Apremilast Cocrystals with Phenolic Coformers.

Apremilast (APR) is an anti-inflammatory drug commonly used in the treatment of psoriasis. In efforts to enhance its solubility, several cocrystals with similar structural features have been developed. This study investigates the cocrystallization of APR with four phenolic-type coformers: phenol, catechol, pyrogallol, and hydroxyquinol. These coformers differ in the number and position of their hydroxyl groups, with their melting points varying by as much as 100 °C. Four novel cocrystal forms were synthesized, purified, and characterized using X-Ray diffraction and thermal analysis techniques. Surprisingly, the resulting cocrystals exhibited minimal differences in their melting points. The molecular packing of APR appears to limit the network-forming potential of the hydroxyl groups, a conclusion supported by the solved crystal structures, Hirshfeld surface analysis, and differential scanning calorimetry (DSC) results.