DESIGN AND EVALUATION OF CONTROLLED RELEASE COLON MATRIX TABLETS OF MESALAMINE BY USING GUM KARAYA

The applicability of gum karaya (GK), obtained from sterculia species was studied for its applicability in the design of colon drug delivery systems of mesalamine. Colon targeted tablets of mesalamine were prepared with varying drug-GK ratios and evaluated for the drug release in colonic pH environment. The optimum concentration of drug-GK was found to be 1:1.25 w/w ratio for extending the drug release around 24 hours. The effect of channeling agents was studied and observed that soluble channeling agent lactose markedly affected the drug release compared to insoluble channeling agents and nearly 90% drug release was observed in 24 hours. The optimized formulations were evaluated in dissolution medium containing rat caecal content and 100% drug release was observed over 24 hours. The formulations followed first order without channeling agent and in rat caecal content medium where as zero order was observed for tablets with lactose as channeling agent. Non-Fickian diffusion was observed in simulated intestinal fluid. The formulations followed erosion mechanism in rat caecal content medium indicating the degradation of GK by intestinal microbial flora. No drug-GK interactions were observed in the studies carried out on optimized formulations by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and Fourier transform infra red spectroscopy (FTIR). Based on the above findings it was concluded that GK can be explored as colon specific release polymer because of its abundant availability, reliability, efficacy, ecofriendly and economical features