title: Drug loading and release of Tobramycin from hydroxyapatite coated fixation pins.
abstract: This paper evaluates the loading and release properties of Tobramycin incorporated by adsorptive loading from a solution into plasma sprayed and biomimetically coated Hydroxyapatite (HA) fixation pins. The aim of this study is to contribute towards designing a functional implant surface offering local release of the antibiotic agent to prevent post-surgical infections. Cathodic arc deposition is used to coat stainless steel fixation pins with a bioactive, anatase phase dominated, TiO₂ coating onto which a HA layer is grown biomimetically. The loading and release properties are evaluated by studying the subsequent release of Tobramycin using high performance liquid chromatography and correlated to the differences in HA coating microstructure and the physical conditions under loading. The results from these studies show that a dual loading strategy consisting of a solution temperature of 90 °C and a pressure of 6 bar during a loading time of 5 min release a sufficient amount of Tobramycin to guarantee the inhibition of Staphylococcus aureus up to 2 days for plasma sprayed HA coatings and for 8 days for biomimetic coatings. The present study emphasizes the advantages of the nanoporous structure of biomimetically deposited HA over the more dense structure of plasma sprayed HA coatings in terms of antibiotic incorporation and subsequent sustained release and provides a valuable outline for the design of implant surfaces aiming for a fast-loading and controlled, local drug administration.
authors.affiliation: Division for Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, 75121 Uppsala, Sweden.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Lilja
authors.forename: Jan Henrik
authors.initials: JH
authors.lastname: Sörensen
authors.forename: Ulrika
authors.initials: U
authors.lastname: Brohede
authors.forename: Maria
authors.initials: M
authors.lastname: Astrand
authors.forename: Philip
authors.initials: P
authors.lastname: Procter
authors.forename: Jörg
authors.initials: J
authors.lastname: Arnoldi
authors.forename: Hartwig
authors.initials: H
authors.lastname: Steckel
authors.forename: Maria
authors.initials: M
authors.lastname: Strømme
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D017886:Durapatite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D013056:Spectrophotometry, Ultraviolet; D014031:Tobramycin / Q000493:pharmacokinetics*
chemical_list: D000900:Anti-Bacterial Agents; D017886:Durapatite; D014031:Tobramycin