Solubility of minoxidil in binary mixture of ethanol + water at various temperatures

ABSTRACT

The solubility of minoxidil in the aqueous binary mixtures of ethanol at different temperature are investigated and the obtained solubility data are fitted by using some cosolvency models including van’t Hoff equation, Yalkowsky model, Jouyban–Acree model and Jouyban–Acree–van’t Hoff model. The mean relative deviations (MRD%) are used to illustrate the models performance. Moreover, the apparent entropy, enthalpy, and Gibbs free energy of minoxidil dissolution process in the investigated solvent mixtures are computed using van’t Hoff and Gibbs equations. Finally, by means of the inverse Kirkwood–Buff integrals preferential solvation of minoxidil by water is observed in water-rich and ethanol-rich mixtures.     

Solubility prediction of deferiprone in N-methyl-2-pyrrolidone + ethanol mixtures at various temperatures using a minimum number of experimental data

Experimental solubility of deferiprone (DFP) in N-methyl-2-pyrrolidone (NMP) + ethanol (EtOH) mixtures at 293.2, 298.2, 303.2 and 308.2 K was determined and mathematically represented using various models. The trained versions of the van’t Hoff equation, its combined version with log-linear model, Jouyban–Acree model and a combination of van’t Hoff + Jouyban–Acree model were reported to simulate DFP solubility in the binary mixture compositions at various temperatures. The mean percentage deviation (MPD) was used as an accuracy criterion. The obtained overall MPDs for back-calculated and predicted solubility of DFP in NMP + EtOH mixtures varied from 1.1% to 3.2% and 2.6% to 6.6%, respectively. Some of apparent thermodynamic quantities for the dissolution processes of DFP are also reported.     

Solubility of budesonide in {ethanol + water} mixtures from T = (293.2 to 313.2) K: Experimental measurement and mathematical modelling

The solubility of budesonide (BDS) in binary mixtures of ethanol and water at T = (293.2–313.2) K is determined and mathematically represented using two cosolvency models, i.e. Jouyban–Acree model and Jouyban–Acree–van’t Hoff model. The mean relative deviations for fitting the solubility data of BDS in binary mixtures of ethanol + water are 6.6% and 6.5%, respectively. Furthermore, the apparent thermodynamic properties, dissolution enthalpy, dissolution entropy, and Gibbs free energy change of dissolution process of BDS in all the mixed solvents were calculated according to van’t Hoff and Gibbs equations. Dissolution of BDS in these mixed solvents is an endothermic process.     

Solubility of Ketoconazole in Polyethylene Glycol 200 + Water Mixtures at 298.2–318.2 K

The solubility of ketoconazole in binary mixtures of polyethylene glycol 200 (PEG 200) + water is reported at temperatures ranging from 298.2 to 318.2 K. The Jouyban–Acree model and its combined version including the van’t Hoff equation were used for correlating the reported data; the obtained mean relative deviations are 9.5 and 9.9 %, respectively. Also, two previously trained versions of the Jouyban–Acree model were used for predicting the reported data points in which the prediction errors were 34.6 and 31.0 %.     

Theoretical and Experimental Study of the Thermodynamic Solubility of Pioglitazone HCl in Ethanol, <Emphasis Type="Italic">N</Emphasis>-Methyl Pyrrolidone or Propylene Glycol + Water Mixtures at Various Temperatures

The solubilities of pioglitazone HCl (99 data points) in binary solvent mixtures of ethanol, N-methyl pyrrolidone (NMP) or propylene glycol (PG) + water are reported at three temperatures ranging from 298.2 to 308.2 K. Three different cosolvency models, those of Yalkowsky, Jouyban–Acree and combined version of the Jouyban–Acree model with the van’t Hoff approach, have been used for correlating the reported data, and the corresponding overall mean relative deviations (OMRDs) are 88.9, 19.1 and 14.8%, respectively. Also, three previously trained versions of the Jouyban–Acree model have been used for predicting the solubilities of pioglitazone HCl in the aqueous binary solvent mixtures of ethanol, NMP and PG which the prediction OMRDs are 38.9, 93.0 and 50.0%, respectively.     

Determination and mathematical modelling of budesonide solubility in N-methyl-2-pyrrolidone + water mixtures from T = 293.2 to 313.2 K

The solubilities of budesonide (BDS) in binary aqueous mixtures of N-methyl-2-pyrrolidone at temperatures ranging from 293.2 to 313.2 K were determined and mathematically correlated by three cosolvency models, i.e. Jouyban–Acree model, Jouyban–Acree–van’t Hoff model and modified Wilson model. The solubilities were measured using the shake-flask method and the models wereused to fit the solubility data of BDS in the solvent mixtures. The obtained mean relative deviations (MRDs %) for cosolvency models trained using whole data points varied between 5.0% and 31.0%. Solubilities were also predicted by the generally trained version of the Jouyban–Acree model with the MRD of 37.0%. Furthermore, the apparent thermodynamic properties of dissolution process of BDS in all the mixed solvents were calculated according to van’t Hoff and Gibbs equations. Dissolution of BDS in these mixed solvents is an endothermic process.     

Correct derivation of a combined version of the Jouyban–Acree and van’t Hoff model and some comments on ‘Determination and correlation of the solubility of myricetin in ethanol and water mixtures from 288.15 to 323.15 K’

The experimental data reported in the paper by Cai and co-workers [DOI: 10.1080/00319104.2016.1163560] pertaining to the solubility of myricetin dissolved in binary aqueous–ethanol solvent mixtures has been reanalysed. A correct mathematical derivation is provided for the correlation expression from a combination of the van’t Hoff and Jouyban–Acree models. Cai et al. who used the expression in their study, however, erroneously implied that the expression resulted from a simple transformation of the Jouyban–Acree model. No mention was made that one needed to assume a van’t Hoff-type mathematical representation for how the solute solubility varied with temperature in the two mixture co-solvents.     

Further calculations on solubility of dipyrone in some binary solvent mixtures at various temperatures

The recently reported solubility data of dipyrone in binary solvent mixtures of {ethanol + water}, {methanol + ethanol} and {methanol + 1-propanol} at various temperatures have been used to report further numerical results based on the Jouyban–Acree model.     

Volumetric properties of {PEG 200 (or 300) (1) + water (2)} mixtures at several temperatures and correlation with the Jouyban–Acree model

Molar volumes and excess molar volumes were investigated from density values for {PEG 200 (1) + water (2)} and {PEG 300 (1) + water (2)} binary mixtures at temperatures from 278.15 to 313.15 K. Both systems exhibit negative excess volumes probably due to increased interactions such as hydrogen bonding and/or large differences in molar volumes of components. Volume thermal expansion coefficients were also calculated for both binary mixtures and pure solvents. The Jouyban–Acree model was used for density and molar volume correlations of the studied mixtures at different temperatures. The mean relative deviations between experimental and calculated density data were 0.02% and 0.04%, for aqueous mixtures of PEG 200 and PEG 300, respectively; whereas the corresponding values for molar volume data were 1.76% and 2.72%.     

Solubility of sildenafil citrate in propylene glycol + water mixtures at various temperatures

The solubility of sildenafil citrate (SC) in aqueous mixtures of propylene glycol (PG) was investigated. This study was carried out at different mass fractions of PG ranging from 0.1 to 0.9 at T = 293.2–313.2 K. The solubility of SC in the mixed solutions increased with increasing temperature and PG mass fraction.

The solubility values were correlated by two co-solvency models (Jouyban–Acree model and van’t Hoff–Jouyban–Acree model). The mean relative deviations (MRD) were 5.7% and 5.5%, respectively. Density of the SC-saturated solutions over the entire solvent composition and temperature range was also measured and the results correlated with the Jouyban–Acree model. Furthermore, the apparent thermodynamic properties, dissolution enthalpy, dissolution entropy and Gibbs free energy change of dissolution process of SC in all the mixed solvents were calculated according to van’t Hoff and Gibbs equations. Dissolution of SC in these mixed solvents is an endothermic process.     

Solubility Data of Diazepam in Binary and Ternary Mixtures of PEGs 200 and 400 with N-Methyl Pyrrolidone and Water at 298.2 K: Experimental Data and Modeling

Experimental solubilities of diazepam in binary and ternary solvents of polyethylene glycols 200 and 400 with N-methyl pyrrolidone and water at T = 298.2 K are reported. The Jouyban–Acree model was used to fit solubility data of diazepam in the binary and ternary solvent mixtures (106 data points) in which the overall mean relative deviations (OMRD %) is 13.1 % and the prediction OMRD % is 31.7 %. The combined version of the Jouyban–Acree model with Hansen solubility parameters was used for fitting and predicting the solubility data and the OMRDs % are 10.0 and 20.8 %, respectively. Also, the previously proposed trained versions of the Jouyban–Acree model were used for predicting the reported data in this work and all results are listed in the tables. The density of the solute-free solvent mixtures were measured and employed to calculate the constants of the Jouyban–Acree model and then the densities of the saturated solutions were predicted.     

Solution Thermodynamics of Piroxicam in some Ethanol + Water Mixtures and Correlation with the Jouyban–Acree Model

The solubility of piroxicam (PIR) in several ethanol + water mixtures was determined at five temperatures from 293.15 to 313.15 K. The thermodynamic functions; Gibbs energy, enthalpy, and entropy of solution and of mixing were obtained from these solubility data and the drug properties of fusion by using the van’t Hoff and Gibbs equations. The greatest solubility value was obtained in pure ethanol. A non-linear enthalpy–entropy relationship was observed from a plot of enthalpy versus Gibbs energy of solution. Accordingly, the driving mechanism for PIR solubility in water-rich mixtures is the entropy, probably due to water-structure loss around the drug’s non-polar moieties by ethanol, whereas, in ethanol-rich mixtures the driving mechanism is the enthalpy, probably due to better PIR solvation by the co-solvent molecules. The solubilities and the derived thermodynamic properties in mixed solvents were correlated using the Jouyban–Acree model.     

Experimental determination and correlation of bosentan solubility in (PEG 200 + water) mixtures at T= (293.15–313.15) K

The solubility of bosentan (BST) in the aqueous mixtures of polyethylene glycol 200 (PEG 200) at the temperature range, T = (293.15–313.15) K, has been studied using a shake-flask method. The experimental solubility data were correlated with Jouyban–Acree, Jouyban-Acree-van’t Hoff, modified Wilson and Yalkowsky models. Deviations of the calculated solubility from experimental one were determined by percent average relative deviations and relative deviations. In addition, to represent the thermodynamic behaviour of BST in PEG 200 solutions, the apparent thermodynamic functions, Gibbs energy, enthalpy and entropy of dissolution were obtained by using the van’t Hoff and Gibbs equations.     

4-(Methylsulfonyl)benzaldehyde Solubility in Binary Solvent Mixtures of Acetonitrile + (Methanol,Ethanol and Isopropanol): Determination and Modelling

The solubilities of 4-(methylsulfonyl)benzaldehyde in the binary mixed solvents acetonitrile + methanol, acetonitrile + ethanol and acetonitrile + isopropanol were determined experimentally using an isothermal dissolution equilibrium method within the temperature range from 283.15 to 318.15 K under atmospheric pressure. The solubility of 4-(methylsulfonyl)benzaldehyde increased with increasing temperature and mass fraction of acetonitrile in each binary system. At the same temperature and mass fraction of acetonitrile, the mole fraction solubility of 4-(methylsulfonyl)benzaldehyde is greater in (acetonitrile + methanol) than in the other two mixed solvents. The solubility data were correlated using the CNIBS/R-K model, Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, Apelblat–Jouyban–Acree model, Ma model and Sun model. The maximum values of relative average deviation (RAD) and root-mean-square deviation (RMSD) are 1.53% and 1.17 × 10^?4, respectively. All of the selected models provided good representation of the experimental solubilities. Furthermore, the standard enthalpies of dissolution were calculated. The dissolution process for 4-(methylsulfonyl)benzaldehyde in these mixed solvents is endothermic. The experimental solubility and the models presented in this work are important for the production and purification of 4-(methylsulfonyl)benzaldehyde.     

Thermodynamic models for determination of the solubility of dibenzothiophene in (methanol + acetonitrile) binary solvent mixtures

In this paper, we focused on solubility and solution thermodynamics of dibenzothiophene. By the gravimetric method, the solubility of dibenzothiophene was measured in (methanol + acetonitrile) binary solvent mixtures at temperatures from (278.15 to 333.15) K under atmosphere pressure. The solubility data were fitted using a modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redich–Kister (CNIBS/R–K) model and Jouyban–Acree model. Computational results showed that the modified Apelblat equation was superior to the other two equations. In addition, the thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy, were calculated by the van’t Hoff analysis. The experimental results showed that methanol could be used as effective anti-solvents in the crystallization process.     

Naproxen solubility in binary and ternary solvents of polyethylene glycols 200, 400 or 600 with ethanol and water at 298.2 K – experimental data report and modelling

The solubilities of naproxen in the binary and ternary mixtures of polyethylene glycols 200, 400 or 600 with ethanol and water (185 data points) at 298.2 K are determined and mathematically represented by cosolvency models. The obtained overall mean relative deviations (OMRDs) for fitting the solubility data of naproxen in binary and ternary mixtures using Williams–Amidon and Jouyban–Acree model are 15.7% and 16.5%, respectively, and the OMRD values for predicting the solubility data of naproxen by the trained versions of Williams–Amison and Jouyban–Acree models are 71.1% and 64.4%, respectively.     

Solution thermodynamics and preferential solvation of hesperidin in aqueous cosolvent mixtures of ethanol,isopropanol, propylene glycol,and n-propanol

The solubility of hesperidin in some {cosolvent (1) + water (2)} mixtures expressed in mole fraction at temperatures from 293.15 K to 333.15 K reported by Xu et al. has been used to calculate the apparent thermodynamic functions, Gibbs energy, enthalpy, and entropy, of the dissolution processes by means of the van’t Hoff and Gibbs equations. Non-linear enthalpy–entropy relationships were observed for this drug in the plots of enthalpy vs. Gibbs energy of dissolution with positive or negative slopes regarding mixtures composition and/or cosolvent. Moreover, the preferential solvation of hesperidin by the cosolvents was analysed by using the inverse Kirkwood–Buff integrals observing that this drug is preferentially solvated by water in water-rich but preferentially solvated by cosolvents in mixtures 0.20 (or 0.24) ≤ x₁° ≤ 1.00. Furthermore, a new mathematical model was proposed for correlating/predicting the solubility of hesperidin in binary solvent mixtures at various temperatures.     

Equilibrium solubility,preferential solvation and apparent specific volume of sucrose in some {cosolvent (1) + water (2)} mixtures at 298.2 K

Sucrose is the most widely used sweetener in food and pharmaceuticals. Solubility data of this excipient in aqueous cosolvent mixtures is not abundant. Thus, the main objective of this research was to determine and correlate the equilibrium solubility of sucrose in some {cosolvent (1) + water (2)} mixtures at 298.2 K. Cosolvents were ethanol, propylene glycol and glycerol. Shaken flask method was used to determine isothermal solubility. Concentration measurements were performed by means of density determinations. Solubility of sucrose decreases non-linearly with the addition of cosolvent to water. By means of the inverse Kirkwood–Buff method it is shown that sucrose is preferentially solvated by cosolvent in water-rich mixtures but preferentially solvated by water in cosolvent-rich mixtures. Jouyban–Acree model correlates solubility values with the mixtures composition for all cosolvent systems. Moreover, apparent specific volume of sucrose was also calculated from density and compositions.     

Study of some volumetric and refractive properties of {PEG 300 (1) + ethanol (2)} mixtures at several temperatures

Molar volumes and excess molar volumes were investigated from measured density values for {PEG 300 (1) + ethanol (2)} binary mixtures at temperatures from 278.15 to 313.15 K. Both systems exhibit negative excess volumes probably due to increased interactions like hydrogen bonding and/or large differences in molar volumes of the components. Volume thermal expansion coefficients were also calculated for both binary mixtures and pure solvents. Refractive indices were also determined for all these non-aqueous mixtures and neat solvents at all temperatures. Furthermore, the Jouyban–Acree model was used for density, molar volume and refractive index correlations of the studied mixtures at different temperatures. The mean relative deviations between experimental and back-calculated density, molar volume and refractive index data were 0.07%, 0.99% and 0.01%, respectively.     

Solubility and solution thermodynamics of 2,3,4,5-tetrabromothiophene in (ethanol + tetrahydrofuran) binary solvent mixtures

The solubility of 2,3,4,5-tetrabromothiophene in (ethanol + tetrahydrofuran) binary solvent mixtures was measured within the temperature range from (278.15 to 322.15) K. The solubility increases with the rise of temperature, while it decreases with increasing ethanol content at constant temperature. The experimental data were fitted using the two variants of the combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R–K) equation and the Jouyban–Acree equation, respectively. All the three equations were proven to give good representations of the experimental values. Computational results showed that the variant two of CNIBS/R–K equation was superior to the other two equations. The thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy, were calculated by the van’t Hoff analysis. The values of both the enthalpy change and the standard molar Gibbs free energy change of solution were positive, which indicated that the process was endothermic.