Pore Networks and Polymer Rearrangement on a Drug-Eluting Stent as Revealed by Correlated Confocal Raman and Atomic Force Microscopy

• Published in: Langmuir Vol. 28; no. 21; pp. 8238 - 8243
• Main Authors: Biggs, Kevin B, Balss, Karin M, Maryanoff, Cynthia A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 29.05.2012
• Subjects: Chemistry; Colloidal state and disperse state; Drug-Eluting Stents; Exact sciences and technology; General and physical chemistry; Methacrylates - chemistry; Microscopy, Atomic Force; Polyvinyls - chemistry; Porous materials; Spectrum Analysis, Raman; Drug; Atomic force microscopy; Correlation; Elution; Device; Ethylene; Polymer; Acetate; Porous material; Pore; Morphology; Topography; Release
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la300808z

Drug release from and coating morphology on a CYPHER sirolimus-eluting coronary stent (SES) during in vitro elution were studied by correlated confocal Raman and atomic force microscopy (CRM and AFM, respectively). Chemical surface and subsurface maps of the SES were generated in the same region of interest by CRM and were correlated with surface topography measured by AFM at different elution times. For the first time, a direct correlation between drug-rich regions and the coating morphology was made on a drug-eluting medical device, linking drug release with pore formation, pore throats, and pore networks. Drug release was studied on a drug-eluting stent (DES) system with a multicomponent carrier matrix (poly(n-butyl methacrylate) [PBMA] and poly(ethylene-co-vinyl acetate) [PEVA]). The polymer was found to rearrange postelution because confluence of the carrier polymer matrix reconstituted the voids created by drug release.