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 ef ciency 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.
1College of Pharmacy, Chung-Ang University, Seoul
2College of Pharmacy, Keimyung University, Daegu, South Korea
Correspondence: Young Wook Choi, College of Pharmacy, Chung-Ang University, 221 Heuksuk-dong, Dongjak-gu, Seoul 156756, South Korea, Tel +82 2 820 5609, Fax +82 2 826 3781, Email rk.ca.uac@iohcwy
*These authors contributed equally to this work
Drug Des Devel Ther. 2017; 11: 45–57.
Published online 2016 Dec 21. doi: 10.2147/DDDT.S123412
