Abstract
The 2:1 co-crystal of nadifloxacin [systematic name: 9-fluoro-8-(4-hy-droxy-piperidin-1-yl)-5-methyl-1-oxo-6,7-di-hydro-1H,5H-pyrido[3,2,1-ij]quinoline-2-carb-oxy-lic acid] with oxalic acid, C19H21FN2O4·0.5C2H2O4, was prepared by slow evaporation from a chloro-form:acetone solvent system. Nadifloxacin belongs to the group of anti-bacterial drugs. The co-crystal is stabilized through an intra-molecular O-H⋯O bond and inter-molecular hydrogen bonds. It was studied by FT-IR spectroscopy, differential scanning calorimetry and X-ray diffraction. Hirshfeld surface analysis indicated that the major contribution to the packing is from O⋯H/H⋯O inter-actions.