BIOABSORBABLE COATING FOR A SURGICAL ARTICLE

Abstract: A bioabsorbable coating for a surgical article comprises a polymer manufactured from at least the monomer caprolactone. The surgical article can be a bioabsorbable suture or ligature.

Description: The invention refers to a suture or ligature with a bioabsorbable coating of a copolymer comprising the monomer caprolactone. Such a suture or ligature is known from US-A-3 867 190. It is the problem of this invention to advance sutures or ligatures of this kind by improving the knot security and the knot repositioning characteristics. This problem is solved by the suture or ligature of Claim 1. The sutures or ligatures of this invention are less stiff than sutures using a coating described in the prior art. Further, tissue drag appears to be equal to, if not better than, suture coatings disclosed in the prior art. Moreover, the coating of this invention does not present a hazy appearance on a suture. In a special embodiment, the inherent viscosity of the random copolymer is 0.2 to 1.4 dl/g (0.5 g/dl in CHCl₃, 30°C) The surgical article coated with the above described polymers can be bioabsorbable. In one embodiment, the invention is a coating in combination with a bioabsorbable suture or ligature. In a specific embodiment, the suture or ligature is manufactured from a polymer prepared from one or more monomers selected from the group consisting of lactide, carbonates and lactones. In a more specific embodiment, the suture or ligature is manufactured from a homopolymer prepared from the monomer glycolide or from a copolymer prepared from the monomers glycolide and either or both 1,3-dioxan-2-one and lactide. The coating in combination with the suture or ligature can be in multifilamentary form. In a specific embodiment, the coating comprises 1/10 to 5% by weight of the coated multifilamentary suture or ligature. In a more specific embodiment, the coating comprises 1/2 to 3% by weight of the coated multifilamentary suture or ligature. In the more specific embodiment, the coating can comprise up to 1 1/2 percent by weight of the coated multifilamentary suture or ligature. A process for manufacturing a coating in combination with a bioabsorbable surgical article has also been invented in accordance with Claim 8. Description of the Preferred Embodiment(s) The following examples describe the best mode of the invention. Unless otherwise specified, all of the inherent viscosity measurements in the examples were conducted at 30°C. COMPARATIVE EXAMPLE A ε-Caprolactone Homopolymer A sample of ε-caprolactone homopolymer was purchased from Scientific Polymer Products, Inc. The sample η inh was measured as 0.27 dl/g (0.5 g/dl in CHCl₃). GPC analysis in CH₂Cl₂ using polystyrene standards gave MW = 17,600 and MN = 8500. COMPARATIVE EXAMPLE B Synthesis of ε-Caprolactone Homopolymer ε-Caprolactone (10g, 0.088 mole), lauryl alcohol (0.122g, 6.57 x 10⁻⁴ mole) and stannous chloride dihydrate (0.988 mg, 4.38 x 10⁻⁶ mole) were combined in a flask. The flask was flushed with nitrogen and evacuated. The flask was heated at 135°c in an oil bath for 24 hours. The resulting polymer had an η inh of 0.53 dl/g (0.5 g/dl in HFAS). GPC analysis in CH₂Cl₂ using polystyrene standards gave MW = 65,200 and MN = 26,900. EXAMPLE 1 Synthesis of ε-Caprolactone-1-Lactide Copolymer ε-Caprolactone (212.5g, 1.86 mole), 1-lactide (37.5 g, 0.31 mole), lauryl alcohol (4.10 ml, 0.018 mole) and stannous chloride dihydrate (35.9 mg, 1.59 x 10⁻⁴ mole) were combined in a stirred reactor under nitrogen at 175°C. The mixture was stirred at 175°C for 3 hours. The resulting polymer had a composition, as determined by H'NMR, of 84 wt. % ε-caprolactone and 16 wt. % 1-lactide. The inherent viscosity of the copolymer was 0.50 dl/g (0.5 g/dl in CHCl₃). EXAMPLE 2 Synthesis of ε-Caprolactone-Glycolide Copolymer ε-Caprolactone (170 g, 1.49 mole), glycolide (30 g, 0.26 mole), lauryl alcohol (1.37 g, 7.3 x 10⁻³ mole) and stannous octoate (0.052 g, 1.2 x 10⁻⁴ mole) were combined in a stirred reactor under nitrogen at 180°C. The mixture was stirred at 180°C for 4.5 hours. The resulting polymer had an inherent viscosity of 0.68 dl/g (0.5 g/dl in CHCl₃). The composition was determined by H'NMR to be 85 wt. % ε-caprolactone and 15 wt. % glycolide. EXAMPLES 3-6 Synthesis of ε-Caprolactone-Glycolide Copolymers A series of ε-caprolactone-glycolide copolymers was prepared by the general procedure described in Example 2. Specific preparative details and properties of the resulting polymers are summarized in Table 1. Table 2 summarizes the in vitro performance for the bioabsorbable coatings of this invention. Table 3 summarizes the in vivo performance for some of the bioabsorbable coatings of this invention.

Claims: A surgical suture or ligature with good knot security and knot repositioning characteristics having a bioabsorbable coating comprising a random copolymer with 70 to 85 wt-% of units of formula (I): the remaining units having the formula (II) wherein R is H or CH₃. A suture or ligature of Claim 1, wherein the remaining units comprise the formula (II) wherein R is H. A suture or ligature of Claim 1, wherein the inherent viscosity of said copolymer is 0.2 to 1.4 dl/g (0.5 g/dl in CHCl₃, 30°C). A suture or ligature of Claim 1 wherein the suture or ligature is manufactured from a bioabsorbable polymer prepared from one or more monomers selected from the group consisting of lactides, carbonates and lactones. A suture or ligature of Claim 3 wherein the suture or ligature is manufactured from a homopolymer prepared from the monomer glycolide, or from a copolymer prepared from the monomers glycolide and either or both 1,3-dioxan-2-one and lactide. A suture or ligature of Claim 4 wherein the suture or ligature is in multifilamentary form. A suture or ligature of Claim 5 wherein the coating comprises about 1/10 to 5 % by weight of the coated suture or ligature. A process for manufacturing a coated suture or ligature of one of Claims 1 to 7 comprising dissolving in acetone the random copolymer; contacting the suture or ligature with the dissolved copolymer; maintaining the contact between said suture or ligature and dissolved copolymer until the copolymer on said suture or ligature comprises from 1/10 to 5 % by weight of the coated suture or ligature; removing said coated suture or ligature from said dissolved copolymer; and drying the copolymer on said suture or ligature.

Inventors: CASEY, DONALD JAMES, JARRETT, PETER KENDRICK, LEHMANN, LEONARD THEODORE
Applicants: AMERICAN CYANAMID COMPANY
Application year: 1987
Main classification: A61L17
IPC codes: C08G63, A61L17