Cocrystal Eutectic Constants and Prediction of Solubility Behavior

Cocrystal eutectic constants (Keu), the ratio of solution concentrations of cocrystal components at the eutectic point, are a fundamental indicator of phase behavior and are shown to be a function of the solubility ratio of cocrystal and drug in pure solvent. Keu is shown to depend on solution chemistry including (i) solvent, (ii) complexation, and (iii) ionization, as does the solubility of cocrystals. More than 40 eutectic constants are presented and shown to provide essential information for cocrystal synthesis, selection, and formulation.