STABLE CRYSTAL OF 4-OXOQUINOLINE COMPOUND.

摘要

The present invention provides a crystal of 6-(3-chloro-2 -fluorobenzyl) -1-[(S)-1-hydroxymethyl-2-methylpropyl] -7-methoxy -4-oxo-1, 4-dihydroquinoline-3 -carboxylic acid, which shows a particular powder X-ray diffraction pattern of a characteristic diffraction peaks at diffraction angles 2theta ( degree ) as measured by powder X-ray diffractometry. The crystal of the present invention is superior in physical and chemical stability.