Resorbable bone implant material and method for producing the same

• US 6,689,375 B1
• Filed: 06/05/2002
• Issued: 02/10/2004
• Est. Priority Date: 11/09/1999
• Status: Active Grant

• Current Assignee: Osartis GmbH
• Original Assignee: Coripharm Medizinprodukte Gmbh & Co. KG
• Inventors: Sattig, Christoph, Wahlig, Helmut, Dingeldein, Elvira, Wüst, Edgar
• Primary Examiner(s): Page, Thurman X.
• Assistant Examiner(s): YOUNG, MICAH PAUL
• Application Number:
  US10/129,753
• Time in Patent Office: 615 Days
• Field of Search: 623/19, 623/17, 623/12, 424/426, 424/423, 523/212, 501/1
• US Class Current: 424/426
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61L 24/0042 Materials resorbable by the body
• CPC Class Codes: A61L 24/0063 Phosphorus containing materials, e.g. apatite
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 27/425 of phosphorus containing material, e.g. apatite
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body

Abstract

The powdery component of the implant material consists essentially of a mixture of hydroxyl apatite powder and calcium sulfate powder, wherein the hydroxyl apatite powder consists of synthetically prepared, precipitated crystalline nanoparticles of high purity, which have a crystal size of 10-20 nm width and 50-60 nm length.

The specific absorbing BET surface area of the nanocrystals is preferably 100-150 m²/g.

Claims

1. Resorbable bone implant material prepared from a powdery component containing hydroxyl apatite and from a liquid, wherein the powdery component consists essentially of a mixture of hydroxyl apatite powder and calcium sulfate powder wherein the BET surface area ratio of the mixture of apatite nanoparticles and calcium sulfate particles is approximately 150 m²/g:

2 m²/g, and that the hydroxyl apatite powder consists of synthetically produced, precipitated crystalline nanoparticles of high purity, which have a crystal size of 10-20 nm width and 50-60 nm length.

2. Implant material according to claim 1, wherein the specific absorbing BET surface area of the nanocrystals is 100-150 m²/g.

3. Implant material according to claim 1, wherein the calcium sulfate powder consists of a synthetically prepared alpha-subhydrate of high purity (bassanite) with n*H₂O (wherein n<

1 and approximately 0.5).

4. Implant material according to claim 3, wherein the specific absorbing BET surface area of the calcium sulfate particles is 1.8-2.7m²/g, preferably 2.0-2.3 m²/g.

5. Implant material according to claim 3, wherein the calcium sulfate powder contains an additional fraction of 2-15 wt. %, preferably 5-10 wt. %, calcium oxide.

6. Implant material according to claim 1, wherein the fraction of hydroxyl apatite powder in the powdery components is 85-55 wt. %, preferably 80-70 wt. %.

7. Implant material according to claim 1, wherein the powdery components is sterilized by β

or γ

radiation before its preparation.

8. Implant material according to claim 7, wherein the sterile powdery component is prepared with sterile water into an initially viscous and subsequently solidifying mass.

9. Implant material according to claim 8, wherein the fraction of the sterile water during preparation of the viscous mass is 100-200 wt. %, based on the weight of the powdery components.

10. Implant material according to claim 8, wherein the viscous mass has a slightly alkaline pH value in the range of pH 7.5-8.2.

11. Implant material according to claim 8, wherein the mass after preparation has a viscous plastic consistency.

12. Implant material according to claim 1, wherein the implant material is present in the form of granules having different grain sizes or in the form of form body, in particular spheres, cylinders, prisms or cuboids having different dimensions.

13. Implant material according to claim 12, wherein the powdery components are prepared with 100-200 wt. % distilled water, based on the weight of the powdery components, and solidified in molds.

14. Implant material according to claim 13, wherein the material that solidified in the molds is comminuted into a granular consistency.

15. Implant material according to claim 12, wherein the implant material is adjusted to a standardized reproducible water retention capacity.

16. Implant material according to claim 12, wherein the form body, after hardening, are sterilized by irradiation with β

and γ

rays or by gassing with ethylene oxide, and are packaged in sterile form.

17. Implant material according to claim 12, wherein the form body are impregnated before application with sterile pharmaceutical solutions containing active ingredients.

18. Implant material according to claim 17, wherein antibiotics or growth factors prepared a liquid form are provided as solutions containing active ingredients.

19. Implant material according to claim 17, wherein the form body are impregnated with a combination of two or more different solutions containing active ingredients.

20. Method for preparing a bone implant material from a powdery component containing hydroxyl apatite with water, wherein the powdery component is prepared by mixing of 85-55 wt. % hydroxyl apatite powder of synthetically produced precipitated nanoparticles of high-purity hydroxyl apatite having a crystal size of 10-20 nm width and 50-60 nm length with 15-45 wt. % calcium sulfate powder in form of a high-purity α

-subhydrate with n*H₂O (wherein n<

1 and approximately 0.5), and the produced powder mixture is prepared with a fraction of 100-200 wt. % sterile water into an initially viscous mass, which subsequently solidifies to form a body.

21. Method according to claim 20, wherein 5-10 wt. % calcium oxide powder is added to the calcium sulfate powder before or during mixing with the hydroxyl apatite powder.

22. Method according to claim 20, wherein the powdery component is sterilized before its preparation by irradiation with β

or γ

rays.

23. Method according to claim 20, wherein the initially prepared viscous mass is introduced into molds, solidified therein and removed from the molds as pellet-like form body.

24. Method according to claim 23, wherein the form body are sterilized by irradiation with β

or γ

rays or by gassing with ethylene oxide and subsequently packaged in sterile form.

25. Method according to claim 23, wherein the sterile form body are impregnated before the application with a pharmaceutical solution containing active ingredients.

26. Method according to claim 23, wherein the sterile form body are impregnated before the application with a combination consisting of two or more pharmaceutical solutions containing different active ingredients.