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US 7,125,967 B2Granted
Water-soluble chitosan having low endotoxin concentration and methods for making and using the same
AssigneeAdjuvant Pharmaceuticals, LLC
InventorsWilliam M Hung, Katrina L. Bergbauer, Kai C. Su, Guigui Wang, Sherry Wages
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Abstract
Water-soluble chitosan having a low concentration of endotoxin is disclosed. Products containing the water-soluble chitosan are also disclosed. Methods of making and using water-soluble chitosan having a low concentration of endotoxin are further disclosed.
Claims38
A method of making water-soluble chitosan, said method comprising the steps of:
- contacting water-insoluble chitosan with a basic solution for a first period of time;
- rinsing the water-insoluble chitosan to remove any residual basic solution;
- partially acetylating the water-insoluble chitosan in a reaction solution containing a phase transfer agent to form partially acetylated water-soluble chitosan;
- dissolving the partially acetylated water-soluble chitosan in an aqueous solution containing a surfactant;
- adjusting a pH of the aqueous solution to a pH of at least 7.0;
- adding a water-miscible solvent into the aqueous solution having a pH of at least 7.0;
- further adjusting the pH of the aqueous solution to a pH of at least 8.0 to cause precipitation of water-soluble chitosan having low endotoxin content;
- separating the water-soluble chitosan having an endotoxin content of less than about 100 equivalent units per gram of dry water soluble chitosan from the aqueous solution;
- and
- washing the water-soluble chitosan having low endotoxin content with the water-miscible solvent.
7 more elements
A method for making water-soluble chitosan, said method comprising the steps of:
- contacting water-insoluble chitosan with a NaOH solution for a first period of time of greater than 1 hour;
- partially acetylating the water-insoluble chitosan in a reaction solution containing a phase transfer agent to form partially acetylated water-soluble chitosan;
- dissolving the partially acetylated water-soluble chitosan in an aqueous solution containing a surfactant and having a pH of from about 7.0 at about 7.4;
- and
- adding a water-miscible solvent into the aqueous solution and further adjusting the pH of the aqueous solution to a pH of at least 8.0 to cause precipitation of water-soluble chitosan having endotoxin content of less than about 100 equivalent units per gram of dry water soluble chitosan from the aqueous solution/water-miscible solvent mixture.
2 more elements
Dependencies are inferred from the claim text.