Material and process for its preparation

• US 5,993,716 A
• Filed: 12/12/1997
• Issued: 11/30/1999
• Est. Priority Date: 10/19/1990
• Status: Expired due to Fees

• Current Assignee: Thurgauer Kantonalbank
• Original Assignee: Klaus Draenert
• Inventors: Draenert, Klaus
• Primary Examiner(s): Watkins, III, William P.
• Application Number:
  US08/990,058
• Time in Patent Office: 718 Days
• Field of Search: 428/131, 428/304.4, 428/312.2, 428/313.3, 428/338, 428/323, 623/16, 623/901, 424/423, 264/49, 264/317, 264/DIG. 44, 264/220, 264/221, 264/222, 264/223, 264/224, 264/225, 264/227, 264/226, 264/219
• US Class Current: 264/221
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: B01D 67/0058 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/1112 comprising hollow spheres or hollow fibres
• CPC Class Codes: B22F 3/1134 Inorganic fillers carbonaceous or paper filler B22F3/1121
• CPC Class Codes: B22F 3/1137 by coating porous removable preforms
• CPC Class Codes: B22F 3/15 Hot isostatic pressing
• CPC Class Codes: B22F 3/22 for producing castings from a slip
• CPC Class Codes: B29C 67/202 comprising elimination of a solid or a liquid ingredient
• CPC Class Codes: C22C 1/081 Casting porous metals into porous preform skeleton without foaming
• CPC Class Codes: Y10S 264/44 using destructible molds or cores in molding processes
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device
• CPC Class Codes: Y10T 428/24273 including aperture
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249967 Inorganic matrix in void-containing component
• CPC Class Codes: Y10T 428/249971 Preformed hollow element-containing
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/268 Monolayer with structurally defined element

Abstract

The invention relates to a material of a three-dimensional framework of supporting, trabecular structures encompassing cavities which are connected with one another and which can be predeterminedly adjusted. The material is obtainable by forming the framework around the shaped bodies serving as space retainers for the cavities and subsequently removing the shaped bodies. The material according to the invention can be used for example as a implant or as a filter.

Claims

1. A process for preparing a homogenous material, said process comprising the steps of:

connecting essentially spherical-shaped bodies at their points of contact to form a three-dimensional shaped body conglomerate;

forming a three-dimensional framework by casting or injecting a generally incompressible liquid material different from the shaped bodies around said connected shaped bodies, the material of the framework being selected from a group consisting of polymers, ceramics and metals;

compressing the three-dimensional framework together with the shaped bodies; and

after at least partial hardening of the three-dimensional framework, removing the connected shaped bodies so that merely the polymer, ceramic or metallic three-dimensional framework remains in the form of the homogenous material.

2. The process according to claim 1, wherein the shaped bodies are chemically or physically bonded to one another.

3. The process according to claim 1, wherein the shaped bodies are washed out of the framework with a liquid after the framework is formed.

4. The process according to claim 1, wherein the shaped bodies are connected to one another by sintering techniques.

5. The process according to claim 1, wherein the three-dimensional framework consists of metal and the shaped bodies consist of ceramic.

11. The process according to claim 1, wherein the three-dimensional framework is selected from a group consisting of an acrylate based polymer, a polymethacrylate based polymer, a copolymer of an acrylate and methacrylate, and of a mixture of an acrylate based polymer, a polymethacrylate polymer and a copolymer of acrylate and methacrylate.

12. The process according to claim 1, wherein the three-dimensional framework is a material which is soluble or absorbable in the body.

13. The process according to claim 1, wherein the three-dimensional framework is selected from a group consisting of a silicone and a caoutchouc derivative.

16. The process according to claim 1, wherein the shaped bodies consist of a ceramic material selected from a group consisting of tricalcium phosphate, a hydroxylapatite, a mixture of tricalcium phosphate and a hydroxylapatite.

17. The process according to claim 1, wherein the shaped bodies are between 0.2 mm and 5 mm in size.

18. The process according to claim 1, wherein a mixture of shaped bodies of varying size is used.

19. The process according to claim 1, wherein the framework further includes 0.01 to 10% of an active substance which is protractedly releasable from the material.

20. The process according to claim 19, wherein the active substance is selected from a group consisting of gentamicin, clindamicin, a gyrase inhibitor, and a combination of two or more different antibiotics.

21. The process according to claim 19, wherein the active substance is a bone growth inducing active substance which induces ingrowth of human or animal vessels or directly stimulates the osteoblasts of a bone.

22. The process according to claim 1, wherein the material of the framework additionally comprises a filler.

23. The process according to claim 22, wherein the filler consists of filler particles with a particle size of 50 to 300 mm and a pore volume of 0.1 ml/g to 0.8 ml/g, and wherein 1 to 95% of the filler particles are selected from a group consisting of tricalcium phosphate, hydroxylapatite, and a mixture of tricalcium phosphate and hydroxylapatite.

24. The process according to claim 22, wherein the filler is selected from a group consisting of a gas-absorbing material, a liquid-absorbing material and a combination of a gas-absorbing material and a liquid-absorbing material.

25. The process according to claim 24, wherein the filler has a concentration of between 5 and 80% by weight.

27. The process according to claim 1, further comprising shaping the three-dimensional framework in the form of an implant.

28. The process according to claim 1, further comprising shaping the three-dimensional framework in the form of a plug or medullary stopper.

29. The process according to claim 1, further comprising shaping the three-dimensional framework in the form of a filter.

30. The process of claim 1, wherein the shaped bodies are water-soluble, and wherein the shaped bodies are connected by vacuum pressing steam through the shaped bodies.

31. The process of claim 1, wherein the compression step is performed by high isostatic pressing.

32. The process according to claim 1, wherein the material of the framework is acrylate, and wherein the shaped bodies are sugar.

6. A process for preparing a material comprising the steps of:

forming a three-dimensional packing or a conglomerate of water-soluble shaped bodies which are connected to one another;

forming a three-dimensional framework of a liquid wax or a liquid polymer around the connected water-soluble shaped bodies;

compressing the three-dimensional framework together with the shaped bodies;

curing the framework of the wax or the liquid polymer into a solid;

removing the water-soluble shaped bodies to form a continuous cavity system having pore sizes between 0.2 and 5 mm;

filling the pores of the continuous cavity system with a ceramic mass; and

removing the framework of the wax or the polymer by applying heat.

7. The process according to claim 6, wherein the pore sizes are less than 3 mm.

8. The process according to claim 6, wherein ceramic spheres are formed in the pores of the cavity system.

9. The process according to claim 8, wherein the ceramic spheres are formed by applying heat or are welded together by sintering techniques to form solid bodies of spherical conglomerates.

10. The process according to claim 6 wherein the shaped bodies are chemically or physically connected to each other and are removed chemically or physically after the framework has been formed.

14. The process according to claim 6, wherein the material of the three-dimensional framework is cast around the connected shaped bodies.

15. The process according to claim 6, wherein the shaped bodies are of sugar, and are connected together by vacuum pressing steam through the shaped bodies.

26. A material prepared by the process of claim 6.