title: In vivo and in vitro characterization of poly(styrene-b-isobutylene-b-styrene) copolymer stent coatings for biostability, vascular compatibility and mechanical integrity.
abstract: The TAXUS Express 2 Paclitaxel Eluting Coronary Stent System employs a coating consisting of the thermoplastic elastomer, poly(styrene-b-isobutylene-b-styrene; SIBS), selected for its drug-eluting characteristics, vascular compatibility, mechanical properties, and biostability. This study was conducted to evaluate the impact of different SIBS (17-51 mole % styrene) compositions on mechanical properties, chemical stability, and vascular compatibility. Mechanical property (stress-strain measurements) and stability studies were conducted on polymer films with five different styrene contents (17, 24, 32, 39, and 51 mole %). The ultimate tensile strength did not change significantly with composition, but the elongation at break decreased with increased styrene content. A pulsatile fatigue test further confirmed the mechanical stability of SIBS up to 39 mole % styrene. The vascular compatibility of five different SIBS compositions was assessed using SIBS-only coated stents, in the coronary and carotid arteries in a porcine model study. The stability of the vessel wall, rate/degree of endothelialization, inflammation, and thrombus at timepoints from 30 to 180 days were evaluated. The results confirm vascular compatibility over the range of 17-51 mole % styrene.
authors.affiliation: Boston Scientific Corporation, One Boston Scientific Place, Natick, Massachusetts 01760, USA.
authors.forename: Fred
authors.initials: F
authors.lastname: Strickler
authors.forename: Robert
authors.initials: R
authors.lastname: Richard
authors.forename: Sharon
authors.initials: S
authors.lastname: McFadden
authors.forename: Jeff
authors.initials: J
authors.lastname: Lindquist
authors.forename: Marlene C
authors.initials: MC
authors.lastname: Schwarz
authors.forename: Rudolf
authors.initials: R
authors.lastname: Faust
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Wilson
authors.forename: Mark
authors.initials: M
authors.lastname: Boden
mesh_terms: D000792:Angiography; D000818:Animals; D001672:Biocompatible Materials; D002339:Carotid Arteries / Q000033:anatomy & histology; D003326:Coronary Circulation / Q000502:physiology; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015607:Stents; D013314:Stress, Mechanical; D013343:Styrenes / Q000737:chemistry*; D013552:Swine; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D013343:Styrenes; C500040:poly(styrene-b-isobutylene-b-styrene)