Multi-phase bioerodible implant/carrier and method of manufacturing and using same

• US 5,607,474 A
• Filed: 09/20/1993
• Issued: 03/04/1997
• Est. Priority Date: 02/14/1992
• Status: Expired due to Term

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Athanasiou, Kyriacos A., Boyan, Barbara D.
• Primary Examiner(s): ISABELLA, DAVID J
• Application Number:
  US08/123,812
• Time in Patent Office: 1,261 Days
• Field of Search: 623/1, 623/2, 623/11, 623/12, 623/16, 623/18, 623/66, 606/151, 606/152, 606/153, 606/154, 606/155, 600/29, 600/30, 600/32
• US Class Current: 623/23.71
• 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 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2002/0086 for preferentially controlling or promoting the growth of specific types of cells or tissues of bone tissue onto implantable joints A61F2002/3093
• CPC Class Codes: A61F 2002/0888 Anchor in or on a blind hole or on the bone surface without formation of a tunnel
• 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 2002/2839 Bone plugs or bone graft dowels
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30032 differing in absorbability or resorbability, i.e. in absorption or resorption time
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/3093 for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2210/0085 hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2230/0069 cylindrical
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: A61F 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2250/003 : differing in adsorbability or resorbability, i.e. in adsorption or resorption time
• CPC Class Codes: A61L 31/14 : Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 31/148 : Materials at least partially resorbable by the body

Abstract

A carrier and method of manufacturing and using the same is provided for receiving supporting replenished tissue growing into a diseased or damaged area within a physiological system. The carrier can be implanted in the interface region between tissue having different mechanical properties to support the growth and regeneration of differing types of tissue within the region. The carrier includes bioerodible polymeric material having differing mechanical properties such as porosity, stiffness and compressibility.

Claims

1. A molded biodegradable polymeric implant comprising:

a first porous layer comprising a first biodegradable polymeric material, the first layer having a predetermined porosity for receiving growth of a first type of tissue during use;

a second porous layer comprising a second biodegradable polymeric material located on top of the first layer and the second layer having a predetermined porosity for receiving growth of a second type of tissue dissimilar from the first type of tissue during use; and

wherein the first and second polymeric materials each have stiffness and compressibility properties corresponding to the first and second types of tissue respectively.

2. The implant as recited in claim 1 wherein at least one of the layers comprises a degradation agent which is adapted to enhance degradation of the polymeric material during use.

3. The implant as recited in claim 1 wherein at least one of the layers comprises a growth factor, a hormone or therapeutic agent to induce, promote or support tissue ingrowth and repair.

4. The implant as recited in claim 2 wherein the degradation agent is incorporated in each of the layers in different amounts in each layer to degrade each polymeric material within different time periods.

5. The implant as recited in claim 1 wherein the first polymeric material has stiffness and compressibility properties substantially comparable to the stiffness and compressibility properties of bone.

6. The implant as recited in claim 1, wherein the second polymeric material has stiffness and compressibility properties substantially comparable to the stiffness and compressibility properties of cartilage.

7. The implant as recited in claim 1 wherein at least one of said polymeric materials comprises a plurality of passages extending into the polymeric material.

12. The implant as recited in claim 2 wherein the degradation agent comprises an enzyme.

13. The implant as recited in claim 1 which is substantially cylinder-shaped.

15. The implant as recited in claim 7 wherein the passages have a diameter of about 1.5 mm.

17. The implant of claim 1 wherein the pores have a size of about 50-200 micrometers.

19. The implant as recited in claim 1 wherein the porosity of each layer is more than 50% of the volume thereof.

8. An implantable molded, biodegradable polymeric tissue support system comprising a two-phase structure comprising a first and second directly adjacent phase:

wherein the first phase comprises a first porous biodegradable polymeric material, the first phase having a predetermined porosity; and

the second phase comprises a second porous biodegradable polymeric material, the second phase having a predetermined porosity; and

wherein the first material and the second material are adapted to be implanted during use into a physiological system at the interface region between a first type of tissue and a second type of tissue, wherein the first and second types of tissue have dissimilar stiffness and compressibility properties, the first and second polymeric materials have dissimilar stiffness and compressibility properties, and the first and second polymeric materials have stiffness and compressibility properties corresponding to the stiffness and compressibility properties of the first and second types of tissue respectively.

9. The system as recited in claim 8 wherein the first phase has stiffness and compressibility properties substantially comparable to the stiffness and compressibility properties of bone.

10. The system as recited in claim 8 wherein the second phase has stiffness and compressibility properties substantially comparable to the stiffness and compressibility properties of cartilage.

11. The system as recited in claim 8 comprising access sites for tissue ingrowth within at least one of the materials comprising passages extending into the material.

14. The system of claim 8 wherein the system is substantially cylinder-shaped.

16. The system as recited in claim 11 wherein the passages have a diameter of about 1.5 mm.

18. The system of claim 8 wherein the pores have a size of about 50-200 micrometers.

20. The system as recited in claim 8 wherein the porosity of each phase is more than 50% of the volume thereof.