Absorbable Poly (p-dioxanone-co-glycolide) Monofilament Fibers Pocessing Mid-Term Strength Retention Post-Implantation

Abstract

Novel absorbable monofilament sutures and fibers having unique and improved properties are disclosed including mid-term strength retention post-implantation. Also disclosed is a novel method of manufacturing absorbable monofilament sutures and fibers. The sutures and fibers are extruded from poly(p-dioxanone-co-glycolide) copolymers.

1 - 38 . (canceled) 
     
     
         39 . A method of manufacturing an absorbable monofilament suture, comprising the steps of:
 a) providing an absorbable copolymer, the copolymer comprising a poly(p-dioxanone-co-glycolide) copolymer, wherein the mole percent of polymerized p-dioxanone is from about 90 to about 94, the mole percent of polymerized glycolide is from about 6 to about 10, the copolymer made utilizing a monofunctional polymerization initiator and a difunctional polymerization initiator at a mole ratio of monofunctional initiator to difunctional initiator of from about 40/60 to about 60/40;   b) melting the copolymer in an extruder having a die and extruding the copolymer as a monofilament fiber at extruder and die temperatures ranging from about 100° C. to about 130° C.;   c) maintaining an air gap between the die and a water surface of a water bath set to from about ¼″ to about 4″;   d) guiding the fiber through the water bath set at temperature between about 5° C. and about 30° C.;   e) moving the fiber to a first set of godets running at a speed Z;   f) moving the fiber to a second set of godets running at a speed of at least 5.5×Z;   g) moving the fiber to a heated oven set at a temperature of about 100° C. to about 120° C.;   h) moving the partially drawn fiber to a third set of godets running at the speed of at least 7.5×Z;   i) moving the fully drawn fiber to a second heated oven set at a temperature of about 100° C. to about 120° C.;   j) moving the fully drawn fiber to a fourth set of godets running at the speed of about 6×Z to about 8×Z;   k) collecting the fiber;   l) annealing the fiber; and,   m) relaxing the fiber to about 5% to about 10%,   wherein, said suture has a straight tensile strength of at least 80 Kpsi, a Young's Modulus of less than 200 Kpsi, and a breaking strength retention (BSR) of at least 50% at 3 weeks post-implantation and at least 30% at 4 weeks post-implantation.   
     
     
         40 . The method of  claim 39 , wherein the fiber is maintained in the water bath for a sufficient
 time such that the fiber has a crystallinity level sufficiently low to allow a total draw ratio of at least 7.5.   
     
     
         41 . The method of  claim 39 , wherein the second set of Godets is heated to about 40° C. to 80° C. 
     
     
         42 . The method of  claim 39 , wherein the poly(p-dioxanone-co-glycolide) copolymer has an inherent viscosity (IV) of about 1.2 to about 2.4 dL/g, as measured in HFIP at 25° C. at a concentration of 0.1 g/dL. 
     
     
         43 . The method of  claim 42 , wherein the poly(p-dioxanone-co-glycolide) copolymer has an inherent viscosity (IV) of about 1.4 to about 2.2 dL/g, as measured in HFIP at 25° C. at a concentration of 0.1 g/dL. 
     
     
         44 . The method of  claim 43 , wherein the poly(p-dioxanone-co-glycolide) copolymer has an inherent viscosity of about 1.8 to about 2.0 dL/g. 
     
     
         45 . The method  claim 39 , wherein the air gap is from about 1.5 to about 4″. 
     
     
         46 . The method of  claim 39 , wherein the fiber is annealed in-line or via a rack process. 
     
     
         47 . The method of  claim 39 , comprising the additional step of forming at least one barb in the suture. 
     
     
         48 . The method of  claim 47 , wherein the barb is formed by a process selected from the group consisting of cutting, pre-forming, forming, attaching and molding. 
     
     
         49 . The method of  claim 39  comprising the additional step of making a surgical fabric from the suture. 
     
     
         50 . The method of  claim 46 , wherein the annealed fiber has a crystallinity level of at least 35%. 
     
     
         51 . The method of  claim 39 , wherein the fiber resides in the water bath for a period of time ranging from about 1 second to about 3 minutes. 
     
     
         52 - 53 . (canceled)