Stable crystal of 4-oxoquinoline compound

Abstract

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 2θ(°) as measured by X-ray powder diffractmetry.

1 - 16 . (canceled) 
     
     
         17 . A method for the prophylaxis of a Human Immunodeficiency Virus (HIV) infection which comprises administering a crystal (type II crystal) of 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, which has a powder X-ray diffraction pattern having a characteristic diffraction peak at a diffraction angle 2θ(°) of 6.56, 13.20, 19.86, 20.84, 21.22, 25.22° as measured by powder X-ray diffraction. 
     
     
         18 . The method according to  claim 17 , wherein the compound is administered at a dosage for inhibiting activity specific for integrases.