New preparation of placenta collagen, their extraction method and their applications
First Claim
1. A method for extraction of placenta collagens in which the placenta is digested enzymatically, characterized in that starting with human or animal placenta in deep-frozen form which is ground and washed:
- the washed placental tissue is subjected to enzymatic digestion, said digestion being carried out with pepsin at an acidic pH, at a temperature between 0°
C. and 20°
C. for a time between 8 and 24 h. the pepsin content with respect to the deep-frozen placenta being between 0.5 and 1.5%,said suspension is diluted with a volume of water,the pH is adjusted to between 7 and 10,said suspension is allowed to rest for 1 to 24 h at a temperature of between 0° and
20°
C.,the residual tissue is separated from the supernatant layer,the residual tissue containing the non-solubilized type I and type III collagens whereas the supernatant contains type IV collagen is practically free from type I and type III collagens,precipitation is made to take place in the supernatant layer at a moderately acidic pH of 4.5-5.5 to remove a precipitate of impurities, the supernatant layer is collected and the collagen it contains is precipitated by precipitation with a salt at a neutral pH, the precipitated collagen is redissolved in a weakly acid solution which is neutralized, the insoluble impurities are removed, and the collagen is precipitated by acid precipitation with salt.
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Abstract
Human or animal placenta is subjected to moderate enzymatic digestion, in particular with pepsin at an acid pH, then, after separation of the residual tissue the impurities are separated at a moderately acid pH, the collagen is precipitated at a neutral pH, redissolved and the residual impurities precipitated at an acid pH. The collagen obtained can be brought back to a neutral pH and dried in the form of fibres. Completely transparent, physiological and hemocompatible gels and solutions can be prepared. Applications for the fabrication of contact lenses and implants.
126 Citations
15 Claims
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1. A method for extraction of placenta collagens in which the placenta is digested enzymatically, characterized in that starting with human or animal placenta in deep-frozen form which is ground and washed:
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the washed placental tissue is subjected to enzymatic digestion, said digestion being carried out with pepsin at an acidic pH, at a temperature between 0°
C. and 20°
C. for a time between 8 and 24 h. the pepsin content with respect to the deep-frozen placenta being between 0.5 and 1.5%,said suspension is diluted with a volume of water, the pH is adjusted to between 7 and 10, said suspension is allowed to rest for 1 to 24 h at a temperature of between 0° and
20°
C.,the residual tissue is separated from the supernatant layer, the residual tissue containing the non-solubilized type I and type III collagens whereas the supernatant contains type IV collagen is practically free from type I and type III collagens, precipitation is made to take place in the supernatant layer at a moderately acidic pH of 4.5-5.5 to remove a precipitate of impurities, the supernatant layer is collected and the collagen it contains is precipitated by precipitation with a salt at a neutral pH, the precipitated collagen is redissolved in a weakly acid solution which is neutralized, the insoluble impurities are removed, and the collagen is precipitated by acid precipitation with salt. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15)
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14. Transparent collagen gel obtained from human or animal collagen enriched with type IV collagen or consisting essentially of type IV collagen, characterized in that it comprises between 2 to 30% of collagen which is non-denaturated, unmodified, completely transparent, free from striated fibers visible under an electron microscope, and soluble in both acid solutions and physiological saline solutions.
Specification