Methods of orienting multifilament yarn and monofilaments of poly-4-hydroxybutyrate and copolymers thereof
Resorbable multifilament yarns and monofilament fibers including poly-4-hydroxybutyrate and copolymers thereof with high tenacity or high tensile strength have been developed. The yarns and fibers are produced by cold drawing the multifilament yarns and monofilament fibers before hot drawing the yarns and fibers under tension at temperatures above the melt temperature of the polymer or copolymer. These yarns and fibers have prolonged strength retention in vivo making them suitable for soft tissue repairs where high strength and strength retention is required. The multifilament yarns have tenacities higher than 8.1 grams per denier, and in vivo, retain at least 65% of their initial strength at 2 weeks. The monofilament fibers retain at least 50% of their initial strength at 4 weeks in vivo. The monofilament fibers have tensile strengths higher than 500 MPa. These yarns and fibers may be used to make various medical devices for various applications.
1. A breast reconstruction or mastopexy device comprising a knitted or woven mesh, wherein the mesh comprises monofilament fiber comprising poly-4-hydroxybutyrate (P4HB) polymer, a copolymer thereof or a polymeric blend thereof, with a tensile strength between 800 MPa and 1,500 MPa and the mesh has one or more properties selected from the group consisting of (i) a burst strength of at least 0.1 Kgf; and (ii) a suture pullout strength of at least 1 Kgf.
2. The device of claim 1 , wherein the device is used for breast lift, breast augmentation, breast reduction, or breast reconstruction following mastectomy.
3. The device of claim 1 , wherein the mesh has one or more of the following properties: (i) a thickness of 0.05-5 mm; (ii) an areal density of 182±50 g/m 2 ; (iii) a suture pullout strength of 1 to 20 Kgf, and (iv) pore diameter of 5 μm to 5 mm.
4. The device of claim 1 , wherein the mesh has a thickness of 0.1-1.0 mm or an areal density of 100-300 g/m 2 .
5. The device of claim 3 , wherein the mesh has one or more of the following properties: (i) a thickness of 0.5±0.2 mm; and (ii) pore diameter of 100 μm to 1 mm.
6. The device of claim 1 , the fiber has an elongation to break from 15-35%.
7. The device of claim 1 , wherein the mesh has a burst strength from 1 to 50 Kgf.
8. The device of claim 1 , wherein the device retains at least 50% of its initial tensile strength 4 weeks after implantation.
9. The device of claim 1 , wherein the device retains at least 40% of its initial tensile strength 12 weeks after implantation.
10. The device of claim 1 , wherein the mesh is annealed.
11. The device of claim 1 , wherein the device has been sterilized by ethylene oxide.
12. The device of claim 1 , wherein the device contains less than 20 endotoxin units.
13. The device of claim 1 , wherein the device further comprises one or more of the following: plasticizer, nucleant, dye, medical marker, bioactive agent, therapeutic agent, antimicrobial agent, diagnostic agent, prophylactic agent, protein, peptide, antibody, polysaccharide, glycoprotein, lipid, lipoprotein, nucleic acid molecule, inorganic or organic synthetic molecule, contrast agent, radiopaque marker, radioactive substance, hyaluronic acid or derivative thereof, collagen, hydroxyapatite, synthetic polymer, natural polymer or one or more absorbable polymers derived from glycolic acid, glycolide, lactic acid, lactide, 1,4-dioxanone, trimethylcarbonate and c-caprolactone.
14. The device of claim 1 , wherein the diameter of the monofilament fiber is 0.05 mm to 0.199 mm.
15. The device of claim 1 , wherein the device is produced by a method comprising (a) spinning the monofilament fiber, (b) cold drawing the monofilament fiber at a temperature below 50° C., and (c) hot drawing the monofilament fiber after cold drawing the monofilament fiber at a temperature above the melt temperature of poly-4-hydroxybutyrate.
16. The device of claim 15 , wherein the monofilament is cold drawn with an orientation ratio of 3 to 4, and then hot drawn in one or more subsequent draws.
17. The device of claim 16 , wherein the monofilament is allowed time to crystallize before drawing.
18. A method of using the device of claim 1 , comprising implanting the device in the breast of a patient in need thereof.
19. The method of claim 18 , wherein the subject is in need of a breast lift, breast augmentation, or breast reconstruction following mastectomy.
20. The device of claim 1 , wherein monofilament fiber comprises a polymeric blend comprising P4HB and one or more one or more absorbable polymers selected from the group consisting of polyglycolic acid, polyglycolide, polylactic acid, polylactide, polydioxanone, polycaprolactone, copolymers of glycolic and copolymers of lactic acid.
21. The device of claim 1 , wherein the mesh has an areal density of 5 to 800 g/m 2 .