PROCESS FOR PRODUCTION OF POROUS BODY AND USES THEREOF

• US 20090319016A1
• Filed: 03/24/2008
• Published: 12/24/2009
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: JMS Company Limited
• Original Assignee: JMS Company Limited
• Inventors: Sajiki, Toshinobu, Hirai, Satoshi
• Granted Patent: US 8,293,046 B2
• Time in Patent Office: Days
• US Class Current: 623/1.100
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08J 2201/052 Inducing phase separation by thermal treatment, e.g. cooling a solution
• CPC Class Codes: C08J 2367/04 Polyesters derived from hydroxy carboxylic acids, e.g. lactones C08J2367/06 takes precedence
• CPC Class Codes: C08J 2467/00 Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
• CPC Class Codes: C08J 9/0061 characterized by the use of several polymeric components
• CPC Class Codes: C08J 9/28 by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum

Abstract

A process for producing a porous body with different physical properties in desired regions is provided by pore forming treatment, not by bonding two or more materials made porous beforehand, with, for example, an adhesive. Raw materials are prepared, each of which contains a polymer and a raw material preparation solvent. At least two types of the raw materials having different compositions are prepared. Thereafter, the respective raw materials are frozen into desired shapes to form frozen bodies thereof. The frozen bodies thus formed are brought into contact with each other to form an assembly thereof, the assembly is exposed to a condition under which the frozen bodies begin to melt, and the assembly is then freeze-dried. Thus, a porous body having regions different in physical properties can be obtained. Such a porous body can be used as, for example, an adhesion inhibitory material or a scaffold for a cell culture.

Claims

1. A process for producing a porous body with different physical properties in desired regions,

wherein the process comprises the following processes (A) to (D):

(A) providing at least two raw materials having different compositions, each of which contains a polymer and a solvent,

(B) freezing the respective raw materials into desired shapes to form frozen bodies of the respective raw materials,

(C) forming an assembly of the frozen bodies, where at least one of the following processes (C1) and (C2) is included,

(C1) forming the assembly of the frozen bodies and then exposing the assembly to a condition under which the frozen bodies begin to melt, and

(C2) exposing the respective frozen bodies to a condition under which the frozen bodies begin to melt and then forming the assembly of the frozen bodies, and

(D) freeze-drying the assembly after the process (C) to form a porous body.

2. The process according to claim 1, wherein the porous body to be formed is a porous body with physical properties varying in its thickness direction, and in the process (C), the frozen bodies are laminated together to form a laminate of the frozen bodies.

3. The process according to claim 1, wherein the physical properties are at least one selected from the group consisting of an average pore size, porosity, strength, thickness, material permeability, and adhesiveness.

4. The process according to claim 1, wherein in the process (B), the respective raw materials are frozen under a temperature condition that is equal to or lower than eutectic points thereof

5. The process according to claim 1, wherein in the process (B), the respective raw materials are frozen at lower than 0°

C.

6. The process according to claim 1, wherein in the process (C1), the assembly is exposed to a temperature condition that is at least the highest melting point among those of the respective frozen bodies that form the assembly.

7. The process according to claim 1, wherein the assembly in the process (C1) or the frozen bodies in the process (C2) are exposed to a temperature condition between 0°

C. and 25°

C.

8. The process according to claim 6, wherein in the process (C1) or (C2), a treatment time under the condition is at least 30 seconds.

9. The process according to claim 1, wherein the polymer is a lactide-caprolactone copolymer.

10. The process according to claim 9, wherein in the lactide-caprolactone copolymer, the molar ratio between lactide and caprolactone is in a range of 90:

10 to 10;

90.

11. The process according to claim 1, wherein the solvent is at least one of a solvent having solubility to the polymer and a mixed solvent containing a solvent having solubility to the polymer and a solvent having insolubility to the polymer.

12. The process according to claim 1, wherein at least one raw material used in the process (A) is a solution containing the polymer dissolved in the solvent.

13. The process according to claim 12, wherein the ratio of the polymer to be added in the solution is 0.1 to 24 wt %.

14. The process according to claim 1, wherein at least one raw material used in the process (A) is a solution containing a lactide-caprolactone copolymer dissolved in the solvent,

the solvent contains a solvent having solubility to the copolymer, and

the ratio of the solvent having solubility to the copolymer exceeds 84.48 wt % in 100 wt % of the raw material.

15. The process according to claim 14, wherein the solvent is a mixed solvent containing a solvent having solubility to the copolymer and a solvent having insolubility to the copolymer, and

the ratio of the solvent having insolubility is lower than 12 wt % in 100 wt % of the raw material.

16. The process according to claim 1, wherein at least one raw material used in the process (A) is a gelled product of the polymer gelled with the solvent.

17. The process according to claim 16, wherein in the process (A), the gelled product is prepared by the following processes (A1) to (A3):

(A1) mixing the polymer and the solvent to prepare a mixture,

(A2) allowing the mixture to stand to separate it into a liquid phase and a gel phase, and

(A3) recovering the gel phase as the gelled product.

18. The process according to claim 17, wherein the ratio of the polymer is 0.1 to 24 wt % in 100 wt % of the mixture obtained in the process (A1).

19. The process according to claim 17, wherein the polymer used in the process (A1) is a lactide-caprolactone copolymer,

the solvent is a mixed solvent containing a solvent having solubility to the copolymer and a solvent having insolubility to the copolymer, and

the ratio of the solvent having insolubility is 12 to 40 wt % in 100 wt % of the mixture obtained in the process (A1).

20. The process according to claim 11, wherein the solvent having solubility to the polymer is at least one selected from the group consisting of 1,4-dioxane, dimethyl carbonate, chloroform, and acetone.

21. The process according to claim 11, wherein the solvent having insolubility to the polymer is at least one solvent selected from the group consisting of water, ethanol, tertiary butyl alcohol, and hexane.

22. A porous body obtained by a process according to claim 1.

23. A biomaterial comprising a porous body according to claim 22.

24. The biomaterial according to claim 23, wherein the biomaterial is an adhesion inhibitory material, scaffold, artificial blood vessel, artificial trachea, or drug delivery system material.