Design of a potential colonic drug delivery system of mesalamine

The aim of the present investigation was to develop a site-specific colonic drug delivery system, built on the principles of the combination of pH and time sensitivity. Press-coated mesalamine tablets with a coat of HPMC E-15 were over-coated with Eudragit S100. The in vitro drug release study was conducted using sequential dissolution technique at pH 1.2, 6.0, 7.2 and 6.4 mimicking different regions of gastrointestinal tract. The optimized batch (F2) showed less than 6% of drug release before reaching colonic pH 6.4 and complete drug release was obtained thereafter within 2 hr. A short-term dissolution stability study demonstrated statistical insignificant difference in drug release.