Cocrystal Screening in Minutes by Solution-Mediated Phase Transformation (SMPT): Preparation and Characterization of Ketoconazole Cocrystals with Nine Aliphatic Dicarboxylic Acids

The rapid and efficient cocrystal screening, based on solution-mediated phase transformation (SMPT), was applied to the screening of cocrystals between ketoconazole (KTZ) and nine aliphatic dicarboxylic acids. Cocrystals formed successfully, in minutes, with a change of suspension characteristics, either a cake formation or the formation of large particles. Bulk cocrystals were characterized by powder X-ray diffraction, thermal analysis, and Raman spectroscopy. Single crystals were grown, and molecular structures were determined. Three previously reported cocrystals were reproduced, and six new cocrystals were discovered, including one that was reported as a failure in literature by solution or grinding method. Two hydrogen-bonded motifs are observed in these nine cocrystals: Most cocrystals form hydrogen bonded discrete tetramer with two KTZ and two acids molecules; while two cocrystals form infinite chain. This study demonstrated the high efficacy of cocrystal generation using the slurry screening method. It should be fully utilized in future cocrystal screening.