Polymorphism and solvatomorphism of bicalutamide

Single crystals of the crystallosolvate [bicalutamide + DMSO] with 1:1 stoichiometry were grown, and their structures were solved by X-ray diffraction methods. Polymorphic modifications I and II, the amorphous state, and the DMSO crystallosolvate of bicalutamide were prepared and thermochemistry of fusion processes was studied by DSC technique. The temperature dependence of the saturated vapor pressure of polymorphic form I was obtained and the thermodynamic characteristics of the sublimation process including the crystal lattice energy were calculated. The solution enthalpies of the forms under consideration and the crystallosolvate were acquired by the solution calorimetry procedure. The phase transition enthalpies estimated for form I, form II, and the amorphous state followed the rank order: form I— > form II, form I— > amorphous state, and form II— > amorphous state. The crystal lattice energy of polymorphic form II was determined using the results of sublimation and solution calorimetric experiments. The difference between the crystal lattice energy of the crystallosolvate and unsolvated phases was observed. The dissolution kinetics of forms I, II, the amorphous state, and DMSO solvate in water were investigated.