Cocrystals of Isoniazid with Polyphenols: Mechanochemical Synthesis and Molecular Structure

Isoniazid is used as anti-tuberculosis drug which possesses functional groups capable of forming hydrogen bonds. A series of cocrystals of isoniazid (INH) with polyphenolic coformers such as catechol (CAT), orcinol (ORC), 2-methylresorcinol (MER), pyrogallol (PYR), and phloroglucinol (PLG) were prepared by solvent-assisted grinding. Powder cocrystals were characterized by infrared (IR) spectroscopy and X-ray powder diffraction. The crystal structure of the cocrystals revealed the unexpected hydration of the INH-MER cocrystal and the preference of the (phenol) O&ndash
H∙∙∙N (pyridine) and (terminal) N-H∙∙∙O (phenol) heterosynthons in the stabilization of the structures. The supramolecular architecture of the cocrystals is affected by the conformation and the substitution pattern of the hydroxyl groups of the polyphenols.