title: Polysaccharides: a targeting strategy for colonic drug delivery.
abstract: BACKGROUND
  Colon targeting has gained increasing importance for the topical treatment of diseases of the colon, such as Crohn's disease, ulcerative colitis, colorectal cancer and amebiasis. Various strategies used for targeting drugs to the colon include formation of a prodrug, coating with time or pH-dependent polymers, use of colon-specific biodegradable polymers, osmotic systems and pressure-controlled drug delivery systems. Among the different approaches used, polysaccharides that are precisely activated by the physiological conditions of the colon hold great promise, as they provide improved site specificity and meet the desired therapeutic needs.
  
  
  METHODS
  This review aims to summarize the natural and modified properties of polysaccharides that are responsible for their colon targeting abilities. Emphasis is placed on describing formulation approaches that use polysaccharides as a strategy for targeting drugs to the colon.
  
  
  CONCLUSIONS
  Polysaccharide-based colon-targeted drug delivery systems are effective when they are precisely activated by the physiological conditions of the colon. Absence of enzymes during colonic disorders might hinder the activation of the delivery system. To guarantee delivery of the drug to the colon, it is preferable to combine polysaccharides with enteric or cellulose polymers.
authors.affiliation: Nirma University, Institute of Pharmacy , Department of Pharmaceutics and Pharmaceutical Technology, Ahmedabad, Gujarat, India. niteshshah83@gmail.com
authors.forename: Nitesh
authors.initials: N
authors.lastname: Shah
authors.forename: Tejal
authors.initials: T
authors.lastname: Shah
authors.forename: Avani
authors.initials: A
authors.lastname: Amin
mesh_terms: D000284:Administration, Oral; D000818:Animals; D003106:Colon / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D003108:Colonic Diseases / Q000188:drug therapy* / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D006801:Humans; D007408:Intestinal Absorption; D015394:Molecular Structure; D011134:Polysaccharides / Q000737:chemistry*; D013608:Tablets, Enteric-Coated
chemical_list: D004337:Drug Carriers; D011134:Polysaccharides; D013608:Tablets, Enteric-Coated