Two phase thermally deformable biocompatible absorbable polymer matrix for use in medical devices

Abstract

An absorbable biocompatible polymeric matrix is described. The matrix has a continuous phase that is preferably amorphous. The matrix also has a disperse phase of low melting biocompatible material that acts as scattering centers for light and melts at a temperature lower than the continuous phase of the matrix. This matrix is especially useful in a variety of medical devices. When this matrix is heated to about the melting temperature of the dispersed phase the matrix undergoes a visual change. This provides a visual cue to a surgeon using the medical devices as to when the device can be safely shaped or manipulated without imparting undue stress to the device. As the medical device cools below the temperature at which it may be safely deformed the matrix resumes its original appearance signalling that it may no longer be safely shaped or manipulated.

We claim:  
     
         1 . An absorbable polymeric matrix for use in medical devices that provides a visual cue when heated so that the absorbable polymeric matrix may be deformed without significantly reducing the strength of a device made from the absorbable polymeric matrix.  
     
     
         2 . The absorbable polymeric matrix of  claim 1  wherein the absorbable polymeric matrix is made from biocompatible aliphatic polyesters.  
     
     
         3 . The absorbable polymeric matrix of  claim 1  wherein the absorbable polymeric matrix comprises a continuous phase and a dispersed phase.  
     
     
         4 . The absorbable polymeric matrix of  claim 3  wherein the continuous phase is an amorphous aliphatic polyester selected from the group consisting of amorphous polylactide, amorphous polyglycolide, amorphous poly-1,4-dioxan-2-one, amorphous polytrimethylene carbonate and miscible blends thereof.  
     
     
         5 . The absorbable polymeric matrix of  claim 3  wherein the dispersed phase is an aliphatic polyester selected from the group consisting of poly(ε-caprolactone); copolymers of ε-caprolactone and with up to 40 mole percent of a second monomer selected from the group consisting of lactide, lactic acid, glycolide, glycolic acid, 1,4-dioxan-2-one, and trimethylene carbonate; copolymers of ε-caprolactone or trimethylene carbonate with greater than 60 mole percent 1,4-dioxan-2-one but less than 90 mole percent and blends thereof.  
     
     
         6 . The absorbable polymeric matrix of  claim 3  wherein the dispersed phase comprises from about 1 to about 50 weight percent of the absorbable polymeric matrix.  
     
     
         7 . The absorbable polymeric matrix of  claim 6  wherein the dispersed phase comprises from about 2 to about 20 weight percent of the absorbable polymeric matrix.  
     
     
         8 . A medical device that at least a portion thereof is formed from an absorbable polymeric matrix that provides a visual cue when heated that the absorbable polymeric matrix may be deformed without significantly reducing the strength of the portions of the medical device made from the absorbable polymeric matrix wherein the visual cue disappears when the absorbable polymeric matrix cools to a temperature at which deformation would reduce the strength of the absorbable polymeric matrix.  
     
     
         9 . The medical device of  claim 8  wherein the medical device is selected from the group consisting of burn dressings, hernia patches, medicated dressings, facial substitutes, gauze, fabric, sheet, felt, sponge for liver hemostasis, gauze bandages, arterial graft or substitutes, bandages for skin surfaces, burn dressings, bone substitutes, needles, intrauterine devices, tubes, surgical instruments, vascular implants, vascular supports, vertebral discs, extracorporeal tubing, artificial skin, stents, suture anchors, injectable defect fillers, preformed defect fillers, bone waxes, cartilage replacements, hemostatic barriers, tissue scaffolds, monofilament sutures and braided sutures, pins, rods and plates.  
     
     
         10 . The medical device of  claim 8  wherein the medical device is selected from the group consisting, bone substitutes, vertebral discs, pins, rods and plates.  
     
     
         11 . The medical device of  claim 8  wherein the absorbable polymeric matrix comprises a continuous phase and a dispersed phase.  
     
     
         12 . The medical device of  claim 11  wherein the continuous phase is an amorphous aliphatic polyester selected from the group consisting of amorphous polylactide, amorphous polyglycolide, amorphous poly-1,4-dioxan-2-one, amorphous polytrimethylene carbonate and miscible blends thereof.  
     
     
         13 . The medical device of  claim 12  wherein the dispersed phase is an aliphatic polyester selected from the group consisting of poly(ε-caprolactone); copolymers of ε-caprolactone and with up to 40 mole percent of a second monomer selected from the group consisting of lactide, lactic acid, glycolide, glycolic acid, 1,4-dioxan-2-one, and trimethylene carbonate; copolymers of ε-caprolactone or trimethylene carbonate with greater than 60 mole percent 1,4-dioxan- 2- one but less than 90 mole percent and blends thereof.  
     
     
         14 . A method of shaping a surgical article having a portion thereof formed from an absorbable polymeric matrix comprises heating that portion of the surgical article that is formed from the absorbable polymeric matrix until a visual cue is provided by the absorbable polymeric matrix that the portion of the surgical article made from the absorbable polymeric matrix may be safely shaped, then shaping that portion of the surgical article to the desired final shape while the visual cue is present and allowing the surgical article to cool.  
     
     
         15 . The process of  claim 14  wherein the surgical article is heated to a temperature in the range of from about 40° C. to about 65° C.  
     
     
         16 . The process of  claim 14  wherein the surgical article is heated in a biocompatible liquid medium.  
     
     
         17 . The process of  claim 14  wherein the surgical article is selected from the group consisting, bone substitutes, vertebral discs, pins, rods and plates.  
     
     
         18 . The process of  claim 14  wherein the absorbable polymeric matrix has a continuous phase that is an amorphous aliphatic polyester selected from the group consisting of amorphous polylactide, amorphous polyglycolide, amorphous poly-1,4-dioxan-2-one, amorphous polytrimethylene carbonate and miscible blends thereof.  
     
     
         19 . The process of  claim 18  wherein the absorbable polymeric matrix has a dispersed phase that is an aliphatic polyester selected from the group consisting of poly(εcaprolactone); copolymers of ε-caprolactone and with up to 40 mole percent of a second monomer selected from the group consisting of lactide, lactic acid, glycolide, glycolic acid, 1,4-dioxan-2-one, and trimethylene carbonate; copolymers of e-caprolactone or trimethylene carbonate with greater than 60 mole percent 1,4-dioxan-2-one but less than 90 mole percent and blends thereof.  
     
     
         20 . The process of  claim 19  wherein the dispersed phase comprises from about 2 to about 20 weight percent of the absorbable polymeric matrix.