Method of sterilizing a medical device

Abstract

A method of sterilizing a medical device component, such as a catheter balloon, in which an electron beam (i.e., e-beam) is applied to the component in an evacuated or inert gas-filled container. The method of the invention allows for electron beam sterilization without significant degradation of the component polymeric material. In one embodiment, the device component is configured to be pressurized or expanded during use. The method of the invention provides a component with a rupture pressure that is not significantly decreased due to electron beam sterilization. Another aspect of the invention is a medical device component, e-beam sterilized according to a method of the invention. A variety of medical device components can be sterilized by the method of the invention, and particularly intracorporeal devices for therapeutic or diagnostic purposes, such as balloon catheters, catheter shafts and balloons, stent covers, and vascular grafts.

1 .- 27 . (canceled)  
   
   
       28 . The balloon catheter of  claim 33  wherein the second rupture pressure of the balloon is at least about 15 to about 20 atm.  
   
   
       29 . The balloon catheter of  claim 33  wherein the balloon has a first fatigue resistance before the sterilization and a second fatigue resistance after the sterilization which is not more than about 5% to about 10% less than the first fatigue resistance of the balloon.  
   
   
       30 . The balloon catheter of  claim 33  wherein the balloon has a wall thickness of about 0.01 to about 0.03 mm.  
   
   
       31 . The balloon catheter of  claim 33  wherein the balloon is formed of a polyether block amide polymeric material.  
   
   
       32 . (canceled)  
   
   
       33 . A balloon catheter, comprising an elongated shaft and a sterilized balloon mounted on the shaft, sterilized by an electron beam applied to the balloon catheter in an evacuated or inert gas-filled environment, so that the balloon has a first rupture pressure before the sterilization, and a second rupture pressure after the sterilization which is equal to or less than the first rupture pressure of the balloon, the second rupture pressure being not more than about 15% to about 25% less than the first rupture pressure.  
   
   
       34 . The balloon catheter of  claim 33  wherein the balloon is formed of a polymeric material selected from the group consisting of polyamides and fluoropolymers.  
   
   
       35 . A stent delivery balloon catheter, comprising an elongated shaft, and balloon mounted on the shaft and formed of a polyether block amide, and a stent mounted on the balloon for implanting in a patient's body lumen, the balloon being sterilized by an electron beam applied to the balloon catheter in an evacuated or inert gas-filled container with the stent mounted on the balloon so that sections of the balloon located directly underneath the stent are penetrated less by the electron beam than are sections of the balloon located at spaces in a wall of the stent, the balloon having a first rupture pressure before the electron beam sterilization, and a second rupture pressure after the electron beam sterilization which is equal to or less than the first rupture pressure of the balloon and which is not more than about 5% to about 25% less than the first rupture pressure of the balloon.  
   
   
       36 . The stent delivery balloon catheter of  claim 35  wherein the stent is a metallic stent.