# US 9,433,705 B2 · Methods for making oxidation-resistant cross-linked polymeric materials

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- Number: US 9,433,705 B2
- Document ID: US9433705B2
- Status: Granted
- Kind: B2
- Application number: 14/036,586
- Filed: 2013-09-25
- Published: 2014-04-10
- Granted: 2016-09-06
- Earliest claimed: 2007-01-25
- Assignees: The General Hospital Corporation; Cambridge Polymer Group, Inc.
- Applicants: The General Hospital Corporation; Cambridge Polymer Group, Inc.
- Inventors: Orhun K. Muratoglu; Edward T. Kopesky; Ebru Oral
- Web page: https://patentgrep.com/patent/US9433705B2

## CPC

- A61L 27/505: {Stabilizers}
- A61L 27/16: obtained by reactions only involving carbon-to-carbon unsaturated bonds
- B29C 43/003: {characterised by the choice of material}
- B29C 43/18: incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles {(B29C43/206 takes precedence)}
- B29C 71/04: by wave energy or particle radiation {, e.g. for curing or vulcanising preformed articles (during moulding, e.g. in a mould B29C35/08)}
- C08F 10/02: Ethene
- C08J 3/24: Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K)
- C08J 3/28: Treatment by wave energy or particle radiation
- C08K 5/1545: Six-membered rings
- B29K 2023/0683: {UHMWPE, i.e. ultra high molecular weight polyethylene}
- B29K 2105/20: Inserts
- B29K 2995/0056: Biocompatible, e.g. biopolymers or bioelastomers
- B29L 2031/753: {Medical equipment; Accessories therefor (bloodbags, medical bags B29L2031/7148; artificial eyes B29L2011/0008)}
- C08F 110/02: Ethene
- C08J 2323/06: Polyethene
- C08K 2201/012: Additives improving oxygen scavenging properties
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

The present invention relates to methods for making cross-linked oxidation-resistant polymeric materials and preventing or minimizing in vivo elution of antioxidant from the antioxidant-containing polymeric materials. The invention also provides methods of doping polymeric materials with a spatial control of cross-linking and antioxidant distribution, for example, vitamin E (α-Tocopherol), and methods for extraction/elution of antioxidants, for example, vitamin E (α-tocopherol), from surface regions of antioxidant-containing polymeric materials, and materials used therewith also are provided.

## Claims

### Claim 1

A method of making an oxidation-resistant cross-linked polymeric material comprising the steps of:
a) blending a polymeric material with an antioxidant, wherein a first portion of the polymeric material is contacted with a concentration of an antioxidant, a second portion of the polymeric material is contacted with another concentration of the antioxidant, and a third portion of the polymeric material is contacted with another concentration of the antioxidant;
b) consolidating the antioxidant-blended polymeric material by layering the third portion of the polymeric material, the second portion of the polymeric material, and the first portion of the polymeric material, thereby forming an antioxidant-blended consolidated polymeric material; and
c) irradiating the antioxidant-blended consolidated polymeric material with ionizing radiation, thereby forming an oxidation-resistant cross-linked consolidated polymeric material.

### Claim 2

A method of making a medical implant preform comprising an oxidation-resistant cross-linked polymeric material, wherein the method comprising the steps of:
a) blending a polymeric material with an antioxidant, wherein a first portion of the polymeric material is contacted with a concentration of an antioxidant, a second portion of the polymeric material is contacted with another concentration of the antioxidant, and a third portion of the polymeric material is contacted with another concentration of the antioxidant;
b) consolidating the antioxidant blended polymeric material by layering the third portion of the polymeric material, the second portion of the polymeric material, and the first portion of the polymeric material, thereby forming a medical implant preform; and
c) irradiating the medical implant preform containing the antioxidant blended polymeric material with ionizing radiation, thereby forming a medical implant preform having an oxidation-resistant cross-linked polymeric material.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the polymeric material is polymeric resin powder, polymeric flakes, polymeric particles, or the like, or a mixture thereof.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the antioxidant is vitamin E.

### Claim 5 (depends on 2)

The method according to claim 2, wherein the blended polymeric material in the first or the second portion, in the surface or in the bulk of the polymeric material contains different concentration of the antioxidant.

### Claim 6 (depends on 2)

The method according to claim 2, wherein the blended polymeric material in the first and second portions contain same concentrations of the antioxidant.

### Claim 7 (depends on 2)

The method according to claim 2, wherein the blended polymeric material in the second and third portions contain same concentrations of the antioxidant.

### Claim 8 (depends on 2)

The method according to claim 2, wherein the blended polymeric material in the first and third portions contain different concentrations of the antioxidant.

### Claim 9 (depends on 2)

The method according to claim 2, wherein the blended polymeric material in the first and third portions contain same concentrations of the antioxidant.

### Claim 10 (depends on 2)

The method according to claim 2, wherein the irradiated medical implant preform contains spatially distributed antioxidant and forms a medical implant preform having an oxidation-resistant cross-linked polymeric material having a spatially controlled cross-linking and antioxidant distribution.

### Claim 11 (depends on 2)

The method according to claim 2, wherein the irradiation is carried out at a temperature that is above the room temperature and below the melting point of the polymeric material, wherein the temperature is between about 40° C. and about 135° C.

### Claim 12 (depends on 2)

The method according to claim 2, wherein the medical implant preform is a direct compression molded implant.

### Claim 13

A method of making an interlocked hybrid material comprising an oxidation-resistant cross-linked polymeric material, wherein the method comprising the steps of:
a) blending a polymeric material with an antioxidant, wherein a first portion of the polymeric material is contacted with a concentration of an antioxidant, a second portion of the polymeric material is contacted with another concentration of the antioxidant, and a third portion of the polymeric material is contacted with another concentration of the antioxidant;
b) compression molding the antioxidant blended polymeric material to another piece or a medical implant by layering the third portion of the polymeric material, the second portion of the polymeric material, and the first portion of the polymeric material, thereby forming an interface and an interlocked hybrid material; and
c) irradiating the interlocked hybrid material containing the antioxidant with ionizing radiation, thereby forming an interlocked hybrid material having an oxidation-resistant cross-linked polymeric material.

### Claim 14 (depends on 13)

The method according to claim 13, wherein the blended polymeric material in the first and second portions contain same concentrations of the antioxidant.

### Claim 15 (depends on 13)

The method according to claim 13, wherein the blended polymeric material in the second and third portions contain same concentrations of the antioxidant.

### Claim 16 (depends on 13)

The method according to claim 13, wherein the blended polymeric material in the first and third portions contain different concentrations of the antioxidant.

### Claim 17 (depends on 13)

The method according to claim 13, wherein the blended polymeric material in the first and third portions contain same concentrations of the antioxidant.

### Claim 18 (depends on 13)

The method according to claim 13, wherein the irradiated interlocked hybrid material contains spatially distributed antioxidant and forms an interlocked hybrid material having an oxidation-resistant cross-linked polymeric material having a spatially controlled cross-linking and antioxidant distribution.

### Claim 19 (depends on 13)

The method according to claim 13, wherein the another piece onto which the resins, flakes or powders are consolidated is a porous metal.

### Claim 20 (depends on 13)

The method according to claim 13, wherein the irradiation is performed when the interlocked hybrid material is at a temperature above room temperature and below the melting point of the polymeric material, wherein the temperature is between about 40° C. and about 135° C.

### Claim 21 (depends on 13)

The method according to claim 13, wherein the oxidation-resistant interlocked hybrid material is machined, thereby forming oxidation-resistant medical implant.

### Claim 22 (depends on 21)

The method according to claim 21, wherein the oxidation-resistant medical implant having a spatially controlled crosslinking and antioxidant distribution is packaged and sterilized.

### Claim 23 (depends on 13)

The method according to claim 13, wherein the interlocked hybrid material is a direct compression molded implant.

### Claim 24 (depends on 13)

The method according to claim 13, wherein the antioxidant is vitamin E.