Coated biomaterials and methods for making same

• US 4,976,736 A
• Filed: 04/28/1989
• Issued: 12/11/1990
• Est. Priority Date: 04/28/1989
• Status: Expired due to Term

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Interpore International Inc. (Interpore Spine Limited)
• Inventors: Shors, Edwin C., White, Eugene W.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/345,194
• Time in Patent Office: 592 Days
• Field of Search: 427/2, 423/173, 423/175, 423/176, 501/1, 623/16, 623/66, 623/11, 433/222.1, 433/201.1, 433/212.1, 606/77
• US Class Current: 424/423
• CPC Class Codes: A61F 2310/00796 Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61L 2300/406 Antibiotics
• CPC Class Codes: A61L 2300/414 Growth factors
• CPC Class Codes: A61L 27/32 Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/40 Composite materials, i.e. containing one material dispersed in a matrix of the same or different material
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges

Abstract

Biomaterials useful for onthopedicanel dental applications is disclosed. These materials have a base portion of calcium carbonate and a surface layer of a synthetic phosphate such as hydroxyapatite. The base portion may be a calcium carbonate structure having three-dimensional interconnected porosity such as may be found in porous skeletal carbonate of marine life, e.g. coral porites skeletal aragonite, or it may be porous or non-porous granules of calcium carbonate.

A method for making the biomaterials is also disclosed. The synthetic phosphate surface is made using a hydroconversion reaction with a soluble or solubilized phosphate such as ammonium dibasic phosphate ((NH4)₂ HPO4).

Claims

1. A biomaterial comprising a base portion consisting essentially of calcium carbonate and having a surface layer of synthetic phosphate.

2. A biomaterial as recited in claim 1 having a three dimensional porous microstructure corresponding to the microstructure of porous carbonate echinoderm or schleractinian coral skeletal material.

3. A biomaterial as recited in claim 1 wherein said surface layer has a thickness less than about 25 microns.

4. A biomaterial as recited in claim 2 wherein said base portion is porous calcium carbonate derived from coral.

5. A biomaterial as recited in claim 4 wherein said surface layer is made by converting the surface of said calcium carbonate base portion to hydroxyapatite.

6. A biomaterial as recited in claim 2 wherein said base portion is Porites coral and said surface layer consists essentially of hydroxyapatite.

7. A biomaterial as recited in claim 2 wherein said base portion is Goniopora or Alveolopora coral and said surface layer consists essentially of hydroxyapatite.

8. A biomaterial as recited in claim 1 wherein said base portion is solid calcium carbonate.

9. A biomaterial as recited in claim 6 having an average pore diameter of about 200 microns.

10. A biomaterial as recited in claim 7 having an averagepore diameter of about 500 microns.

11. A biomaterial as recited in claim 2 having pore sizes in the range of about 5-1000 microns.

12. A biomaterial as recited in claim 2 wherein said base portion is Porites or Goniopora coral and said surface layer is made by converting calcium carbonate to calcium phosphate.

13. A biomaterial in accordance with claim 2 having substantially uniform pore connections or openings in the range from about 5 microns to about 1000 microns.

14. A biomaterial in accordance with claim 1 wherein the synthetic phosphate is hydroxyapatite or whitlockite.

15. A biomaterial in accordance with claim 2 wherein said base portion is coral skeletal aragonite and said surface layer consists essentially of hydroxyapatite.

16. A biomaterial in accordance with claim 15 wherein said coral skeletal aragonite is Porites skeletal aragonite.

17. A biomaterial in accordance with claim 1 wherein said base portion is a calcium carbonate granule.

18. A biomaterial in accordance with claim 17 wherein said base portion is solid.

19. A biomaterial in accordance with claim 17 wherein said calcium carbonate granule is porous and is derived from coral.

20. A biomaterial in accordance with claim 17 wherein the diameter of said granule ranges from about 425 microns to about 5 millimeters.

21. A biomaterial in accordance with claim 20 wherein the average diameter of said granule ranges from about 425 microns to about 600 microns.

22. A biomaterial as recited in claim 2 wherein said base portion is derived from porous echinoderm skeletal material and said surface layer consists essentially of whitlockite.

23. A synthetic biomaterial characterized by a substantially uniform pore volume in the range from about 10% to about 90% and having a microstructure characterized by a pronounced three dimensional fenestrate structure corresponding to the microstructure of the porous carbonate echinoderm or schleractinian coral skeletal material of marine life and providing a periodic minimal surface, said periodic minimal surface dividing the volume of said material into two interpenetrating regions, each of which is a single, multiply connected domain, said material having a substantially uniform pore size diameter and substantially uniform pore connection or openings in the range from about 5 microns to about 1000 microns, said synthetic material comprising a base portion of calcium carbonate and a surface layer of calcium phosphate.

24. A biomaterial in accordance with claim 23, wherein said biomaterial has the microstructure of echinoderm skeletal calcite and surface layer consists essentially of whitlockite.

25. A biomaterial in accordance with claim 23 having the microstructure of coral skeletal aragonite and said surface layer consists essentially of hydroxyapatite.

26. A biomaterial in accordance with claim 25 wherein said coral skeletal aragonite is Porites skeletal aragonite.

27. A biomaterial in accordance with claim 23 having the microstructure of Alveolopora or Goniopora skeletal aragonite and wherein said surface layer consists essentially of hydroxyapatite.

28. A biomaterial in accordance with claim 23 wherein the microstructure has the ratio of pore volume to the volume of solid of approximately 1 and has a cross-sectional diameter of both the pore and solid phase of about the same dimension ranging from about 5 microns to about 1000 microns.

29. A biomaterial in accordance with claim 23 having pore sizes in the range from about 40 to about 250 microns.

30. A biomaterial in accordance with claim 23 wherein said biomaterial is shaped or formed into a shape commensurate with a bone repair or replacement function.

31. A biomaterial in accordance with claim 30 wherein said phosphate surfaced calcium carbonate biomaterial is hydroxyapatite surfaced calcium carbonate.

32. A biomaterial in accordance with claim 23 having an average pore size of about 500 microns.