ethyl (R)-9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylate Levofloxacin DiaMine Levofloxacin Impurity 4 Levofloxacin Impurity 18 Levofloxacin Tetrafluoro Impurity 1 Levofloxacin Hydroxy Acid Levofloxacin (R)-9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid 9-Piperazino Levofloxacin 9-Defluoro-9-(4-Methyl-1-piperazinyl) Levofloxacin Levofloxacin Impurity 11 Levofloxacin Acyl-β-D-glucuronide Ethyl (S)-9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylate Levofloxacin Impurity 12 Levofloxacin Impurity 16 Levofloxacin Impurity 7 Descarboxyl Levofloxacin Levofloxacin Impurity 19