Polysaccharides in colon-specific drug delivery

Natural polysaccharides are now extensively used for the development of sol id dosage forms for delivery of drug to the colon. The rationale for the de velopment of a polysaccharide based delivery system for colon is the presen ce of large amounts of polysaccharidases in the human colon as the colon is inhabited by a large number and variety of bacteria which secrete many enz ymes e.g. beta -D-glucosidase, beta -D-galactosidase, amylase, pectinase. x ylanase, beta -D-xylosidase, dextranase, etc. Various major approaches util izing polysaccharides for colon-specific delivery are fermentable coating o f the drug core, embedding of the drug in biodegradable matrix, formulation of drug-saccharide conjugate (prodrugs). A large number of polysaccharides have already been studied for their potential as colon-specific drug carri er systems, such as chitosan, pectin, chondroitin sulphate, cyclodextrin, d extrans, guar gum, inulin, amylose and locust bean gum. Recent efforts and approaches exploiting these polysaccharides in colon-specific drug delivery are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.