GATIFLOXACIN RELATED COMPOUND A;1-Cyclopropyl-6-fluoro-1,4-dihydro-8-hydroxy-7-(3-methyl-1-piperazinyl)-4-oxo-3-quinolinecarboxylic Acid;O-Desmethyl Gatifloxacin;1-Cyclopropyl-6-fluoro-8-hydroxy-7-(3-Methylpiperazin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid;Gatifloxacin USP IMpurity A