Devices that change size/shape via osmotic pressure

• US 6,692,528 B2
• Filed: 11/08/2001
• Issued: 02/17/2004
• Est. Priority Date: 11/09/2000
• Status: Expired due to Term

• Current Assignee: Polymer Technology Group, Inc. (DSM-Firmenich AG)
• Original Assignee: Polymer Technology Group, Inc. (DSM-Firmenich AG)
• Inventors: Ward, Robert S., Coviello, Sallie K.
• Primary Examiner(s): Philogene, Pedro
• Application Number:
  US09/986,371
• Publication Number:
  US 20020082699A1
• Time in Patent Office: 831 Days
• Field of Search: 623/17.12, 623/17.11, 623/17.13, 623/17.14, 623/17.15, 623/17.16, 623/11.11, 623/16.11, 623/18.11, 623/23.51, 623/23.58
• US Class Current: 623/17.12
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30075 swellable, e.g. when wetted
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0061 swellable
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/50 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: B01D 61/002 Forward osmosis or direct osmosis
• CPC Class Codes: B01D 61/0022 Apparatus therefor
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/54 Polyureas; Polyurethanes
• CPC Class Codes: B01D 71/80 Block polymers
• CPC Class Codes: C02F 1/44 by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C08L 33/26 Homopolymers or copolymers of acrylamide or methacrylamide
• CPC Class Codes: C08L 75/00 Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers
• CPC Class Codes: Y02A 20/131 Reverse-osmosis

Abstract

Devices implantable in animal bodies, possibly configured as self-inflating spinal disc prostheses. Alternatively, non-implantable water-desalination and/or purification devices. The devices include specified types of water-absorbing solute encapsulated by non-porous, water-permeable polymer membranes having specified properties. Also, methods of using the devices in biomedical applications or water treatment.

Claims

1. A device implantable in an animal body, said device comprising a water-absorbing solute encapsulated by a non-porous, water-permeable polymer membrane,

wherein said polymer is a block copolymer having a polyurethane and/or polyurea hard segment and a soft segment selected from the group consisting of polyalkylene oxides, polyalkylene carbonates, poly-siloxanes, and linear or branched hydrocarbons,

wherein said membrane has a thickness of 1 to 16 mil and has a moisture vapor transmission rate by ASTM Method E96BW greater than 100 g/square meter/day at 1 mil thickness, a dry tensile strength of greater than 500 psi, and a permeability to said solute of less than 10⁻

3 cm²/sec, and

wherein said solute is capable of providing said device with a pressure of approximately 0.1 psi or more for a period of at least 24 hours.

2. The device of claim 1,

wherein said membrane has a moisture vapor transmission rate by ASTM Method E96BW greater than 2000 g/square meter/day at 1 mil thickness, a dry tensile strength of greater than 2000 psi, and a permeability to said solute of less than 10^{− 4} cm²/sec, and

wherein said solute is capable of providing said device with a pressure of approximately 100 psi or more for a period of at least six weeks.

3. The device of claim 1, wherein said soft segment is a polyalkylene oxide soft segment.

4. The device of claim 1, wherein said membrane has dispersed therein or covalently bound thereto a water-soluble additive and said device decreases in permeability over time.

5. The device of claim 4, wherein said water-soluble additive is selected from the group consisting of sodium chloride, glycerine, and polyethylene oxides.

6. The device of claim 1, wherein said solute is a polyacrylamide having a nominal weight-average molecular weight of 1200-3000 Daltons.

7. The device of claim 1, wherein said solute is present in an amount of 0.1-50 grams.

8. The device of claim 7, wherein said solute is present in an amount of 1-3 grams.

9. The device of claim 1, which comprises a self-inflating prosthetic spinal disc nucleus.

10. The device of claim 9, which comprises a self-inflating spinal disc nucleus surrounded by a reinforced perimeter and attachment means, configured to form a complete spinal disc prosthesis.

11. The device of claim 1, in which the solute comprises a blend of low molecular weight solute for quick inflation of the device and a high molecular weight solute to provide long term pressure and stability.

12. The device of claim 1, in which the membrane decreases in permeability over time to permit rapid short term inflation and persistent long term avoidance of solute leakage.

13. A method for treating a spine of a vertebrate which comprises inserting a device according to claim 9 or 10 into an area of the spine that contains a degenerated, damaged, or missing disc and allowing the device to expand by permeation of aqueous fluid into a cavity containing the solute.

14. A device implantable in an animal body, said device comprising a water-absorbing solute encapsulated by a non-porous, water-permeable polymer membrane,

wherein said polymer comprises a member selected from the groups consisting of polyurethane elastomers, crosslinked silicone elastomers, silicon-containing copolymers, polyolefin elastomers, Kraton styrene-diene elastomers, Hytrel polyester-polyether elastomers, and Pebax polyamide-polyether elastomers,

wherein said membrane has a thickness of 1 to 16 mil and has a moisture vapor transmission rate by ASTM Method E96BW greater than 2000 g/square meter/day at 1 mil thickness, a dry tensile strength of greater than 2000 psi, and a permeability to said solute of less than 10⁻

4 cm²/sec, and

wherein said solute is present in an amount of 0.1-50 grams and is capable of providing said device with a pressure of approximately 100 psi or more for a period of at least six weeks.

15. The device of claim 14, wherein said membrane has dispersed therein or covalently bound thereto a water-soluble additive and said device decreases in permeability over time.

16. The device of claim 15, wherein said water-soluble additive is selected from the group consisting of sodium chloride, glycerine, and polyethylene oxides.

17. The device of claim 14, wherein said solute is a polyacrylamide having a nominal weight-average molecular weight of 1200-3000 Daltons.

18. The device of claim 14, wherein said solute is present in an amount of 1-3 grams.

19. The device of claim 14, which comprises a self-inflating prosthetic spinal disc nucleus.

20. The device of claim 19, which comprises a self-inflating spinal nucleus surrounded by a reinforced perimeter and attachment means, configured to form a complete spinal disc prosthesis.

21. The device of claim 14, in which the solute comprises a blend of low molecular weight solute for quick inflation of the device and a high molecular weight solute to provide long term pressure and stability.

22. The device of claim 14, in which the membrane decreases in permeability over time to permit rapid short term inflation and persistent long term avoidance of solute leakage.

23. A method for treating a spine of a vertebrate which comprises inserting a device according to claim 19 or 20 into an area of the spine that contains a degenerated, damaged, or missing disc and allowing the device to expand by permeation of aqueous fluid into a cavity containing the solute.