METHOD OF PURIFYING LOW MOLECULAR WEIGHT HYALURONIC ACID OR CATIONIZED HYALURONIC ACID VIA PRECIPITATION FROM AQUEOUS SOLUTION BY ADDITION OF ALCOHOL OR ACETONE FOLLOWED BY pH ADJUSTMENT

Abstract

Provided a method of producing a purified hyaluronic acid type which comprises adding a water-soluble organic medium to a solution which comprises a hyaluronic acid type having an average molecular weight of 400 to 100,000 and has a pH of 3 or less to obtain a suspension, and adjusting a pH of the suspension in a range of 3.5 to 8 to precipitate a purified hyaluronic acid type.

1 . A method of producing a purified hyaluronic acid derivative, comprising: adding a water-soluble organic medium to a solution which comprises a hyaluronic acid derivative having an average molecular weight of 400 to 100,000 and has a pH of 3 or less to obtain a suspension; and
 adjusting a pH of the suspension in a range of 3.5 to 8 to precipitate a purified hyaluronic acid derivative.   
     
     
         2 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein a pH of the solution before adding the water-soluble organic medium is 0.1 to 2.5.   
     
     
         3 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein the purified hyaluronic acid derivative is a compound such that a hydroxyl group, a carboxyl group or an amide group contained in a hyaluronic acid is modified.   
     
     
         4 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein the hyaluronic acid derivative is an acylated hyaluronic acid.   
     
     
         5 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein the average molecular weight of the purified hyaluronic acid derivative is 400 to 10,000.   
     
     
         6 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein the hyaluronic acid derivative is a hyaluronic acid derivative that dissolves in a solution having a pH of 3 or less, and   wherein the solution is a solution that suspends when 2.5 to 20 mass part of the water-soluble organic solvent is added to one mass part of the solution.   
     
     
         7 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein the purified hyaluronic acid derivative comprises a 90 mass % or more of the hyaluronic acid derivative.   
     
     
         8 . The method of producing the purified hyaluronic acid derivative according to  claim 1 ,
 wherein the purified hyaluronic acid derivative is a purified hyaluronic acid derivative except a cationized hyaluronic acid.   
     
     
         9 . A purified hyaluronic acid derivative obtained by the method of producing the purified hyaluronic acid derivative according to  claim 1 , comprising a 90 mass % or more of the hyaluronic acid derivative.