• FORMULATION AND EVALUATION OF COLON TARGETED DRUG DELIVERY SYSTEM CONTAININGANTI DIABETIC AGENT

Abstract

The aim of the present study was to develop colon targeted matrix tablets of Metformin HCl using various concentrations of selected polymers such as HPMC, Ethyl Cellulose Guar gum and combination of the same. Prepared granules were subjected to both pre-compression and post- compression parameters for all batches and the results were in the acceptable range. Tablets were prepared by direct compression method. Short term accelerated stability studies was performed according to ICH guidelines and a temperature of 400±20 C and relative humidity of 75%±5% RH to study any physical changes and chemical decomposition of drug, no formulation shown any physical or chemical changes. The compatibility of drugs, polymers and excipients were determined by FT-IR Spectroscopy, results showed that the drug was compatible with polymers and excipients. Dissolution studies were performed for 12 hours in 1.2 pH for first 2 hrs then in 7.4 pH for next 3hrs followed by 6.8pH phosphate buffer at the temperature of 37±0.50c at 100rpm. The dissolution data so obtained was fitted to various mathematical kinetic models and the drug release followed mixed order and Higuchi’s model. To study release mechanism of drug from matrices the data were fitted to Koresmeyer-Peppas model. In –vitro release profile of Metformin HCl from various polymers showed that the increase in the concentration of polymers resulted in reduction in the release rate of drug (MTF1 to MTF12). Formulation containing combination of E.C-G.G, HPMC-G.G and E.C-HPMC showed drug release profile for MTF-12 about 38.72% after 12 hrs, MTF-11 about 40.66% after 12 hrs, for MTF-10 about 45.45% after 12 hrs. This is an indication of retardation of drug release when polymer combination was changed. Results showed that the tablets with higher binding concentration showed minimum drug release. Combination of polymers shows greater retardation of drug release.