Natural and Synthetic Polymers for Colon Targeted Drug Delivery

Colon targeted drug delivery system have recently gained importance in delivery of number of therapeutic agents for both local and systemic action. Colon targeted drug delivery system is useful for delivery of proteins and peptides, drugs undergoing degradation in stomach and small intestine. Targeting of drugs to colon is also favorable for the chronotherapy of diseases. To achieve successful, colonic delivery, a drug is needed to be protected from absorption in upper gastrointestinal tract (GIT). Out of the several approaches for colon targeting, coating the drug core with a polymer or polymer combinations is an important strategy. Coating of drug core with a pH dependent polymer or a polymer biodegraded in colon by colonic flora has been widely investigated approach for colonic delivery. Polysaccharides are important polymers from either natural or synthetic origin which have been exhaustively studied for successful colon targeting. This review describes some important natural and synthetic polysaccharides and polymers investigated for colonic drug delivery by coating the drug core.