Novel crystalline forms of gatifloxacin

Abstract

Provided are two novel crystalline forms of gatifloxacin, denominated form O and form V, and methods for their preparation.

1 - 18 . (canceled) 
     
     
         19 . A crystalline form of gatifloxacin characterized by x-ray reflections at about 6.0°, 14.1°, 21.1° and 22.5°±0.2° 2θ. 
     
     
         20 . The crystalline form of gatifloxacin of  claim 19  having an x-ray diffraction diagram substantially as shown in  FIG. 3 . 
     
     
         21 . The crystalline form of gatifloxacin of  claim 19  having a water content of about 1 wt-% to about 3 wt-%. 
     
     
         22 . A method of making the crystalline gatifloxacin of  claim 19  comprising the steps of:
 a) providing, at reflux, a solution of gatifloxacin in acetonitrile,   b) cooling the solution to ambient temperature at a cooling rate of at least about 1° C. per minute whereby a suspension is obtained,   c) further crash cooling the suspension to about 5° C. or less,   d) isolating the solid from the suspension, and   e) treating the isolated solid with moist gas to obtain form V.   
     
     
         23 . Gatifloxacin crystalline form V. 
     
     
         24 . (canceled) 
     
     
         25 . A pharmaceutical composition comprising gatifloxacin form V.