Porous tissue scaffolds for the repair and regeneration of dermal tissue

Abstract

The present invention provides synthetic, biocompatible, bioabsorbable, porous foam tissue scaffolds possessing physicochemical properties suitable for use in the repair and regeneration of dermal tissue and to methods of preparing such foam scaffolds.

We claim:  
     
         1 . A process for making biomedical absorbable foams suitable for use in the repair and regeneration of dermal tissue, comprising: 
 preparing a homogenous solution comprising a synthetic, biocompatible, bioabsorbable, aliphatic, elastomeric copolymer comprising copolymerized ε-caprolactone and glycolide at a molar ratio of ε-caprolactone:glycolide ranging from about 30:70 to about 40:60 and a solvent in which the copolymer is soluble, wherein the homogenous solution comprises about 5 percent by weight of the copolymer and about 95 percent by weight of the solvent,    placing the homogenous solution in a mold or other device suitable for preparing foam tissue scaffolds suitable for use in repair and regeneration of dermal tissue,    quenching the homogenous solution at a temperature and rate of temperature reduction sufficient to provide foam tissue scaffolds suitable for use in repair and regeneration of dermal tissue,    solidifying the solution to form a solid; and    removing the solvent from the solid to provide a biocompatible, bioabsorbable porous foam suitable for use in the repair and regeneration of dermal tissue.    
     
     
         2 . The process of  claim 1  wherein the copolymer comprises copolymerized ε-caprolactone and glycolide at a molar ratio of ε-caprolactone:glycolide of about 35:65.  
     
     
         3 . The process of  claim 1  wherein the solution is quenched by exposing the solution to a temperature of about −17°, whereby the temperature of the solution is reduced at a rate of from about 2° C./min to about 50° C./min.  
     
     
         4 . The process of  claim 2  wherein the solution is quenched by exposing the solution to a temperature of about −17°, whereby the temperature of the solution is reduced at a rate of from about 4° C./min to about 20° C./min.  
     
     
         5 . The process of  claim 1  wherein the solution further comprises a therapeutic agent.  
     
     
         6 . The process of  claim 5  wherein the therapeutic agent is selected from the group consisting of anti-microbial agents, hemostatic agents, cytostatic and cytoxic drugs, anti-infectives, hormones, analgesics, anti-inflammatory agents, oncological pharmaceuticals, peptides, small molecules, growth factors and anti-fungal agents.  
     
     
         7 . A synthetic, biocompatible, bioabsorbable foam scaffold suitable for use in the repair and/or regeneration of dermal tissue: comprising, 
 a synthetic, biocompatible, bioabsorbable, aliphatic, elastomeric copolymer comprising copolymerized ε-caprolactone and glycolide at a molar ratio of ε-caprolactone:glycolide ranging from about 30:70 to about 40:60, wherein said scaffold is about 0.25 mm to about 0.75 mm thick and has porosity of 90 percent or greater.    
     
     
         8 . The foam scaffold of  claim 7  wherein said foam scaffold is about 0.4 mm to about 0.6 mm thick and has porosity from 90 percent to 97 percent.  
     
     
         9 . The foam scaffold of  claim 7  wherein the copolymer comprises about 35 mole percent ε-caprolactone copolymerized with about 65 mole percent glycolide.  
     
     
         10 . The foam scaffold of  claim 9  wherein the scaffold is about 0.5 mm thick and has porosity of about 93 percent.  
     
     
         11 . The foam scaffold of  claim 7  wherein said scaffold is substantially absorbed by the body within about 120 days of implantion.  
     
     
         12 . The foam scaffold of  claim 7  wherein said foam scaffold is completely absorbed by the body within about 90 days of implantion.  
     
     
         13 . The foam scaffold of  claim 7  wherein about 50 percent of said thickness of said foam scaffold is infiltrated by granulation tissue within about 10 days of implantation.  
     
     
         14 . The foam scaffold of  claim 7  wherein about 75 percent of said thickness of said foam scaffold is infiltrated by granulation tissue within about 7 days of implantation.  
     
     
         15 . The foam scaffold of  claim 7  wherein said foam scaffold is substantially submerged in or enveloped by granulation tissue within about 28 days of implantation.  
     
     
         16 . The foam scaffold of  claim 7  wherein said foam scaffold is completely submerged in or enveloped by granulation tissue within about 28 days of implantation.