Metallic stents are treated with a gaseous species in a
plasma state under conditions causing the species to polymerize and to be deposited in polymerized 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, leaving only the underlying
plasma-deposited
polymer. In certain cases, the plasma-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
stent deployment.