Stable crystal of 4-oxoquinoline compound

摘要

Provision of a stabilized crystal of 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1, 4-dihydroquinoline-3-carboxylic acid (compound A). A crystal of compound A, which shows a particular X-ray powder diffraction pattern of a characteristic diffraction peaks at diffraction angles 2theta(°) as measured by X-ray powder diffractmetry.