Medical device for delivering a therapeutic agent and method of preparation

Abstract

A device useful for localized delivery of a therapeutic agent is provided. The device includes a structure including a porous polymeric material and an elutable therapeutic agent in the form of a solid, gel, or neat liquid, which is dispersed in at least a portion of the porous polymeric material. Methods for making a medical device having a blood-contacting surface is also provided. One method involves: providing a structure comprising a porous material; contacting the structure comprising a porous material with a concentrating agent to disperse the concentrating agent throughout at least a portion of the porous material; contacting the structure comprising a porous material and the concentrating agent with a solution of a therapeutic agent; and removing the therapeutic agent from solution within the porous material at the locations of the concentrating agent. Another method involves multiple immersion steps without the use of a concentrating agent.

We claim:  
     
         1 . A medical device having at least one blood-contacting surface comprising: 
 a porous polymeric material comprising a nonswellable biostable polymer; and    an elutable therapeutic agent in the form of a solid, gel, or neat liquid, which is dispersed in at least a portion of the porous polymeric material.    
     
     
         2 . The medical device of  claim 1  wherein the porous polymeric material comprises a film.  
     
     
         3 . The medical device of  claim 1  wherein the nonswellable biostable polymer is selected from the group consisting of silicone, polyurethane, polysulfone, cellulose, polyethylene, polypropylene, polyamide, polyester, polytetrafluoroethylene, and a combination of two or more of these materials.  
     
     
         4 . The medical device of  claim 3  wherein the porous polymeric material comprises an integral portion of the device.  
     
     
         5 . The medical device of  claim 1  wherein the therapeutic agent comprises an antithrombotic material.  
     
     
         6 . The medical device of  claim 5  wherein the antithrombotic material is heparin.  
     
     
         7 . The medical device of  claim 1  wherein the therapeutic agent is a peptic drug.  
     
     
         8 . The medical device of  claim 1  wherein the device has a generally cylindrical shape.  
     
     
         9 . The device of  claim 8  wherein the device is selected from the group consisting of a catheter, a stent, and a guide wire.  
     
     
         10 . The device of  claim 1  wherein the device has a generally sheet-like shape.  
     
     
         11 . The medical device of  claim 1  wherein the device is an intralumenal stent.  
     
     
         12 . An intralumenal stent comprising: 
 a generally cylindrical stent body; and    and an adherent layer on the stent body comprising a porous polymeric material and an elutable therapeutic agent in the form of a solid, gel, or neat liquid, which is dispersed in at least a portion of the porous polymeric material.    
     
     
         13 . A method for making a medical device comprising: 
 (a) providing a structure comprising a porous material;    (b) contacting the structure comprising a porous material with a concentrating agent to disperse the concentrating agent throughout at least a portion of the porous material;    (c) contacting the structure comprising a porous material and the concentrating agent with a solution of a therapeutic agent; and    (d) removing the therapeutic agent from solution within the porous material at the locations of the concentrating agent.    
     
     
         14 . The method of  claim 13  wherein precipitating agent is selected from the group of a binding agent, sequestering agent, a nucleating agent, a seed crystal, or combinations thereof.  
     
     
         15 . The method of  claim 13  wherein the porous material is selected from the group consisting of a natural hydrogel, a synthetic hydrogel, silicone, polyurethane, polysulfone, cellulose, polyethylene, polypropylene, polyamide, polyester, polytetrafluoroethylene, and a combination of two or more of these materials.  
     
     
         16 . The method of  claim 13  wherein the therapeutic agent is an antithrombotic material.  
     
     
         17 . The method of  claim 13  wherein the step of removing the therapeutic agent from solution comprises reducing the temperature of the solution of the therapeutic agent.  
     
     
         18 . The method of  claim 13  wherein the step of removing the therapeutic agent from solution comprises changing the pH of the solution of the therapeutic agent.  
     
     
         19 . The method of  claim 13  wherein the step of removing the therapeutic agent from solution comprises changing the ionic strength of the solution of the therapeutic agent.  
     
     
         20 . A method for making a medical device comprising: 
 (a) providing a structure comprising a porous material;    (b) immersing the structure comprising a porous material in a saturated solution of a therapeutic agent for a sufficient period of time to allow the solution to fill the porous material;    (c) removing the medical device from the solution;    (d) drying the medical device; and    (e) repeating steps (b) through (d) to provide a therapeutic agent dispersed within the porous material.    
     
     
         21 . The method of  claim 20  further comprising a step of removing air bubbles from the porous material while being immersed in the solution of the therapeutic agent.  
     
     
         22 . The method of  claim 21  wherein the step of removing air bubbles from the porous material comprises applying ultrasonics, reduced pressure, elevated pressure, or a combination thereof, to the solution.  
     
     
         23 . The method of  claim 20  wherein the medical device is a stent.  
     
     
         24 . The method of  claim 23  wherein the stent has a porous polymeric film thereon.  
     
     
         25 . The method of  claim 23  further comprising a step of applying an overlayer of a polymer.