Moxifloxacin-d4 hydrochloride (BAY 12-8039-d4) is the hydrochloride salt form of deuterium labeled Moxifloxacin (Moxifloxacin). Moxifloxacin is an orally active antimicrobial, that can be used in the research of acute bacterial sinusitis, acute bacterial exacerbations of chronic bronchitis, and community-acquired pneumonia.