PROCESS FOR PREPARING MONOPROPIONYL ERYTHROMYCIN LAURYL SULFATE.

摘要

A process for preparing monopropionyl erythro-mycin lauryl sulfate comprising: treating an aqueous solution of erythromycin acetate (pH 7) as obtained from the broth by the conventional method and containing about 30,000 to 45,000 micrograms erythromycin per millilitre, with a water miscible organic solvent, bringing the pH of the solution to about 8.2 to 8.5, adding a salting out agent which is soluble in water in a quantity sufficient to saturate the solution, stirring and heating the mixture to about 45C and adjusting the pH between 9.5 and 10.8, separating the organic solvent phase from the lower saturated aqueous phase, extracting the lower aqueous phase once more with a smaller quantity of the said organic solvent as above, mixing the two organic solvent phases, drying the combined organic solvent phase with a drying agent, filtering, concentrating the organic solvent phase to a smaller volume, adding an excess of both sodium lauryl sulfate and propionic anhydride in a one step reaction allowing to stand for a few hours, adding distilled water slowly till crystallisation starts in the clear solution, allowing to stand for some time for completion of crystallisation, filtering the monopropionyl erythromycin lauryl sulfate obtained, washing with cooled distilled water containing 30 to 40 per cent, of the water miscible organic solvent used above, followed by washing with water alone  and drying under vacuum at about 65C.