title: Development of a chitosan based double layer-coated tablet as a platform for colon-specific drug delivery.
abstract: A double layer-coated colon-specific drug delivery system (DL-CDDS) was developed, which consisted of chitosan (CTN) based polymeric subcoating of the core tablet containing citric acid for microclimate acidification, followed by an enteric coating. The polymeric composition ratio of Eudragit E100 and ethyl cellulose and amount of subcoating were optimized using a two-level factorial design method. Drug-release characteristics in terms of dissolution efficiency and controlled-release duration were evaluated in various dissolution media, such as simulated colonic fluid in the presence or absence of CTNase. Microflora activation and a stepwise mechanism for drug release were postulated. Consequently, the optimized DL-CDDS showed drug release in a controlled manner by inhibiting drug release in the stomach and intestine, but releasing the drug gradually in the colon (approximately 40% at 10 hours and 92% at 24 hours in CTNase-supplemented simulated colonic fluid), indicating its feasibility as a novel platform for CDD.
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Min Soo
authors.initials: MS
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Dong Woo
authors.initials: DW
authors.lastname: Yeom
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Sung Rae
authors.initials: SR
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Ho Yub
authors.initials: HY
authors.lastname: Yoon
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Ho Yong
authors.initials: HY
authors.lastname: Son
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Jin Han
authors.initials: JH
authors.lastname: Kim
authors.affiliation: College of Pharmacy, Keimyung University, Daegu, South Korea.
authors.forename: Sangkil
authors.initials: S
authors.lastname: Lee
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul.
authors.forename: Young Wook
authors.initials: YW
authors.lastname: Choi
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D003106:Colon / Q000378:metabolism* / Q000382:microbiology; D004339:Drug Compounding; D016503:Drug Delivery Systems; D065546:Drug Liberation; D006026:Glycoside Hydrolases / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D009928:Organ Specificity; D010666:Phenylpropionates / Q000008:administration & dosage / Q000378:metabolism; D011108:Polymers / Q000737:chemistry; D013607:Tablets
chemical_list: D010666:Phenylpropionates; D011108:Polymers; D013607:Tablets; C040656:loxoprofen; D048271:Chitosan; D006026:Glycoside Hydrolases; C019868:chitosanase
keywords: acidification; chitosan; colon-specific delivery; controlled release; factorial design; microflora