Process for the manufacture of hydroxocobalamine from cyanocobalamine

摘要

Hydroxocobalamine is obtained from an aqueous solution of cyanocobalamine and a ferrous salt having a pH between 3 and 5, by adding to this solution a strong base to bring the pH to a value over 6.2 to precipitate the cyanide group as ferrous ferrocyanide, and then oxidizing the solution with air or oxygen to obtain hydroxocobalamine. When the ferrous ferrocyanide has been precipitated either further base is added to bring pH to 8.5 to 9 to precipitate excess ferrous salts, the precipitates are filtered off and air or oxygen bubbled into the solution, or the ferrous ferrocyanide precipitate is filtered off, air or oxygen is bubbled into the solution, and ferric salts precipitated in the oxidation are filtered off. In examples, ferrous chloride and ferrous sulphate are added to aqueous solutions of cyanocobalamine and the bases are sodium hydroxide, potassium hydroxide, barium hydroxide and calcium hydroxide; the hydroxocobalamine is recovered chromatographically on alumina.