Article

In vitro and in vivo degradation of poly(D, L-lactide-co-glycolide)/amorphous calcium phosphate copolymer coated on metal stents.

Biomedical Engineering and Biotechnology Doctoral Program, University of Massachusetts, Lowell, Massachusetts 01854, USA.
Journal of Biomedical Materials Research Part A (impact factor: 2.63). 03/2011; 96(4):632-8. DOI:10.1002/jbm.a.33016
Source: PubMed

ABSTRACT The purpose of this study was to optimize a novel biodegradable polymer for drug eluting stent (DES) applications. Degradation profiles of different poly(D,L-lactide-co-glycolide)/amorphous calcium phosphate (PLGA/ACP) composites coated on stents were studied both in vitro and in vivo for three months. For the in vitro study, stents were immersed into the phosphate buffered saline (37 °C, pH 7.4) with constant shaking. The polymer weight loss was measured weekly and morphological changes were analyzed. The results demonstrated that approximately 60% of polymer was degraded within the three-month period and there was no significant difference between the different PLGA/ACP composites. However, the composite of 50% PLGA (65/35) with 50% ACP showed a slightly faster degradation rate than other composites. Morphologically, all stent surfaces changed from a micro-porous before degradation to a corrugated solid micro-net-like structure at two months post degradation. Based on in vitro results, 65% PLGA (65/35) with 35% ACP) coated stents were selected and implanted into rat aortas (n = 12) for the in vivo study. Microscopic observation showed that no composite was found on any of the implanted stents at 12 weeks post implantation, which indicated the selected PLGA/ACP composite is desired for DES applications.

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Keywords

12 weeks post implantation
 
corrugated solid micro-net-like structure
 
DES applications
 
drug eluting stent
 
implanted stents
 
months post degradation
 
Morphologically
 
novel biodegradable polymer
 
phosphate buffered saline
 
polymer weight loss
 
rat aortas
 
selected PLGA/ACP composite
 
stent surfaces
 
stents
 
three-month period
 
vitro
 
vitro results
 
vitro study
 
vivo study