[en] Highlights: • The solubility of allisartan isoproxil in binary solvent mixtures were determined. • Apelblat, CNIBS/R-K and Jouyban-Acree models were used to correlate the solubility. • Solubility parameter theory was used to explain the co-solvency phenomenon. • Regular mixing rules were used to calculate solubility parameter of binary solvents. • The mixing thermodynamics were calculated and discussed based on NRTL model. - Abstract: In this work, the solubility of allisartan isoproxil in binary solvent mixtures, including (acetone + water), (acetonitrile + water) and (methanol + water), was determined by a gravimetric method with the temperature ranging from (278.15 to 313.15) K at atmospheric pressure (p = 0.1 MPa). The solubility of allisartan isoproxil in three binary solvent mixtures all increased with the rising of temperature at a constant solvent composition. For the binary solvent mixtures of (methanol + water), the solubility increased with the increasing of methanol fraction, while it appeared maximum value at a certain solvent composition in the other two binary solvent mixtures (acetone + water and acetonitrile + water). Based on the theory of solubility parameter, Fedors method and two mixing rules were employed to calculate the solubility parameters, by which the proximity of solubility parameters between allisartan isoproxil and binary solvent mixtures explained the co-solvent phenomenon. Additionally, the modified Apelblat equation, CNIBS/R-K model and Jouyban-Acree model were used to correlate the solubility data in binary solvent mixtures, and it turned out that all the three correlation models could give a satisfactory result. Furthermore, the mixing thermodynamic properties were calculated based on NRTL model, which indicated that the mixing process was spontaneous and exothermic.

[en] Highlights: • The solubility data of cefmetazole acid in three (alcohol + water) binary solvents were experimentally determined. • The experimental solubility data of cefmetazole acid were correlated by three models. • Almost all studied solutions show good agreement with the “like dissolves like” empirical rule. • Thermodynamic properties of cefmetazole acid of mixing process were calculated and discussed. - Abstract: The solubility of cefmetazole acid in binary solvent mixtures, (methanol + water), (ethanol + water) and (isopropanol + water), was determined by UV spectroscopic method at temperatures from 278.15 to 303.15 K. The solubility of cefmetazole acid increased with the increase of temperature in all solvents. In (methanol + water) co-solvent mixture, the solubility of cefmetazole acid is maximal in neat methanol. In (ethanol + water) and (isopropanol + water) solvent mixtures, the solubility of cefmetazole acid reaches its maximum when the mole fraction of alcohol is 0.5 and 0.4, respectively. The modified Apelblat equation, the CNIBS/R-K model and the Jouyban–Acree model were applied to correlate the experimental solubility of cefmetazole acid. Moreover, the activity coefficients as well as the thermodynamic properties of mixing were calculated and discussed based on the NRTL model and experimental solubility values.

[en] Highlights: • The solubility data of pyraclostrobin in pure and binary solvents were determined and correlated. • The theory of solubility parameter was used to explain the cosolvency in binary solvents. • A modified mixing rule was proposed to calculate the solubility parameter of binary solvents. • The dissolution thermodynamic properties were calculated and discussed. - Abstract: The solubility of pyraclostrobin in five pure solvents and two binary solvent mixtures was measured from 283.15 K to 308.15 K using a static analytical method. Solubility in five pure solvents was well correlated by the modified Apelblat equation and Wilson model. While the CNIBS/R–K model was applied to correlate the solubility in two binary solvent mixtures, the correlation showed good agreement with experimental results. The solubility of pyraclostrobin reaches its maximum value at a certain cyclohexane mole fraction in the two binary solvent mixtures. The solubility parameter of pyraclostrobin was calculated by the Fedors method and a new modified mixing rule with preferable applicability was proposed to determine the solubility parameter of solvents. Then the co-solvency in the binary solvent mixtures can be explained based on the obtained solubility parameters. In a addition, the dissolution thermodynamic properties were calculated from the experimental values using the Wilson model.

[en] Highlights: • The solubility of calcium D-pantothenate in water + methanol mixtures was measured by HPLC analysis method. • The effect of β-alanine on the solubility of calcium D-pantothenate in a constant mole ratio of methanol and water was also determined by HPLC analysis method. • The quaternary NRTL equation was first applied to correlating the quaternary solid-liquid equilibrium. - Abstract: The solubility of calcium D-pantothenate in (water + methanol) mixtures and the effect of β-alanine on the solubility of calcium D-pantothenate in a constant mole ratio of methanol and water was measured from 263.15 K to 303.15 K by the HPLC analysis method (P = 0.1 MPa). The solubility of calcium D-pantothenate increased with increasing temperature in all the mixtures at constant composition. Besides, it also increased with mole fraction of water in (water + methanol) mixtures at a constant temperature. Additionally, the solubility of calcium D-pantothenate was enhanced by β-alanine at a given temperature. The experimental solubility in (water + methanol) mixtures was correlated by the modified Apelblat equation, the ternary NRTL equation and Solubility-Polarity Model. The Apelblat equation, the quaternary NRTL equation and the Cohn equation were adopted to correlate the experimental solubility in the (water + methanol + β-alanine) mixtures. Worthwhile, the quaternary NRTL equation was first applied to correlating the quaternary solid-liquid equilibrium. It turned out that all the selected models give good performance on solubility prediction.

[en] Highlights: • The solubility of 4-aminobutyric acid in mono-solvents and binary solvent mixtures were experimentally determined. • The solubility data in five mono-solvents were correlated by three models. • Four models were employed to correlate solubility data in methanol + water binary solvent mixtures. • Solution mixing thermodynamics were calculated and the dissolution process were discussed. - Abstract: A laser monitoring dynamic method was used to determine the solubility of 4-aminobutyric acid in five mono-solvents of methanol, formamide, 1,2-propanediol, 1,3-propanediol and water, and (methanol + water) binary solvent mixtures over the temperature ranging from 283.15 K to 323.15 K at atmospheric pressure. It turns out to be that in different mono-solvents, the solubility of 4-aminobutyric acid is temperature dependent and increases with the increasing temperature. While in (methanol + water) binary solvent mixtures, the solubility is positively correlated with temperature and negatively correlated with the mole fraction of methanol. The modified Apelblat equation, λh equation and NRTL-Binary model were employed to correlate the solubility data in five mono-solvents. While in (methanol + water) binary solvent mixtures, the NRTL-Ternary model, CNIBS/R-K model and Jouyban-Acree models were applied. It is found that the correlated results are in good agreement with the experimental results. Furthermore, with the activity coefficients considered, solution mixing thermodynamics were calculated and the dissolution process of 4-aminobutyric acid is also discussed.

[en] Highlights: • The ternary phase diagrams of l-Val/l-Nva/water and l-Val/l-Ala/water at 293.15 K were determined. • Complete solid solution and partial solid solution were formed. • Molecular investigation of the complete solid solution was developed. • Fractional crystallization were verified as an effective purification method for solid solution system. The ternary phase diagram of l-valine (l-Val)/l-norvaline (l-Nva)/water system was determined at 293.15 K, in which the tie lines clearly indicate the formation of complete solid solution and X-ray powder diffraction (XRPD) analysis of the solid phases further confirms complete miscibility of l-Val and l-Nva molecules in the solid state. Further, homogeneous solid solution can be obtained via mechano-chemical method of non-solution system and via anti-solvent method. Similar composition analysis of solid and liquid phase suggests that l-Val and l-alanine (l-Ala) is partially miscible with only a narrow scope of component substitution. The similarity degree of the three amino acids in cell dimensions and supramolecular organization determines the miscibility of l-Val and l-Nva or l-Val and l-Ala, and the investigation in molecular incorporation of l-Val/l-Nva system was developed. Applying the experimental solid-liquid equilibrium data, fractional crystallization is verified as an effective purification method.

[en] Highlights: • Solubility data of clozapine in eighteen pure organic solvents were determined. • Different thermodynamic models were used to correlate solubility data. • Solubility increase with the increasing of temperature. • Dissolution properties of clozapine were calculated based on the Wilson model. The solid-liquid equilibrium solubility of clozapine in eighteen organic solvents (i.e., methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, acetone, 2-butanone, acetonitrile, N, N-dimethylformamide, tetrahydrofuran, chloroform, ethyl formate, methyl acetate, and ethyl acetate) was determined using a gravimetric method over a temperature ranging from 278.15 K to 323.15 K at atmospheric pressure. The modified Apelblat equation, λh equation, NRTL equation, and Wilson equation were selected to correlate the solubility data. The fitting degree of thermodynamic models was evaluated by the relative average deviation, and root mean root mean square deviation. Dissolution properties, including enthalpy, entropy, and Gibbs energy changes of clozapine were evaluated by the Wilson model. The solubility data, thermodynamic parameters and dissolution properties for clozapine will be of crucial guiding value for the optimization of the industrial crystallization process.

[en] A stable poly-alpha olefin oil based magnetic fluid of bilayer surfactant coated (oleic acid and succinimide) Fe₃O₄ nanoparticles was prepared by a using phase transfer method. The bilayer surfactant-coated magnetic particles are characterized by Fourier-transform infrared spectroscopy, the result shows that the Fe₃O₄ nanoparticles are coated by oleic acid, and the bilayer surfactant succinimide wraps the oleic acid coated Fe₃O₄ nanoparticles. Transmission electron microscopy images indicate that the dispersibility of the bilayer coated Fe₃O₄ nanoparticles is better than that of the uncoated ones. Vibrating sample magnetometer measurement confirms that both the coated and uncoated Fe₃O₄ nanoparticles are super-paramagnetic. Stability measurements show the magnetic fluids prepared by bilayer coated Fe₃O₄ nanoparticles is nearly constant for 360 days at room temperature. - Highlights: ► The oleic acid coated Fe₃O₄ nanoparticles are functionalized with polyisobutylene succinimide. ► The poly alpha olefin oil based magnetic fluid is obtained by phase-transfer method. ► The magnetic fluid is stable and superparamagnetic. ► The magnetic fluid exhibits well oil disperse characteristic. ► The magnetic fluid can be widely used in loudspeaker

[en] Highlights: • Solubility of pyridoxine hydrochloride in three binary mixtures was determined. • Experimental solubility of pyridoxine hydrochloride was correlated by four models. • Mixing thermodynamics of pyridoxine hydrochloride were calculated and discussed. - Abstract: The solubility of pyridoxine hydrochloride in binary solvent mixtures, including (acetone + water), (methanol + water) and (ethanol + water), was measured over temperature range from (278.15 to 313.15) K by a gravimetric method at atmospheric pressure (P = 0.1 MPa). The solubility increased with increasing temperature in binary solvent mixtures at constant solvent composition. Besides, the dissolving capacity of pyridoxine hydrochloride in the three binary solvent mixtures at constant temperature ranked as (methanol + water > ethanol + water > acetone + water) in general, partly depending on the polarity of the solvents. Additionally, the modified Apelblat equation, van’t Hoff equation, CNIBS/R–K model and Jouyban–Acree model were used to correlate the solubility data in binary mixtures, it turned out that all the selected thermodynamic models could give satisfactory results. Furthermore, the mixing thermodynamic properties of pyridoxine hydrochloride in different binary solvent mixtures were also calculated and discussed. The results indicate that the mixing process of pyridoxine hydrochloride in the selected solvents is exothermic.

[en] Highlights: • The solubility of L-histidine in three binary solvents was determined. • Apelblat, CNIBS/R-K, Jouyban-Acree and NRTL models were used to correlate the data. • The mixing thermodynamics were calculated and discussed based on NRTL model. - Abstract: In this study, the solubility of L-histidine in three different binary solvents, including (water + acetone), (water + ethanol) and (water + 2-propanol), was measured over temperatures from 283.15 K to 318.15 K by employing a gravimetric method at atmospheric pressure. It was found that the solubility of L-histidine in the binary mixed solvents increases with the increasing temperature at a given solvent composition, whereas it decreases with the rise of mole fraction of organic solvents. The experimental results were well correlated by the modified Apelblat equation, CNIBS/R-K model, combined version of the Jouyban-Acree model and NRTL model, respectively. This shows that these models can correlate the solubility in three binary mixed solvents accurately. Furthermore, the mixing thermodynamic properties of L-histidine in different binary solvent mixtures were also calculated based on the NRTL model. The result indicates that the mixing process of L-histidine is endothermic and spontaneous.