Anhydroerythromycin A

Anhydroerythromycin A is a degradation product of the macrolide antibiotic erythromycin. Anhydroerythromycin A is formed via degradation of erythromycin in acidic aqueous solutions in vitro as well as in vivo. Anhydroerythromycin A is active against S. aureus and B. cereus in vitro (MICs = 12.5 and 6.25 μg/ml, respectively). Anhydroerythromycin A also inhibits steroid 6β-hydroxylase activity associated with the cytochrome P450 (CYP) isoform CYP3A in human liver microsomes.