A pharmaceutical composition, which comprises a therapeutically effective amount of active principle(s) or a pharmaceutically acceptable salt or enantiomer or polymorph thereof, optionally one or more release controlling agent(s) and pharmaceutical acceptable excipient(s) thereof, wherein the composition is formulated to increase the residence time of the said pharmaceutical composition and/or active principle(s) in the gastrointestinal tract. The active principles are selected from rifaximin, vancomycin, mesalamine, cholestesamine, balsalazide and sulfasalazine.