Surface and Depth Profiling Investigation of a Drug-Loaded Copolymer Utilized To Coat Taxus Express2 Stents

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• 作者：Robert M. Braun ; Juan Cheng ; Edward E. Parsonage ; Jeff Moeller ; Nicholas Winograd
• 刊名：Analytical Chemistry
• 出版年：2006
• 出版时间：December 15, 2006
• 年：2006
• 卷：78
• 期：24
• 页码：8347 - 8353
• 全文大小：638K
• 年卷期：v.78,no.24(December 15, 2006)
• ISSN：1520-6882

文摘

The surface of a styrene-b-isobutylene-b-styrene triblockcopolymer, containing a solid-phase drug, was studied bytime-of-flight secondary ion mass spectrometry employing15-keV Ga⁺ and 20-keV C<SUB>60⁺ ion sources. This polymer/drug system has direct application in the cardiac stentarena, where it has been used to treat restenosis orrenarrowing of arterial walls after stent or angioplastyprocedures. Overall, the results illustrate the successfuluse of a cluster ion beam for greatly enhancing the high-mass fragment ion and molecular ion intensities from thesurface and bulk of the polymer system. The use of C₆₀⁺also established the ability to remove common overlayerslike poly(dimethylsiloxane), which was not possible usinga Ga⁺ ion source. Furthermore, the use of C₆₀⁺ alloweddepth profiles to be obtained using primary ion dosedensities in excess of 6 × 10¹⁴ C₆₀⁺/cm². Resultantsputter craters reached depths of ~2 m and possessedrelatively flat bottoms without the need for sample rotation. AFM and profilometry studies support the relativelygentile removal of surface species via phase contrast andtopographic imaging. In addition, the findings suggest thatrelatively high ion doses do not significantly alter thephase distribution or surface topography of the polymersurface; however, a slight increase in surface roughnesswas detected.