A REVIEW ON TIME-DEPENDENT SYSTEMS FOR COLONIC DELIVERY

Abstract

 Over the past two decades the major challenge for scientist is to target the drugs specifically to the colonic region of gastro intestine track (GIT). Previously colon was considered as a innocuous organ solely responsible for absorption of water, electrolytes & temporary storage of stools. But now it is accepted as important site for drug delivery. Time dependent delivery systems are formulated to undergo a lag-time of predetermined span of time of no release, followed by a rapid & complete release loaded drugs(s). The approach is based on the principle of delaying the time of drug release until the system transits from mouth to colon. This system offers many advantages over conventional oral drug delivery systems like patient compliance, reduced dosage, reduce dosage frequency, avoidance of side effects, avoidance of peak & valley fluctuation, and nearly constant drug level at the target site.