Process for purifying diacerein

摘要

A process for obtaining diacerein with an aloe-emodine content lower thatn 100 ppm, prefereably of 0-5 ppm, is herein disclosed. The process comprises subjecting an an aqueous-organic solution of a diacerein salt with a weak base to extraction with a water immiscible or sparingly water-miscible solvent, such as toluene, aetates of C₂-C₄ alcohols, halohydrocarbons and the like.