GB683254A - Improvements in or relating to a process of purifying erythrotin (vitamin b) - Google Patents

Abstract

Erythrotin (vitamin B12) is purified by contacting an aqueous solution thereof at acid pH with a carboxylic ion-exchange resin and eluting the erythrotin from the resin. If desired, the impure solution may first be contacted with the resin at an alkaline pH to fix the impurities, but not the erythrotin; the resin is then washed to remove the impurities and the pH of the resin and solution adjusted to acid conditions, e.g. pH 3-6, preferably 5. In a preferred method the resin in the form of a column is adjusted to pH 8.5 with aqueous pyridine, alkaline phosphate or other alkali for the first step. After passing the erythrotin solution through it, the resin is washed with water or dilute acid to bring its pH to 5 and the acid erythrotin solution passed through. The resin is washed with dilute mineral acid to remove non-adsorbed substances and the erythrotin eluted with an acid or alkaline solution containing a water-miscible polar organic solvent, e.g. pyridine, tributylamine, picoline, acetone, alcohols or glycols. When an organic base is used, this serves both as alkali and organic solvent. Acetone with hydrochloric acid is the preferred eluting agent, the acid concentration being 0.05-0.1,N. Examples are given of the treatment of liver extract and a Streptomyces culture medium. The eluate may be evaporated in vacuo or freeze-dried and the erythrotin may be further purified by adsorption on alumina or silica gel and/or recrystallization. Actidione from the culture medium may be removed by precipitation with excess acetone and ammonium sulphate and extraction with ethanol.