaluation of Sustained Release Tablets of Metformin Hydrochloride by Solid Dispersion Technique Using pH dependent and pH independent Eudragit Polymers

Objectives: The purpose of the present investigation was to evaluate the influence of solid dispersion of pH dependent and pH independent Eudragit polymers on the sustained release metformin hydrochloride matrix tablets. Materials and methods: Matrix formulations were prepared by direct compression techniques. The excipients used in this study did not alter physicochemical properties of the drug, as tested by FTIR and DSC. All the batches were evaluated various physical parameters. The in vitro drug dissolution and SEM studies were also carried out. Mean dissolution time is used to characterize drug release rate from a dosage form. Results and discussion: Among the different examined polymer blends, Eudragit RLPO with S100 and Ll00 matrix tablets based on solid dispersion showed highly sustained release pattern. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled to anomalous type. Conclusions: Fitting the data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.