Patent ID: 7109300

Claim:
A process for extracting collagen from calcified tissue containing collagen, said process comprising the steps of: (a) treating the tissue with an aqueous alkali solution, in a concentration and for a time sufficient to remove at least some non-collagen protein from the tissue; (b) treating the tissue with ethanol, in an amount and for a time sufficient to dissolve at least some odoriferous substances from the tissue, and then separating the alcohol from the tissue; (c) rinsing the tissue with water, in an amount and for a time sufficient to bring the pH of the tissue between about 7 and about 8; (d) treating the tissue with an aqueous solution of acid and pepsin, in concentrations and for a time sufficient to dissolve at least some collagen from the tissue into the aqueous solution; (e) filtering the mixture of tissue and aqueous solution, to separate the aqueous solution with dissolved collagen from the undissolved tissue components; (f) dissolving salt in the filtered aqueous solution containing dissolved collagen, in a concentration and for a time sufficient to cause at least some of the collagen to precipitate from the aqueous solution; and (g) collecting the precipitated collagen; wherein: prior to the step of treating the tissue with the aqueous solution of acid and pepsin, no substantial decalcification of the tissue occurs; and wherein: said process does not employ ethylenediaminetetraacetic acid (EDTA); and wherein: steps (a) through (g) occur consecutively in the order listed above; except that steps (a) and (b) may occur in either order, or steps (a) and (b) may occur concurrently.