Medical devices having durable and lubricious polymeric coating

Abstract

A medical device having a contact surface exposed repeatedly to bodily tissue is disclosed. The contact surface is coated with a silicone polymer and one or more non-silicone hydrophobic polymers. The preferred medical device is a surgical needle, and the preferred coating is a polydimethylsiloxane and polypropylene wax hydrocarbon mixture. The incorporation of the non-silicone hydrophobic polymer increases the durability of the coating on the device without sacrificing lubricity.

What is claimed is: 
     
         1 . A process for coating a contact surface of a medical device exposed repeatedly to bodily tissue, the process comprising the steps of:
 a) applying a first layer of a non-silicone hydrophobic polymer to the contact surface; and,   b) applying a second layer of a silicone polymer over the first layer.   
     
     
         2 . The process for coating as set forth in  claim 1  wherein the silicone polymer is a polyalkylsiloxane. 
     
     
         3 . The process for coating as set forth in  claim 2  wherein the polyalkylsiloxane is a polydimethylsiloxane. 
     
     
         4 . The process for coating as set forth in  claim 3  wherein the non-silicone hydrophobic polymer has a critical surface tension of less than about 50 mN/m. 
     
     
         5 . The process for coating as set forth in  claim 4  wherein the non-silicone hydrophobic polymer is a thermoplastic polymer. 
     
     
         6 . The process for coating as set forth in  claim 5  wherein the thermoplastic polymer is flowable at less than about 210 C. 
     
     
         7 . The process for coating as set forth in  claim 1  wherein the second layer comprises about 50 to about 100 weight percent of polydimethylsiloxane and the first layer comprises about 50 to about 100 weight percent of a thermoplastic polymer. 
     
     
         8 . The process for coating as set forth in  claim 7  wherein the medical device is a surgical needle. 
     
     
         9 . The process for coating as set forth in  claim 8  wherein the polydimethylsiloxane is hydroxy terminated. 
     
     
         10 . The process for coating as set forth in  claim 9  wherein the thermoplastic polymer is polyethylene, polypropylene or polycaprolactone. 
     
     
         11 . The process of  claim 8 , wherein the medical device comprises at least one piercing point. 
     
     
         12 . The process of  claim 8 , wherein the medical device comprises at least one cutting edge. 
     
     
         13 . The process of  claim 8 , wherein the medical device comprises a tissue penetrating portion. 
     
     
         14 . A process for coating a contact surface of a medical device exposed repeatedly to bodily tissue, the process comprising the steps of
 a) mixing a silicone polymer and a non-silicone hydrophobic polymer with a solvent to form a coating mixture,   b) applying the coating mixture to the contact surface, and   c) removing the solvent from the coating mixture.   
     
     
         15 . The process for coating as set forth in  claim 14 , wherein the silicone polymer is soluble in the solvent. 
     
     
         16 . The process for coating as set forth in  claim 15  wherein the silicone polymer is a polyalkylsiloxane. 
     
     
         17 . The process for coating as set forth in  claim 16  wherein the polyalkylsiloxane is a polydimethylsiloxane. 
     
     
         18 . The process for coating as set forth in  claim 17  wherein the non-silicone hydrophobic polymer has a critical surface tension of less than about 50 mN/m. 
     
     
         19 . The process for coating as set forth in  claim 18  wherein the non-silicone hydrophobic polymer is a thermoplastic polymer. 
     
     
         20 . The process for coating as set forth in  claim 19  wherein the thermoplastic polymer is flowable at less than about 210 C. 
     
     
         21 . The process for coating as set forth in  claim 17  wherein the coating has about 44 to about 66 weight percent of the polydimethylsiloxane and about 34 to about 56 weight percent of the thermoplastic polymer. 
     
     
         22 . The process for coating as set forth in  claim 21  wherein the medical device is a surgical needle. 
     
     
         23 . The process for coating as set forth in  claim 22  wherein the polydimethylsiloxane is hydroxy terminated. 
     
     
         24 . The process for coating as set forth in  claim 23  wherein the thermoplastic polymer is polyethylene, polypropylene or polycaprolactone.