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The solubility of 2,5-furandicarboxylic acid (FDCA) and its synthetic intermediates (e.g., 5-formylfuran-2-carboxylic acid, FFCA) provides fundamental information for the preparation and purification of the value-added biocompound FDCA. We measured the solubility of FDCA and FFCA in binary water + 1,4-dioxane mixtures with different mixing ratios at 303.15 K–342.15 K. The obtained solubility values were correlated with the Jouyban-Acree-van't Hoff model, and the preferential solvation theory was used to study the microscopic dissolution mechanism. The solubility of FDCA/FFCA increases with increasing temperature, and pure 1,4-dioxane dissolves more solutes than pure water. FFCA shows higher solubility than FDCA. In the binary solvent mixtures, the phenomenon of co-solvency exists for both FDCA and FFCA, i.e., at a 1,4-dioxane mole fraction of about 0.60, FDCA and FFCA dissolve the most. Acceptable mean percentage deviations (MPD) (5.5% and 6.9%) are obtained for FDCA and FFCA (Jouyban-Acree-van't Hoff model). The calculated preferential solvation parameters show different dissolution mechanisms at different solvent compositions. When the 1,4-dioxane mole fraction is 0.17~0.62/0.63, FDCA/FFCA are preferentially solvated by 1,4-dioxane. Otherwise, they are preferentially solvated by water. A trend similar to the "co-solvency phenomenon" is observed in the differences in solubility of FFCA and FDCA. This study gives important guidance for the use of binary water and 1,4-dioxane solvents in practical FDCA purification. [ABSTRACT FROM AUTHOR]

Wheat gluten protein (WG) is a kind of plant protein with high quality, low price and rich nutrition. But its low solubility limits its application in food products. Therefore, this work modified WG by pH cycling combined with heat treatment, to enhance its solubility and processing properties. Under the condition of pH cycling combined with heat treatment at 80 °C, the solubility of WG increased from 6.7% to 71.1%; the free sulfhydryl group and surface hydrophobicity were significantly improved (from 2.45 μmol/g and 340.86 to 15.27 μmol/g and 2080.73 respectively). The results of SDS-PAGE and the particle size showed that the WG molecules became smaller. The proteomic method was used and there were 3 subunits (A0A3B6LVB5, A0A3B5XV32 and A0A0A7AA82) observed having an impact on the improvement of solubility. Besides, the emulsifying activity index and emulsifying stability index of modified WG have been improved 8 times and 1.6 times, respectively. Furthermore, the powder oils made of the modified WG exhibited enhanced emulsifying and rehydrating characteristics than those of powder oils made of sodium caseinate and soybean protein isolates. Therefore, this work provided a feasible way to enhance solubility and processing properties of WG, by which the modified WG has a good application prospect in powder oils and other products. • The solubility of WG improved to 71.1% by pH cycling combined with heat treatment. • The change in subunits during treatment has been analyzed by proteomics. • The treated WG exhibited good emulsifying properties in powder oils system. [ABSTRACT FROM AUTHOR]

• Research the solubility of bezafibrate in pure and mixed solvents; • Solubility data was correlated by Jouyban-Acree model and van't Hoff-Jouyban-Acree model; • Discuss the influence of solvent properties on solubility. By using the saturation shake-flask method, the saturated solubility of bezafibrate in neat water, methanol, ethanol, n-propanol and isopropanol and aqueous co-solvent mixtures of methanol (1) + water (2), ethanol (1) + water (2), isopropanol (1) + water (2) and n-propanol (1) + water (2) was experimentally acquired at temperatures from 283.15 Kto 323.15 K and local atmospheric pressure. The maximum solubility magnitudes in mole fraction were recorded in the neat solvents of methanol/ethanol/ n -propanol/isopropanol for corresponding solutions. The mole fraction solubility was described mathematically by using the van't Hoff-Jouyban-Acree and Jouyban-Acree models. The largest value of relative average deviations was 6.23%; and, root-mean-square deviations, 8.92 × 10−5. The local mole fractions of water and co-solvent (methanol, ethanol, n -propanol or isopropanol) around the drug bezafibrate were quantitatively investigated by the use of Inverse Kirkwood–Buff integrals method. Results indicated that the bezafibrate was preferentially solvated by methanol (ethanol, n -propanol or isopropanol) in alcohol-rich and intermediate compositions in the alcohol mixtures; while in water-rich compositions, bezafibrate was preferentially solvated by water. The main factors relating to solvent effect were inspected through Kamlet and Taft linear solvation energy relationships, demonstrating that the cavity formation energy and dipolarity-polarizability in methanol solutions, cavity formation energy and basicity in ethanol solutions, and cavity formation energy in n -propanol (isopropanol) solutions played the principal role upon the bezafibrate solubility variation. [ABSTRACT FROM AUTHOR]

[Display omitted] Due to the poor water solubility of rubidate, it is difficult to prepare and apply. In this work, the objective is to study the dissolution behaviour of rubidate in (methanol + water) and (ethanol + water) mixtures and calculate apparent thermodynamic properties. In selected two mixtures, it increased monotonically with the increasing mass fraction of alcohols at all researched temperatures. When the mass fraction of alcohol is more than w = 0.5, the solubility increases sharply, and the largest mole solubility data was found in pure alcohols (3.344 × 10−2 in methanol at 318.15 K, and 5.506 × 10−2 in ethanol), the minimum data was in pure water (0.581 × 10−6 at 318.15 K), an increase of 5.76 × 104 folds in methanol aqueous, and 9.48 × 104 folds in ethanol aqueous. The commonly used thermodynamic models (Jouyban-Acree model and CNIBS/R-K model) were used to correlate the experimental results. Because the relative average deviation (RAD) of two models was more than 5%, the calculated value by two models was further evaluated with residual value analysis. In the following, the analysis of apparent thermodynamic properties indicated that the dissolution process is apparently not only endothermic but also entropy-driving. The study on the dissolution behaviour of rubidate in alcohol aqueous is helpful to optimize the preparation and purification process. [ABSTRACT FROM AUTHOR]

• Study the solubility of macitentan (form I) in three mixed solvents; • The solubility data were correlated by some thermodynamic models; • Statistical analysis of calculation results; • Some thermodynamic properties of dissolution process were evaluated. Due to macitentan (form I) is hydrophobic and has poor solubility, in this work, the solubility of macitentan in (methanol + ethyl acetate), (ethanol + ethyl acetate) and (isopropanol + ethyl acetate) was studied and correlated. In three mixed solvents, the solubility increased with the increase of temperature. In pure solvents, the largest mole solubility data was in ethyl acetate (1.223 × 10−2 at 313.15 K), followed by methanol (6.02 × 10−4 at 313.15 K), ethanol (4.58 × 10−4 at 313.15 K) and isopropanol (2.46 × 10−4 at 313.15 K). The solubility increased monotonically with the increase of ethyl acetate mass fraction at all studied temperatures. In mixtures of (ethyl acetate + methanol), the values varied from 6.02 × 10−4 to 1.223 × 10−2 at 313.15 K, an increase of 20.32 folds, meanwhile, 26.70 folds for mixtures of (ethanol + ethyl acetate) and 49.72 folds for mixtures of (isopropanol + ethyl acetate). The values of relative average deviations (RAD) in three systems with Jouyban-Acree model are 6.20%, 5.95% and 4.95%, respectively. For CNIBS/R-K model, the data is less than 5.0% at the temperature range from 273.15 K to 293.15 K only in mixture of (ethyl acetate + methanol). However, the data of Residual Sum of Squares (RSS) for Jouyban-Acree model and CNIBS/R-K model are 5.72 and 2.26, respectively. According to the result of analysis, the CNIBS/R-K model could provide a suitable prediction in three mixed solvents. In the following, the analysis of apparent thermodynamic properties for the dissolution processes indicate the dissolution process is not only endothermic but also entropy-driving. [ABSTRACT FROM AUTHOR]

• The solubility of doxofylline in pure and binary solvents. • The solubility data were correlated by some thermodynamic models. • The effect of solvent properties on the solubility was analysed. • Some thermodynamic properties of dissolution process were evaluated. Crystallization and purification is an important step in drug preparation. In this work, the solubility of doxofylline in some pure and mixed solvents at T = 273.15–313.15 K was experimentally determined under 101.2 kPa. Infrared spectroscopy (IR) was used to evaluate the crystal form of doxofylline, and no solvates or new form formation were observed during the whole experiment. In pure solvent, the solubility data increased with the increasing temperature. At 313.15 K, the solubility maximum value (mole fraction) was obtained in ethyl acetate (3.8552 × 10−2), followed by acetonitrile (2.8699 × 10−2), ethanol (1.7179 × 10−2), methanol (0.7069 × 10−2), iso propanol (0.4928 × 10−2) and n-propanol (0.1533 × 10−2), and similar trend was obtained at each temperature studied. In mixture of (isopropanol + ethyl acetate), the solubility increased monotonically with the increasing mass fraction of ethyl acetate at each temperature studied. The Apelblat equation and λh equation were applied to correlate the solubility data in selected pure solvents. All relative average deviation (RAD) values in the modified Apelblat equation are less than those in λh equation. Therefore, modified Apelblat is more suitable for correlating the solubility profile in selected pure solvents. In addition, Jouyban-Acree model was used to evaluate the results in mixed solvents, and the RAD value is 5.48%. During the dissolution process, the apparent dissolution standard enthalpy (Δ H sol o), apparent molar standard Gibbs energy (Δ G sol o) and apparent dissolution standard enthalpy (Δ S sol o) were calculated. The values of Δ H sol o and Δ S sol o are all positive in this experiment, which indicates the dissolution process is not only endothermic but also entropy-driving. Moreover, the contribution of dissolution enthalpy, (% ξ H) is greater than entropy (% ξ TS ) to the change of dissolution Gibbs energy in the dissolution process. [ABSTRACT FROM AUTHOR]