Natural Eutectic Solvent Mixture of l-Menthol/Malonic acid (4?:?1) and Its Ibuprofen Solution: Thermal and Physical Characterizations and NMR Studies of Molecular Interaction |
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Authors: | Jehovani M Lázaro-Rangel Analilia Sánchez Dr Motomichi Inoue Dr José Luis Olivares-Romero Dr Rocío Meza-Gordillo Dr Magali Salas-Reyes Dr Claudia Virués Dr Zaira Domínguez |
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Institution: | 1. Instituto de Química Aplicada, Universidad Veracruzana, Av. Dr. Luis Castelazo Ayala S/N Col. Industrial-Ánimas, Xalapa, 91190 Ver., México;2. Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Blv. Luis Encinas y Rosales S/N, Col. Centro, Hermosillo, Sonora, 83000 México;3. Red de Estudios Moleculares Avanzados, Clúster Científico y Tecnológico BioMimic, Campus III, Instituto de Ecología, Carretera antigua a Coatepec 351, El Haya, Xalapa, 91073, Ver. México;4. Departamento de Ingeniería Química y Bioquímica, Tecnológico Nacional de México/IT de Tuxtla Gutiérrez, Carretera Panamericana km 1080, Tuxtla Gutiérrez, 29050, Chis. México |
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Abstract: | A eutectic mixture of L-menthol and malonic acid, Me / MA (4 : 1), was characterized by calorimetry and other physical measurements. The new deep eutectic solvent (m.p. 6 °C) solvates 338 mg of ibuprofen per mL, and the solution is stable in a wide temperature range. Strategies of NMR titration used in supramolecular chemistry were employed to explore binding forces between the eutectic constituents as well as solute-solvent interaction in ibuprofen solution. Even in acetonitrile, Me 4 MA is formed through a hydrogen-bonding network, where the constituents act as hydrogen donors and acceptors at the same time. The estimated association constant is around 30 M?1; the binding forces are enough to build the eutectic mixture at high concentrations. The aggregate Me 4 MA forms a molecular complex with ibuprofen in acetonitrile as a result of the cooperative effect of the constituents. In addition, van der Waals interactions are operative between ibuprofen and menthol in the saturated IB - Me / MA (4 : 1) solution. |
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Keywords: | drug delivery hydrogen bonds ibuprofen NADES NMR titration |
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