Gatifloxacin-d3 (hydrochloride) is the deuterium labeled Gatifloxacin (hydrochloride). Gatifloxacin hydrochloride (AM-1155, BMS-206584, PD135432) is a potent fluoroquinolone antibiotic with broad-spectrum antibacterial activity. Gatifloxacin hydrochloride inhibits bacterial type II topoisomerases (IC50=13.8 µg/ml for S. aureus topoisomerase IV) and E. coli DNA gyrase (IC50 = 0.109 µg/ml). Gatifloxacin hydrochloride can be used to treat bacterial conjunctivitis in vivo.