Bacitracin powder, min. 55 IU/mg

Bacitracin from Bacillus licheniformis consists of several peptides (A, B, C, D, E, F1-3), bacitracin A, a cyclic dodecapeptide, being the most important component with approximately 70%. For its bactericidal action, the presence of divalent cations (eg, zinc) is required, with which Bacitracin forms stable complexes. Like Vancomycin, it inhibits the biosynthesis of the cell wall (especially gram-positive bacteria and cocci) by binding to bactoprenylpyrophosphate.

Bacitracin is very stable as a dry substance (moisture content <1%) with a shelf life of about 15 months at room temperature and is stable for about 15 months. At higher temperatures (>55°C) the antibiotic is unstable.

Bacitracin is readily soluble in water or alcohols (1g/mL) and forms stable salts with zinc. In aqueous solutions, it is relatively stable in the acidic pH range (pH4-5) and relatively rapidly inactivated in the range above pH5 (pH5 - 9) at 25°C. Above pH8 it is not durable at all. In solution, 10% of the activity is lost at +2°C to +8°C within about 2 months.