Medical devices containing radiation resistant block copolymer

• US 20060013849A1
• Filed: 07/19/2004
• Published: 01/19/2006
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation)
• Inventors: Richard, Robert E., Strickler, Frederick H.
• Granted Patent: US 7,713,539 B2
• Time in Patent Office: Days
• US Class Current: 424/422
• CPC Class Codes: A61L 2300/00 Biologically active materials used in bandages, wound dressings, absorbent pads or medical devices
• CPC Class Codes: A61L 29/041 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 29/16 Biologically active materials, e.g. therapeutic substances A61L29/048 takes precedence
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/16 Biologically active materials, e.g. therapeutic substances A61L31/047 takes precedence

Abstract

The present invention relates generally to radiation-resistant medical devices which contain polymer regions for release of therapeutic agents. The present invention also relates to radiation-resistant block copolymer materials for use in connection with insertable or implantable medical devices. The radiation-sterilized medical device comprise (a) a release region and (b) at least one therapeutic agent and the release region comprises a radiation resistant copolymer that includes (i) a low T_g hydrocarbon polymer block and (ii) one or more high T_g polymer blocks.

Claims

1. A radiation stable medical device comprising (a) a release region and (b) at least one therapeutic agent, said release region comprising a radiation stable copolymer that further comprises (i) a low T_g hydrocarbon polymer block and (ii) one or more high T_g polymer blocks.

2. The device of claim 1, wherein said copolymer comprises a low T_g hydrocarbon polymer midblock and a plurality of high T_g polymer endblocks.

3. The device of claim 1, wherein said copolymer is a triblock copolymer

4. The device of claim 1, wherein said copolymer is a star copolymer.

5. The device of claim 1, wherein said copolymer is a dendritic copolymer.

6. The device of claim 1, wherein said copolymer is a comb copolymer comprising a low T_g hydrocarbon polymer main chain and a plurality of high T_g polymer side chains.

7. The device of claim 1, wherein said hydrocarbon block is a polyolefin block.

8. The device of claim 1, wherein said hydrocarbon block is a polydiene block.

9. The device of claim 1, wherein said hydrocarbon block is a poly(olefin-co-diene) block.

10. The device of claim 1, wherein said hydrocarbon block is a poly(olefin-co-diene) block in which the olefin comprises one or both of ethylene and propylene and the diene comprises vinyl norbornene or ethylidene norbornene.

11. The device of claim 1, wherein said high T_g block is selected from the group consisting of a poly (vinyl aromatic) block, a poly(alkyl methacrylate) block and a poly(vinyl pyridine) block.

12. The device of claim 1, wherein said high T_g block comprises polystyrene.

13. The device of claim 1, wherein said release region is a carrier region that comprises said therapeutic agent.

14. The device of claim 1, wherein said release region is a barrier region disposed over a therapeutic-agent-containing region that comprises said therapeutic agent.

15. The device of claim 1, wherein said release region is in the form of a coating layer that covers all or a part of said medical device.

16. The device of claim 1, wherein said medical device is an implantable or insertable medical device.

17. The device of claim 1, wherein said implantable or insertable medical device is selected from a catheter, a guide wire, a balloon, a filter, a stent, a stent graft, a vascular graft, a vascular patch and a shunt.

18. The device of claim 1, wherein said implantable or insertable medical device is adapted for implantation or insertion into the coronary vasculature, peripheral vascular system, esophagus, trachea, colon, biliary tract, urinary tract, prostate or brain.

19. The device of claim 1, wherein said therapeutic agent is selected from one or more of the group consisting of anti-thrombotic agents, anti-proliferative agents, anti-inflammatory agents, anti-migratory agents, agents affecting extracellular matrix production and organization, antineoplastic agents, anti-mitotic agents, anesthetic agents, anti-coagulants, vascular cell growth promoters, vascular cell growth inhibitors, cholesterol-lowering agents, vasodilating agents, and agents that interfere with endogenous vasoactive mechanisms.

20. The device of claim 2, wherein said copolymer is made by a process that comprises (a) providing a macro-initiator, said macro-initiator comprising a free radical terminated low T_g hydrocarbon block and (b) conducting a free radical polymerization reaction in the presence of a macro-monomer comprising said endblocks each having a free-radical polymerizable end group.

21. The device of claim 20, wherein the macro-monomer comprises a polystyrene block, a polyethylene oxide block, a polyvinylpyrrolidone block, a polyalkylmethacrylate block, or a combination thereof.

22. The device of claim 20, wherein the macro-initiator is a free radical terminated polyolefin or polydiene.

23. The device of claim 20, wherein the free radical polymerization reaction is further conducted in the presence of one or more hydrophilic monomers selected from vinyl amine monomers, alkyl vinyl ether monomers, methacrylic acid and acid salt monomers, acrylic acid monomer, acrylic acid amide monomers, alkyl vinyl ether monomers, cyclic ether monomers, or one or more hydrophobic monomers selected from vinyl aromatic monomers, vinyl ester monomers, vinyl halide monomers, alkyl vinyl ether monomers, 1-vinyl-2-pyrrolidone monomer, vinyl ferrocene monomer, acenaphthalene monomer, indene monomer, alkyl acrylate monomers, arylalkyl acrylate monomers, alkoxyalkyl acrylate monomers, halo-alkyl acrylate monomers, cyano-alkyl acrylate monomers, alkyl methacrylate monomers, aminoalkyl methacrylate monomers, methacrylonitrile monomer, acrylonitrile monomer, ethylene monomer, isotactic propylene monomer, 4-methyl pentene monomer, 1-octadecene monomer, tetrafluoroethylene monomer, cyclic ether monomers, ether monomers, and epsilon-caprolactone monomer.

24. A method of forming the medical device of claim 1, comprising:

(a) providing a solution comprising (i) a solvent system and (ii) said copolymer; and

(b) forming said release region from said solution by removing said solvent system from said solution.

25. The method of claim 24, wherein said solution further comprises a therapeutic agent in dissolved or dispersed form.

26. The method of claim 24, wherein said solution is applied over a therapeutic-agent-containing region that comprises said therapeutic agent.

27. The method of claim 24, wherein said release region is formed by a technique comprising a spraying process.