Method and apparatus for coating a medical device by electroplating

Abstract

Methods and apparatuses for coating surfaces of medical devices by electroplating are disclosed. In one embodiment, the invention includes a coating method in which a mixture of a therapeutic agent, and a plating material are electroplated onto the surface of the medical device. The electroplating method may be performed at a relatively low temperature to avoid destruction of the therapeutic agent. In another embodiment, a coating method is disclosed in which the coating is formed by suspending a therapeutic agent in an electrolytic solution and electroplating a plating material onto the medical device wherein the plating material carries the suspended therapeutic agent. Thus, the coating of plating material contains the suspended therapeutic agent. These methods and apparatuses are used to apply one or more coating materials, simultaneously or in sequence by varying the electroplating voltage. In certain embodiments of the invention, the coating materials include therapeutic agents and cationic drugs.

1 . A method for coating at least a portion of a medical device comprising: 
 ionizing a therapeutic agent in an electrolytic solution; and    electroplating a mixture of a plating material and the ionized therapeutic agent onto the medical device, thereby forming a coating with the therapeutic agent on a medical device.    
   
   
       2 . The method of  claim 1  further comprising dissolving a measured amount of therapeutic agent in the electrolytic solution.  
   
   
       3 . The method of  claim 1  wherein the step of electroplating comprises introducing a voltage source having a measured voltage.  
   
   
       4 . The method of  claim 3  further comprising regulating the mixture of the therapeutic agent and plating material by changing the voltage.  
   
   
       5 . The method of  claim 1  further comprising treating a surface of the medical device to be coated.  
   
   
       6 . The method of  claim 5  wherein the step of treating a surface to be coated comprises creating a porous surface layer.  
   
   
       7 . The method of  claim 6  wherein the porous surface layer is made by vapor deposition, plasma deposition, sintering, sputtering or electroplating.  
   
   
       8 . The method of  claim 1  wherein the plating material is gold, titanium, halfnium, halfnium oxide, zirconium, iridium, iridium oxide, alumina, niobium, or niobium oxide.  
   
   
       9 . The method of  claim 1  wherein the electrolytic solution comprises an acid or salt of the plating metal.  
   
   
       10 . The method of  claim 1  wherein the coating comprises a polymeric material.  
   
   
       11 . The method of  claim 1  wherein the therapeutic agent is selected from the group consisting of pharmaceutically active compounds, proteins, oligonucleotides, DNA compacting agents, recombinant nucleic acids, gene/vector systems, and nucleic acids.  
   
   
       12 . The method of  claim 1  wherein the therapeutic agent is a cationic drug.  
   
   
       13 . The method of  claim 12  wherein the cationic drug is amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, or vancomycin.  
   
   
       14 . The method of  claim 1  wherein the medical device is a stent.  
   
   
       15 . A bio-compatible medical device for insertion into a body prepared according to the method of  claim 1 .  
   
   
       16 . A method for coating at least a portion of a medical device comprising: 
 suspending a therapeutic agent in an electrolytic solution; and    electroplating a plating material onto the medical device, wherein the coating of plating material contains suspended therapeutic agent, thereby forming a coating with the therapeutic agent on the medical device.    
   
   
       17 . The method of  claim 16  further comprising treating a surface of the medical device to be coated.  
   
   
       18 . The method of  claim 17  wherein the step of treating a surface to be coated comprises creating a porous surface layer.  
   
   
       19 . The method of  claim 18  wherein the porous surface layer is made by vapor deposition, plasma deposition, sintering, sputtering, or electroplating.  
   
   
       20 . The method of  claim 16  wherein the therapeutic agent is selected from the group consisting of pharmaceutically active compounds, proteins, oligonucleotides, DNA compacting agents, recombinant nucleic acids, gene/vector systems, and nucleic acids.  
   
   
       21 . The method of  claim 16  wherein the medical device is a stent.  
   
   
       22 . A bio-compatible medical device for insertion into a body prepared according to the method of  claim 16 .  
   
   
       23 . A method for coating at least a portion of a medical device comprising: 
 providing a medical device having a surface;    treating the surface of the medical device;    ionizing a therapeutic agent in an electrolytic solution; and    electroplating a mixture of the therapeutic agent and a plating material onto the surface of the medical device.