Poly(vinyl alcohol) cryogel

• US 5,981,826 A
• Filed: 09/17/1997
• Issued: 11/09/1999
• Est. Priority Date: 05/05/1997
• Status: Expired due to Term

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Wootton, David M., Braddon, Linda G., Ku, David N.
• Primary Examiner(s): Isabella, David J.
• Assistant Examiner(s): Black, John M.
• Application Number:
  US08/932,029
• Time in Patent Office: 783 Days
• Field of Search: 623/1, 623/11, 623/12, 623/13, 623/15, 602/41, 602/48, 602/49
• US Class Current: 623/23.72
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61K 47/32 Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. carbomers , poly(meth)acrylates, or polyvinyl pyrrolidone
• CPC Class Codes: A61K 9/0024 Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L
• CPC Class Codes: A61K 9/06 Ointments; Bases therefor; Other semi-solid forms, e.g. creams, sticks, gels composition of ointments, creams or gels A61K47/00
• CPC Class Codes: A61L 2300/236 Glycosaminoglycans, e.g. heparin, hyaluronic acid, chondroitin
• CPC Class Codes: A61L 2300/252 Polypeptides, proteins, e.g. glycoproteins, lipoproteins, cytokines
• CPC Class Codes: A61L 2300/254 Enzymes, proenzymes
• CPC Class Codes: A61L 2300/256 Antibodies, e.g. immunoglobulins, vaccines
• CPC Class Codes: A61L 2300/414 Growth factors
• CPC Class Codes: A61L 2300/42 Anti-thrombotic agents, anticoagulants, anti-platelet agents
• CPC Class Codes: A61L 2300/426 Immunomodulating agents, i.e. cytokines, interleukins, interferons
• CPC Class Codes: A61L 2300/432 Inhibitors, antagonists A61L2300/402 - A61L2300/43 take precedence
• CPC Class Codes: A61L 2300/64 Animal cells
• CPC Class Codes: A61L 27/16 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/38 containing added animal cells organs or tissue containing native cells A61L27/36
• CPC Class Codes: A61L 27/3804 characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells
• CPC Class Codes: A61L 27/52 Hydrogels or hydrocolloids
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: C08J 2329/04 Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: C08J 3/075 Macromolecular gels
• CPC Class Codes: C08L 29/04 : Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
• CPC Class Codes: Y10S 623/901 : Method of manufacturing prosthetic device

Abstract

The present invention includes a poly(vinyl alcohol) hydrogel construct having a wide range of mechanical strengths for use as a human tissue replacement. A process in connection with the present invention eliminates any step involved with dehydration of the hydrogel prior to implantation thereof. The hydrogel construct may include a tissue scaffolding, a load bearing surface within a joint, or any other structure which is suitable for supporting the growth of tissue.

Claims

1. A process for preparing a PVA construct comprising the steps of:

pouring an aqueous PVA polymer mixture into a mold;

freezing and thawing said PVA polymer mixture within said mold at least once to create an interlocking mesh between PVA polymer molecules to create the PVA cryogel;

removing, at least partially, said PVA cryogel from said mold;

immersing said PVA cryogel in an aqueous solution; and

freezing and thawing said PVA cryogel at least once while immersed in water.

2. The process of claim 1, comprising the further step, before immersing said PVA cryogel in water, of:

removing, at least partially, said PVA cryogel from said mold.

3. The process of claim 1, wherein said aqueous PVA polymer mixture comprises a PVA polymer starting material having a molecular weight ranging from approximately 11,000 to approximately 500,000.

4. The process of claim 1, wherein said aqueous PVA polymer mixture is biocompatible and comprises a PVA polymer starting material in the form of a dry powder.

5. The process of claim 1, wherein said aqueous PVA polymer mixture comprises a PVA starting material in the form of a dry powder, and further wherein a degree of polymerization of the PVA starting material ranges from approximately 500 to approximately 3500.

6. The process of claim 1, wherein said aqueous PVA polymer mixture comprises a PVA starting material in the form of a dry powder with a degree of hydrolysis in excess of approximately 80 percent.

7. The process of claim 1, wherein said aqueous PVA polymer mixture comprises a PVA starting material in the form of a dry powder with a degree of hydrolysis in excess of approximately 99 percent.

8. The process of claim 1, wherein said aqueous PVA polymer mixture comprises approximately 2 to approximately 40 parts by weight PVA and approximately 98 to approximately 60 parts by weight water.

9. The process of claim 1, wherein said aqueous PVA polymer mixture comprises approximately 20 to approximately 40 parts by weight PVA and approximately 60 to approximately 80 parts by weight water.

10. The process of claim 1, wherein said aqueous PVA polymer mixture comprises an isotonic saline solution to prevent osmotic imbalances between the tissue replacement and surrounding tissues.

11. The process of claim 10, wherein said isotonic saline solution comprises approximately 0.9 percent NaCl and approximately 99.1 percent water.

12. The product according to the process of claim 1.

13. The product of claim 12, further comprising a bioactive agent.

14. The product of claim 13, wherein said bioactive agent is selected from the group consisting of:

a heparin, a β

APN, an antibody, a cytokine, an integrin, a protease, a matrix inhibitor, an anticoagulant, a sphyngolipid, a thrombin, a thrombin inhibitor, and a glycosaminoglycan.

15. The product of claim 1 comprising a tissue replacement.

16. The product of claim 1 comprising a tissue scaffold.

17. The product of claim 16 wherein said tissue scaffold has an open-celled structure for promoting tissue ingrowth.

18. The product of claim 1 comprising a tissue expander.

19. The product of claim 1 comprising an implantable articulating surface for a load bearing joint.

20. The product of claim 19 wherein the articulating surface is fixed to bone with internal fixators comprising at least one of screws or sutures.

21. The product of claim 19 wherein the articulating surface is arranged and configured to be fixed to bone with a glue.

22. The product of claim 21 wherein the glue comprises a collagen glue.

23. The product of claim 1 comprising a cartilage replacement.

24. The product according to the process of claim 2.

25. The product according to the process of claim 3.

26. The product according to the process of claim 4.

27. The product according to the process of claim 5.

28. The product according to the process of claim 6.

29. The product according to the process of claim 8.

30. The product according to the process of claim 10.