Cocrystallization and coamorphization are similar yet
independent
approaches toward modifying various pharmaceutically relevant properties
of modern drug compounds, in particular, solubility, dissolution rate,
and the associated bioavailability. In this work, both strategies
were applied to enzalutamide (Enz), a poorly soluble nonsteroidal
antiandrogen drug, which led to the development of new multicomponent
crystalline and amorphous solid forms of the drug with saccharin (Schr)
in a 1:1 molar ratio. The structural analysis of the cocrystal formed
by Enz and Schr revealed multiple intermolecular interactions between
the components. Both Enz···Enz and Schr···Schr
interactions were observed in the crystal packing. With the aid of
N–H···O, C–H···O, C–H···N,
and C–H···S hydrogen bonds, the molecules were
aggregated into a three-dimensional hydrogen-bonded network. In the
coamorphous composition, however, the components do not seem to involve
in any strong intermolecular interactions and undergo recrystallization
separately upon storage at room and elevated temperatures. The thermodynamic
solubility of the cocrystal, evaluated using eutectic concentrations
of the components, was found to be higher than that of the parent
enzalutamide over an entire range of physiological pH values. The
advantages and drawbacks of both formulation methods were analyzed
and discussed, taking into account a tradeoff between physical stability
and dissolution performance of the considered coamorphous composition
and the cocrystal.