Hariprasad, V.M.Nechipadappu, S.K.Trivedi, D.R.2026-02-052016Crystal Growth and Design, 2016, 16, 8, pp. 4473-448115287483https://doi.org/10.1021/acs.cgd.6b00606https://idr.nitk.ac.in/handle/123456789/25950Pharmaceutical cocrystals of an analgesic drug ethenzamide (ETZ) with various coformers, namely, gallic acid (GA), 2-nitrobenzoic acid (2NB), 3-nitrobenzoic acid (3NB), 2,4-dinitrobenzoic acid (DNB), and 3-toluic acid (3TA) were synthesized by the solvent evaporation method. All the cocrystals were characterized by various analytical techniques, and the crystal structures were determined by the single-crystal X-ray diffraction method (SCXRD). SCXRD analysis revealed that all the synthesized cocrystals were formed through a robust supramolecular acid-amide heterosynthon except the ethenzamide/gallic acid cocrystal, where molecules interacted through O-H···O hydrogen bond involving -OH of gallic acid and oxygen of amide group of the ETZ molecule. The physicochemical properties such as stability, hygroscopicity, and solubility studies of the ETZ-GA cocrystal were evaluated. It was found that the ETZ-GA cocrystal has a higher solubility (2-fold) than that of the pure ETZ drug molecule. Hygroscopic study of the ETZ-GA cocrystal revealed that synthesized cocrystal was non-hygroscopic at ?75% RH conditions. The ETZ-GA cocrystal found to be stable for a time period of four months at ambient temperature. © 2016 American Chemical Society.AmidesHydrogen bondsMoleculesSingle crystalsSolubilityX ray diffractionAnalgesic drugsDrug moleculesNon-hygroscopicPhysicochemical propertySingle crystal X-ray diffraction methodSolubility studiesSolvent evaporation methodTime-periodsSynthesis (chemical)