The present work is aimed to develop colon targeted compression-coated matrix tablets of naproxen using guar gum (GG) and xanthan gums (XG) as coating materials. It was found that the compression-coated tablets released 0 to 7.82% of drug in the physiological environment of stomach and small intestine and 66.40% to 97.82% of drug was released in simulated colonic fluid. The DSC and FTIR studies indicated that the drug is intact in the formulations and no possibility of interaction between the naproxen and other formulation excipients was observed. The formulation showed no change in physical appearance, physical parameters, drug content and in vitro release pattern after storage at 40 oC/75% RH for 3 months. The presence of XG in the coat retarded the release of the drug in first 5 h, but in alkaline pH, enhancement in drug release rate was observed due to swelling of xanthan gum and increased susceptibility of guar gum with time resulting in a loose porous gel structure, leading to faster drug release of more then 95% in the colonic area.
