Piracetam Co-Crystals with OH-Group Functionalized Carboxylic Acids

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• 作者：Martin Viertelhaus ; Rolf Hilfiker ; Fritz Blatter ; Markus Neuburger
• 刊名：Crystal Growth & Design
• 出版年：2009
• 出版时间：May 6, 2009
• 年：2009
• 卷：9
• 期：5
• 页码：2220-2228
• 全文大小：286K
• 年卷期：v.9,no.5(May 6, 2009)
• ISSN：1528-7505

文摘

We report the synthesis, crystal structures, and basic physicochemical properties of six co-crystals of piracetam. Co-crystals of piracetam with l-tartaric acid, with citric acid in a 1:1 and 3:2 ratio, with racemic mandelic acid, and with l-mandelic acid, as well as a piracetam−citric acid ethanol solvate were found in a focused screening approach. Sample amounts of up to several hundred milligrams of each co-crystal were obtained from either solvent-drop grinding, solution evaporation, or crystallization from solution. Crystal structure analysis revealed that the often observed amide-carboxylic acid R²₂(8) synthon is rarely found in the herein reported crystal structures. The mentioned motif can be used as a target for hydrogen bonds; however, in presence of a multitude of hydrogen bond donors and acceptors it cannot serve for an anticipation of co-crystals. Compared to piracetam the piracetam−l-tartaric acid co-crystal shows improved hygroscopic properties.