Process for the preparation of hard tissue prosthetics

• US 4,661,536 A
• Filed: 10/02/1986
• Issued: 04/28/1987
• Est. Priority Date: 02/19/1985
• Status: Expired due to Fees

• Current Assignee: The Dow Chemical Company (Dow, Inc.)
• Original Assignee: The Dow Chemical Company (Dow, Inc.)
• Inventors: Meyers, Paul A., Dorman, Linneaus C.
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US06/914,687
• Time in Patent Office: 208 Days
• Field of Search: 524/414, 524/417, 523/113, 523/114, 523/115, 3/1.9
• US Class Current: 523/113
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61L 27/46 with phosphorus-containing inorganic fillers
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08G 69/10 Alpha-amino-carboxylic acids polysuccinimides C08G73/1092
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: C08L 77/04 Polyamides derived from alpha-amino carboxylic acids C08L77/10 takes precedence

Abstract

An in situ polymerization process is disclosed whereby an α-amino acid N-carboxyanhydride is blended intimately and efficiently with one or more calcium phosphate biomaterials. The polymerization proceeds at ambient temperature and pressure without the need for initiators or surface modification of the calcium phosphate biomaterials. The resulting composite material may subsequently be ground and blended with a compatible water soluble pore-forming agent and then molded to form dense, shaped objects which may be made porous by leaching out said water soluble pore-forming agent. The resulting shaped objects may then be used as hard tissue prosthetics either alone or in conjunction with conventional prostheses.

Claims

1. A process for the preparation of a composite material containing from about 25 to about 75 percent by weight of a calcium phosphate biomaterial and about 75 to about 25 percent by weight of an α

-amino acid polymer which comprises polymerizing in situ an N-carboxyanhydride of an α

-amino acid in the presence of a powdered calcium phosphate biomaterial, said polymerization taking place in an inert organic solvent.

3. The process of claim 1 wherein said N-carboxyanhydride is glutamic acid N-carboxyanhydride and said calcium phosphate biomaterial is hydroxyapatite, tricalcium phosphate, or mixtures thereof.

5. The process of claim 3 wherein said glutamic acid N-carboxyanhydride has a γ

-ester residue.

7. The process of claim 5 wherein said γ

-ester residue is a methyl or benzyl ester of glutamic acid.

9. The process of claim 1 carried out at ambient temperature and pressure.

11. The process of claim 1 wherein said inert organic solvent is selected from the group consisting of chloroform, dioxane, tetrahydrofuran, methylene chloride, and mixtures thereof.

2. A process for the preparation of a composite material containing from about 40 to about 60 percent by weight of a calcium phosphate biomaterial and from about 60 to about 40 percent by weight of an α

-amino acid polymer which comprises polymerizing in situ an N-carboxyanhydride of an α

-amino acid in the presence of a powdered calcium phosphate biomaterial, said polymerization taking place in an inert organic solvent.

4. The process of claim 2 wherein said N-carboxyanhydride is glutamic acid N-carboxyanhydride and said calcium phosphate biomaterial is hydroxyapatite, tricalcium phosphate, or mixtures thereof.

6. The process of claim 4 wherein said glutamic acid N-carboxyanhydride has a γ

-ester residue.

8. The process of claim 6 wherein said γ

-ester residue is a methyl or benzyl ester of glutamic acid.

10. The process of claim 2 carried out at ambient temperature and pressure.

12. The process of claim 2 wherein said inert organic solvent is selected from the group consisting of chloroform, dioxane, tetrahydrofuran, methylene chloride, and mixtures thereof.