title: Ca-alginate microspheres encapsulated in chitosan beads.
abstract: Chitosan beads (CBs) incorporating Ca-alginate microspheres (CAMs), containing a drug, were prepared as an oral sustained delivery system. Stable and monodisperse Ca-alginate microspheres loaded with drug were obtained by a membrane emulsification method. The Ca-alginate microspheres were encapsulated in chitosan beads by the ionotropic gelation method with a polyelectrolyte complex reaction between two oppositely charged polyions. The surface and internal characteristics of the beads were improved by ionic cross-linking in tripolyphosphate (TPP) solution adjusted to pH 5.0. The release experiments were performed using lidocaine.HCl (cationic drug) and sodium salicylate (anionic drug) as model drugs. Initial release of drugs depended on the degree of swelling. Ca-alginate microspheres encapsulated in chitosan beads were superior to both drug-loaded CBs and CAMs beads for sustained release because they had a three-layer composition; a calcium alginate core bounded by an inter-phasic chitosan-alginate membrane, which itself was surrounded by a layer of chitosan-TPP.
authors.affiliation: Department of Chemical Engineering, College of Engineering and Bioproducts Research Center, Yonsei University, Seoul 120-749, South Korea.
authors.forename: S-B
authors.initials: SB
authors.lastname: Park
authors.forename: H-W
authors.initials: HW
authors.lastname: Kang
authors.forename: S
authors.initials: S
authors.lastname: Haam
authors.forename: H-Y
authors.initials: HY
authors.lastname: Park
authors.forename: W-S
authors.initials: WS
authors.lastname: Kim
mesh_terms: D000464:Alginates; D048271:Chitosan; D004337:Drug Carriers; D004339:Drug Compounding / Q000379:methods*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D008863:Microspheres
chemical_list: D000464:Alginates; D004337:Drug Carriers; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D048271:Chitosan