Specialized hollow fiber membranes for plasmapheresis and ultrafiltration

• US 20070023353A1
• Filed: 04/14/2006
• Published: 02/01/2007
• Est. Priority Date: 04/13/2000
• Status: Active Grant

• Current Assignee: Transvivo, Inc.
• Original Assignee: Transvivo, Inc.
• Inventors: Peters, Harold, Grage, Henry, Kearns, Jacob, Handley, Harold, Gorsuch, Reynolds
• Granted Patent: US 7,585,412 B2
• Time in Patent Office: Days
• US Class Current: 210/500.230
• CPC Class Codes: A61M 1/1678 intracorporal peritoneal dialysis A61M1/28
• CPC Class Codes: B01D 67/0088 Physical treatment with compounds, e.g. swelling, coating or impregnation
• CPC Class Codes: B01D 67/0093 Chemical modification
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/08 Hollow fibre membranes manufacture of hollow fibres D01D5/24, D01F1/08

Abstract

A plasmapheresis and/or ultrafiltration membrane comprises elongated hollow fibers each fiber having an interior lumen extending along the fiber length, the fiber wall having a plurality of zones between the inner and outer wall surfaces, each of the zones having a mass density different than the mass density of an adjacent zone. The fiber wall is characterized by having a lower mass density zone at the inner wall surface and a higher mass density zone at the outer wall surface. The fiber is further characterized by having an average elongation breaking force strength of at least about 0.2 lbs. and an average elongation of at least about 45%.

Claims

1. A plasmapheresis and/or ultrafiltration membrane comprising:

a plurality of elongated hollow fibers each fiber having an outer wall, an inner wall and an interior lumen extending along the length thereof, and characterized by having an average elongation breaking force strength of at least about 0.2 lbs. and an average elongation of at least about 45%, and wherein the fiber wall structure is a continuous change in mass density from said outer wall to said inner wall and comprises a continuum of voids bounded by solid frames, said fiber wall having a plurality of zones between inner and outer wall surfaces, each of said zones having a mass density different than the mass density of an adjacent zone, said fiber wall having a lower mass density zone at the inner wall surface and a higher mass density zone at the outer wall surface, said fibers capable of separating blood plasma and toxins from whole blood within a blood vessel by passing the plasma and toxins through said fiber wall from the outer wall surface to the interior lumen.

2. A membrane of claim 1 wherein said membrane fiber wall has two mass density zones.

3. A membrane of claim 1 wherein said membrane fiber wall has three mass density zones.

4. A membrane of claim 1 wherein membrane fiber wall has four or more mass density zones.

5. A membrane of claim 1, 2, 3, or 4 wherein each of said zones is characterized by a different average nominal pore size.

6. A membrane of claim 5 wherein said lower mass density zone is characterized by a nominal average pore diameter of from about 1 μ

m to about 60 μ

m.

7. A membrane of claim 5 wherein said higher mass density zone is characterized by a nominal average pore diameter of from about 0.10 μ

m to about 1 μ

m.

8. A membrane of claim 6 wherein said higher mass density zone is characterized by a nominal average pore diameter of from about 0.10 μ

m to about 1 μ

m.

9. A membrane of claim 5 wherein said higher mass density zone is characterized by a nominal average pore diameter of from about 0.003 μ

m to about 0.006 μ

m.

10. A membrane of claim 1, 2, 3, or 4 comprising polysulfone.

11. A membrane of claim 1, 2, 3, or 4 comprising polyethersulfone.

12. A membrane of claim 11 wherein said polyethersulfone is blended with at least one of polyethylene oxide and polyethylene glycoL

13. A membrane of claim 10 wherein said polysulfone is modified with polyethylene oxide-polyethylene glycol.

21. A membrane of claim 1 or 14 wherein said higher mass density is characterized by a nominal average pore diameter of from about 0.15 μ

m to about 1 μ

m.

22. A membrane of claim 21 wherein said lower mass density is characterized by a nominal average pore diameter of from about 5 μ

m to about 40 μ

m.

23. A membrane of claim 22 having a plasma trans-membrane flux of from about 1 to about 12 ml/min/cm²/@ 100 mm Hg.

24. A membrane of claim 1 or 14 wherein said higher mass density is characterized by a nominal average pore diameter of from about 0.003 μ

m to about 0.006 μ

m.

25. A membrane of claim 24 wherein said lower mass density is characterized by a nominal average pore diameter of from about 5 μ

m to about 40 μ

m.

26. A membrane of claim 25 having a trans-membrane flux (H₂O) of from about 0.15 to about 2 ml/min/cm²/@ 500 mm Hg.

14. A plasmapheresis or ultrafiltration membrane comprising a plurality of elongated hollow fibers each fiber having an outer wall, an inner wall and an interior lumen extending along the length thereof and defined by an inner wall surface, and characterized by having an average elongation breaking force strength of at least about 0.3 lbs. and an average elongation of at least about 45%, and wherein the fiber wall structure is a continuous change in mass density from said outer wall to said inner wall and comprises a continuum of voids bounded by solid frames, said fiber wall having an asymmetrical pore size and asymmetrical mass density between said inner wall surface and the outer wall surface said fiber wall having a higher mass density adjacent to the outer wall and a lower mass density adjacent to said inner wall, said fibers capable of separating blood plasma and toxins from whole blood within a blood vessel by passing the plasma and toxins through said fiber wall from the outer wall surface to the interior lumen.

15. A membrane of claim 14 wherein the higher mass density fiber wall is characterized by pores having a smaller average nominal pore size as compared to the average nominal pore size in the lower mass density fiber wall.

16. A membrane of claim 15 wherein said lower mass density is characterized by a nominal average pore diameter of from about 1 μ

m to about 60 μ

m.

17. A membrane of claim 15 or 16 wherein said higher mass density is characterized by a nominal average pore diameter of from about 0.10 μ

m to about 1 μ

m.

18. A membrane of claim 15 wherein said higher mass density is characterized by a nominal average pore diameter of from about 0.003 μ

m to about 0.006 μ

m.

19. A membrane of claim 18 wherein said lower mass density is characterized by a nominal average pore diameter of from about 1 μ

m to about 60 μ

m.

20. A membrane of claim 6 or 16 having a plasma trans-membrane flux of from about 0.5 to about 9 ml/min/cm² @ 100 mm Hg.

27. A membrane of claim 14 comprising a polyethersulfone.

28. A membrane of claim 27 wherein said polyethersulfone is blended with polyethylene oxide and/or polyethylene glycol.

29. A membrane of claim 14 comprising a polysulfone.

30. A membrane of claim 14 comprising polysulfone modified with polyethyleneoxide-polyethylene glycol copolymer.