Chemically modified hyaluronic acid or salts thereof, and a process for producing thereof
AssigneesChisso Corporation, Nobuhiko Yui
InventorsNobuhiko Yui, Tooru Ooya, Ikuo Sato
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Abstract
This invention relates to a chemically modified hyaluronic acid and salts thereof, which are obtained by O-acylating, alkoxylating or crosslinking a complex consisting of hyaluronic acid or a salt thereof and a cationic compound in a nonaqueous solvent, and a process for the production thereof. The nonaqueous solvent used in the invention is preferably one or more solvents selected from the group consisting of chloroform, toluene, methylene chloride and heptane.
Claims10
A process for producing a chemically modified hyaluronic acid or a salt thereof, which comprises O-acylating, alkoxylating or crosslinking a complex consisting of hyaluronic acid or a salt thereof and a quaternary ammonium salt having at least one alkyl group with not less than 8 carbon atoms in a nonaqueous solvent.
The process as claimed in claim, 1, in which the O-acylating reaction is a reaction with an organic acid employing at least one acid catalyst selected from the group consisting of mineral acids, organic acids and Lewis acids, a reaction with an organic acid employing at least one dehydrating agent selected from the group consisting of N,N′-dicyclohexylcarbodiimide, 2-chloro-1-methyl pyridiniumiodide and N,N′-carbonyl diimidazole, or an O-acylation employing an acid anhydride or an acid halide in the presence of a base.
A method for reducing an amount of a pyrogen and/or an antigenic substance in a chemically modified hyaluronic acid or a salt thereof, wherein a complex consisting of hyaluronic acid or a salt thereof and a quaternary ammonium salt having at least one alkyl group with not less than 8 carbon atoms is O-acylated, alkoxylated or crosslinked in a nonaqueous solvent to produce a chemically modified hyaluronic acid or a salt thereof having a reduced amount of a pyrogen and/or an antigenic substance.
Dependencies are inferred from the claim text.