Patent GB-915066-A (GB)
Title: Collagen article and the manufacture thereof
IPC: D01F4/00
Filed: 1959-10-22
Abstract: The invention comprises a dispersion of swollen undegraded collagen fibres in an aqueous solution containing cyanoacetic acid.  The term "swollen collagen fibre" is defined as a thread-like collagen structure that has been swollen in cyanoacetic acid solution and has a diameter of 200 to 100,000 Angstrom Units.  The dispersion, which may be suitable for extrusion to form a shaped article, may contain 0.8 to 2% by weight collagen, 0.2 to 0.5% by weight cyanoacetic acid, and methanol, and may be prepared by swelling and dispersing undegraded collagen fibres in an aqueous solution of cyanoacetic acid.  The pH of the solution may be between 2 and 3, and a temperature of below 25 DEG C. may be maintained during the process. The collagen fibres are obtained from animal tendons which are sliced and then treated with an enzyme composition to isolate the collagen. The enzyme treatment is terminated by the addition of hydrogen peroxide, and after washing with water, soluble proteins and lipids may be removed by treatment with a dilute aqueous solution of a chelating agent e.g. ethylenediamine tetrasodium tetra-acetate.  The tendons are then swollen and dispersed in the aqueous solution of cyanoacetic acid, homogenized, and after removal of fibres of unswollen non-collagenous material by forcing the dispersion under pressure through a leaf filter, the dispersion may be dehydrated under mild conditions to recover highly purified collagen fibres, or de-aerated under vacuum for storage or extrusion into an acetone dehydrating bath to form collagen filaments e.g. sutures, or tubes e.g. edible sausage casings, which may then be tanned, stretched and twisted.ALSO:Surgical sutures are prepared by extrusion of a dispersion of swollen undegraded collagen fibres in an aqueous solution containing cyanoacetic acid.  The term "swollen collagen fibre" is defined as a thread-like collagen structure that has been swollen in cyanoacetic acid solution and has a diameter of 200 to 100,000 Angstrom units.  The dispersion may contain 0.8 to 2% by weight collagen, 0.2 to 0.5% by weight cyanoacetic acid, and methanol, and may be prepared by swelling and dispersing undegraded collagen fibres in an aqueous solution of cyanoacetic acid.  The pH of the solution may be between 2 and 3, and a temperature of below 25 DEG  C. may be maintained during the process. The collagen fibres are obtained from animal tendens which are sliced and then treated with an enzyme composition to isolate the collagen.  The enzyme treatment is terminated by the addition of hydrogen peroxide, and after washing with water, soluble proteins and lipids may be removed by treatment with a dilute aqueous solution of a chelating agent, e.g. ethylenediamine tetrasodium tetraacetate.  The tendons are then swollen and dispersed in the aqueous solution of cyanoacetic acid, homogenized, and after removal of fibres of unswollen non-collagenous material by forcing the dispersion under pressure through a leaf-filter, the dispersion is deaerated under vacuum and extruded into an acetone dehydrating bath to form filaments which may then be tanned, stretched and twisted to form sutures.