Polymer-bioceramic composite for orthopaedic applications and method of manufacture thereof

• US 20040002770A1
• Filed: 06/02/2003
• Published: 01/01/2004
• Est. Priority Date: 06/28/2002
• Status: Abandoned Application

• Current Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Original Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Inventors: Smith, Todd S., King, Richard S.
• Application Number:
  US10/449,058
• Publication Number:
  US 20040002770A1
• Time in Patent Office: Days
• US Class Current: 623/23.51
• 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 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• 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 2300/252 Polypeptides, proteins, e.g. glycoproteins, lipoproteins, cytokines
• CPC Class Codes: A61L 2300/414 Growth factors
• CPC Class Codes: A61L 2300/43 Hormones, e.g. dexamethasone
• CPC Class Codes: A61L 2300/602 Type of release, e.g. controlled, sustained, slow
• CPC Class Codes: A61L 2300/64 Animal cells
• 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 27/46 with phosphorus-containing inorganic fillers
• CPC Class Codes: A61L 27/54 Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body

Abstract

Polymer-bioceramic structures are described for use in the repair of bone defects. The composites of the present disclosure are characterized by a polymer disposed in a porous bioceramic matrix. Processes for preparing the composites of the present invention by compression molding are described, including compression molding to induce orientation of the polymer is multiple directions. The composites of the present invention are also useful as drug delivery vehicles to facilitate the repair of bone defects.

Claims

1. A bioresorbable implantable bone repair structure, the structure comprising:

a porous ceramic matrix having a plurality of pores, and

a polymer molded into the plurality of pores of the porous ceramic matrix.

2. The structure of claim 1, wherein the polymer is compression molded into the plurality of pores of the porous ceramic matrix.

3. The structure of claim 1, wherein the polymer is transfer molded into the plurality of pores of the porous ceramic matrix.

4. The structure of claim 1, wherein the polymer is squeeze-flow compression molded into the plurality of pores of the porous ceramic matrix.

5. The structure of claim 1, wherein the polymer is oriented in multiple directions in the plurality of pores of the porous ceramic matrix.

6. The structure of claim 1, wherein a number of the plurality of pores are interconnecting.

7. The structure of claim 1, wherein the plurality of pores form an open-cell configuration.

8. The structure of claim 1, wherein the plurality of pores of the pores open onto a substantial number of the exterior surfaces of the ceramic matrix.

9. The structure of claim 1, wherein the plurality of pores comprises macropores.

10. The structure of claim 1, wherein the plurality of pores comprises micropores.

11. The structure of claim 1, wherein each of the plurality of pores has a diameter in the range from about 1 to about 1000 micrometers.

12. The structure of claim 1, wherein each of the plurality of pores has a diameter in the range from about 100 to about 1000 micrometers.

13. The structure of claim 1, wherein the porous ceramic matrix comprises a bioresorbable substance selected from the group consisting of hydroxyapatite, beta-tricalcium phosphate, calcium sulfate, and calcium carbonate.

14. The structure of claim 1, wherein the polymer is a water soluble polymer or a hydrophilic polymer.

15. The structure of claim 1, wherein the polymer is selected from the group consisting of poly(ethylene oxide), poly(N-vinylpyrrolidinone), poly(vinylalcohol), poly(lactic acid), poly(L-lactic acid), poly(glycolic acid), polycaprolactone, poly(hydroxycaproic acid), polydioxanone, bioresorbable polycarbonate, poly(trimethylene carbonate), polypeptides, (ethylene oxide-propylene oxide) block copolymers, and copolymers thereof, and collagen and gelatin.

16. The structure of claim 1, wherein the polymer is a polypeptide containing tyrosine, lysine, arginine, glutamine, glutamic acid, or a combination thereof.

17. The structure of claim 1, further comprising a drug.

18. The structure of claim 17, wherein the drug is incorporated in the polymer.

19. The structure of claim 17, wherein the drug is present at a higher concentration at the perimeter of the structure than in the interior of the structure.

20. The structure of claim 19, wherein the drug is present in the structure as a concentration gradient, the gradient increasing from the interior of the structure to the perimeter of the structure.

21. The structure of claim 17, wherein the drug comprises an osteogenic agent.

22. The structure of claim 17, wherein the drug is a protein, protein fragment, or peptide.

23. The structure of claim 22, wherein the protein is selected from the group consisting of bone morphogenetic proteins, parathyroid hormone, and growth factors.

24. The structure of claim 17, wherein the drug is a peptide fragment of a bone morphogenetic protein.

25. The structure of claim 17, wherein the drug comprises an osteogenic agent, and an additional ingredient, where said additional ingredient is capable of enhancing the efficacy of the drug.

26. The structure of claim 25, wherein the additional ingredient is selected from the group consisting of antibiotics, anti-inflammatory agents, and analgesics.

27. The structure of claim 1, further comprising a population of cells.

28. A process for fabricating a bioresorbable implantable bone repair structure, the process comprising the step of:

molding a polymer into a plurality of pores of a porous ceramic matrix.

29. The process of claim 28, wherein the molding step comprises compression molding the polymer into the plurality of pores of the porous ceramic matrix.

30. The process of claim 28, wherein the molding step comprises transfer molding the polymer into the plurality of pores of the porous ceramic matrix.

31. The process of claim 28, wherein the molding step comprises squeeze-flow compression molding the polymer into the plurality of pores of the porous ceramic matrix.

32. The process of claim 28, wherein the molding step comprises:

positioning a polymer block and the porous ceramic matrix in a mold, and

compression molding the polymer block and the porous ceramic matrix.

33. The process of claim 28, wherein the molding step comprises compression molding a polymer block in a molten state.

34. The process of claim 28, wherein the molding step comprises inducing an orientation in the polymer within at least a portion of the plurality of pores of the porous ceramic matrix.

35. The process of claim 28, wherein the ceramic matrix comprises a bioresorbable substance selected from the group consisting of hydroxyapatite, betatricalcium phosphate, calcium sulfate, and calcium carbonate.

36. The process of claim 28, wherein the polymer is selected from the group consisting of poly(ethylene oxide), poly(N-vinylpyrrolidinone), poly(vinylalcohol), poly(lactic acid), poly(L-lactic acid), poly(glycolic acid), polycaprolactone, poly(hydroxycaproic acid), polydioxanone, bioresorbable polycarbonate, poly(trimethylene carbonate), polypeptides, (ethylene oxide-propylene oxide) block copolymers, and copolymers thereof, and collagen and gelatin.

37. The process of claim 28, wherein the polymer comprises a drug.

38. The process of claim 28, wherein the polymer comprises an osteogenic agent.

39. A process for fabricating a bioresorbable implantable bone repair structure, the process comprising the steps of:

disposing a polymer precursor into a plurality of pores of a porous ceramic matrix, and

polymerizing the polymer precursor in the plurality of pores of the porous ceramic matrix.

40. A method for repairing a bone defect comprising the step of:

implanting a bioresorbable implantable bone repair structure in contact with the defect, wherein the structure comprises a porous ceramic matrix having a polymer molded therein.

41. A method for delivering a drug to a bone defect comprising the step of:

implanting a bioresorbable implantable bone repair structure in contact with the defect, said structure comprising (i) a porous ceramic matrix, (ii) a polymer molded into the porous ceramic matrix, and a drug.

42. The method of claim 41, further comprising the step of releasing the drug from the structure.

43. The method of claim 42, wherein the releasing step includes releasing the drug by bioresorption of the structure.