Ion exchange purification of neomycin

Claim 1

THE PROCESS OF SEPARATING FERMENTATION-PRODUCED NEOMYCIN FROM A MIXTURE THEREOF WITH GENETIC CONTAMINANTS, WHICH COMPRISES CONTACTING THE MIXTURE WITH A CATION EXCHANGE RESIN, WHICH DERIVES ITS EXCHANGE CAPACITY ESSENTIALLY FROM CARBOXYLIC GROUPS AND IS IN ITS AMINE SALT FORM, THE AMINE BEING SELECTED FROM THE GROUP CONSISTING OF ALKYL AMINES, CYCLOALKYL AMINES, ARALKYL AMINES, AND UNSUBSTITUTED AND ALKYL SUBSTITUTEDX PIPERIDINE, PYRROLIDINE AND MORPHOLINE, SEPARATING THE NEOMYCINSTRIPPED EFFLUENT FROM THE RESIN, CONTACTING THE RESIN WITH A SUFFICIENT QUANTITY OF DILUTE MINERAL ACID AT A PH IN THE RANGE OF ABOUT 1.5 TO ABOUT 4.5 TO ELUTE ALL THE NEOMYCIN AND ANY AMINE PRESENT ON THE RESIN, MIXING THE THUS-PRODUCED ELUATE WITH A SUBSTANTIALLY WATER-MISCIBLE POLAR ORGANIC SOLVENT WHEREIN THE NEOMYCIN SAIT OF THE MINERAL ACID IS INSOLUBLE AND ANY AMINE SALT OF THE MINERAL ACID PRESENT IS SOLUBLE, AND RECOVERING THE PRECIPITATED NEOMYCIN SALT.