Extended release tablets of Metformin HCl were developed due to lower half-life, high solubility and less bioavailability. The tablets were prepared by hydrophilic matrix technique and combination of hydrophilic matrix with hydrophobic coating as reservoir. Hypromellose was used as matrixing agent and ethyl cellulose as hydrophobic coating material. In vitro dissolution studies of optimized, F3a (3% coated) formulation showed satisfactory results for f2 and f1 values i.e 80.29 and 2.87 respectively. And the dissolution profile was almost similar with that of reference product. The results of the dissolution study were examined according to Zero, First and Higuchi model as shown for reference product. The regression coefficient (R2) value obtained from the log %ARR (Amount Remaining to Release) versus time was 0.9396 which is nearer to 1, indicating first order release for formulation F3a. Results of stability study carried out on formulation F3a for three months indicated that, there was no any significant change in drug release of the tablet as well as % assay results were found within specifications. Hence, the optimized formulation was stable.
Key words: Type II diabetes, Hypromellose, Extended release, Metformin HCl, Matrix tablets
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