Biocompatible Self-Lubricating Polymer Compositions and Their Use in Medical and Surgical Devices

Abstract

The invention comprises self-lubricating polymer compositions that are especially useful in medical devices and valves and gaskets of medical devices. In a preferred embodiment, the polymer compositions comprise a thermosetting or thermoplastic silicone elastomer in combination with a lubricity enhancing polyfluoropolyether fluid or hydrocarbon-based synthetic oil. In other preferred embodiments, the polymer compositions contain only biocompatible components. The improved anti-friction properties of the self-lubricating polymers can be demonstrated over a course of insertion and withdrawal cycles, where conventional polymers have changing and mostly increasing force required for each insertion and withdrawal, while the polymer compositions of the invention remain stable.

1 . A biocompatible, self-lubricating polymer composition consisting essentially of:
 a polymer matrix of dimethyl and methylvinyl siloxane copolymers, wherein the polymer matrix is selected from the group consisting of: (a) a polymer matrix, measured as in-mold cured for 10 minutes at 116° C., that has a specific gravity of 1.11, a durometer of 22 in Shore A hardness scale, and a tensile strength of 1347 psi and (b) a polymer matrix, measured as in-mold cured for 10 minutes at 116° C., that has a specific gravity of 1.12, a durometer of 35 in Shore A hardness scale, and a tensile strength of 1427 psi, and   a polyfluoropolyether (PFPE) synthetic oil at a concentration of about 1 to about 20 parts per hundred by weight (phr), wherein the PFPE synthetic oil migrates through the polymer matrix during the use of the biocompatible, self-lubricating polymer composition, and wherein the migration of PFPE synthetic oil maintains consistent surface lubricity when exposed to frictional force.   
     
     
         2 . (canceled) 
     
     
         3 . The self-lubricating polymer composition of  claim 1 , wherein the PFPE synthetic oil is present at about 4 to about 20 phr. 
     
     
         4 . (canceled) 
     
     
         5 . The self-lubricating polymer composition of  claim 1 , wherein the PFPE synthetic oil is present at about 4 to about 6 phr. 
     
     
         6 . (canceled) 
     
     
         7 . The self-lubricating polymer composition of  claim 1 , further comprising a biocompatible, solid lubricant micropowder. 
     
     
         8 - 28 . (canceled) 
     
     
         29 . A method of producing a biocompatible self-lubricating polymer for use in a medical device, comprising:
 mixing a polymer matrix of dimethyl and methylvinyl siloxane copolymers having a durometer hardness of about 10 to about 90 on the Shore A scale with at least one liquid lubricant having a surface energy of about 10 to about 20 dyne/cm with a two-roller mill compounding process until the lubricant occupies the molecular pores of the matrix;   molding the mixture into the desired shape; and   thermally curing the molded shape until the lubricant is trapped in the polymer matrix.   
     
     
         30 . The method of  claim 29 , wherein the liquid lubricant is PFPE synthetic oil and PFPE is present at about 4 to about 10 phr. 
     
     
         31 . The method of  claim 29 , wherein the liquid lubricant is PFPE synthetic oil and PFPE is present at about 4 to about 6 phr. 
     
     
         32 . The method of  claim 29 , wherein the polymer matrix has a durometer hardness of about 30 to about 40 on the Shore A scale. 
     
     
         33 . The method of  claim 29 , wherein the medical device is a tube having an outside diameter from about 5 mm to about 2 mm and an inside diameter of about 3.5 mm to about 1.5 mm. 
     
     
         34 . The method of  claim 29 , wherein the medical device is an introducer. 
     
     
         35 . The method of  claim 29 , wherein the medical device is a hemostasis valve. 
     
     
         36 . The method of  claim 29 , further comprising adding a biocompatible, solid lubricant micropowder to the mixture. 
     
     
         37 - 40 . (canceled) 
     
     
         41 . The method of  claim 29 , wherein the biocompatible self-lubricating polymer is used in the production of a sheath, tube or tubing, whereby the tube, sheath or tubing comprises at least about 10% or more of the self-lubricating polymer over its insertion length or receiving length. 
     
     
         42 - 56 . (canceled)