Marbofloxacin-d 8 (hydrochloride) is deuterium labeled Marbofloxacin (hydrochloride). Marbofloxacin hydrochloride is a third generation fluoroquinolone and orally active antimicrobial agent, which has a broad spectrum bactericidal activity and good efficacy. Marbofloxacin hydrochloride can be used for the research of infections by Gram-positive and Gram-negative bacteria and Mycoplasma.