Process for producing an implantable apparatus comprising a biomedical device coated with crosslinked TPU

Abstract

A method for producing increased resistance to biodegradability is provided for biomedical devices subject to in vivo implantation. Among the steps required to produce such resistance are the application of a thermoplastic polyurethane coating to the device to provide a coating, and the subsequent crosslinking of the thermoplastic polyurethane coating through the application of radiation of a sufficient intensity and duration to convert said thermoplastic polyurethane coating to a thermoset coating possessing the attribute of increased biostability.

What is claimed is:  
     
         1 . A method for manufacturing a coated biomedical device exhibiting enhanced in vivo biostability comprising: 
 (a) applying a radiation cross-linkable thermoplastic polyurethane coating to the device in order to insulate said device from biological elements; and    (b) irradiating said thermoplastic polyurethane coating to form a thermoset coating through the application of radiation of a sufficient intensity and duration to cause said thermoplastic polyurethane coating to convert to a thermoset coating, said thermoset coating exhibiting enhanced in vivo biostability relative to said thermoplastic coating.    
     
     
         2 . The method of  claim 1  including the additional step of incorporating a crosslinking agent predominantly free of hydroxyl groups and predominantly nonincorporable into the thermoplastic polyurethane coating prior to irradiation.  
     
     
         3 . The method of  claim 2  wherein the crosslinking agent comprises an allylic monomer.  
     
     
         4 . The method of  claim 2  wherein the crosslinking agent comprises an acrylic or methacrylic monomer.  
     
     
         5 . The method of  claim 2  wherein the crosslinking agent comprises meta-phenylene dimaleimide.  
     
     
         6 . The method of  claim 1  wherein step(b) is effected simultaneously with, or after, step(a).  
     
     
         7 . The method of  claim 1  wherein the biomedical device comprises an electrically conductive wire.  
     
     
         8 . The method of  claim 1  wherein the polyurethane coating comprises an aromatic thermoplastic polyurethane.  
     
     
         9 . The method of  claim 1  wherein the polyurethane coating comprises an aliphatic thermoplastic polyurethane.  
     
     
         10 . The method of  claim 1  wherein the polyurethane coating comprises a mixture of differing amounts of aromatic and aliphatic polyurethanes.  
     
     
         11 . The method of  claim 1  wherein the polyurethane coating comprises differing amounts of thermoplastic polyurethane and other polymeric materials or a copolymer of TPU.  
     
     
         12 . The method of  claim 1  wherein the polyurethane coating is crosslinked utilizing UV radiation.  
     
     
         13 . The method of  claim 1  wherein the polyurethane coating is crosslinked utilizing electron beam irradiation.  
     
     
         14 . The method of  claim 1  wherein the polyurethane coating is crosslinked utilizing gamma radiation.  
     
     
         15 . The method of  claim 2  wherein the polyurethane coating is crosslinked utilizing electron beam irradiation, gamma or LN radiation.  
     
     
         16 . An apparatus for use in in vivo implantation comprising a biomedical device, at least a portion of which is encapsulated in a coating to provide an encapsulated device, said encapsulated device being encapsulated with a cross-linked thermoplastic polyurethane coating providing enhanced biostability as compared to a biomedical device free of crosslinked thermoplastic polyurethane coating.  
     
     
         17 . The coated biomedical device produced by the method of  claim 1.