Composite sutures of silk and hydrophobic thermoplastic elastomers

Claim 1

A composite suture essentially retaining the handling qualities of silk, which, in the case of size 5-0, is capable of retaining at least 32% of its initial mechanical strength, in vivo, after eight weeks; said suture having surface barrier properties against cell infiltration comparable to those of a monofilament and tissue reaction comparable to common synthetic sutures; comprising multifilament silk embedded in a hydrophobic, limp thermoplastic elastomer, substantially all the interstices between the silk filaments being filled by said elastomer; said elastomer having a suitable molecular weight sufficient to provide a solution viscosity that is consistent with optimum diffusion into the interior of the suture structure, resulting in a high integrity matrix which does not flake when the suture is subjected to mechanical stress; said elastomer being selected from the group consisting of copolymers having the following recurring units: ##STR24## wherein each G individually represents an alkylene group of from 2 to 6 carbon atoms, and p is 9 to 15, e and f each represent a number having a value greater than 1 such that the B units comprise 50 to 80 weight percent of the copolymer and the A units comprise the remainder; wherein Z represents 1,4-phenylene, 1,3-phenylene or trans-1,4-cyclohexylene; (Q) a copolymer consisting essentially of a multiplicity of recurring A [poly(alkylene terephthalate, isophthalate or cyclohexane-1,4-dicarboxylate)] and B [poly(alkylene dimerate)] units having the following general formula: ##STR25## wherein x and y are integers, such that the B units comprise 50 to 80 weight percent of the copolymer, and the A units comprise the remainder; ##STR26## denotes a branched hydrocarbon chain containing from 24 to 32 carbon atoms and Z and G are as hereinabove defined; (R) a copolymer consisting essentially of a multiplicity of recurring poly(alkylene) terephthalate, isophthalate or cyclohexane-1,4-dicarboxylate, and poly(alkylene) alkyl or alkenyl succinate units having the following general formula: ##STR27## wherein Alk 1 is a linear or branched alkyl or alkenyl radical with a chain length of about 4 to 30 carbon atoms and g and h are integers such that the A units comprise 20 to 50 weight percent of the copolymer and the B units comprise the remainder and Z and G are as hereinabove defined; or, (S) a random copolymer having the following general formula: ##STR28## wherein J is either: ##STR29## wherein Alk 2 is alkyl or alkenyl moieties with a chain length of 8 to 30 carbon atoms; ##STR30## denotes a branched hydrocarbon chain with an estimated formula of C 32 H 60 , or ##STR31## wherein p is 9 to 15, G is an hereinabove defined and R' is an aliphatic or aromatic disubstituted moiety and wherein e and f are such that the B units comprise about 25 to 50% by weight of the copolyester and the A units comprise the remainder.