USE OF PLASMA IN FORMATION OF BIODEGRADABLE STENT COATING

摘要

Metallic stents are treated with a gaseous species in a plasma state unde r conditions causing the species to polymerize and to be deposited in polyme rized form on the metallic stent surface prior to the application of a drug- polymer mixture, which is done by conventional non-plasma deposition methods . The drug-polymer mixture once applied forms a coating on the stent surface that releases the drug in a time-release manner and gradually erodes, leavi ng only the underlying plasma-deposited polymer. In certain cases, the plasm a-deposited polymer itself erodes or dissolves into the physiological medium over an extended period of time, leaving only the metallic stent. While the various polymers and drug remain on the stent, the plasma-deposited polymer enhances the adhesion of the drug-polymer anchor coating and maintains the coating intact upon exposure to the mechanical stresses encountered during s tent deployment.