title: Design and evaluation of floating multi-layer coated tablets based on gas formation.
abstract: Floating multi-layer coated tablets were designed based on gas formation. The system consists of a drug-containing core tablet coated with a protective layer (hydroxypropyl methylcellulose), a gas forming layer (sodium bicarbonate) and a gas-entrapped membrane, respectively. The mechanical properties of acrylic polymers (Eudragit RL 30D, RS 30D, NE 30D) and ethylcellulose were characterized by the puncture test in order to screen a suitable film for the system. Eudragit RL 30D was chosen as a gas-entrapped membrane due to its high flexibility and high water permeability. The obtained tablets enabled to float due to the CO2-gas formation and the gas entrapment by polymeric membrane. The effect of formulation variables on floating properties and drug release was investigated. The floating tablets using direct-compressed cores had shorter time to float and faster drug release than those using wet-granulated cores. The increased amount of a gas forming agent did not affect time to float but increased the drug release from the floating tablets while increasing coating level of gas-entrapped membrane increased time to float and slightly retarded drug release. Good floating properties and sustained drug release were achieved. These floating tablets seem to be a promising gastroretentive drug delivery system.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand. sungts2000@yahoo.com <sungts2000@yahoo.com>
authors.forename: Srisagul
authors.initials: S
authors.lastname: Sungthongjeen
authors.forename: Pornsak
authors.initials: P
authors.lastname: Sriamornsak
authors.forename: Satit
authors.initials: S
authors.lastname: Puttipipatkhachorn
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003692:Delayed-Action Preparations; D004339:Drug Compounding / Q000379:methods*; D016503:Drug Delivery Systems; D005740:Gases; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000737:chemistry; D010539:Permeability; D011108:Polymers / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties; D013607:Tablets / Q000737:chemistry*; D013608:Tablets, Enteric-Coated / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D005740:Gases; D011108:Polymers; D013607:Tablets; D013608:Tablets, Enteric-Coated; D002245:Carbon Dioxide; D065347:Hypromellose Derivatives; D008747:Methylcellulose