A test method to evaluate chronic particulate generation from durable polymer stent coatings: a case study of CYPHER® sirolimus-eluting coronary stents

In order to predict the long term coating durability of drug-eluting stent (DES) products, we developed a new testing methodology using a novel mechanical tester to evaluate the potential of drug–polymer coatings to generate particles over time. The tester simulates the device radial fatigue expected during in vivo conditions due to expansion and contraction of the implanted vessel. Analysis by Scanning Electron Microscopy (SEM) of particulate collected via an in-line filtration system allows for evaluation of the chronic durability of DES polymer coatings. Data provided within show the durable polymer coating of CYPHER® Stents generates small amounts of particulates upon fatigue indicating coating integrity is maintained even when the DES system is subjected to expansion, deployment, and repetitive cycling modalities.