Medical device with drug

Abstract

A method of coating implantable open lattice metallic stent prosthesis is disclosed which includes sequentially applying a plurality of relatively thin outer layers of a coating composition comprising a solvent mixture of uncured polymeric silicone material and crosslinker and finely divided biologically active species, possibly of controlled average particle size, to form a coating on each stent surface. The coatings are cured in situ and the coated, cured prosthesis are sterilized in a step that includes preferred pretreatment with argon gas plasma and exposure to gamma radiation electron beam, ethylene oxide, steam.

1 - 23 . (canceled)  
     
     
         24 . An implantable medical device having an outer surface, covered at least in part by a conformal coating comprising an undercoat of a hydrophobic biostable elastomeric material which does not degrade, and incorporates an amount of a biologically active material therein for timed delivery therefrom; 
 and a topcoat comprising a polymeric material, which at least partially covers the undercoat,    wherein the undercoat and the topcoat are of different formulations.    
     
     
         25 . The medical device of  claim 24 , wherein the medical device is a stent for vascular implantation.  
     
     
         26 . The medical device of  claim 25 , wherein the stent is expandable.  
     
     
         27 . The medical device of  claim 25 , wherein the stent comprises a tubular body having open ends and an open lattice sidewall structure and wherein said coating conforms to said sidewall structure in a manner that preserves said open lattice.  
     
     
         28 . The medical device of  claim 25 , wherein the stent comprises stainless steel.  
     
     
         29 . The medical device of  claim 24 , wherein the undercoat comprises an ethylene vinyl acetate copolymer.  
     
     
         30 . The medical device of  claim 24 , wherein most or all of the biologically active material is contained in the undercoat.  
     
     
         31 . The medical device of  claim 24 , wherein the topcoat consists of the polymeric material.  
     
     
         32 . The medical device of  claim 24 , wherein the biologically active material is an antibiotic.  
     
     
         33 . A method of making the medical device of  claim 24 , wherein said method comprises the steps of: 
 (a) applying an undercoat of a formulation containing uncured hydrophobic elastomeric material in solvent mixture and an amount of the biologically active material that is finely divided;    (b) curing said hydrophobic elastomeric material; and    (c) applying a topcoat of a formulation comprising the polymeric material to form the topcoat.    
     
     
         34 . A method of coating an implantable prosthesis with a first polymeric material incorporating an amount of biologically active material therein for timed delivery therefrom comprising the steps of: 
 (a) applying a first formulation comprising the first polymeric material and the biologically active material to a surface of the prosthesis to form an under layer when the biologically active material is particulate;    (b) applying a second formulation comprising a second polymeric material over the under layer to form a top layer; and    (c) curing the first and second polymeric materials, wherein the first polymeric material is a hydrophobic elastomeric material, the average particle size of the biologically active material in the first formulation is less than or equal to about 15 μm and at least some of the biologically active material is particulate after curing, whereby the first and second formulations are applied to the prosthesis in a manner to adheringly conform thereto.    
     
     
         35 . The method of  claim 34  wherein the elastomeric material is selected from the group consisting of silicones, polyurethanes, polyamide elastomers, ethylene vinyl acetate copolymers, polyolefin elastomers, EPDM rubbers and combinations thereof.  
     
     
         36 . The method of  claim 34 , wherein the first formulation comprises about 25-45 weight percent of the biologically active material includes heparin.  
     
     
         37 . The method of  claim 34 , wherein the biologically active material has an average particle size less than or equal to about 10 μm before curing.  
     
     
         38 . The method of  claim 34 , wherein the biologically active material includes heparin.  
     
     
         39 . The method of any one of  claim 34 , wherein the implantable prosthesis is an expandable stent having a tubular metal body with a surface of an open lattice nature having openings therein, and wherein the first and second formulations are applied with the stent expanded.  
     
     
         40 . The method of  claim 39  wherein the expandable stent is a self-expanding stent.  
     
     
         41 . The method of  claim 34  wherein the second formulation is substantially free of any biologically active material.  
     
     
         42 . The method of  claim 34  wherein the second formulation is substantially free of the biologically active material in the first formulation.  
     
     
         43 . The method of  claim 34  wherein the under layer and the top layer each have a thickness and the ratio of the thickness of the top layer to the thickness of the under layer is from about 1:10 to 1:2.