Preparation of high purity collagen

1. A method for producing a collagen preparation, comprising in the following order:

providing a connective tissue having a surface ranging from 20 mm 2 to 2 m 2 ,

swelling the connective tissue with a first acidic solution by at least 50% in volume to form a swollen connective tissue, wherein the acidic solution is substantially free of salt and has a pH of 1-6,

washing the swollen connective tissue to remove non-collagenous material in a wash solution comprising a detergent, chelating agent, protelyotyic enzyme or mixtures thereof, thereby producing a collagen matrix, and

extracting collagen from the collagen matrix with an extraction solution to produce a collagen-containing solution.

2. The method according to claim 1 , wherein the extracting step is performed by comminuting the collagen matrix to produce collagen powders and mixing the powders with the extraction solution to produce the collagen-containing solution.

3. The method according to claim 2 , wherein the comminuting step and the mixing step are conducted simultaneously.

4. The method according to claim 1 , further comprising, after the extracting step, precipitating the collagen from the collagen-containing solution and drying the collagen or dispersing the collagen in a second acidic solution.

5. The method of claim 4 , wherein in the precipitating step, the collagen is precipitated by dialysis.

6. The method according to claim 4 , wherein the precipitating step is performed by mixing the collagen-containing solution with a salt at a concentration of 1.0 M to 4.0 M to precipitate the collagen and the method further comprising, after the precipitating step, desalting the collagen.

7. The method according to claim 4 , wherein the precipitating step is performed by adjusting the pH of the collagen-containing solution to 4.5-8 to precipitate the collagen.

8. The method according to claim 1 , further comprising, after the extracting step, mixing the collagen-containing solution with a solution containing a proteolytic enzyme to produce a telopeptide collagen.

9. The method according to claim 8 , wherein the proteolytic enzyme is selected from the group consisting of pepsin, bromelain, chymopapain, chymotrypsin, collagenase, ficin, papain, peptidase, proteinase A, proteinase K, trypsin, microbial proteases, and a mixture thereof.

10. The method according to claim 1 , wherein the extraction solution contains an acid selected from the group consisting of formic acid, oxalic acid, acetic acid, citric acid, lactic acid, malic acid, boric acid, phosphoric acid, and a mixture thereof.

11. The method according to claim 1 , wherein the extraction solution contains a salt.

12. The method according to claim 4 , wherein the second acidic solution contains an acid selected from the group consisting of oxalic acid, acetic acid, citric acid, lactic acid, malic acid, boric acid, phosphoric acid, and a mixture thereof.

13. The method according to claim 1 , wherein the swelling step is performed by soaking the connective tissue in the first acidic solution and concurrently squirting a liquid into the connective tissue.

14. The method according to claim 1 , wherein the washing step is performed by soaking the swollen connective tissue in the wash solution and concurrently squirting a liquid into the swollen connective tissue.

15. The method according to claim 1 , wherein the swelling step is performed by soaking the connective tissue in the first acidic solution and concurrently treating the connective tissue with ultrasound.

16. The method according to claim 1 , wherein the washing step is performed by soaking the swollen connective tissue in the wash solution and concurrently treating the swollen connective tissue with ultrasound.

17. The method according to claim 1 , wherein the connective tissue is derived from dermis or tendon.

18. The method according to claim 1 , wherein the connective tissue has a surface ranging from 25 mm 2 to 900 cm 2 .

19. The method according to claim 1 , wherein the first acidic solution contains an acid selected from the group consisting of formic acid, oxalic acid, acetic acid, citric acid, lactic acid, malic acid, boric acid, phosphoric acid, and a mixture thereof.

20. The method according to claim 19 , wherein the acidic solution has a pH value of 2 to 4.

21. The method according to claim 1 , wherein the first acidic solution contains acetic acid at a concentration of 0.1-6 M.