Preparation of cell seeded ceramic compositions

• US 6,139,578 A
• Filed: 02/13/1998
• Issued: 10/31/2000
• Est. Priority Date: 05/19/1995
• Status: Expired due to Term

• Current Assignee: Life Science Enterprises , INC.
• Original Assignee: Etex Corporation (Zimmer Biomet Holdings, Inc.)
• Inventors: Rey, Christian, Aiolova, Maria, Lee, Dosuk D.
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US09/023,344
• Time in Patent Office: 991 Days
• Field of Search: 623/23.61, 623/23.62, 623/23.63, 623/16.11, 424/423, 424/602, 424/440, 423/305, 423/308, 423/311
• US Class Current: 623/16.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30762 Means for culturing cartilage
• CPC Class Codes: A61F 2002/4648 Means for culturing bone graft
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61K 9/2009 Inorganic compounds
• CPC Class Codes: A61L 2300/252 Polypeptides, proteins, e.g. glycoproteins, lipoproteins, cytokines
• CPC Class Codes: A61L 2300/414 Growth factors
• CPC Class Codes: A61L 2300/426 Immunomodulating agents, i.e. cytokines, interleukins, interferons
• CPC Class Codes: A61L 2300/64 Animal cells
• CPC Class Codes: A61L 24/02 containing inorganic materials
• CPC Class Codes: A61L 2400/06 Flowable or injectable implant compositions
• 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 27/3821 Bone-forming cells, e.g. osteoblasts, osteocytes, osteoprogenitor cells
• CPC Class Codes: A61L 27/3847 Bones
• CPC Class Codes: A61L 27/3852 Cartilage, e.g. meniscus
• CPC Class Codes: A61L 27/425 of phosphorus containing material, e.g. apatite
• CPC Class Codes: A61L 27/54 : Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 27/58 : Materials at least partially resorbable by the body
• CPC Class Codes: C01B 25/16 : Oxyacids of phosphorus; Salts thereof peroxyacids or salts thereof C01B15/00
• CPC Class Codes: C01B 25/32 : Phosphates of magnesium, calcium, strontium, or barium
• CPC Class Codes: C01B 25/321 : Methods for converting an alkaline earth metal ortho-phosphate into another ortho-phosphate by reaction, e.g. of phosphate rock with phosphoric acid C01B25/322
• CPC Class Codes: C01B 25/325 : Preparation by double decomposition
• CPC Class Codes: C04B 2111/00836 : for medical or dental applications
• CPC Class Codes: C04B 28/344 : the phosphate binder being present in the starting composition solely as one or more phosphates
• CPC Class Codes: Y10S 623/919 : Bone

Abstract

The present invention provides a synthetic, poorly-crystalline apatitic (PCA) calcium phosphate material seeded with cells. Preferably, the cells are tissue-forming or tissue-degrading cells. The compositions provided by the present invention are useful for a variety of applications, including in vivo and in vitro tissue growth (preferably bone or cartilage), osseous augmentation, and methods of diagnosing disease states by assaying tissue-forming potential of cells isolated from a host. The invention also provides in vitro cell culture systems and cell encapsulation matrices.

Claims

1. A method for preparing a therapeutic, structural or cosmetic implant, comprising:

a. providing a composition in hydrated precursor form, wherein the hydrated precursor is capable of conversion into a hardened poorly crystalline apatitic (PCA) calcium phosphate;

b. promoting conversion of the hydrated precursor so that the composition becomes hardened PCA calcium phosphate; and

c. introducing at least one cell into the composition prior to hardening of the hydrated precursor.

2. The method of claim 1 wherein the step of providing comprises providing a hydrated precursor comprising:

a. an amorphous calcium phosphate (ACP) precursor;

b. a second precursor selected from the group consisting of;

a calcium source, a phosphate source, combinations of calcium and phosphate sources, and calcium phosphates; and

c. a limited amount of an aqueous solution.

3. The method of claim 2 wherein the aqueous solution is a buffered solution selected for compatibility with the at least one cell.

4. The method of claim 2 wherein the cell is selected from the group consisting of chondrocytes, osteocytes, osteoblasts, osteoclasts, mesenchymal stem cells, fibroblasts, muscle cells, hepatocytes, parenchymal cells, cells of intestinal origin, nerve cells, and skin cells.

5. The method of claim 2 wherein the at least one cell comprises at least one tissue-forming cell.

6. The mathod of claim 2 wherein the at least one cell comprises at least one bone-forming cell.

7. The implant of claim 2 wherein the at least one cell comprises at least one cartilage-forming cell.

8. The method of claim 2 wherein the at least one cell comprises a tissue-degrading cell.

9. The method of claim 2 wherein the step of introducing at least one cell comprises introducing a sufficient number of cells so that the PCA calcium phosphate is populated by at least about 20,000-1,000,000 cells/cm³.

10. The method of claim 2, further comprising a step of shaping the hydrated precursor into a pre-determined form prior to hardening.

11. The method of claim 2, further comprising a step of shaping the hardened PCA calcium phosphate into a pre-determined form.

12. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient that a PCA calcium phophate characterized by an X-ray diffraction pattern comprising broad peaks at 2θ

values of 26°

, 28.5°

, 32°

, and 33°

is produced.

13. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient that a PCA calcium phophate characterized by a calcium to phosphate ratio of less than about 1.5 is produced.

14. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient to produce a PCA calcium phophate characterized in that, when a vehicle comprising at least 1 g of PCA calcium phosphate is formed, at least about 80% of the PCA calcium phosphate is resorbed within one year when the vehicle is placed in a rat intramuscular site.

15. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient to produce a PCA calcium phophate characterized in that, when a vehicle comprising at least 1 g of PCA calcium phosphate is formed, at least about 80% of the PCA calcium phosphate is resorbed within 9 months when the vehicle is placed in a rat intramuscular site.

16. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient to produce a PCA calcium phophate characterized in that, when a vehicle comprising at least 1 g of PCA calcium phosphate is formed, at least about 80% of the PCA calcium phosphate is resorbed within 6 months when the vehicle is placed in a rat intramuscular site.

17. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient to produce a PCA calcium phophate characterized in that, when a vehicle comprising at least 1 g of PCA calcium phosphate is formed, at least about 80% of the PCA calcium phosphate is resorbed within 3 months when the vehicle is placed in a rat intramuscular site.

18. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient to produce a PCA calcium phophate characterized in that, when a vehicle comprising at least 1 g of PCA calcium phosphate is formed, at least about 80% of the PCA calcium phosphate is resorbed within 1 month when the vehicle is placed in a rat intramuscular site.

19. The method of claim 1 wherein the step of promoting conversion involves exposing the hydrated precursor to appropriate conditions for a time sufficient to produce a PCA calcium phophate characterized in that it is fully resorbable.

20. The method of claim 2 wherein the step of providing comprises providing a hydrated precursor that is a paste.

21. The method of claim 20 wherein the step of promoting comprises allowing the hydrated precursor to harden at 22°

C. for a time longer than one hour.

22. The method of claim 20 wherein the step of promoting comprises allowing the hydrated precursor to harden at 37°

C. for a time shorter than one hour.

23. The method of claim 22 wherein the step of promoting comprises allowing the hydrated precursor to harden at 37°

C. for about 10-30 minutes.

24. The method of claim 1 or claim 2 further comprising, prior to the step of promoting, a step of combining with the hydrated precursor an addtional material selected to change a physical parameter of the vehicle, which physical parameter is selected from the group consisting of:

strength, resorption time, adherence, injectability, frictional characteristics, and release kinetics.

25. The method of claim 2 further comprising, prior to the step of promoting, a step of combining with the hydrated precursor a biologically active agent.

26. The method of claim 2 wherein the biologically active agent is one that affects a process selected from the group consisting of cell growth, cell migration, cell differentiation, and cell localization.

27. The method of claim 26 wherein the biologically active agent is selected from the group consisting of growth factors and extracellular matrix components.

28. The method of claim 26 werein the biologically active agent is selected from the group consisting of lamin, fibronectin, collagen, and combinations thereof.

29. The method of claim 26 wherein the biologically active agent is selected from the group consisting of nutrients, angiogenic factors, and immunomodulatory factors.

30. A method for preparing a structural implant comprising:

a. providing a composition in hydrated precursor form, wherein the hydrated precursor is capable of conversion into a hardened poorly crystalline apatitic (PCA) calcium phosphate;

b. promoting conversion of the hydrated precursor so that the composition becomes hardened PCA calcium phosphate, said PCA calcium phosphate composition having sufficient tensile strength, hardness and fracture toughness so that said PCA calcium phosphate composition is capable of serving as a structural implant in a living organism; and

c. before or after step b, introducing at least one cell into the composition.