Inverse Kirkwood Buff Integrals Method Research Articles

Solubility of atenolol in aqueous propylene glycol mixtures revisited: IKBI preferential solvation analysis

ABSTRACT The preferential solvation parameters of atenolol in aqueous binary mixtures of propylene glycol (PG) were derived from reported molar solubility values after conversion to mole fractions by using the inverse Kirkwood–Buff integrals method. This drug is sensitive to preferential solvation effects in this binary system. The preferential solvation parameter by PG (δx 1,3) is negative in water-rich mixtures but positive in mixtures of 0.20 < x 1 < 1.00. It is conjecturable that hydrophobic hydration around the non-polar methyl and phenylene groups of this drug observable in water-rich mixtures could play a relevant role in drug solvation. Otherwise, in mixtures of 0.20 < x 1 < 1.00, the preferential solvation by PG could be due to the acidic behaviour of atenolol.

Musk ketone solubility in binary systems ethyl acetate with methanol, ethanol, and isopropanol: preferential solvation according to the inverse Kirkwood–Buff integrals method

ABSTRACT Three co-solvent mixtures {methanol (1) + ethyl acetate (2), ethanol (1) + ethyl acetate (2), and isopropanol (1) + ethyl acetate} were used to calculate the preferred solvation parameters () of musk ketone (MK) (2). In all co-solvent mixes, values vary non-linearly with the percentage of co-solvent (1). According to the study, values are negative in mixes rich in alcohol but positive in those high in ethyl acetate. The mixtures {methanol (1) + ethyl acetate (2)} and {ethanol (1) + ethyl acetate (2)} show the most favoured solvation of MK by ethyl acetate at 298.15 K and 293.15 K, respectively. When {isopropanol (1) + ethyl acetate (2)} is combined; it is maximum at 298.15 K. Since the values are positive, MK preferentially solvates with ethyl acetate. The most significant values for x 1 = 0.18–0.40 are obtained towards the non-polar regions of MK for the three co-solvent mixes.

Research on sulfenone in four aqueous cosolvent systems at (278.15–323.15) K: solubility, modelling, hansen solubility parameter, preferential solvation and thermodynamic properties

The equilibrium solubility of sulfenone in various aqueous cosolvent systems was determined by isothermal saturation method at 278.15–323.15 K under 101.2 kPa. Four cosolvents (methanol, ethanol, isopropanol and n-propanol) exhibited different power in dissolving. The specific performance was that in the saturated state, the content of sulfenone in n-propanol + water was the most and in methanol + water was the least. The Jouyban-Acree (J-A), van’t Hoff-Jouyban-Acree (V-J-A) and Apelblat-Jouyban-Acree (A-J-A) models were utilized to correlate the obtained solubility data of sulfenone. The maximum of relative average deviation (RAD) and root-mean-square deviation (RMSD) were 1.47 × 10−2 (from A-J-A) and 6.07 × 10−5 (from V-J-A). In addition, the difference in dissolution was explained from a microscopic point of view through the acquisition of hansen solubility parameters (HSPs). The preferential solvation parameter δx1,3 was calculated by Inverse Kirkwood-Buff Integrals (IKBI) method, the change trend of δx1,3 presented in the entire concentration range was non-linear. The apparent thermodynamic parameters were calculated by van’t Hoff plots and the results indicated that the dissolution process of sulfenone is an endothermic and entropy increment process.

Solubility measurement of syringic acid, trans-cinnamic acid, p-coumaric acid, and vanillin constituent of Deverra DC. genus in (ethyl acetate + ethyl alcohol) mixtures: Thermodynamic modeling and preferential solvation

This work aims firstly to measure the solubility of four natural phenolic compounds (syringic acid, trans-cinnamic acid, p-coumaric acid, and vanillin) present in Deverra DC. Genus in (ethyl alcohol + ethyl acetate) using the gravimetric method from 283.15 to 323.15 K at normal pressure and then to analyze the solubility using the Jouyban-Acree and van't Hoff-Jouyban-Acree models. Secondly, based on the obtained solubility data, the preferential solvation parameters (δx1,3) of four natural phenolic compounds (PhC) in double solvent mixtures of ethyl alcohol (1) + ethyl acetate (2) were calculated using the inverse Kirkwood-Buff integrals method. The δx1,3 numbers differ indirectly with the co-solvent (1) fraction in all the binary mixtures. For the ethyl alcohol (1) + ethyl acetate (2) systems, the δx1,3 values are negative in ethyl acetate-rich mixtures and positive in constituents (x1) ranging from 0.59 to 1 for syringic acid, 0.51 to 0.63 trans-cinnamic acid, and 0.48 to 0.63 for vanillin in the mole fraction of ethyl alcohol. However, for the ethyl alcohol (1) + ethyl acetate (2) +p-coumaric acid (3) mixtures comprising 0 <x1 < 0.63, the values of δx1,3 are positive. This indicates that the co-solvent preferentially dissolved p-coumaric acid. The positive amounts of δx1,3 obtained are because the phenolic molecules that interact with the hydrogen acceptor groups existing in the co-solvent have higher acidic properties.

Equilibrium solubility, non-covalent interactions and solvation thermodynamics of thiamphenicol in aqueous cosolvents of n-propanol/acetone/acetonitrile

This study investigated the thermodynamic equilibrium solubility and its model correlation of thiamphenicol in aqueous solutions of n-propanol/acetone/acetonitrile as well as the solvation behavior of the compound. To explain the electrostatic properties of the basicity and the acidity of thiamphenicol molecule, a quantitative study of the molecular surface and a Hirshfeld surface analysis were utilized. These studies revealed that oxygen atoms in > SO2 and > CO groups are the most important electrophilic sites, and hydrogen atoms in –OH groups are the most important nucleophilic sites. An independent gradient model that was on the basis of the Hirshfeld partition was used to qualitatively clarify the inter-molecular interactions occurred between thiamphenicol and various solvents. At 101.1 kPa and temperatures ranging from 278.15 to 318.15 K with increments of 5 K, the isothermal dissolution technique was utilized to investigate the solubilities of this drug. The Apelblat equation, the modified van't Hoff Jouyban–Acree model, the Jouyban–Acree model, and the modified Wilson model all gave good findings for the solubility connection, with a relative average deviance of 3.41 percent. The extended Hildebrand solubility approach was used to inspect the solvation behavior at 298.15 K. The inverse Kirkwood-Buff integrals method was utilized in order to carry out the task of quantifying the thiamphenicol solvation that was favored. Positive solvation values in acetone/acetonitrile-rich and -middle solution compositions show that acetone/acetonitrile preferentially solvates thiamphenicol.

Increasing the Equilibrium Solubility of Meloxicam in Aqueous Media by Using Dimethyl Sulfoxide as a Cosolvent: Correlation, Dissolution Thermodynamics and Preferential Solvation

Meloxicam is widely prescribed as an analgesic and anti-inflammatory drug in human therapeutics. Owing the very low aqueous solubility of meloxicam, this property has been studied in dimethyl sulfoxide (DMSO)-aqueous solvent systems at several temperatures from 273.15 to 313.15 K to expand the solubility database about analgesic drugs in mixed solvents. The flask shake method followed by ultraviolet-visible (UV-vis) spectrophotometry analysis were used for meloxicam solubility determinations. A number of cosolvency models, including the Jouyban–Acree model, were challenged for solubility correlation/prediction of this drug in these mixtures. The van’t Hoff and Gibbs equations were employed to calculate the apparent standard thermodynamic quantities relative to dissolution and mixing processes. The inverse Kirkwood–Buff integral method was employed for calculating the preferential solvation parameters of meloxicam by DMSO in the mixtures. Meloxicam solubility increases with increasing temperature and maximum solubilities are observed in neat DMSO at all temperatures studied. Dissolution processes were endothermic in all cases and entropy-driven in the composition interval of 0.40 ≤ x1 ≤ 1.00. A nonlinear enthalpy–entropy relationship was observed in the plot of enthalpy vs. Gibbs energy for drug transfer processes. Meloxicam is preferentially solvated by water in water-rich mixtures but preferentially solvated by DMSO in the composition interval of 0.21 &lt; x1 &lt; 1.00.

Milrinone solubility in aqueous cosolvent solutions revisited: Inter/intra-molecular interactions, enthalpy-entropy compensation, and preferential solvation

• Intermolecular interactions and charge distribution of milrinone were studied by MEPS and HS analysis. • Solvent effect was studied via linear solvation energy relationships. • Preferential solvation were investigated via inverse Kirkwood–Buff integrals method. • Transfer and dissolution properties together with enthalpy-entropy compensation was studied. Analysis of molecular electrostatic potential surface and Hirshfeld surface were severally employed here to probe into the overall charge distribution and inter/intra-molecular interactions of milrinone. H···H and N···H contacts predominate among all contact interactions and milrinone has powerful ability of hydrogen-bonding donor and acceptor. The solubility profile of milrinone was additionally illustrated by means of three-dimensional Hansen solubility parameters. The mole fraction solubility at 298.15 K in ethanol/ethylene glycol(EG)/isopropanol/ N , N -dimethylformamide(DMF) + water was inspected in the light of molecular interactions via the well-known linear solvation energy relationships. The solubility parameter, dipolarity-polarizability and hydrogen-bonding acidity of systems presented dominant contributions to the solubility variation. The inverse Kirkwood–Buff integrals was applied to probe the local compositions of milrinone in the aqueous solutions of co-solvent. Regarding the aqueous ethanol/isopropanol/DMF solutions within middle and ethanol/isopropanol/DMF-rich mole fractions, preferential solvation of milrinone by ethanol/isopropanol/DMF was observed. Milrinone was not solvated favorably by EG molecule in above regions. The transfer and thermodynamic dissolution properties including entropy, enthalpy and Gibbs free energy change were derived. Moreover, the analysis of enthalpy-entropy compensation was carried out, stating that the milrinone solubility variation in solutions was controlled by two mechanisms, enthalpy-driven and entropy-driven.

Inter-/intra-molecular interactions, preferential solvation, and dissolution and transfer property for tirofiban in aqueous co-solvent mixtures

Using Hirshfeld surface, interaction region indicator and quantitative molecular surface analysis, the microscopic electrostatic features of basicity and acidity of the tirofiban molecule were clearly demonstrated. Both the O atoms in >SO2 and H atom in –COOH serve as primary electrophilic site and nucleophilic site, respectively. Utilizing solubility data for tirofiban in four different water-based co-solvent mixtures {isopropanol/ethylene glycol (EG)/methanol/ethanol (1) + water (2)}, the inverse Kirkwood–Buff integral method was utilized to determine the preferred solvent for the tirofiban solvation according to the results of preferential solvation analysis. In water-rich composition ranges, the drug is surrounded by water, whereas in isopropanol/methanol/ethanol-intermediate and -rich composition ranges, the drug is surrounded by ethanol/methanol/isopropanol. Isopropanol solutions had the largest magnitude of preferential solvation. Alcohols may have a greater basicity that enhances interactions with the Lewis acidic function groups of tirofiban, giving rise to selective solvation of this drug. The linear solvation energy relationships were used to determine the relative impact of solvent-solvent and solvent-solute interactions in determining the variation of solubility magnitudes. The properties of dissolution and transfer, such as entropy, enthalpy and Gibbs energy change were computed. Entropy-driven and enthalpy-driven mechanisms were shown to be responsible for the change in tirofiban solubility in the four aqueous solutions, according to the enthalpy–entropy compensation analysis.

Acetamiprid in several binary aqueous solutions: Solubility, intermolecular interactions and solvation behavior

This study focused on the solubility profile, dissolving characteristics, computational methods, and solvation behavior of acetamiprid in aqueous solutions of isopropanol/acetone/methanol/EG (1). The quantitative analysis of molecular surface, as well as Hirshfeld surface analysis, were used herein to explain the electrostatic features of basicity of acetamiprid molecule. The primary and second electrophilic sites are the CN and N groups, respectively. All solubility tests were carried out in a shake-flask technique at p = 101.2 kPa and temperatures ranging from 278.15 to 318.15 K. The solubility parameter and dipolarity-polarizability of solutions played a significant role in solubility variation. To investigate solubility performance, the three-dimensional Hansen solubility parameter was used. Several common relationships, such as the modified van't Hoff Jouyban–Acree model, the mixture response surface model, and the Jouyban–Acree model, provided acceptable correlation results for the solubility magnitudes with relative average deviations of < 4.98 percent. The preferred solvation of acetamiprid was further investigated by quantification using the inverse Kirkwood–Buff integrals method. Positive preferential solvation values in isopropanol/ethanol/acetone/methanol-rich and -intermediate composition solutions suggest that isopropanol/ethanol/acetone/methanol preferentially solvates acetamiprid. Nonetheless, EG in the EG + water solution didn’t preferentially solvate acetamiprid. Moreover, the dissolution and transfer properties as well as enthalpy–entropy compensation were discussed.

Solubility, solvation analysis and enthalpy–entropy compensation of musk ketone in some cosolvent solutions

The present work was mainly devoted to the solubility and modeling, intra- and inter-molecular interactions and solvation behavior for musk ketone dissolved in aqueous solutions of ethanol, N,N-dimethylformamide (DMF), methanol and isopropanol accompanied by various computational methodology. Solubility experiments were conducted by means of the common shake-flask technique under local pressure of p = 101.2 kPa at elevated temperatures from 278.15 to 318.15 K. For each aqueous cosolvent solution, the highest solubility magnitude of musk ketone appeared in neat cosolvent (ethanol, DMF, methanol or isopropanol) at T = 318.15 K; and the lowest one, in water at 278.15 K. The solubility behavior was studied by means of the Hansen solubility parameter. The mixture response surface model, Jouyban–Acree model, modified Wilson model and Jouyban–Acree–van’t Hoff model correlated satisfactorily the solubility magnitudes in mole fraction with relative average deviations of <4.15%. The relative contributions of solute–solvent and solvent–solvent molecular interactions to variation of musk ketone solubility at 298.15 K was quantitatively investigated through the linear solvation energy relationships, demonstrating that the dipolarity-polarizability along with solubility parameter of aqueous solvent systems were chiefly responsible for musk ketone solubility. The solvation performance was studied by an extended Hildebrand solubility approach applied to the solubility in four aqueous solutions and in ethyl acetate + methanol/isopropanol/ethanol solutions at 298.15 K, acquiring RAD of <4.05%. In addition, the preferential solvation of musk ketone was investigated quantitatively by means of the inverse Kirkwood–Buff integrals method in the four aqueous and three non-aqueous solutions. Musk ketone was preferentially solvated by ethanol/DMF/methanol/isopropanol (1) in aqueous solutions within middle and rich ethanol/DMF/methanol/isopropanol (1) compositions, and by ethyl acetate (1) in non-aqueous solutions within middle and rich ethyl acetate (1) compositions. Furthermore, the dissolution and transfer properties as well as enthalpy–entropy compensation were discussed in detail.

Extended Hildebrand Solubility Approach and Inverse Kirkwood–Buff Integrals Method Applied to Chloroxine Solubility in Several Blended Solvents

ABSTRACT Extended Hildebrand solubility approach (EHSA) was used in this work to analyse the chloroxine solubility in mixtures at temperature of 298.15 K. A good prediction results of EHSA were observed to correlate the interaction parameter (W) and solubility parameter of blends in the absence of chloroxine (δ 1+2). Nonetheless, the forecasting outcomes of EHSA were similar with that attained when natural logarithm of solubility (lnx 3) was associated with δ 1+2. Additionally, the local mole fraction of ethyl acetate and n-propanol/methanol/isopropanol/ethanol in the vicinity of chloroxine were quantitatively derived by the inverse Kirkwood–Buff integrals method. It could be conjectured that in the alcohol-rich solutions, the interactions of acidic sites of alcohols on basic sites of chloroxine have crucial responsibility for the solvation. It is remarkable the present work does expand the preferential solvation analysis of chloroxine by the particular solvent species in the ethyl acetate + alcohol mixtures.

Thermodynamic study and preferential solvation of sulfamerazine in acetonitrile + methanol cosolvent mixtures at different temperatures

This paper discusses sulfamerazine (SMR) solubility in Acetonitrile (MeCN) + Methanol (MeOH) cosolvents at nine temperatures (278.15–318.15 K). Herein, the maximum SMR solubility was reached in a cosolvent mixture at the highest studied temperature, and the minimum SMR solubility was reached in neat methanol at the lowest studied temperature. Using experimental data, thermodynamic functions were calculated for both the solution and mixture using the Gibbs and van’t Hoff equations, thus determining that the solution process is endothermic with entropic favoring. In addition, the preferential solvation parameters (δx3,1), calculated using the inverse Kirkwood-Buff integrals (IKBI) method, are reported; SMR is preferentially solvated by MeOH in MeOH-rich mixtures, and in intermediate and MeCN-rich mixtures, the δx3,1 values indicate that SMR is not preferentially solvated by any of the two solvents in the mixture (MeCN + MeOH). Finally, eight models were assessed (Apelblat, van’t Hoff, Yaws, λh, Weibull, NRTL, Wilson, and Wilson modified), with all presenting mean relative deviation percentages (MRD%) under 6%, which indicates a good correlation with the experimental data.

Solubility, solvent effect, enthalpy–entropy compensation and solvation thermodynamics of 4-(bromomethyl)-2(1H)-quinolinone in several aqueous blends

The current study was mainly devoted to solubility for the systems formed by 4-(bromomethyl)-2(1H)-quinolinone (BMQ) and blended solvents of isopropanol, N-methyl-2-pyrrolidinone (NMP), ethanol and n-propanol with water. Experiments for solubility determination were conducted by employing the shake-flask equilibration method from 278.15 to 318.15 K under 101.2 kPa. For each aqueous cosolvent mixture, the minimum solubility was recorded in water at 278.15 K; and the maximum value, in neat organic solvents at 318.15 K. The solubility performance was illustrated by Hansen solubility parameters of water, BMQ and co-solvents. No occurrence of polymorphic transformation or solvation was observed after experiments based on the XRD spectra of raw BMQ and excess solids analyzed. The satisfactory correlation results for solubility data was obtained by modified Wilson model, mixture response surface model, modified van’t Hoff-Jouyban–Acree model and Jouyban–Acree model. The relative average deviations were calculated to be no more than 8.72 %. Investigation on the relative contributions from inter- and intra-molecular interactions to the solubility variation of BMQ at temperature of 298.15 K was quantitatively performed via the linear solvation energy relationships (LSER). The descriptors of solvent blends including solubility parameter, dipolarity-polarizability and hydrogen-bond basicity were primarily responsible for the solubility variation. As well, the preferential solvation of BMQ was researched quantitatively via the inverse Kirkwood–Buff integrals method on the basis of some obtainable properties of solvent blends. The positive preferential solvation parameters for BMQ in middle and cosolvent-rich blends strongly suggest that the crystalline solute of BMQ is preferentially solvated by cosolvents of isopropanol, NMP, ethanol and n-propanol. The transfer and apparent dissolution properties including apparent Gibbs energy change (298.15 K), dissolution enthalpy and dissolution entropy (298.15 K) were derived and discussed. Analysis of enthalpy–entropy compensation indicates the entropy-driven mechanism of BMQ dissolved in all blend solvents.

Preferential solvation and solute-solvent interactions of posaconazole in mixtures of (ethyl acetate + ethanol/isopropanol) at several temperatures

In this work, the dissolution process of stable crystalline form I in mixtures of (ethyl acetate + ethanol/isopropanol) at several temperatures was studied and represented by using Jouyban-Acree model, which was considered to be useful in the development of a pharmaceutical product. The influence of solvent properties of mixed solvents on the solubility of posaconazole was analyzed by KAT-LSER method. The solubility of posaconazole in mixture of ethyl acetate + isopropanol increased monotonically with the increasing mass fraction of ethyl acetate. However, it increased firstly and then decreased with the rising mass fraction of ethyl acetate in ethyl acetate + ethanol, and the maximum mole solubility was 4.871 × 10−4 when the mass fraction of ethyl acetate is w = 0.50 at T = 313.15 K. The co-solvency phenomenon was investigated by solubility parameters method. More importantly, preferential solvation parameters (δx1,3) of posaconazole in two mixtures were calculated by using the inverse Kirkwood-Buff integrals method, and it was all negative in ethyl acetate + ethanol system and ethanol-rich mixture in ethyl acetate + isopropanol, but positive at the mole compositions of ethyl acetate from 0.44 to 1.0 in ethyl acetate + isopropanol. Furthermore, some apparent thermodynamic properties including apparent molar standard dissolution enthalpy (ΔHsolo), apparent molar standard Gibbs energy (ΔGsolo), apparent molar standard dissolution entropy (ΔSsolo), the relative contributions by enthalpy (ζH) and by entropy (ζTS) toward to Gibbs energy were calculated by the van’t Hoff equation. Consequently, the experimental solubility and thermodynamic parameters could be used as the reference for simulation in the purification and separation of posaconazole.

Solubility of N-(9-fluorenylmethoxycarbonyloxy)-succinimide in several aqueous co-solvent solutions revisited: Solvent effect, preferential solvation and dissolution and transfer properties

Preferential solvation of N-(9-fluorenylmethoxycarbonyloxy)-succinimide (Fmoc-OSu) in mixtures of DMF (1) + water (2), ethanol (1) + water (2), ethylene glycol (EG, 1) + water (2) and DMSO (1) + water (2) was investigated by inverse Kirkwood–Buff integrals method. In ethanol-rich and intermediate contents, ethanol preferentially solvated Fmoc-OSu; and for the four aqueous co-solvent blends in water-rich composition regions, Fmoc-OSu was preferentially solvated by water. The solvent effect was described through modeling the Gibbs energy change of Fmoc-OSu solubility by linear solvation energy relationships. The main contribution to solubility variation of Fmoc-OSu was the solvent dipolarity-polarizability and solubility parameter. The dissolution and transfer enthalpy, entropy and Gibbs free energy were discussed in detail. Analysis outcomes of thermodynamic dissolution and enthalpy–entropy compensation demonstrated that two different mechanisms, enthalpy-driven and entropy-driven controlled the solubility variation of Fmoc-OSu in the DMF/EG/DMSO + water mixtures; and enthalpy-driven, in the ethanol + water mixture.

Solubility, solvation thermodynamics and solvent effect of thiabendazole in several cosolvent blends

Equilibrium solubility determination and model correlation were performed in the present research for the systems formed by solid solute of thiabendazole and binary aqueous blends of acetonitrile, methanol, n-propanol and isopropanol. Experiments at temperatures ranging from 283.15 to 323.15 K were conducted by the use of the shake-flask saturation technique at 101.2 kPa. For the given binary solvent blends, the minimum mole fraction solubility was recorded in water at 283.15 K; and the maximum one, in neat organic solvent at 323.15 K. The generated equilibrium solubility was satisfactorily described by two models, modified van’t Hoff-Jouyban–Acree and Jouyban–Acree, with the relative average deviations (%) of no more than 6.08. Good prediction results of extend Hildebrand solubility approach (relative average deviations < 4.10%) were observed in terms of quartic polynomial for the four solution systems to correlate the interaction parameter (W) and solubility parameters of the solvents’ blends in the absence of thiabendazole (δ1+2). Analysis of the relative contributions from intra- and inter-molecular interactions to solubility variation of solid solute of thiabendazole (298.15 K) was quantitatively carried out via the linear solvation energy relationships (LSER). The descriptors of blended solvents comprising solubility parameter and hydrogen-bond basicity were principally responsible for the variation of determined solubility. Besides, the preferential solvation of thiabendazole was quantitatively researched via the inverse Kirkwood–Buff integrals method on the basis of some accessible properties for blended solvent systems. The positive preferential solvation parameters for thiabendazole in the middle and cosolvent-rich blends powerfully suggested that thiabendazole was preferentially solvated by cosolvents of isopropanol, acetonitrile, n-propanol, ethanol and methanol. The conjecture was reasonable that in above compositions, thiabendazole mainly served as Lewis acidic in terms of its interactions with alcohol molecules; while for the acetonitrile mixtures, this behavior was contributed by polarization effect. Besides, thiabendazole was preferentially solvated by ethanol (2) in ethyl acetate (1) + ethanol (2) solutions with ethyl acetate-rich compositions, and by water (2) solvent in aqueous blends with rich water compositions.

Rimsulfuron solubility in several aqueous solutions revisited: Solvent effect, dissolution behavior and preferential solvation

Preferential solvation was analyzed with the help of the inverse Kirkwood–Buff integrals method based on the available equilibrium solubility of rimsulfuron in four solutions of EG (1) + water (2), ethanol (1) + water (2), DMF (1) + water (2) and methanol (1) + water (2). Rimsulfuron was preferentially surrounded by water solvent in water-rich composition regions. For the aqueous ethanol/methanol mixtures in intermediate and methanol/ethanol-rich composition ranges, methanol/ethanol preferentially solvated rimsulfuron; while EG/DMF didn’t preferentially solvate the rimsulfuron for the EG/DMF in the ranges. Selective solvation of rimsulfuron by methanol/ethanol was perhaps resulted from higher basicity of methanol/ethanol that was in favor of interactions with the acidic groups of rimsulfuron. The performance of rimsulfuron solubility was investigated by means of Hansen solubility parameter concept in detail. The study on relative prominence of solvent–solvent and solute–solvent molecule interactions on rimsulfuron solubility variation identified the hydrogen-bond basicity, dipolarity-polarizability and solubility parameter of solution descriptors analyzed in terms of the linear solvation energy relationships. As well, the dissolution and transfer Gibbs free energy change, enthalpy and entropy were resulted, representing the solubilization capacity more favorable with the rising compositions of EG/ethanol/DMF/methanol. Thermodynamic analysis of enthalpy–entropy compensation demonstrated a shift of dominant dissolution mechanism from entropy-driven (water-rich regions) to enthalpy-driven (organics-rich regions).

Solubility, Hansen solubility parameter, solvent effect and preferential solvation of benorilate in aqueous mixtures of isopropanol, N,N-dimethylformamide, ethanol and N-methyl-2-pyrrolidinone

This contribution was devoted to the equilibrium solubility profile, solute–solvent and solvent–solvent interactions and solvation behavior of benorilate in aqueous binary mixtures of the cosolvent (i.e. ethanol, N-methyl-2-pyrrolidinone (NMP), isopropanol and N,N-dimethylformamide (DMF)) together with several mathematical associations. All experiments were conducted by a shake-flask method under ambient pressure of 101.2 kPa from 278.15 to 318.15 K. The maximum scale of equilibrium benorilate solubility in neat cosolvent at T = 318.15 K; while the minimum one was observed in pure water at 278.15 K. The equilibrium benorilate solubility was analyzed by using the Hildebrand and Hansen solubility parameters. Various solubility models including Jouyban–Acree–van’t Hoff, modified Wilson, Jouyban–Acree and mixture response surface (MRS) were employed to fit the mole fraction solubility data, attaining the average relative deviations (RAD) of no more than 9.62%. The relative significance of molecular interactions of solvent–solvent and solute–solvent species upon the equilibrium solubility of benorilate at 298.15 K analyzed through the linear solvation energy relationships specified that the dominant contributions to solubility variation were observed as solubility parameter and dipolarity-polarizability of systems. The solubility data was investigated by means of the extended Hildebrand solubility approach gaining relative average deviation values of no higher than 3.71%. In terms of solution properties, a quantitative analysis on preferential solvation of benorilate was conducted by inverse Kirkwood–Buff integrals method. The preferential solvation parameters for neat cosolvent were recorded as positive in cosolvent-rich and intermediate regions in solutions, suggesting that benorilate was preferentially solvated by the cosolvents. In the above composition regions, it is conjectured that benorilate is performing as a Lewis acid with the cosolvent molecules.

Dissolution behavior and preferential solvation of diacerein in mixtures of (ethyl acetate/acetonitrile + ethanol) at several temperatures

Because the chemical structure of diacerein is plane structure, the solubility of diacerein is poor, and most of the products crystallized by solvent contain solvate, so it is difficult to get a large amount of diacerein without solvate. The present work demonstrates cosolvent as a successful technique to improve the dissolution property of diacerein. The solid liquid equilibrium phase diagram of diacerein in mixtures of (ethyl acetate/acetonitrile + ethanol) within the temperature range from (273.15 to 313.15) K was studied and represented using Jouyban-Acree model. The solubility profile of diacerein in two mixtures increased at first and then decreased with the increasing mass fraction of ethyl acetate/acetonitrile. In (ethyl acetate + ethanol) and (acetonitrile + ethanol) mixtures, the minimum mole solubility was obtained in pure ethanol, 5.085 × 10−5, and the maximum data in (ethyl acetate + ethanol) mixtures was 2.568 × 10−4 at the composition of w(ethyl acetate) = 0.8 (mass fraction), and 1.727 × 10−4 for (acetonitrile + ethanol) systems at w(acetonitrile) = 0.6, respectively. Preferential solvation parameters (δx1,3) of diacerein in two mixtures were evaluated by using the inverse Kirkwood-Buff integrals method, and it was all negative in ethanol-rich mixtures but positive at the mole compositions of ethyl acetate from 0.37 to 0.61, and with the range from 0.53 to 0.61 for acetonitrile. However, it should be noted that the positive preferential solvation parameters in acetonitrile + ethanol mixtures are lower than 0.01, near 0.002, and thus, a consequence of uncertainties propagation in IKBI calculations must be taken into account here. Moreover, the corresponding relative average deviations (RAD) of solubility correlation are 4.96% and 5.74%, respectively. The values of ΔHsolo were from 22.68 to 36.45 kJ·mol−1. The analysis of apparent thermodynamic properties shows that the dissolution process in all investigated solvent mixtures is an endothermic and entropy driven process.

Thermodynamic analysis and preferential solvation of sulfanilamide in different cosolvent mixtures

ABSTRACT The thermodynamic analysis and preferential solvation of the solubility of sulphanilamide (SA) in five cosolvent mixtures (ethanol + water; 1,4-dioxane + water, acetonitrile + water, dimethyl-sulphoxide + water, and dimethylsulphoxide + water) are presented. The thermodynamic functions are calculated employing the Gibbs and van´t Hoff equations, and the analysis of preferential solvation is developed by inverse Kirkwood–Buff integrals method. The solubility process is endothermic, with entropic favouring in all cases. Finally, according to the solvation parameter, SA is solvated preferentially by water in more polar mixtures, and in DMF + W, and DMSO + W mixtures it is solvated by organic solvent. In the other mixtures (EtOH + W, DIOX + W, and MeCN + W) the SA is solvated by the organic solvent in intermediate mixtures and by water in the less polar mixtures.