Process for the preparation of collagen and obtained product

Claim 1

A process for treating bovine tendon to extract high purity collagen in the form of a viscous gel, said extracted collagen having the triple helix configuration of natural collagen and being suitable for direct use in surgical sponges and the like, said extraction being effected without the use of an enzymatic treatment to solubilize the collagen and said extracted collagen not being subjected to a cross-linking procedure to modify its structure, which comprises: suspending a finely divided mass of bovine tendon in a 0.5-14 2.0 M aqueous acetic acid solution in an amount to provide a bovine tendon/acid weight ratio of 01-0.01/1; mildly agitating the resultant suspension for a period of 24-72 hrs. at a temperature not exceeding about 25° C.; separating the suspended solid phase and precipitating collagen from the liquid phase by the addition thereto of sodium chloride, said precipitated collagen being in the form of a gummy, thready product of milky white color; separating said precipitated collagen and suspending it in acetic acid and agitating until complete gelatin is obtained; diluting the resultant collagen gel to a concentration of 0.005-0.5% and subjecting it to tangential filtration through a molecular exclusion membrane having an exclusion limit of 10,000-100,000 using acetic acid of 0.01-1.0 M whereby a filtrate containing impurities of molecular weight below the exclusion is removed while the collagen gel is retained recycling the collagen gel through tangential filtration until all impurities are removed; recovering and drying the purified collagen gel and lyophilizing the same.