title: Functionally gradient chitosan/hydroxyapatite composite scaffolds for controlled drug release.
abstract: This study explored the potential of chitosan/hydroxyapatite (HA) composites to act as a controlled drug delivery system by developing functional scaffolds with a gradient of structure and drug concentration. Firstly, a porous composite scaffold was prepared and tetracycline hydrochloride (TCH) was impregnated in the scaffold as a model drug. The pore size of the scaffold was negatively dependent on the HA content and ranged about 40-250 microm. Subsequently, a porous chitosan/HA composite layer without drug was coated on the scaffold to create a gradient drug concentration in the specimen. The in vitro drug-release test demonstrated that the porous layer without drug on the outer surface of the scaffold significantly reduced the initial burst of drug release and extended the release period. Finally, a successive and dense chitosan/HA composite layer endowed the scaffold with a sustained, drug-release pattern without any initial drug burst. These findings confirmed the high effectiveness of the hybrid scaffolds in regulating the release of drugs, and hence their capability to serve as a temporary drug carrier in tissue regeneration. These functional scaffolds also have potential application to the delivery of some bioactive molecules such as growth factors.
authors.affiliation: Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea.
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Teng
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Shin-Hee
authors.initials: SH
authors.lastname: Jun
authors.forename: Cheol-Min
authors.initials: CM
authors.lastname: Han
authors.forename: Hyoun-Ee
authors.initials: HE
authors.lastname: Kim
mesh_terms: D048271:Chitosan; D004337:Drug Carriers; D017886:Durapatite; D008855:Microscopy, Electron, Scanning; D010599:Pharmacokinetics; D014961:X-Ray Diffraction
chemical_list: D004337:Drug Carriers; D048271:Chitosan; D017886:Durapatite