Azithromycin-d3 is intended for use as an internal standard for the quantification of azithromycin (Item No. 15004) by GC- or LC-MS. Azithromycin is a macrolide antibiotic. It is active against S. pneumoniae, S. aureus, N. gonorrhoeae, M. pneumoniae, H. pylori, C. trachomatis, and H. influenzae in vitro (MIC90s = <0.01-2 mg/L). Azithromycin increases survival in mouse models of intraperitoneal S. pyogenes, S. pneumoniae, E. faecalis, or H. influenzae infection (ED50s = 0.78, 8.7, 12.7, and 30.3 mg/kg, respectively). It inhibits replication of severe acute respiratory coronavirus 2 (SARS-CoV-2), but not Middle East respiratory syndrome CoV (MERS-CoV), when used at concentrations of 5 and 10 μM. Azithromycin also decreases plasma levels of IL-6, TNF-α, and IL-1β and increases survival in a mouse model of LPS-induced sepsis when administered at a dose of 100 mg/kg. Formulations containing azithromycin have been used in the treatment of a variety of bacterial infections.
