Evaluation of two polymeric blends (EVA/PLA and EVA/PEG) as coating film materials for paclitaxel-eluting stent application
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The ethylene vinyl acetate copolymer (EVA)/Poly (lactic acid) (PLA) blend and EVA/Poly (ethylene glycol) (PEG) blend were applied as the drug carrier materials for a bi-layer drug-loaded stent coating film, which consisted of a paclitaxel (PTX)-loaded layer and a drug-free EVA layer. The changes of weight and appearance of the drug-free polymeric blend films with increasing time were examined by X-ray diffraction analysis (XRD), gel permeation chromatography (GPC) tests and scanning electronic microscopy (SEM), and the results showed the degradation of PLA and the leaching of PEG from the films. The effects of PLA, PEG and drug contents on in vitro drug release were investigated, and the results demonstrated that the addition of PLA promoted the drug release while the addition of PEG almost did not. Franz cells diffusion test results indicated that the bi-layer structure successfully endowed the stent coating with the release of drug in a unidirectional fashion. The release profiles of films incorporated PTX and the mechanical performance of the film could be customized by readily adjusting the contents of the blend components. Therefore, the polymeric blends could be useful drug carrier materials for drug-loaded stent coating capable of releasing drug in a highly tunable manner.
KeywordsDrug Release Coating Film Maximum Tensile Strength Ethylene Vinyl Acetate Ethylene Vinyl Acetate
This work was supported by National Natural Science Foundation of China (NSFC) (30872554, 81071244), Shanghai Science and Technology Committee (1052nm01000, 10441902000) and the Key program of Shanghai Municipal Education Committee (09ZZ24). The authors would like to thank Instrumental Analysis Center of Shanghai Jiao Tong University for their technical support.
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