Purifying And Decoloring Method Of Bacitracin Zinc

Bacitracin Zinc is a widely used metallopeptide antibiotic with a potent bactericidal activity directed primarily against Gram-positive organisms. At present there is only feed grade BcZn product in our country, so it is very important to develop a processing method for producing pharmacopoeia specification BcZn.By using extraction and membrane separation method, the purification of bacitracin zinc were investigated in this paper. In the extract method, the effects of hydrochloric acid and ammonia aqueous solution on the purified result, the decolored effects of active carbon on different pH solution, and the effects of different zinc salts for crystallization of final BcZn on the potency and product yield were discussed. The final processing conditions were ascertained that hydrochloric acid aqueous solution is solvent, acetic acid butyric ester is extractant, active carbon is decolored agent, and zinc salt for crystalling is ZnSO₄ or ZnCl₂.The average potency of purified product has increased about 50 percent, and the average yield is up to 51 percent. The color and potency of the obtained product meet the US pharmacopoeia specification. In the purification study with membrane separation method, the ultrafiltration membranes of molecular weight cut-off 60000 and 10000 with inner-hollow fibre structure, and MWCO 8000, 3500 and 2500 with twist structure were used. The effects of different pH of solution on the ultrafiltration process were discussed in this part. The results show that the potency isn't increased so much, and the color can't satisfy the pharmacopoeia specification.The system of determining the diameter of inhibition-zone was established in this paper and successfully used in the microbial assay method of antibiotics. The assay results determined by the system show the high repeatability and precision, and the system solve the problems resulted by handiwork method.In this paper, suitable HPLC method with gradient elution was used in order to separate components of Bacitracin in different BcZn samples, the assay results show the potency of BcZn changes along with the active components of Bacitracin in a consistent trend.