Irridating aluminum

More specifically, the invention relates to methods of manufacturing antioxidant doped medical devices containing cross-linked polyethylene, for example, cross-linked ultra-high molecular weight polyethylene (UHMWPE), and materials used therein.

The present invention relates generally to methods of making oxidation resistant medical devices that comprises one or more polymeric materials.

In another aspect, the invention provides methods of making a medical implant containing cross-linked polymeric material comprising: a) machining a consolidated polymeric material, thereby forming a medical implant; by) doping the medical implant with an antioxidant by diffusion; c) packaging the medical implant; and d) irradiating the packaged medical implant by ionizing radiation, thereby forming a consolidated and cross-linked and sterile medical implant.

In another aspect, the invention provides methods of making cross-linked polymeric material comprising the steps of: a) placing a consolidated and cross-linked polymeric material in a pressure chamber; b) filling the chamber with an antioxidant; and c) pressurizing the chamber to enhance diffusion of the antioxidant into the consolidated and cross-linked polymeric material.

In another aspect, the polymeric material of the instant invention is a polymeric resin powder, polymeric flakes, polymeric particles, or the like, or a mixture thereof, wherein the irradiation can be carried out in an atmosphere containing between about 1% and about 22% oxygen, wherein the radiation dose is between about 25 k Gy and about 1000 k Gy.

In another aspect, the polymeric material of the instant invention is polymeric resin powder, polymeric flakes, polymeric particles, or the like, or a mixture thereof, wherein the polymeric material is irradiated after consolidation in an inert atmosphere containing a gas, for example, nitrogen, argon, helium, neon, or the like, or a combination thereof, wherein the radiation dose is between about 25 k Gy and about 1000 k Gy.

Oxidation resistant cross-linked polymeric material, such as ultra-high molecular weight polyethylene (UHMWPE), is desired in medical devices because it significantly increases the wear resistance of the devices. According to another aspect, the invention provides methods of making cross-linked polymeric material, comprising the steps of: a) consolidating a polymeric material; b) irradiating the polymeric material with ionizing radiation, thereby forming a consolidated and cross-linked polymeric material; c) doping the consolidated and cross-linked polymeric material with an antioxidant by diffusion; and d) heating the consolidated and cross-linked polymeric material at a temperature below the melting point of the consolidated and cross-linked polymeric material.

In another aspect, the invention provides methods of making a medical implant containing cross-linked polymeric material comprising: a) doping the consolidated polymeric material with an antioxidant by diffusion; and b) irradiating the polymeric material with ionizing radiation, thereby forming a consolidated and cross-linked polymeric material.

In one aspect, antioxidant-doped medical implants are packaged and sterilized by ionizing radiation or gas sterilization to obtain sterile and cross-linked medical implants.

In another aspect, the invention provides methods of making a medical implant containing antioxidant-doped cross-linked polymeric material comprising: a) machining a consolidated polymeric material, thereby forming a medical implant; b) irradiating the medical implant, thereby forming a medical implant containing cross-linked polymeric material; and c) doping the medical implant with an antioxidant by diffusion.

In another aspect, the invention provides methods of making a medical implant containing cross-linked polymeric material comprising: a) direct compression molding polymeric material, thereby forming a medical implant; b) doping the medical implant with an antioxidant by diffusion; c) packaging the medical implant; and d) irradiating the packaged medical implant by ionizing radiation, thereby forming a consolidated and cross-linked and sterile medical implant.

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