Zabofloxacin (DW-224a Free base) is a potent and seletive inhibitor of the bacterial type II and IV topoisomerases. Zabofloxacin has excellent activity against gram-positive pathogens including Steptococcus aureus, Streptococcus pyogenes and S.pneumonia. Zabofloxacin is a novel fluoronaphthyridone quinolone that is considered as an alternative antibiotic for treatment of quinolone-susceptible (QSSP) and quinolone-resistant gonorrhea (QRSP)^[1]. IC50 & Target: IC50: bacterial; topoisomerases^[1] In Vitro: Zabofloxacin shows a highly potent in vitro activity against clinical isolates of penicillin-sensitive S. pneumoniae (minimum inhibitory concentration, MIC₉₀: 0.03 mg/L) and penicillin-resistant S. pneumoniae (MIC₉₀: 0.03 mg/L). Against quinolone-resistant S. pneumoniae, zabofloxacin (MIC₉₀: 1 mg/L) is more active than ciprofloxacin, sparfloxacin, and moxifloxacin^[1].