Patent ID: 11919976
Assignee: SHANDONG FOCUSFREDA BIOTECH CO., LTD
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  Y | IPC C

Claim 5:
6. The preparation and purification method for cationic quaternary ammonium salt of sodium hyaluronate in homogeneous medium according to claim 1, wherein the method further comprising the following steps:
after the graft reaction, subjecting the reaction system to alcohol precipitation to obtain a mixed solution A containing a first precipitate, separating the first precipitate, and sufficiently dissolving the first precipitate with water to obtain a feed liquid;
adding a 1-5 wt % NaCl or KCl aqueous solution to the feed liquid, stirring to allow sufficient dissolution, and adjusting a pH value of the feed liquid to 6.0-7.5;
carrying out a second alcohol precipitation, separating a second precipitate, dissolving the second precipitate with water, and then carrying out alcohol precipitation again to obtain a third precipitate; and
washing the third precipitate with alcohol, dewatering, and drying to obtain a final product.