Studies on the crystal forms of pefloxacin: preparation, characterization, and dissolution profile.

Different crystal forms of pefloxacin were prepared using solvents of varying polarity. X-ray diffractometry (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), infrared absorption spectroscopy (FT-IR), melting point, microcalorimetry and in vitro dissolution rate studies were conducted to investigate various characterstics of different crystalline forms of the pefloxacin. Five different polymorphs of pefloxacin have been identified on the basis of instrumental techniques. The polymorphs differed in their dissolution profile and all of them showed unusual behavior of highest dissolution in the first 15 min. The rate of dissolution went on decreasing and got stabilized to a constant value after 4 h.