Kinetic Retraction at the Onset of Concomitant Crystallization and Implication on Polymorphic Formation.

The four-quadrant regimes of attainable polymorph crystallization (FQR-APC) plot was recently developed through numerical simulations of crystallization kinetics of a dipolymorphic system. Retraction in the polymorphic composition of the most stable form in crystallized samples was unveiled a characteristic indication of concomitant polymorphism. Comparisons were made with a recently developed concept, the Ostwald ratio (OR), in light of characterization of polymorphic formation. It was shown that both schemes display a good agreement in describing polymorphic outcomes, despite their distinct theoretical origins.