The aim of these research of an oral colon specific, pulsatile device to attain time and or site specific release of Mesalamine, based on chronopharmaceutical consideration. The basic design consists of an insoluble hard gelatin capsule body, filled with Eudragit microcapsules of Mesalamine and sealed with a hydrogel plug. The entire device was enteric coated, so that the variability in gastric emptying time can be overcome and a colon-specific release can be achieved. The Mesalamine microcapsules were prepared in three batches, with Eudragit L-100 and S-100 (1:2) by changing drug to polymer ratio and evaluated for the particle size, drug content and in vitro release profile and from the obtained results; one better formulation was selected for further fabrication of pulsatile capsule.... Different hydrogel polymers were used as plugs, to maintain a suitable lag period and it was found that the drug release was controlled by the proportion of polymers used. In vitro release studies of pulsatile device revealed that, increasing the hydrophilic polymer content resulted in delayed release of Mesalamine from microcapsules. Pulsatile, colon-specific release has been achieved from a capsule device over a 2–24 h period, consistent with the demands of chronotherapeutic drug delivery.