Hydroxylapatite material containing tricalcium phosphate with microporous structure

• US 20020114755A1
• Filed: 04/15/2002
• Published: 08/22/2002
• Est. Priority Date: 11/30/1999
• Status: Active Grant

• Current Assignee: Logon Patentverwertungs-Verwaltungs GmbH
• Original Assignee: Margarita Jordanova-Spassova
• Inventors: Jordanova-Spassova, Margarita
• Granted Patent: US 6,881,227 B2
• Time in Patent Office: Days
• US Class Current: 423/306
• CPC Class Codes: A61L 27/425 of phosphorus containing material, e.g. apatite
• CPC Class Codes: C01B 25/32 Phosphates of magnesium, calcium, strontium, or barium

Abstract

The invention relates to a hydroxylapatite material containing phosphate wherein the microporous structure of algae hard-tissue raw material is retained in the end product and which can be obtained by reacting an organic compound devoid of algae hard-tissue in an alkaline aqueous phosphate solution by adding magnesium ions at an elevated temperature. The invention also relates to a method for the production of said hydroxylapatite material containing tricalcium phosphate, which is characterized in that it is especially well resorbed in the body, is especially suitable as a bone substitute material or as a carrier material for active ingredients. Said material can also be used as a filter material.

Claims

1. A hydroxylapatite material containing tricalcium phosphate, obtainable by converting a hard algae tissue free of organic compounds in an alkaline aqueous phosphate solution with addition of Mg²⁺ ions at increased temperature, wherein the microporous structure of the hard algae tissue starting materials remains intact in the end product, and the material has a tricalcium phosphate content of 50 to 90% by weight.

2. The hydroxylapatite material containing tricalcium phosphate as set forth in claim 1, with a tricalcium phosphate content of 70 to 90% by weight.

3. The hydroxylapatite material containing tricalcium phosphate as set forth in claim 1, wherein said hard algae tissue is obtained from lime-encrusting sea algae and in particular from such species as Amphiroa Ephedra, Corallinacea or Codiacea.

4. The hydroxylapatite material containing tricalcium phosphate as claimed in claim 1, with a content of at least one active ingredient, in particular a growth-promoting or growth-inhibiting compound, an antibiotic, chemotherapeutic, a tumor-inhibiting or bone-inductive compound, in particular at least one bone-morphogenic protein.

5. A process for producing a hydroxylapatite material containing tricalcium phosphate obtainable by converting a hard algae tissue free of organic compounds in an alkaline aqueous phosphate solution with addition of Mg2+ ions at increased temperature, wherein the microporous structure of the hard algae tissue starting materials remains intact in the end product, and the material has a tricalcium phosphate content of 50 to 90% by weight, in said process a hard algae tissue free of organic compounds is converted in an alkaline aqueous phosphate solution with the addition of a water-soluble magnesium salt at increased temperature.

6. The process as claimed in claim 5, wherein magnesium nitrate is used as water-soluble magnesium salt.

7. The process as claimed in claim 5, wherein said magnesium salt is added in such quantity that a content of 50 to 90% by weight tricalcium phosphate is obtained in the end product.

8. The process as claimed in claim 7, wherein said magnesium salt is added in a quantity of 5.5 to 6.0% by weight.

9. The process as claimed in claim 5, wherein (NH₄)₂HPO₄ is used as phosphate.

10. The process as claimed in claim 5, wherein said conversion is carried out at a pH value between 8 and 11 and in particular between 9 and 9.5.

11. The process as claimed in claim 10, wherein the pH value is adjusted with NH₃.

12. The process as claimed in claim 5, wherein the reaction temperature is between 200 and 250°

C., preferably between 230 and 250°

C.

13. The process as claimed in claim 5, wherein the reaction temperature varies between 200 and 240°

C.

14. The process as claimed in claim 13, wherein the reaction temperature is maintained respectively in cycles of ca. 200°

and ca. 240°

C.

15. The process as claimed in claim 14, wherein said cycles are two hours in each case.

16. The process as claimed in claim 5, wherein said conversion is carried out at increased pressure.

17. The process as claimed in claim 16, wherein said conversion takes place in an autoclave coated with polytetrafluorethylene.

18. The process as claimed in claim 17, wherein said autoclave is filled to a maximum two thirds of capacity.