title: [Study on in vitro release empirical method and the release mechanism of budesonide colonic localization tablet].
abstract: The three-step dissolution experiment was established to investigate the in vitro release of budesonide colon-specific tablet and to elucidate the drug release mechanism by fitting to different mathematical models. The physiological parameters of stomach, small intestine and colon such as pH value, intestinal flora, specific organic enzyme, vermiculation and conveying time were mimicked to plot the in vitro dissolution, separately. Sample were taken at predetermined time intervals in 24 h and the accumulated drug releases were determined by using HPLC method. Drug release curves of the localization tablets were fitted to various mathematical models. It shows that no drug release was found in 2 h. About 5% release was determined after 6 h while 77.5% accumulated release was reached within 24 h. Drug release from the in house formulation fitted well into first-order model. The three-step dissolution method could be used to evaluate the colon-specific characteristics of budesonide colonic localization tablet. The drug release behavior of the localization tablet conforms to the drug release mechanisms of controlled porosity osmotic pump where osmotic pressure is the main driving force for controlled delivery of drugs.
authors.affiliation: Wuhan General Hospital of Guangzhou Command, Wuhan 430070, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.forename: Wei-San
authors.initials: WS
authors.lastname: Pan
authors.forename: Shu-Fang
authors.initials: SF
authors.lastname: Nie
authors.forename: Xing-Gang
authors.initials: XG
authors.lastname: Yang
authors.forename: Ting-Xu
authors.initials: TX
authors.lastname: Yan
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019819:Budesonide / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003106:Colon / Q000378:metabolism*; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004339:Drug Compounding; D016503:Drug Delivery Systems / Q000379:methods*; D005079:Excipients; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007419:Intestinal Secretions; D008962:Models, Theoretical; D051381:Rats; D013607:Tablets
chemical_list: D000893:Anti-Inflammatory Agents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005079:Excipients; D013607:Tablets; D019819:Budesonide