Polymorphism of spironolactone.

Single crystals of two polymorphic and four solvated crystalline forms of spironolactone (C24H32O4S) were obtained using different solvents. The morphology, symmetry, and crystallographic parameters were determined for all crystal forms except for the one obtained from methanol. The stability and transformation of each type of crystal were studied by DSC, TGA, and X-ray diffraction analysis. The structural data of three forms allowed the observation of the change of conformation of the molecules of spironolactone in the three different lattices.