STRONTIUM-DOPED CALCIUM PHOSPHATE BONE GRAFT MATERIALS

• US 20110151027A1
• Filed: 12/21/2009
• Published: 06/23/2011
• Est. Priority Date: 12/21/2009
• Status: Abandoned Application

• Current Assignee: Orthovita Inc. (Stryker Corporation)
• Original Assignee: Orthovita Inc. (Stryker Corporation)
• Inventors: Havener, Matthew B., Clineff, Theodore D, Martin, Justin J., Darmoc, Marissa M.
• Application Number:
  US12/643,218
• Publication Number:
  US 20110151027A1
• Time in Patent Office: Days
• US Class Current: 424/722
• 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 27/425 of phosphorus containing material, e.g. apatite
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61P 19/00 Drugs for skeletal disorders

Abstract

The present invention is directed to strontium-containing calcium phosphate bone graft materials. Methods of making and using the bone grafts are also described.

Claims

1. A bone graft material comprising calcium phosphate homogeneously blended with from 0.1 to about 4.5 percent, by weight of the graft material, of strontium;

the bone graft material having a pore volume of at least about 70%.

2. The bone graft material of claim 1, having macroporosity, mesoporosity, and microporosity.

3. The bone graft material of claim 1, wherein at least 90% of the calcium phosphate is β

-tricalcium phosphate.

4. The bone graft material of claim 1, wherein the pore volume is at least about 75%.

5. The bone graft material of claim 1, further comprising collagen.

6. The bone graft material of claim 1, further comprising bioactive glass.

7. The bone graft material of claim 1, further comprising collagen and bioactive glass.

8. The bone graft material of claim 1 in the form of a block, a strip, or morsels.

9. A method of preparing a bone graft comprising

providing an aqueous solution comprising calcium nitrate, a strontium source providing from 0.1 to 5.0 mol % of strontium, based on the moles of divalent salts present in the solution and at least one phosphite-containing anion oxidizable by the nitrate anion;

imbibing the aqueous solution onto a porous substrate, the porous substrate having a pore volume of at least 70%;

heating the imbibed porous substrate to a temperature sufficient to initiate an oxidation-reduction reaction between the nitrate anion and the phosphate-containing anion to form a solid and sufficient to incinerate the porous substrate; and

sintering the resulting solid at a temperature of at least 800°

C. to form the bone graft material.

10. The method of claim 9 wherein the step of sintering the resulting solid occurs at a temperature of at least 1100°

C. to form the bone graft material.

11. A bone graft material for the local delivery of strontium comprising strontium-doped calcium phosphate with from 0.1 to about 4.5 percent, by weight of the graft material, of strontium;

the bone graft material having a pore volume of at least about 70%.

12. The bone graft material of claim 11 wherein the release of strontium ranges from about 3 ppm to about 145 ppm strontium per day for the first 12 weeks and from about 1 ppm to about 81 ppm strontium per day for the next 12 to 24 weeks post-implantation.

13. A method of inducing local bone formation in a defect site comprising the steps of:

accessing a defect site and

placing a strontium-doped calcium phosphate material within the defect site, wherein the strontium-doped calcium phosphate material includes from about 0.1 mol % to about 5 mol % strontium.