Ciprofloxacin is a quinolone that is quinolin-4(1H)-one bearing cyclopropyl, carboxylic acid, fluoro and piperazin-1-yl substituents at positions 1, 3, 6 and 7, respectively. It has a role as an antiinfective agent, a topoisomerase IV inhibitor, an antibacterial drug, an EC 5.99.1.3 [DNA topoisomerase (ATP-hydrolysing)] inhibitor, a DNA synthesis inhibitor, an antimicrobial agent, an environmental contaminant and a xenobiotic. It is a quinolone antibiotic, a fluoroquinolone antibiotic, a member of cyclopropanes, a N-arylpiperazine, a quinolone, an aminoquinoline and a quinolinemonocarboxylic acid. It is a conjugate base of a ciprofloxacin(1+). It is a tautomer of a ciprofloxacin zwitterion.