Patent ID: 9598504
Date: 2017-03-21
CPC Classifications: C08B,D01F,D06L

Claim:
1. A process for making a) low-endotoxin chitosan or b) low-endotoxin alkali-stable polysaccharides comprising: suspending c) bulk chitosan fibers or chitosan flakes or d) alkali-stable polysaccharides, respectively, having endotoxins therein in a solution of alcohol and water to form a reaction mixture; adding ammonia to the reaction mixture to raise pH of the reaction mixture to above 9.5; heating the reaction mixture with the pH above 9.5 at a temperature of at least 130° C. for at least 20 minutes; then cooling the reaction mixture to less than 60° C.; sparging the cooled reaction mixture with an inert gas to remove ammonia from the cooled reaction mixture containing the a) chitosan fibers or flakes or b) alkali-stable polysaccharide; at least partially separating the a) chitosan fibers or flakes or b) alkali-stable polysaccharide from the sparged reaction mixture; rinsing the separated a) chitosan fibers or flakes or alkali-stable polysaccharide with an endotoxin-free aqueous liquid to form a rinsed mass; further rinsing the rinsed mass with liquid comprising a water-free alcohol to remove water; and drying the rinsed mass with water removed at a temperature below 100° C.