Channeled biomedical foams an method for producing same

• US 7,674,408 B2
• Filed: 09/19/2005
• Issued: 03/09/2010
• Est. Priority Date: 03/25/2002
• Status: Active Grant

• Current Assignee: Endo-Surgery, Inc.
• Original Assignee: Ethicon Incorporated (Johnson & Johnson)
• Inventors: Chun, Iksoo, Brown, Kelly R., Melican, Mora C.
• Primary Examiner(s): Del Sole; Joseph S.
• Assistant Examiner(s): KENNEDY, TIMOTHY J
• Application Number:
  US11/230,220
• Publication Number:
  US 20060069435A1
• Time in Patent Office: 1,632 Days
• Field of Search: 264/28, 264/41, 264/101, 264/49, 264/237, 264/348, 424/426, 424/486, 521/61, 521/63
• US Class Current: 264/49
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• 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 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2002/2817 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 2002/30199 Three-dimensional shapes
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30762 Means for culturing cartilage
• CPC Class Codes: A61F 2002/30766 Scaffolds for cartilage ingrowth and regeneration
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3093 for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/4648 Means for culturing bone graft
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2230/0063 Three-dimensional shapes
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 31/06 : obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/146 : Porous materials, e.g. foams or sponges
• CPC Class Codes: C08L 67/04 : Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

The present invention provides a biomedical, biocompatible, polymeric foam scaffold suitable for use in the repair and regeneration of tissue and which contains located therein a network of, branched channels that are effective to encourage and facilitate vascularization and tissue growth within the scaffold and to methods for making such biomedical scaffolds.

Claims

1. A process for making biomedical, biocompatible scaffolds suitable for use in the repair and regeneration of tissue, comprising:

preparing a homogenous mixture comprising a synthetic, biocompatible polymer, a solvent in which said polymer is soluble, and a non-solvent in which said polymer is not soluble, wherein said solvent and said non-solvent are miscible, and wherein the freezing point of said non-solvent is higher than the freezing point of said solvent,

placing said homogenous mixture in a mold or other device suitable for preparing foam scaffolds suitable for use in repair and regeneration of tissue,

cooling said homogenous mixture to a first temperature effective to freeze said non-solvent;

maintaining said first temperature for a sufficient period of time effective to allow phase separation of said non-solvent from said homogenous mixture and to generate dendritic crystals;

cooling said homogenous mixture to a second temperature sufficient to form a solid; and

,

removing said solvent and said non-solvent from said solid to provide a biocompatible, porous foam scaffold which comprises a network of branched channels.

2. The process of claim 1 wherein said polymer is bioabsorbable.

3. The process of claim 2 wherein said bioabsorbable polymer is selected from the group consisting of aliphatic polyesters, poly(amino acids), polyalkylenes oxalates, polyamides, tyrosine derived polycarbonates, polyorthoesters, polyoxaesters and poly(anhydrides).

4. The process of claim 3 wherein said polymer comprises an aliphatic polyester selected from the group consisting of homopolymers and copolymers of lactide, lactic acid, glycolide, glycolic acid, ε

-caprolactone, p-dioxanone, trimethylene carbonate, alkyl derivatives of trimethylene carbonate, δ

-valerolactone, β

-butyrolactone, γ

-butyrolactone, ε

-decalactone, hydroxybutyrate, hydroxyvalerate, 1,4-dioxepan-2-one, 1,5,8,12-tetraoxacyclotetradecane-, 14-dione, 1,5-dioxepan-2-one, and 6,6-dimethyl-1,4-dioxan-2-one.

5. The process of claim 4 wherein said aliphatic polyester comprises an elastomer selected from the group consisting of copolymers of lactide and ε

-caprolactone, lactide and glycolide, and blends thereof.

6. The process of claim 5 wherein said copolymer of lactide and ε

-caprolactone comprises a mole ratio of lactide to ε

-caprolactone from about 30/70 to about 50/50.

7. The process of claim 5 wherein said copolymer of lactide and glycolide comprises a mole ratio of lactide to glycolide from about 75/25 to about 95/5.

8. The process of claim 3 wherein said solvent is selected from the group consisting of dimethyl carbonate, 1,4-dioxane and diethyl carbonate.

9. The process of claim 8 wherein said non-solvent is selected from the group consisting of t-butanol, tert-amyl alcohol, 3,3 dimethyl-2 butanol, octanol, nonanol, decanol, n-decanol and dodecanol.