Cocrystals of Ethenzamide: Study of Structural and Physicochemical Properties

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• 作者：Vijaya M. Hariprasad ; Sunil Kumar Nechipadappu ; Darshak R. Trivedi
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4473-4481
• 全文大小：469K
• 年卷期：0
• ISSN：1528-7505

文摘

Pharmaceutical 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.