Chemistry: molecular biology and microbiology – Process of utilizing an enzyme or micro-organism to destroy... – Treating animal or plant material or micro-organism
Patent
1981-06-08
1983-06-21
Yoncoskie, Robert A.
Chemistry: molecular biology and microbiology
Process of utilizing an enzyme or micro-organism to destroy...
Treating animal or plant material or micro-organism
426 32, 604368, 128DIG8, C07G 700
Patent
active
043894879
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to the preparation of a collagen product for medical and cosmetic purposes which has a felt-, sponge- or fleece-like structure and which has significantly improved physicochemical and mechanical properties (absorption, strength) as compared with known collagen products.
BACKGROUND ART
It is known practice to use collagen products prepared from animal tissues in medicine for treating wounds and for filling pathological cavities in bones. Collagen products of this type are described e.g. in the following patents: British Pat. No. 1,147,072, South African Pat. No. 6,705,871, U.S. Pat. No. 4,016,877, U.S. Pat. No. 3,823,212, U.S. Pat. No. 3,810,473 and U.S. Pat. No. 4,066,083 (P. Ries).
The process described in U.S. Pat. No. 4,066,083 comprises comminuting collagen-containing animal tissues at a temperature not exceeding 40.degree. C., degreasing the resulting tissue pulp and simultaneously removing therefrom undesirable water-soluble non-collagen ballast substances by repeatedly treating the tissue pulp with about a five-fold volume, based on the pulp volume, of a 5 to 15% aqueous sodium chloride solution containing about 0.2 to 1 part by weight of sodium azide as a preserving agent per 1000 parts by weight of the said solution and 0.5 to 2% by weight of a non-ionic fat-dispersing wetting agent, washing the resulting fiber pulp with water or 0.1 to 0.5% aqueous formic, acetic or citric acid, digesting the fiber pulp for 8 to 48 hours at a pH of about 2.5 to 3.5 in a five-fold volume, based on the volume of the pulp, of 0.1 to 5% aqueous acetic acid containing about 1 part by weight of pepsin per 1000 parts by weight of the tissue used as the starting material in order to remove non-collagen type proteins and telopeptides, precipitating collagen from the resulting collagen suspension by the addition thereto of aqueous sodium chloride in such a quantity that the sodium chloride concentration of the suspension is about 3 to 5%, separating the precipitated collagen and desalting it by ultrafiltration, dialysis or washing with 60 to 75% aqueous ethyl alcohol, dissolving the desalted collagen in demineralized or distilled water containing up to 3% by weight of a strong organic acid in such a proportion that the concentration of collagen in the resulting solution corresponds to a dry residue of about 0.5 to 2% by weight, freeze-drying the collagen solution, and sterilizing the freeze-dried collagen product.
The collagen product obtained by this process possesses a number of advantageous properties which appear to make it particularly suitable as an auxiliary material in medicine, but has the disadvantage that it is slow in taking up aqueous solutions or body fluids and has insufficient mechanical strength in moist or wet condition.
DISCLOSURE OF THE INVENTION
Surprisingly, it was found that the physicochemical and mechanical properties of the collagen product could be substantially improved by treating the freeze-dried collagen product, before or after sterilization, with heat or gaseous hydrogen halide. The improved collagen product is even more suitable and easier to handle for medical purposes. Due to its improved physicochemical and mechanical properties, the new collagen product can also be used as a cosmetic mask for skin care.
According to the invention, the collagen product can be subjected, after freeze-drying, either before or after sterilization, to a heat treatment at temperatures of 80.degree. to 150.degree. C., preferably 100.degree. to 130.degree. C., for 15 minutes to 12 hours, preferably 1 to 6 hours, at normal pressure or in vacuo. The freeze-dried collagen product can also be subjected, before or after sterilization, to a treatment with gaseous hydrogen halide, preferably hydrogen chloride, for 1 to 60 minutes, preferably 5 minutes. As a result of these treatments, the absorption and the wet strength of the collagen product are increased. Simultaneously, a reduction in the number of germs in the collagen product is achieved. The collagen product
REFERENCES:
patent: 3303038 (1967-02-01), Klevens
patent: 3664844 (1972-05-01), Miller
patent: 4066083 (1978-01-01), Ries
Pentapharm A.G.
Yoncoskie Robert A.
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