crystalline forms of fusidic acid and procedures for obtaining them.

crystalline forms of fusidic acid and processes for their preparation. By crystallization in mixtures of water-alcohol or ketone of low molecular weight can be obtained various crystalline forms of fusidic acid, designated Forms I, II and III. Each of these crystalline forms having a melting point, infrared spectra, X-ray diffractogram of dust and a record of differential calorimetry scanning characteristic. The crystalline form identified as Form III is stable hemihydrate.