Abstract

DEVELOPMENT & EVALUATION OF PECTIN-BASED CONTROLLED POROSITY OSMOTIC PUMP FOR COLONSPECIFIC DELIVERY SYSTEM

Rajneesh Kumar* and Dr. Awani Kumar Rai

Abstract

A pectin based osmotic dosage form consisting of a enteric coated with a pH- dependent polymer is proposed for colonic specific delivery of drugs. Different approaches for colon-specific drug delivery have been studied over the last decade, including prodrugs, polymeric coating using pH-sensitive or bacterial degradable polymers and matrices. In this work, we present a new osmotic system to deliver active molecules to the colonic region, which combines pH-dependent and controlled drug release properties. The tablet core was constituted by drug (dexamethasone), pH modifier (citric acid) and pectin coated by an enteric polymer (Eudragit L 100-55). The pectin based colon-targeted osmotic pump was developed based on both the gellable property at acid conditions and colon-specific biodegradation of pectin. The SEM indicated that the pectin was accessible to enzymatic degradation which allowed the in situ formation of delivery pores for releasing drug under conditions that may be expected to pertain in the colon, the number of pore being dependent on the initial level of pore former in the membrane. Dexamethasone release from the developed formulation was inversely proportional to the osmotic pressure of the release medium. Thus the developed system was found to be a potential system for targeting and controlling the release of dexamethasone to the colon.

Keywords: Pectin, dexamethasone, Eudragit L-100-55, osmotic tablet.