IMPLANTABLE OR INSERTABLE MEDICAL DEVICES

• US 20100256720A1
• Filed: 09/21/2009
• Published: 10/07/2010
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Pandit, Aditya, Overstreet, Edward Holman, Orinski, William, DiPietro, Kerri, Brito, Shaina G., Richard, Robert E., Boden, Mark, Strickler, Frederick H., Kuzma, Janusz A., Pham, Lan, Pianca, Anne M.
• Granted Patent: US 9,220,811 B2
• Time in Patent Office: Days
• US Class Current: 607/117
• CPC Class Codes: A61L 2300/222 Steroids, e.g. corticosteroids
• CPC Class Codes: A61L 2300/602 Type of release, e.g. controlled, sustained, slow
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61N 1/0534 Electrodes for deep brain stimulation
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: C08L 83/06 containing silicon bound to oxygen-containing groups C08L83/12 takes precedence

Abstract

In various aspects, the present invention is directed to implantable neurostimulation leads and methods for their formation. In various additional aspects, the present invention is directed to medical devices having silicone-containing regions with overlying polymeric layers and to methods of forming the same.

Claims

1. An implantable or insertable medical device comprising (a) a silicone-containing region that comprises silicone and (b) a polymeric layer comprising a block copolymer disposed over the silicone-containing region, said block copolymer comprising a high Tg polymer block comprising a first monomer and a low Tg polymer block comprising a second monomer.

2. The medical device of claim 1, wherein the high Tg polymer block is a homopolymer or copolymer block comprising a monomer selected from high Tg vinyl aromatic monomers, high Tg alkyl methacrylate monomers, high Tg acrylate monomers, and combinations thereof and wherein the low Tg polymer block is a homopolymer or copolymer block comprising a monomer selected from low Tg alkene monomers, low Tg fluorinated monomers, low Tg alkyl acrylate monomers, low Tg alkyl methacrylate monomers, and combinations thereof.

3. The medical device of claim 1, wherein the block copolymer comprises a polystyrene block and a polyisobutylene block.

4. The medical device of claim 1, wherein the block copolymer comprises two polystyrene blocks and a polyisobutylene block between the two polystyrene blocks.

5. The medical device of claim 1, wherein said medical device is a neurostimulation device.

6. The medical device of claim 5, wherein said neurostimulation device is a neurostimulation lead that comprises an electrical contact and an elongated conductor in electrical communication with the electrical contact and extending along at least a portion of the length of the lead, and wherein said silicone-containing region is a polymeric lead body that supports the contact and encapsulates at least a portion of the length of the elongated conductor.

7. The medical device of claim 5, wherein the neurostimulation device is selected from a spinal cord stimulation lead, a deep brain stimulation lead, and a cochlear lead.

8. The medical device of claim 3, wherein the block copolymer further comprises a hydrophilic block.

9. The medical device of claim 8, wherein the hydrophilic block is selected from homopolymer or copolymer blocks comprising monomers selected from carboxylic acid monomers and salts thereof, sulfonic acid monomers and salts thereof, vinyl pyrrolidone, vinyl alcohol, hydroxyethyl methacrylate, methyl methacrylate, hydroxystyrene, methyl vinyl ether, ethylene oxide, and combinations thereof.

10. The medical device of claim 1, wherein the block copolymer is blended with a maleic anhydride polymer.

11. The medical device of claim 10, wherein the maleic anhydride polymer is a styrene-maleic anhydride copolymer and wherein the wherein the first monomer is styrene.

12. The medical device of claim 1, wherein the polymeric layer further comprises a therapeutic agent.

13. The medical device of claim 12, wherein the therapeutic agent is a corticosteroid.

14. The medical device of claim 2, wherein the block copolymer further comprises a polysiloxane block.

15. The medical device of claim 3, wherein said polymeric layer comprises a low molecular weight poly(styrene-b-isobutylene-b-styrene) triblock copolymer, and where said medical device further comprises an additional layer over said polymeric layer that comprises high molecular weight poly(styrene-b-isobutylene-b-styrene) triblock copolymer.

16. The medical device of claim 1, wherein said medical device comprises an antioxidant.

17. The medical device of claim 16, wherein the antioxidant is released into a subject upon implantation into said subject.

18. The medical device of claim 16, wherein the antioxidant is an antioxidant polymer.

19. The medical device of claim 18, wherein the antioxidant polymer is a polymer that comprises a hydroxystyrene monomer.

20. The medical device of claim 1, further comprising a tie layer between the silicone-containing region and the polymeric layer, said tie layer comprising an additional polymer, wherein the block copolymer and the additional polymer are different from one another, and wherein the additional polymer comprises (a) a silicon-containing monomer and (b) said first monomer, said second monomer, or a combination of said first and second monomers.

21. The medical device of claim 20, wherein the block copolymer comprises a polystyrene block and a polyisobutylene block and wherein the additional polymer is a copolymer that comprises (a) a siloxane monomer and (b) styrene, isobutylene, or a combination of styrene and isobutylene.

22. The medical device of claim 20, wherein the additional polymer is a block copolymer that comprises (a) a polysiloxane block and (b) an additional polymer block comprising said first monomer, said second monomer, or a combination of said first and second monomers.

23. The medical device of claim 20, wherein the block copolymer comprises a polystyrene block and a polyisobutylene block and wherein the additional polymer is a block copolymer comprises (a) a polysiloxane block and (b) a polystyrene block, a polyisobutylene block, or both a polystyrene block and a polyisobutylene block.

24. The medical device of claim 1, further comprising a tie layer that comprises an additional polymer between the silicone-containing region and the polymeric layer, wherein the block copolymer and the additional polymer are different from one another, wherein the additional polymer comprises said first monomer, said second monomer, or a combination of said first and second monomers, and wherein said additional polymer is grafted to the surface of the silicone-containing region.

25. The medical device of claim 24, wherein the block copolymer comprises a polystyrene block and a polyisobutylene block, wherein the additional polymer comprises a monomer selected from styrene, isobutylene, and a combination of styrene and isobutylene.

26. The medical device of claim 24, wherein the silicone-containing region is ozonated, followed by graft polymerization of the additional monomer.

27. The medical device of claim 1, further comprising a tie layer between the silicone-containing region and the polymeric layer, said tie layer being formed using an organosilicon compound.

28. The medical device of claim 27, wherein the organosilicon compound is SiR¹_nR²_4-n where n is one, two, three or four, where the R¹ groups are independently selected from straight chain or branched C1-C10 alkoxy and alkanoyloxy groups, and wherein the R² groups are independently selected from hydride, anhydride, azide, epoxy, ester, halogen, hydroxyl, isocyanate, phosphate and vinyl groups.

29. The medical device of claim 28, wherein n is one, two or three and wherein the first polymer comprises a functional group that is reactive with the R² groups.

30. The medical device of claim 28, wherein n is one, two or three, wherein the R² groups comprise at least one hydride group and wherein the block copolymer comprises an allyl group.

31. The medical device of claim 27, wherein the organosilicon compound is selected from a dialkloxysilane compound and a trialkloxysilane compound.

32. The medical device of claim 27, wherein the organosilicon compound is selected from triethoxysilane and triacetoxysilane.

33. The medical device of claim 1, wherein said silicone-containing region comprises a textured surface comprising protrusions, depressions, or both.

34. The medical device of claim 33, wherein the textured surface comprises laser ablated pores or molded pores.