Method for producing clinical dextran

Claim 1

IN THE SEPARATION OF HYDROLYZED DEXTRAN FROM AQUEOUS SOLUTIONS THEREOF RESULTING FROM THE HYDROLYTIC ACTION OF THE DEXTRANASE ELABORATED BY THE MOLD ASPERGILLUS WENTII ON DEXTRAN OF RELATIVELY HIGH MOLECULAR WEIGHT, WHICH SOLUTIONS CONTAIN, IN ADDITION TO THE HYDROLYZED DEXTRAN, DEXTRANIC ACID PRODUCED AS A BY-PRODUCT OF THE HYDROLYSIS OF THE DEXTRAN BY SAID MOLD, THE IMPROVEMENT WHICH COMPRISES SEPARATING THE HYDROLYZED DEXTRAN FROM SAID SOLUTION IN A CONDITION IN WHICH IT IS SUBSTANTIALLY FREE OF THE DEXTRANIC ACID, BY THE STEP OF (A) ADDING TO THE SOLUTION, AT A PH OF 1.0 TO 5.0, ABOUT 50% BY VOLUME OF A PRECIPITANT BY THE HYDROLYZED DEXTRAN SELECTED FROM THE GROUP OF WATER-MISCIBLE LOWER ALIPHATIC ALCOHOLS AND KETONES, COLLECTING THE PRECIPITATED HYDROLYZED DEXTRAN AND THE STEP (B) OF DISSOLVING THE PRECIPITATED HYDROLYZED DEXTRAN IN WATER, AND ADDING TO THE SOLUTION THUS OBTAINED, AT A PH OF 1.0 TO 5.0, ABOUT 50% OF THE PRECIPITANT FOR THE HYDROLYZED DEXTRAN, STEP (B) BEING PERFORMED AT LEAST ONCE.