| abstract |
The present invention relates to a method for modifying polysaccharides. This method comprises (a) modifying a (X—R—C (O) NH) b R ′ type in the presence of a base (preferably a combination of water and isopropanol) in the presence of a base. Polyetheramine (wherein R ′ is a polyether, b = 1, 2 or 3, X is a halogen (preferably Cl or Br), and R is an alkyl group (which may be substituted) Or the aromatic group (which may be substituted), and (b) the product obtained in step (a) is at least partly obtained by membrane separation in the presence of NaCl. A step of purifying, wherein the purification is carried out at a pH of 9 to 13 (preferably 10 to 12), and (c) at least the product obtained in step (b) is separated by membrane separation. A partial purification step, the purification comprising a pH After neutralization at 6-8 (preferably 6.5-7.5), if necessary, the product is freeze-dried and the freeze-dried product is washed (preferably with ethanol) And a step that is performed after. |