Calcium phosphate bone replacement materials and methods of use thereof

• US 7,045,105 B2
• Filed: 12/20/2002
• Issued: 05/16/2006
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: Richard J. Lagow
• Original Assignee: Richard J. Lagow
• Inventors: Lagow, Richard J.
• Primary Examiner(s): Langel, Wayne A.
• Application Number:
  US10/327,344
• Publication Number:
  US 20040022825A1
• Time in Patent Office: 1,243 Days
• Field of Search: 423/308, 423/309, 423/311, 423/305, 623/16.11, 623/23.56, 501/84
• US Class Current: 423/305
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00359 Bone or bony tissue
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 27/12 Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: C01B 25/32 Phosphates of magnesium, calcium, strontium, or barium
• CPC Class Codes: C04B 2235/3212 Calcium phosphates, e.g. hydroxyapatite
• CPC Class Codes: C04B 2235/44 Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/665 Local sintering, e.g. laser sintering
• CPC Class Codes: C04B 2235/667 Sintering using wave energy, e.g. microwave sintering
• CPC Class Codes: C04B 2235/722 Nitrogen content
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 35/447 based on phosphates , e.g. hydroxyapatite
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F

Abstract

Methods of making porous calcium phosphate bone replacement materials are discussed.

Claims

1. A method of producing a porous calcium phosphate material;

composing;

forming a mixture of calcium ions and phosphate ions having a calcium to phosphorus ratio of between 0.1 and about 0.80;

heating said mixture to temperature of about 5°

C. to 150°

C. below the melting point of the mixture; and

cooling the reaction mixture, such that a porous calcium phosphate material is produced.

2. The method of claim 1, further comprising preheating said mixture to 400°

C. to 760°

C. for at least 1 second.

3. The method of claim 2, wherein said mixture is preheated to 400°

C. to 760°

C. for at least 1 second two or more times.

4. The method of claim 1, further comprising compressing said mixture to a pressure of 10,000 psi.

5. The method of claim 1, wherein said ratio of calcium to phosphate ions is about 0.40 to about 0.60.

6. The method of claim 4, further comprising heating said mixture at 250°

C. to 400°

C. for at least thirty minutes.

7. The method of claim 1, further comprising placing the mixture into a mold prior to heating and pressing the mixture to a pressure of 100 psi to 20,000 psi for at least 1 second.

8. The method of claim 7, further comprising ultrasonic vibration bombardment of said mixture.

9. The method of claim 1, further comprising adding an acid catalyst to said mixture.

10. The method of claim 9, wherein said acid catalyst is an inorganic or organic acid.

11. The method of claim 1, wherein said calcium ions are from apatitic calcium phosphates, non-apatitic calcium phosphates, calcium hydroxide, calcium oxide, calcium carbonate, calcium salts, calcium halide, calcium metal, or combinations thereof.

12. The method of claim 1, wherein said phosphate ions are from orthophosphoric acid, pyrophosphoric acids, condensed phosphates, phosphate of non-metal cations, metal phosphates, or combinations thereof.

13. The method of claim 1, wherein said mixture is heated by an electric furnace, laser radiation, microwave radiation or radio frequency heating.

14. A method of producing a porous calcium phosphate material comprising:

forming a mixture of calcium ions and phosphate ions, wherein the ratio of calcium ions to phosphorous ions is between 0.1 and about 0.80;

adding a gas-generating material to said mixture;

heating said mixture to about 5°

C. to 150°

C. below the melting point of the mixture; and

cooling said mixture such that a solid, porous calcium phosphate material, is produced.

15. The method of claim 14, wherein said gas-generating material is a source of ammonium ions selected from the group consisting of ammonium carbonate, ammonium bicarbonate, ammonium acetate, ammonium hydroxide, ammonium nitrates, ammonium sulfates, ammonium hydrogen phosphate, ammonium dihydrogenphosphate, ammonium fluorophosphates, ammonium citrate, ammonium hydrogencitrate, ammonium hydrogen difluoride, ammonium hydrogen oxalate hemihydrate, ammonium halides, ammonium salts, ammonia anhydride, ammonia solutions, and combinations thereof.

16. A method of producing a porous non-apatatic calcium phosphate material comprising:

mixing a gas-generating material and a calcium phosphate ceramic precursor, heating said mixture to below the sintering temperature to generate a gas; and

sintering the calcium phosphate ceramic precursors to make solid ceramic materials, such that a porous non-apatitic calcium phosphate material is produced.

17. The method of claim 16, wherein said calcium phosphate ceramic precursor is monocalcium phosphate hydrate (MCP), dicalcium phosphate hydrate (DCPD), dicalcium phosphate anhydrous (DCPA), octacalcium phosphate pentahydrate (OCP), tricalcium phosphate (TCP), alpha and beta form (hydroxyapatite), pentacalcium hydroxylphosphate (HAP), tetracalcium phosphate monoxide (TCPM), calcium pyrophosphate, calcium metaphospates, polycalcium metaphospates, or combinations thereof.