Solvent effect on solubility and preferential solvation analysis of buprofezin dissolved in aqueous co-solvent mixtures of N,N-dimethylformamide, ethanol, acetonitrile and isopropanol

J. Chem. Thermodynamics 138 (2019) 179–188

Contents lists available at ScienceDirect

J. Chem. Thermodynamics journal homepage: www.elsevier.com/locate/jct

Solvent effect on solubility and preferential solvation analysis of buprofezin dissolved in aqueous co-solvent mixtures of N,Ndimethylformamide, ethanol, acetonitrile and isopropanol Xiaoying Chen a, Ali Farajtabar b, Wenping Jia a, Hongkun Zhao c,⇑ a b c

School of Pharmaceutical and Materials Engineering, TaiZhou University, Taizhou, Zhejiang 318000, People’s Republic of China Department of Chemistry, Jouybar Branch, Islamic Azad University, Jouybar, Iran College of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, People’s Republic of China

a r t i c l e

i n f o

Article history: Received 2 May 2019 Received in revised form 15 June 2019 Accepted 18 June 2019 Available online 20 June 2019 Keywords: Buprofezin Solubility Jouyban-Acree Preferential solvation Inverse Kirkwood–Buff integrals Solvent effect

a b s t r a c t The mole fraction solubility of buprofezin in aqueous co-solvent mixtures of N,N-dimethylformamide (DMF,1) + water (2), ethanol (1) + water (2), isopropanol (1) + water (2) and acetonitrile (1) + water (2) over the temperature range from (273.15 to 318.15) K was reported. At the same composition of DMF, ethanol, isopropanol or acetonitrile and temperature, the buprofezin solubility was highest in DMF (1) + water (2) mixtures. By using the Jouyban-Acree model, the buprofezin solubility was correlated obtaining RAD lower than 5.86% and RMSD lower than 15.60
104. Quantitative values for local mole fraction of DMF (ethanol, isopropanol or acetonitrile) and water nearby the buprofezin were calculated through the Inverse Kirkwood–Buff integrals method applied to the solubility. The values of preferential solvation parameters (dx1,3) were negative in water-rich mixtures but positive in co-solvent compositions from 0.19, 0.20 (0.25) or 0.25 to 1 in mole fraction of DMF, isopropanol, ethanol or acetonitrile, respectively. It was conjecturable that in water-rich mixtures, the hydrophobic hydration around the nonpolar methyl groups and aromatic ring group of buprofezin played a relevant important role in the solvation. The preference of buprofezin in water-rich mixtures could be explained in terms of the higher basic behaviour of buprofezin molecules interacting with the proton-donor functional groups of the water. In addition, solute-solvent and solvent-solvent interactions of buprofezin in the DMF (ethanol, isopropanol or acetonitrile) + water mixtures were investigated from the solubility data by using the linear solvation energy relationships concept. The variation of buprofezin solubility depended mainly upon the hydrogen bond acidity and cavity term for ethanol (isopropanol) + water mixtures, and the cavity term for DMF (acetonitrile) + water mixtures. Ó 2019 Elsevier Ltd.

1. Introduction The knowledge upon the drug solubility is nowadays a valuable subject in the pharmaceutical industry. The solubility of drugs in co-solvents mixtures, especially in aqueous co-solvents mixtures is an essential physicochemical property which plays an important role during numerous biological processes for purifying raw material and understanding the mechanisms pertaining to the chemical and physical stability of a solid dissolution [1–6], because the solubility is required in controlling the desired polymorphic form, supersaturation, yield and particle size. Co-solvency technique is effective for solubilizing poorly soluble drugs, as aqueous cosolvent mixtures is generally employed as the synthesis reaction ⇑ Corresponding author. E-mail address: [email protected] (H. Zhao). https://doi.org/10.1016/j.jct.2019.06.019 0021-9614/Ó 2019 Elsevier Ltd.

medium or crystallization solvents for purification process of lots of drugs [1,5]. Poor aqueous solubility is likely to lead to formulation difficulty or low bioavailability in clinical development [1,7]. Additionally, drug solubility in co-solvent mixtures is employed to carry out some thermodynamic analysis to insight deeply the molecular mechanisms concerning the drug dissolution process and to estimate the preferential solvation of a drug by solvent components in mixed solvents [8–11]. Buprofezin (CAS No. 69327-76-0; chemical structure shown in Fig. 1) is a chitin synthesis inhibitor which is widely employed around the world [12]. It is a molting inhibitor and thiadiazine insect regulator due to its low risk to the humans and environment [13–15]. Buprofezin has little insecticidal effect [16,17], however, compared to conventional insecticides, it presents longer residual activity against lugens nymphs. As a result, buprofezin is believed by lots of researchers to be a single insecticide for planthopper in

180

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

Fig. 1. Chemical structure of buprofezin.

China. Additionally, buprofezin has been suggested as a chief methamidophos substitute [18]. Although the buprofezin has been widely employed in a lot of areas, a little attention has been paid upon the physico-chemical property of buprofezin in some solvent mixtures, especially in aqueous co-solvent mixtures. A detailed literature examination demonstrates that only the solubility of buprofezin dissolved in some neat solvents is reported by Chen and co-workers up to now [19]. On the basis of the literature’ results [19], buprofezin exhibits up to near 102–103-fold increase in solubility in going from pure water to DMF, ethanol, acetonitrile or isopropanol. This case recommends the existence of preferential solvation of buprofezin in these co-solvent mixtures of DMF, ethanol, acetonitrile and isopropanol [10,11]. This prompts us to perform deep investigation about the buprofezin solubility in some aqueous co-solvent mixtures and analysis about thermodynamic analysis of buprofezin in these co-solvent mixtures. In addition, although solvent mixtures have been extensively used in pharmacies many years ago [5], recently the mechanisms pertaining to decreasing or increasing the drugs’ solubility start to be investigated from a deep thermodynamic point of view, containing the analysis of preferential solvation of a solute by solvent components in solvent mixtures [8–11]. The linear solvation energy relationship, LSER, is a generalized method to treat the solvent effect through dividing the solutesolvent interactions into two types of non-specific (dipole-dipole, dipole-induced dipole and dispersion) and specific (hydrogen bonding) interactions. Additionally, each interaction term has a linear contribution to Gibbs energy of solvent properties [20]. In this way, the empirical magnitudes provide an appropriate method to characterize the capability of solvent to interact with solute, well-defined as the polarity of solvent, at a molecular level. Kamlet, Abboud and Taft, KAT, introduce an extensively employed solvent scales via the solvatochromic study of pairs of probing molecules in the set of solvents with diverse interacting properties [20–23]. The scales include the dipolarity/polarizability, p*, the hydrogen bond acidity, a, and the hydrogen bond basicity, b, which are obtained directly from the energy changes resulting from intermolecular solute-solvent interactions. As a result, the study of solvent effect according to the LSER reveals the extent and nature of solutesolvent interaction affected by the solvent-dependent properties. The KAT-LSER had revealed noteworthy success in explaining a wide range of chemical phenomena, including the solubility in pure and solvent mixtures [24–27]. It should be noted that isopropanol is a flammable and colourless substance with a strong odour. It can dissolve a widespread range of non-polar substances. Compared to alternative organic solvents, isopropanol has low non-toxic. It is often employed solely or in solvent mixtures with other solvents for diverse aims including in penetration-improving pharmaceutical compositions for percutaneous and transepidermal applications [28,29]. Because DMF is aprotic and miscible with water, it is generally used as a co-solvent to study the interactions between drug solubility and medium polarity [30]. The DMF-water mixture shows strong

non-ideal, as a result it can act in the solute-solvation process via preferential solvation and hydrophobic interactions [31]. Acetonitrile is widely used because it has high resolution attainable probably due to the low viscosity of water-acetonitrile solutions [32]. In addition, the water-acetonitrile solutions may is partially hydrophobic similar to the methanol system since only the OH group in methanol is replaced by the CN group of acetonitrile. Ethanol is a common solvent used in pharmaceutical liquid formulations. It has high solubilization power and commonly employed in the liquid formulations at concentrations smaller than 50%. Ethanol may also affect the drug’s absorption, metabolism, distribution, and excretion [33]. Based on these points considered above, the chief objective of the present work is to report the equilibrium solubility of buprofezin in aqueous co-solvent mixtures of DMF, ethanol, isopropanol and acetonitrile under atmospheric pressure so as to acquire the respective thermodynamic quantities of these mixtures, as well as the preferential solvation of buprofezin by the co-solvents. 2. Theoretical aspects In the present paper, the Jouyban–Acree model [34–36] is used in describing the buprofezin solubility in the aqueous co-solvent mixtures of DMF, ethanol, isopropanol and acetonitrile. Additionally, the Kamlet and Taft linear solvation energy relationship [20] is employed to examine the solvent effect upon the buprofezin solubility. 2.1. Jouyban-Acree model The Jouyban-Acree model is expressed as Eq. (1), which is generally used in mathematical description for solute solubility dependence on both temperature and solvent compositions for solvent mixtures [34–36].

lnxw;T ¼ w1 lnx1;T þ w2 lnx2;T þ

2 w1 w2 X J ðw1  w2 Þi T=K i ¼ 0 i

ð1Þ

here xw,T refers to the mole fraction solubility of a solute in solvent mixtures at T/K; w1 and w2 are the mass fraction of co-solvents 1 (DMF, ethanol, isopropanol or acetonitrile) and 2 (water) in the absence of solute (buprofezin), respectively; x1,T and x2,T are the mole fraction solubility of solute in neat solvents; and Ji are the Jouyban-Acree model parameters. 2.2. Kamlet and Taft linear solvation energy relationship model One way to understand the environmental effects on chemical systems is by using the linear solvation energy relationships analysis, LSER. Kamlet, Abboud and Taft develop a multi-parameter expression of LSER so-called KAT-LSER to unveil the level of importance of the different intermolecular interaction responsible for the solvent effect [20]. Applied to the solubility, this model reads Eq. (2) [20,22,24,27].

lnx ¼ c0 þ c1 p  þc2 b þ c3 a þ c4

V s d2H 100RT

! ð2Þ

where, x denotes the solubility in mole fraction scale, and thus its logarithm represents the Gibbs energy of solubility. This quantity is related to energies of intermolecular interactions defined by a sum of four terms on the right hand side of Eq. (2). The first three terms represent specific and non-specific solute-solvent interactions, while the last term accounts for all solvent-solvent interactions. The first term in Eq. (2) accounts for the electrostatic, induction and dispersion interactions in term of the dipolarity-

181

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

polarizability scale, p *, of solvent. Hydrogen bonding interactions are captured by the next two terms, in which b and a are scales for the hydrogen bond basicity and hydrogen bond acidity of the solvent, respectively [20,22,24]. The last is named as the cavity term that is connected with the energy spent to create a hole within the solvent to accommodate the solute. In this term, Vs represents the molar volume for solute, dH is the Hildebrand solubility parameter, R is the gas constant and T is the temperature. Each of coefficients ci=1-4 reflects the relative sensitivity of the solubility to that particular interaction; c0 is the intercept of model at a = b = p *= dH = 0. The objective function is described as Eq. (3) during the regression.

F¼

2 X lnxew;T  lnxcw;T

ð3Þ

Sartorius Scientific Instrument (Beijing) having a standard uncertainty of 0.0001 g. The apparatus for solubility determination was given in Fig. S1 in Supporting material. It comprised a 100 mL jacketed glass vessel, a magnetic stirrer system and a circulating water bath, which is used to keep the system temperature. The temperature of the systems was controlled by using a thermostatic water bath (Model: QYHX-1030) with a standard uncertainty of 0.05 K, which was provided by Shanghai Joyn Electronic Co., Ltd., China. So as to avoid escaping of solvent, a condenser was used here and connected with the glass vessel. Prior to experiment, the reliability of experimental apparatus was verified through determining the benzoic acid solubility in neat toluene [37,38]. 3.2. Solubility measurement

i¼1

In addition, with the intention of showing the error of the selected model, the relative average deviation (RAD) and rootmean-square deviation (RMSD) are employed, which are described as Eqs. (4) and (5).

1 0 c e  1 X @xw;T  xw;T A RAD ¼ N xew;T

ð4Þ

sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi PN 2 c e i¼1 ðxw;T  xw;T Þ RMSD ¼ N

ð5Þ

herein, N refers to the number of experimental data points. xew;T is the mole fraction solubility obtained in the present work; and xcw;T , computed by using the solubility model. 3. Experimental 3.1. Materials and apparatus Buprofezin having a mass fraction of 0.987 was provided by Sigma Chemical Co., Ltd, China. It was purified through recrystallization in neat methanol for three times. The final mass fraction of buprofezin used in measurement was 0.997, which was obtained through a high-performance liquid chromatography (HPLC, Agilent 1260). The solvents such as DMF, isopropanol, ethanol and acetonitrile were provided by Sinopharm Chemical Reagent Co., Ltd., China, the mass fraction purities of which were no lower than 0.994, which were confirmed by gas chromatography (Smart (GC-2018)). The twice-distilled water used here (conductivity < 2mScm1) was prepared in our lab. The detailed aspects of these compounds were collected and tabulated in Table 1. The analytical balance (BSA224S) was used in determining the mass of solvent, solute and saturated solution. It was provided by

During the determination process, the analytical balance (BSA224S) was used to prepare the mixed solvents. Each mixture used in experiment was around 60 mL, and the relative standard uncertainty of which was assessed to be 0.0002. The mass fraction of organic solvent in mixtures changed from 0.1 to 0.9. The atmospheric pressure was about 101.2 kPa during experiment. The buprofezin solubility in the binary co-solvent mixtures of (DMF + water), (ethanol + water), (isopropanol + water) and (acetonitrile + water) was determined by using the isothermal saturation method [19,37,38], and the Agilent-1260 HPLC was employed to determine the buprofezin solubility in equilibrium liquid phase. The experiments were carried out from T = 273.15 K to 318.15 K at intervals of 5 K. Approximately 60 mL mixed solvents and excess buprofezin were added in the 100 mL jacketed vessel for each experiment. The system temperature was kept through circulating water coming from the thermostatic water-circulator bath. The real temperature of the solution was displayed by using a mercury glass micro thermometer (standard uncertainty: 0.05 K), which was inserted in the inner chamber of the vessel. A magnetic stirrer was used to mix the solvent and solid sufficiently. With the purpose of obtaining the equilibration time, the liquor was taken out at intervals of 1 h with a 2 mL syringe attached with a 0.2 lm pore filter, and then analyzed by the high-performance liquid phase chromatograph (HPLC, Agilent-1260). If the liquor composition did not change, the solution system was expected to be in equilibrium. To ensure that sampling was carried out at the equilibrium conditions, a primary experiment was made in which the liquor composition was determined as a function of time. Two kinds of tests were carried out, one starting from a supersaturated solution, in which the solid precipitated to arrive at equilibrium and the other beginning from non-saturated system, in which the excess solid dissolved to arrive at equilibrium. The experimental results showed that 12 h were sufficient to make all solution systems equilibrium. Then stop the stirring and allow the excess solid to be precipitated from the studied systems, which would take another 30 min. Around 3 mL (standard uncertainty: 0.01 mL) of

Table 1 Detailed information of buprofezin and the selected solvents.

a b

Chemicals

Molar mass/ gmol1

Source

Initial mass fraction purity

Final mass fraction purity

Purification method

Analytical method

buprofezin DMF isopropanol ethanol acetonitrile water

305.44 73.09 60.07 46.07 41.05 18.01

Sigma Chemical Co., Ltd, China Sinopharm Chemical Reagent Co., Ltd., China

0.987 0.994 0.995 0.995 0.994

0.997 0.994 0.995 0.995 0.994 Conductivity < 2 mScm1

Recrystallization none none none none Distillation

HPLCa GCb GC GC GC Conductivity meter

Our lab

High-performance liquid chromatography. Gas chromatography.

182

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

equilibrium liquor was withdrawn with the 2 mL syringe precooled or preheated in the thermostatic bath. The sample was transferred instantaneously into a 25 mL volumetric flask, and weighed by using the analytical balance. Of course, the flask was weighted before. It was diluted (if necessary) to 25 mL with methanol, and then 1 ll solution was withdrawn to analyze by using the HPLC. The mole fraction solubility of buprofezin (xw;T ) in the four mixtures is obtained with Eq. (6), and the initial compositions of mixture (w) are computed by employing Eqs. (7) and (8).

xw;T ¼

m1 =M 1 m1 =M 1 þ m2 =M 2 þ m3 =M3

w1 ¼ w ¼ w2 ¼

ð6Þ

m2 m2 þ m3

ð7Þ

m3 m2 þ m3

ð8Þ

herein m1 refers to the mass of buprofezin; m2 is the mass of DMF, ethanol, isopropanol and acetonitrile, and m3 is the mass of water. M1, M2 and M3 are corresponding molar mass. 3.3. Analysis method The composition of buprofezin in equilibrium liquid phase was confirmed through the Agilent 1260 HPLC, which comprised an UV detector (G1314F) and a quaternary pump. The separation was carried out through a ‘‘Waters C18 reverse phase column (250 mm
4.6 mm, 5 lm)”, which was bought from ‘‘Waters (Waters Inc., Bedford, MA, USA)”. The flow rate of mobile phase (neat methanol) was 1 mLmin1. The column temperature was around 303 K, and the detection wavelength of buprofezin was set to 250 nm [19]. Before test, the HPLC system was calibrated through standard solutions. The calibration curve was constructed between the HPLC area and the buprofezin concentration. Each test was carried out triple times. The solubility value was the average of three measurements. The relative standard uncertainty was evaluated to be 0.067 for the obtained mole fraction solubility. 3.4. X-ray powder diffraction In order to confirm whether polymorph transformation or solvate formation of buprofezin existed during solubility determination, the excess solid was identified by using X-ray powder diffraction (XRD). The test was carried out on a HaoYuan DX2700B (HaoYuan, China) instrument at ambient temperature. All

samples determination was performed by Cu Ka radiation (k = 0.154184 nm), and the tube voltage and current were, respectively, set at 40 kV and 30 mA. The determined data was gathered from 5° to 50° (2-Theta) at a scan speed of 6 degmin1 under atmospheric pressure. 4. Results and discussion 4.1. Results of X-ray powder diffraction The XRD scans of equilibrated solids with liquor and raw buprofezin are given in Fig. S2 of Supporting material. The XRD spectra obtained for the raw and equilibrated buprofezin shows sharp characteristics peaks at different 2h values (Fig. S2). The XRD spectra of equilibrated solids with liquor are very similar to that of the raw buprofezin and equilibrated solids with neat solvents [19], which suggest that buprofezin presents in neat crystalline state and no transform to polymorphic or amorphous form occurs in experiment. 4.2. Solubility values The determined mole fraction solubility of buprofezin in solvent mixtures of (DMF + water), (ethanol + water), (acetonitrile + water) and (isopropanol + water) as well as that in neat solvents [19] is listed in Tables 2–5, respectively. Moreover, the relationship between the mole fraction solubility and temperature and cosolvent composition is given in Fig. 2. They show that, for the studied mixed solvents, the buprofezin solubility is a function of solvent composition and temperature. The solubility of buprofezin increases with an increase in temperature and mass fraction of DMF (ethanol, isopropanol or acetonitrile) for the DMF (ethanol, isopropanol or acetonitrile) + water mixtures. The maximum solubility value of buprofezin is observed in pure DMF (ethanol, isopropanol or acetonitrile). As can also be found from the Tables 2–5 that the buprofezin solubility in (DMF + water) is greater than that in the other three mixtures at the same temperature and cosolvent composition. Here the KAT-LSER model is employed to illustrate the solvent effect on the buprofezin solubility in different mixtures. 4.3. Effect of solvent-solvent and solvent-solute interactions on solubility We employed the KAT-LSER model to provide quantitative information on effect of various solute-solvent and solvent-

Table 2 Experimental mole fraction solubility (xeT;W  104 ) of buprofezin in mixed solvent of DMF (w) + water (1-w) with various mass fractions within the temperature range from T/K = (273.15 to 318.15) under p = 101.2 kPa.a T/K

xeT;W  104 w

273.15 278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15

0b

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1b

0.2841 0.3479 0.4182 0.5080 0.6049 0.7257 0.8541 1.008 1.204 1.439

0.4632 0.5716 0.7115 0.9266 1.161 1.444 1.810 2.199 2.677 3.270

0.9049 1.134 1.455 1.824 2.304 2.777 3.374 4.099 5.058 6.290

1.796 2.251 2.770 3.508 4.374 5.397 6.538 8.013 9.729 11.28

3.563 4.607 5.684 6.961 8.523 10.27 12.31 14.70 17.58 21.03

8.261 10.08 12.21 14.64 17.52 21.03 25.03 29.69 34.67 40.45

18.00 21.87 26.36 32.02 38.01 45.82 53.96 63.54 74.84 89.51

39.52 47.64 59.24 70.66 84.92 99.82 118.0 138.4 165.6 198.1

82.16 94.52 117.2 142.8 172.6 204.3 245.7 298.9 353.6 421.6

187.6 219.2 256.1 299.2 344.7 401.2 465.2 545.1 632.0 755.9

306.4 389.0 492.6 608.0 725.1 871.4 1039 1220 1407 1618

a Standard uncertainties u are u(T) = 0.05 K, u(p) = 0.45 kPa; Relative standard uncertainty ur is ur (x) = 0.067. Solvent mixtures were prepared by mixing different masses of the solvents with relative standard uncertainty ur(w) = 0.0002. w represents the mass fraction of DMF in mixed solvents of DMF(w) + water (1-w). b Taken from Ref. [19].

183

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

Table 3 Experimental mole fraction solubility (xeT;W  104 ) of buprofezin in mixed solvent of ethanol (w) + water (1-w) with various mass fractions within the temperature range from T/K = (273.15 to 318.15) under p = 101.2 kPa.a T/K

xeT;W  104 w

273.15 278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15

0b

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1b

0.2841 0.3479 0.4182 0.5080 0.6049 0.7257 0.8541 1.008 1.204 1.439

0.4555 0.5575 0.6729 0.7953 0.934 1.128 1.331 1.585 1.867 2.220

0.7367 0.921 1.143 1.389 1.653 1.981 2.352 2.749 3.204 3.814

1.268 1.510 1.816 2.169 2.529 2.957 3.480 4.174 5.094 6.180

1.927 2.378 2.838 3.422 4.107 4.909 5.906 7.120 8.623 10.82

3.204 4.032 5.005 6.083 7.240 8.678 10.47 12.94 16.39 20.62

5.673 7.148 8.648 10.52 12.61 15.15 18.11 22.20 27.09 32.84

10.40 13.00 15.69 19.07 22.70 27.27 31.93 38.63 47.42 58.87

17.91 22.07 27.39 33.30 40.90 48.84 58.95 72.30 87.54 105.7

30.41 39.63 49.19 59.78 72.76 87.71 107.0 129.8 155.5 184.1

53.85 69.96 91.73 115.7 146.4 181.7 228.2 275.7 341.8 424.8

a Standard uncertainties u are u(T) = 0.05 K, u(p) = 0.45 kPa; Relative standard uncertainty ur is ur (x) = 0.067. Solvent mixtures were prepared by mixing different masses of the solvents with relative standard uncertainty ur(w) = 0.0002. w represents the mass fraction of ethanol in mixed solvents of ethanol (w) + water (1-w). b Taken from Ref. [19].

Table 4 Experimental mole fraction solubility (xeT;W  104 ) of buprofezin in mixed solvents of acetonitrile (w) + water (1-w) with various mass fractions within the temperature range from T/K = (273.15 to 318.15) under p = 101.2 kPa.a T/K

xeT;W  104 w

273.15 278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15

0b

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1b

0.2841 0.3479 0.4182 0.5080 0.6049 0.7257 0.8541 1.008 1.204 1.439

0.4555 0.5575 0.6919 0.8409 1.001 1.200 1.448 1.712 2.051 2.425

0.8235 1.001 1.208 1.468 1.760 2.074 2.495 2.962 3.515 4.182

1.563 1.848 2.169 2.636 3.138 3.754 4.529 5.349 6.399 7.644

2.685 3.235 3.966 4.867 5.793 6.753 7.926 9.369 11.09 13.18

4.833 5.897 6.992 8.265 9.837 11.79 14.21 17.03 20.21 24.32

8.265 9.837 11.55 14.03 16.70 20.60 26.10 32.04 40.11 50.63

13.46 16.43 19.94 24.49 29.84 35.68 42.62 52.58 64.02 77.54

24.00 28.70 35.25 42.93 53.02 64.54 78.59 97.87 125.7 156.4

39.69 47.15 62.34 82.58 105.10 133.50 163.3 200.9 240.8 292.7

53.40 77.43 101.5 133.2 170.9 219.4 284.5 354.2 448.1 563.9

a Standard uncertainties u are u(T) = 0.05 K, u(p) = 0.45 kPa; Relative standard uncertainty ur is ur (x) = 0.067. Solvent mixtures were prepared by mixing different masses of the solvents with relative standard uncertainty ur(w) = 0.0002. w represents the mass fraction of acetonitrile in mixed solvents of acetonitrile (w) + water (1-w). b Taken from Ref. [19].

Table 5 Experimental mole fraction solubility (xeT;W  104 ) of buprofezin in mixed solvents of isopropanol (w) + water (1-w) with various mass fractions within the temperature range from T/K = (273.15 to 318.15) under p = 101.2 kPa.a T/K

xeT;W  104 w

273.15 278.15 283.15 288.15 293.15 298.15 303.15 308.15 313.15 318.15

0b

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

0.9000

1b

0.2841 0.3479 0.4182 0.5080 0.6049 0.7257 0.8541 1.008 1.204 1.439

0.5260 0.6287 0.7527 0.9195 1.091 1.330 1.627 1.907 2.313 2.688

0.8749 1.071 1.334 1.555 1.883 2.245 2.691 3.174 3.764 4.532

1.497 1.752 2.120 2.590 3.044 3.739 4.389 5.261 6.257 7.464

2.502 2.929 3.493 4.165 5.060 6.360 7.383 8.683 10.35 12.42

4.037 4.877 5.840 6.941 8.555 10.39 12.58 14.84 17.38 20.35

6.828 8.008 9.582 11.81 14.27 17.75 21.61 25.65 30.63 36.34

12.23 13.72 16.59 20.84 25.48 31.62 38.39 45.80 53.66 63.35

20.92 24.16 28.96 36.17 44.62 54.95 66.85 79.54 94.20 110.5

35.66 45.08 56.97 69.88 84.92 104.3 125.6 152.0 185.2 228.1

58.64 78.52 102.8 130.5 165.0 207.0 254.0 309.8 375.7 453.7

a Standard uncertainties u are u(T) = 0.05 K, u(p) = 0.45 kPa; Relative standard uncertainty ur is ur (x) = 0.067. Solvent mixtures were prepared by mixing different masses of the solvents with relative standard uncertainty ur(w) = 0.0002. w represents the mass fraction of isopropanol in mixed solvents of isopropanol (w) + water (1-w). b Taken from Ref. [19].

solvent interactions on the solubility of buprofezin in the studied four aqueous mixtures at 298.15 K. The required parameters a, b, p * for DMF + water, ethanol + water, isopropanol + water + and acetonitrile + water mixtures are available from different sources [39–42]. These data show quite small discrepancies in KAT param-

eters for water. Thus, the gathered data, p, from different studies were corrected according Eq. (9) [43,44].

pc ¼ plit 2 þ

lit plit 1  p2 ðp  p2 Þ p1  p2

ð9Þ

184

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

1500

(a)

400

(b)

300

4

4

10 x

10 x

1000

200

500 100

320

310

300

T/K

500

290

0.2

280 270

0.4

1.0 0.8 0.6

320

310

w

300

290

T/K

0.0

(c)

400

0.2

280 270

0.4

0.0

1.0 0.8 0.6

w

(d)

10 x

200

200 100

100 320

300

4

300

4

10 x

400

310

300

T/K

290

0.4 280

0.2

0.6

1.0 0.8

w

270 0.0

320

310

300

T/K 290

0.4 0.2

280 270

0.6

1.0 0.8

w

0.0

Fig. 2. Mole fraction solubility (x) of buprofezin in (a) DMF (w) + water (1-w), (b) ethanol (w) + water (1-w), (c) Acetonitrile (w) + water (1-w) and (d) isopropanol (w) + water (1-w) mixtures with various mass fractions at different temperatures: w, mass fraction; j, w = 0 [19]; d, w = 0.1000; ▲, w = 0.2000; ◆, w = 0.3000; ., w = 0.4000; w, w = 0.5000; 4, w = 0.6000; s, w = 0.7000; q, w = 0.8000; J, w = 0.9000; h, w = 1 [19]. —, calculated curves by the Jouyban–Acree model.

where, pc stands for the corrected KAT parameter in binary mixtures; plit i is the accepted literature data for pure solvents and pi represent the original KAT parameter for the pure solvent i in mixtures. Data of plit i are available from the compilation of Marcus [45]. Tables S2 and S3 in the Supporting material show the values obtained by Eq. (9) as a function of mole fraction. For binary mixtures, dH data are estimated by /1 d H1 + /2 dH2 from the volume fraction, / I, and values of dHi for pure solvents taken from Hansen [8,46]. For buprofezin, Vs is estimated from the molar mass and density (1.120 g3cm3) taken from Ref. [19]. Eq. (2) represents an expression in which all energy terms are considered for modelling the solvent effect. In reality, depending the nature of system, some of these terms can be completely neglected. In this work, term b was not submitted to the correlation analysis, because buprofezin, as evidence in Fig. 1, is not a Lewis acid, and unable to act as hydrogen bonding donor solute. Therefore, we made seven KAT-LSER models including one threeparameter, three two-parameter and three single-parameter models from different combination of a, p * and cavity term. Then, for each binary mixtures, these models are fitted to experimental solubility data by using the least square fit carried out by LINEST function in Excel Microsoft program. The results of correlation analysis are shown in Tables S4–S7 of Supporting material. For a valid model, a positive value for ci=1-3 and negative value for c4 should be met. The reason is that solute-solvent interactions are favorable to the solubility, while solvent-solvent interactions

hamper it. Of the retained models, the best, as bolded in Tables S4–S7, is that which is resulted in the highest F-statistic value. Results in Tables S4 and S7 show that the cavity term is the major factor that governs the solubility variation of buprofezin in DMF (acetonitrile) (1) + water (2) mixtures. In these cases, the single-parameter KAT-LSER including cavity term does succeed to explain 96–97% of the solvent effect on the solubility. The reason is the relatively large size of buprofezin, which causes a large energy of cavity formation in dissolution process. It means the increase in the solubility is mainly attributed to the decrease in the cohesive energy density of solvent, represented by dH, as the mole fraction of aprotic solvent increases in the mixture. It was expected that a of solvent plays an important role in solubility of buprofezin, since the solute is a Lewis base. However, it is not needed for the best model, perhaps because, in the case mixture of water and a strong hydrogen bond accepting aprotic solvent (DMF and acetonitrile), water prefers to donate hydrogen bond to solvent rather than to the solute. Analysis in Tables S5 and S6 reveals the best expression is a two-parameter KAT-LSER model including the hydrogen bond acidity and cavity term. In mixtures of water and ethanol, the model explain 99% of the variance; the contribution from a and cavity term to solvent effect is 47% and 53% respectively. In mixtures of water and isopropanol, the model explains 98% of the variance; the contribution from a and cavity term to solvent effect is 56% and 44%, respectively. Increase in the susceptibility of the solubility to a in the case of isopropanol

185

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

is may be due to the weaker interaction of water with isopropanol than with ethanol, which leads to somewhat favorable hydrogen bonding interaction with solute in water-rich regions.

with 

G1;3 ¼ RT jT  V 3 þ



x2 V 2 D Q

4.4. Solubility modelling According to the determined solubility data, the parameters of Eq. (1) are acquired by using Mathcad software. The gained values of model parameters together with the RAD and the RMSD are presented in Table S1 of the Supporting material. In addition, the solubility of buprofezin in the four mixtures is evaluated based on the regressed parameters’ values and plotted in Fig. 2. As is observed in Table S1 that for the studied mixtures, the values of relative average deviations (RAD) are 4.48% for (DMF + water) mixture, 4.60% for (ethanol + water) mixture, 5.86% for (acetonitrile + water) mixture and 3.59% for (isopropanol + water) mixture. Additionally, the maximum RMSD value is 15.60
104, which is obtained for (DMF + water) mixture. In general, the Jouyban-Acree model offers satisfied correlation results for these co-solvent mixtures. 4.5. Preferential solvation of buprofezin As discussed previously, the buprofezin solubility shows 102– 10 -fold increase in going from neat water to the DMF (ethanol, isopropanol or acetonitrile). The significant rise in solubility suggests the presence of preferential solvation of buprofezin in the mixed solvents [10,11,36]. The inverse Kirkwood–Buff integrals (IKBI) is a valuable method to describe the local composition near a solute with respect to components existing in the mixtures. The treatment depends upon the values of standard molar Gibbs energies of transfer of a solute (compound 3) from neat water (compound 2) to the mixture of co-solvent (compound 1) + water (compound 2) and the excess molar Gibbs energy of mixing for the solute-free mixture. Accordingly, this treatment is of actual importance in chemical and pharmaceutical sciences to insight the solute–solvent interactions. The general equation of inverse Kirkwood-Buff integral is described as: 3

Z

Gi;3 ¼

r cor

0

ðg i;3  1Þ4pr 2 dr

ð10Þ

wherein, gi,3 refers to the pair correlation function for molecules of solvent i in the co-solvent (1) + water (2) solutions nearby buprofezin (3); r is the distance between the centers of molecules of buprofezin (3) and that of co-solvent (1) or water (2); and rcor is the correlation distance. The preferential solvation parameter (dx1;3 ) of buprofezin (compound 3) by the co-solvent (compound 1) in co-solvent (1) + water (2) mixtures can be expressed as [8–11]:

dx1;3 ¼ xL1;3  x1 ¼ dx2;3

ð11Þ

xL1;3

where is local mole fraction of co-solvent (1) in the environment near to buprofezin (3) and x1 is the bulk mole fraction of co-solvent (1) in the original solutions. If dx1,3 > 0, buprofezin is preferentially solvated by the co-solvent (1); on the contrary, if dx1,3 is <0, buprofezin is preferentially solvated by water (2). On the other hand, if | dx1,3| < 0.01, the preferential solvation procedure is ignored, but if xL1;3  1, complete solvation of buprofezin is performed by the DMF, ethanol, isopropanol or acetonitrile (1). Values of dx1,3 is attainable from the IKBI method for the individual solvent components calculated based on following thermodynamic quantities [8–11,36]:

dx1;3 ¼

x1 x2 ðG1;3  G2;3 Þ x1 G1;3 þ x2 G2;3 þ V cor

ð12Þ

G2;3

ð13Þ





x1 V 1 D ¼ RT jT  V 3 þ Q

ð14Þ

 3    1=3  0:085 V cor ¼ 2522:5 r 3 þ 0:1363 xL1;3 V 1 þ xL2;3 V 2

ð15Þ

In Eqs. (13)–(15), jT refers to the isothermal compressibility of 



the solvent mixtures (expressed in GPa1); V 1 and V 2 refer to the partial molar volumes of neat solvents in the mixtures (expressed 

in cm3mol1); V 3 is the partial molar volume of buprofezin in mixtures (expressed in cm3mol1). The function D described as Eq. (16) is the derivative of the standard molar Gibbs energies of transfer of buprofezin from water (2) to co-solvent (1) + water (2) mixtures with respect to the solvent composition (expressed in kJmol1, as is RT). The function Q defined as Eq. (17) comprises the second derivative of excess molar Gibbs energy of mixing of the two solvents (GExc 1þ2 ) with respect to the water proportion in mixtures (expressed in kJmol1). Vcor is the correlation volume and r3 is the molecular radius of buprofezin computed with Eq. (18) with NAv as the Avogadro’s number.

D¼

@ Dtr Goð3;2!1þ2Þ

!

@x1

Q ¼ RT þ x1 x2

ð16Þ T;P

" # @ 2 GExc 1þ2 @x22

ð17Þ

T;p

sffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 21 3 3
10 V3 r3 ¼ 4pNAV

ð18Þ

Because of the dependence of jT upon composition, this term is not known for all systems studied. Instead, the RTjT term has slight contribution to the IKBIs, the values of jT may be assessed approximately as an additive property through the mixture compositions and reported values for neat solvents by [10,11,36]:

jT ¼ x1 joT;1 þ x2 joT;2

ð19Þ

here xi is the mole fraction of component i in mixtures and joT;i is the isothermal compressibility of neat component i. Consequently the RTjT values can be obtainable by employing the reported values of joT;i for DMF (0.653 GPa1), ethanol (1.153 GPa1), isopropanol (1.332 GPa1), acetonitrile (1.070 GPa1), and water (0.457 GPa1) at 298.15 K [47], taken as independent of temperature [8–11,36]. Standard molar Gibbs energies of transfer of buprofezin from water (2) to DMF (1) + water (2), ethanol (1) + water (2), isopropanol (1) + water (2) + and acetonitrile (1) + water (2) mixtures are computed through Eq. (20) from the determined solubility.

 x3;2 Dtr G03;2!1þ2 ¼ RTln x3;1þ2

ð20Þ

The obtained Dtr G03;2!1þ2 values are correlated with the empirical Eq. (21), where A0, A1, t1, A2 and t2 are equation parameters. Fig. S3 of Supporting material shows the Gibbs energy of transfer at several temperatures, while the values are tabulated in Tables S8 and S9 of Supporting material. The regressed equation coefficients are presented in Table S10 of Supporting material. x

t 1

Dtr Go3;2!1þ2 ¼ A0 þ A1 e

1

x

t 1

þ A2 e

2

ð21Þ

186

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

Thus, the values of D reported in Tables S11 and S12 of Supplementary material are computed from the first derivative of Eq. (21) solved in terms of the mixtures composition varying by 0.05 in mole fraction of DMF (1), ethanol (1), isopropanol (1) or acetonitrile (1). Because no partial molar volumes of buprofezin (3) in these solutions can be obtainable in the publications, here they are supposed as similar to that of neat buprofezin [10,11,36]. Accordingly, solute radius value (r3) is computed with Eq. (18) as 0.476 nm. Additionally, the values of RTjT and the partial molar volumes of two neat solvents in the ethanol (1) + water (2) mixtures as well as the Q values at different temperatures have been reported [36]. However, for the DMF (1) + water (2), isopropanol (1) + water (2) + and acetonitrile (1) + water (2) mixtures, these properties can 1 only be found at 298.15 K [10,11]. The GExc ) at 1þ2 values (Jmol 298.15 K are calculated by using Eqs. (22), (23) and (24) for the DMF (1) + water (2), isopropanol (1) + water (2) + and acetonitrile

(1) + water (2) mixtures [8]. The values of GExc 1þ2 at the other studied temperatures can be computed with Eq. (25), here HExc 1þ2 is the excess molar enthalpy of the solvent mixtures, T1 is 298.15 K, and T2 is the temperature under consideration. HExc 1þ2 values for DMF (1) + water (2), isopropanol (1) + water (2) and acetonitrile (1) + water (2) mixtures (expressed as Eqs. (26), 27 and 28) are cited in Ref. [8].

h i 2 GExc 1þ2 ¼ x1 ð1  x1 Þ 978  653ð1  2x1 Þ þ 222ð1  2x1 Þ

ð22Þ

h i 2 GExc 1þ2 ¼ x1 ð1  x1 Þ 5253  639ð1  2x1 Þ þ 1316ð1  2x1 Þ

ð23Þ

h i 2 GExc 1þ2 ¼ x1 ð1  x1 Þ 3843  984ð1  2x1 Þ  98ð1  2x1 Þ

ð24Þ

Z Exc GExc 1þ2 ðT 2 Þ ¼ G1þ2 ðT 1 Þ  T

T2 T1

  1 T 2 Exc T2 Exc  HExc d G ðT Þ þ H 1  1 1þ2 1þ2 T T 1 1þ2 T1 ð25Þ

h

2 HExc 1þ2 ¼ x1 ð1  x1 Þ 7616 þ 7751ð1  2x1 Þ  1904ð1  2x1 Þ

i ð26Þ

h

2 HExc 1þ2 ¼ x1 ð1  x1 Þ 854 þ 5167ð1  2x1 Þ  7243ð1  2x1 Þ

i

ð27Þ

h i 2 3 HExc 1þ2 ¼ x1 ð1  x1 Þ 4640 þ 2922ð1  2x1 Þ  1028ð1  2x1 Þ  8ð1  2x1 Þ ð28Þ

The partial molar volumes of co-solvent and water in mixtures are computed from the reported density values of co-solvent mixtures at studied temperatures under study by Bernal-García for DMF + water mixtures [48], by Pang for isopropanol + water mixtures [49] and by Saleh and Handa for acetonitrile (1) + water (2) mixtures [50,51] using Eqs. (29) and (30), where V refers to the molar volume of solutions calculated as V =(x1M1 + x2M2)/q; M1 is 73.09 gmol1 for DMF, 60.06 gmol1 for isopropanol, 41.05 gmol1 for acetonitrile, and M2 is 18.01 gmol1 for water. As a result, the values of G1,3 and G2,3 in the four mixtures can be obtainable and presented in Tables S13–S16 of Supplementary material. 

dV dx1

ð29Þ



dV dx1

ð30Þ

V 1 ¼ V þ x2 V 2 ¼ V  x1

The definitive correlation volume is dependent on the local mole fractions round the solute, so it requires iteration. This procedure is made by substituting dx1,3 and Vcor into the Eqs. (11), (12) and (15) to recalculate xL1;3 until a non-variant Vcor value is attained. The achieved values of Vcor and dx1,3 are also tabulated in Tables S17–S20 of Supplementary material for DMF (1) + water (2), ethanol (1) + water (2), isopropanol (1) + water (2) and acetonitrile (1) + water (2) mixtures, respectively. In addition, the dx1,3 dependence upon solvent composition is shown graphically in Fig. 3. It shows that the dx1,3 values vary non-linearly with the co-solvent (1) composition in all aqueous mixtures. According to Fig. 3, addition of DMF (ethanol, isopropanol or acetonitrile) (2) makes negative the dx1,3 values of buprofezin (3) from neat water (1) up to x1 = 0.19 mol fractions of DMF, x1 = 0.25 mol fraction of ethanol, x1 = 0.25 mol fraction of acetonitrile and x1 = 0.20–0.25 mol fraction of isopropanol. In these regions, the local mole fractions of DMF (ethanol, isopropanol or acetonitrile) (1) are lower than that of the mixtures and therefore the dx1,3 values are negative, which shows that buprofezin is preferentially solvated by water. Perhaps the structuring of water molecules nearby the nonpolar aromatic group of buprofezin (i.e. hydrophobic hydration of aromatic ring group and methyl group) contributes to lowering of the net dx1,3 to negative values in the DMF (ethanol, isopropanol or acetonitrile) mixtures. Maximum negative values are attained with the composition x1 = 0.05 with dx1,3 = 1.580
102 to 1.454
102 for the DMF (1) + water (2), x1 = 0.10 with dx1,3 = 1.627
102 to 1.336
102 for the ethanol (1) + water (2), x1 = 0.15 with dx1,3 = 4.280
102 to 3.377
102 for the acetonitrile (1) + water (2) and x1 = 0.05–0.10 with dx1,3 = 1.469
102 to 1.214
102 for isopropanol (1) + water (2) mixtures. In the DMF (1) + water (2) mixtures with composition 0.19 < x1 < 1, isopropanol (1) + water (2) mixtures with composition 0.20–0.25 < x1 < 1 and ethanol (1) + water (2) mixtures with composition 0.25 < x1 < 1, the local mole fractions of DMF (isopropanol or ethanol) are higher than that of the mixtures and as a result the dx1,3 values are positive, which indicate buprofezin is solvated preferentially by the DMF (isopropanol or ethanol). The co-solvents action to increase the solute solubility may be relation to the breaking of ordered structure of water around the polar moiety of buprofezin which increases the solvation having maximum values near to x1 = 0.50 with dx1,3 = 1.974
102 to 2.128
102 for the DMF (1) + water (2), x1 = 0.65–0.70 with dx1,3 = 5.685
102 to dx1,3 = 6.053
102 for the ethanol (1) + water (2) and x1 = 0.60–0.65 with dx1,3 = 17.90
102 to dx1,3 = 25.35
102 for the isopropanol (1) + water (2) mixtures. In the case of acetonitrile (1) + water (2) mixture, the exhibited behaviour in intermediate and acetonitrile-rich mixtures is erratic because some extreme positive-negative-positive jumps are observed. This anomalous behaviour is perhaps the consequence of positive Q values observed in the mixture regarding the highly negative excess Gibbs energy of mixing. Similar behaviours have been described with other drugs in different aqueous co-solvent mixtures also exhibiting high excess Gibbs energies of mixing [52,53]. Nevertheless, as a qualitative result for the mixtures with composition 0.25 < x1 < 1.00, it may also be believed that buprofezin is preferentially solvated by acetonitrile. Based on the structural and functional group study, buprofezin can act as a Lewis base because of the free electron pairs in nitrogen atom of –N = and > N- and oxygen atom of C = O (Fig. 1), which interact with acidic hydrogen atoms of water. On the basis of preferential solvation results, it is conjecturable that in the region of 0 < x1 < 0.19 for DMF, 0 < x1 < 0.25 for ethanol and acetonitrile and 0 < x1 < 0.20–0.25 for isopropanol, buprofezin is acting mainly as a Lewis base in front to water because the water is more acidic than DMF, ethanol, isopropanol or acetonitrile as described by the

187

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

2.0

6

(a)

(b)

1.5

4

x1,3

x1,3

1.0 0.5 0.0 293.15 K 298.15 K 303.15 K 308.15 K 313.15 K

-0.5 -1.0 -1.5 0.0

60

0.2

0.4

x1

0.6

0

0.8

-2 0.0

1.0

25

(c)

x1,3

x1,3

0.2

0

-60

x1

0.6

0.8

1.0

0.6

0.8

1.0

293.15 K 298.15 K 303.15 K 308.15 K 313.15 K

15 10

293.15 K 298.15 K 303.15 K 308.15 K 313.15 K

-30

0.4

(d)

20

30

-90 0.0

293.15 K 298.15 K 303.15 K 308.15 K 313.15 K

2

5 0

0.2

0.4

x1

0.6

0.8

1.0

0.0

0.2

0.4

x1

Fig. 3. dx1,3 values of buprofezin (3) from water (2) to DMF (1) + water (2), ethanol (1) + water (2), acetonitrile (1) + water (2) and isopropanol (1) + water (2) mixtures at several temperatures. (a), DMF (1) + water (2); (b), ethanol (1) + water (2); (c), acetonitrile (1) + water (2); (d), isopropanol (1) + water (2) vs co-solvent composition x1.

Kamlet–Taft hydrogen bond donor parameters, i.e. a = 1.17 for water, 0.00 for DMF, 0.76 for isopropanol, 0.19 for acetonitrile and 0.86 for ethanol, respectively [22,47]. Contrary to other drugs [36,53], there is apparently no possible Lewis acid behaviour for buprofezin because no acidic hydrogen atoms are present (Fig. 1). So it is not easy to find a reasonable explanation for the positive values of dx1,3 in those mixtures with intermediate and co-solvent-rich composition. In the case of other drugs with hydrogen donation capacity, these tendency has been explained based on the Lewis acidic behaviour with the co-solvent molecules because they are normally more basic than water as described by the Kamlet–Taft hydrogen bonding acceptor parameters b, that are higher than that for water. These values are as follows: b = 0.69 for DMF, b = 0.84 for isopropanol, b = 0.75 for ethanol, b = 0.40 for acetonitrile and 0.47 for water [21,47].

5. Conclusion The equilibrium solubility of buprofezin in four co-solvent mixtures of DMF (1) + water (2), ethanol (1) + water (2), isopropanol (1) + water (2) + and acetonitrile (1) + water (2) was determined experimentally through the isothermal saturation method within the temperature range from 278.15 K to 318.15 K under 101.2 kPa. At the same temperature and mass fraction of DMF (ethanol, isopropanol or acetonitrile), the mole fraction solubility of buprofezin was greater in (DMF + water) than that in the other three mixtures. The values of preferential solvation parameters (dx1,3) for DMF, ethanol, isopropanol or acetonitrile were positive in the isopropanol mixture with composition 0.20–0.25 < x1 < 1, DMF mixture with composition 0.19 < x1 < 1 and ethanol and acetonitrile mixtures with composition 0.25 < x1 < 1, which indicated that buprofezin was preferentially solvated by co-solvent. In addition, the drug’ solubility was mathematically expressed by employing the Jouyban-Acree model model obtaining average rel-

ative deviations lower than 5.86% for correlative investigations. KAT-LSER model was successfully conducted in modelling of solvent effect on the solubility variation of buprofezin in mixtures studied. It was found that the decrease in the cavity term is the most important factor for the solubility enhanced when the mole fraction of aprotic solvent increases in DMF (acetonitrile) + water mixtures. The combination of a and cavity term explains adequately the variance on the solubility in ethanol (isopropanol) + water mixtures. Acknowledgement The project was supported by the Science and Technology Plan Project in Zhejiang Province (Grants 2016C37040 and 2015C33224), the State Key Laboratory of Chemical Resources Engineering under Grant CRE-2012-C-303, and the National Natural Science Foundation of China (Grants 21506138, 21375092, and 21575097). Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.jct.2019.06.019. References [1] S.H. Yalkowsky, Solubility and Solubilization in Aqueous Media, American Chemical Society and Oxford University Press, New York, 1999, pp. 180–235. [2] R. Sanghvi, R. Narazaki, S.G. Machatha, S.H. Yalkowsky, Solubility improvement of drugs using N-methyl pyrolidone, Aaps Pharmscitech 9 (2008) 366–376. [3] A. Jouyban, Handbook of Solubility Data for Pharmaceuticals, CRC Press, BocaRaton, FL, 2010. [4] F. Martínez, A. Jouyban, W.E. Acree Jr, Pharmaceuticals solubility is still nowadays widely studied everywhere, Pharmaceut. Sci. 23 (2017) 1–2. [5] J.T. Rubino, Cosolvents and Cosolvency, in: J. Swarbrick, J.C. Boylan (Eds.), Encyclopedia of Pharmaceutical Technology, 3, Marcel Dekker, New York, NY, 1988.

188

X. Chen et al. / J. Chem. Thermodynamics 138 (2019) 179–188

[6] P. Kolárˇ, J.W. Shen, A. Tsuboi, T. Ishikawa, Solvent selection for pharmaceuticals, Fluid Phase Equilibr. 194–197 (2002) 771–782. [7] M.E. Aulton, Pharmaceutics. The Science of Dosage Forms Design, second ed., Churchill Livingstone, London, 2002. [8] Y. Marcus, Solvent Mixtures: Properties and Selective Solvation, Marcel Dekker Inc., New York, NY, 2002. [9] Y. Marcus, Preferential solvation in mixed solvents, in: P.E. Smith, E. Matteoli, J.P. O’Connell (Eds.), Fluctuation Theory of Solutions: Applications in Chemistry, Chemical Engineering, and Biophysics, CRC Press, Taylor & Francis Group, BocaRaton, FL, 2013. [10] F. Martínez, A. Jouyban, W.E. Acree Jr, Preferential solvation of etoricoxib in some aqueous binary cosolvent mixtures at 298.15 K, Phys. Chem. Liq. 55 (2016) 291–303. [11] A. Jouyban, W.E. Acree Jr, F. Martínez, Modelling the solubility and preferential solvation of gallic acid in cosolvent + water mixtures, J. Mol. Liq. 224 (2016) 502–506. [12] A.M. Dessouki, H.F. Aly, H.H. Sokker, The use of gamma radiation for removal of pesticides from waste water, Czech J. Phys. 49 (1999) 521–533. [13] Y.H. Wang, C.F. Gao, Z.P. Xu, Y.C. Zhu, J.S. Zhang, W.H. Li, D.J. Dai, Y.W. Lin, W.J. Zhou, J.L. Shen, Buprofezin susceptibility survey, resistance selection and preliminary determination of the resistance mechanism in Nilaparvata lugens (Homoptera: Delphacidae), Pest Manage. Sci. 64 (2008) 1050–1056. [14] M.S. Ibrahim, K.M. Al-Magboul, M.M. Kamal, Voltammetric determination of the insecticide buprofezin in soil and wate, Anal. Chim. Acta 432 (2001) 21–26. [15] Y. Izawa, M. Uchida, T. Sugimoto, T. Asai, Inhibition of chitin synthesis by buprofezin analogs in relation to their activity controlling Nilaparvata lugens (Stål), Pestic. Biochem. Physiol. 24 (1985) 343–347. [16] I. Ishaaya, Z. Mendelson, V. Melamed-Madjar, Effect of buprofezin on embryogenesis and progeny formation of sweet potato whitefly (Homoptera: Aleyrodidae), J. Econ. Entomol. 81 (1988) 781–784. [17] T.T. Ku, W. Yan, W.Y. Jia, Y. Yun, N. Zhu, G.K. Li, N. Sang, Characterization of synergistic embryotoxicity of nickel and buprofezin in zebrafish, Environ. Sci. Technol. 49 (2015) 4600–4608. [18] M. Basit, M.A. Saleem, S. Saeed, A.H. Sayyed, Cross resistance, genetic analysis and stabi lity of resistance to buprofezin in cotton whitefly, Bemisia tabaci (Homoptera: Aleyrodidae), Crop Prot. 40 (2012) 16–21. [19] X.Y. Chen, Z.H. Zhou, J.J. Chen, C. Chu, J.L. Zheng, S.T. Wang, W.P. Jia, J. Zhao, R.R. Li, D.M. Han, Solubility determination and thermodynamic modelling of buprofezin in different solvents and mixing properties of solutions, J. Chem. Eng. Data 64 (2019) 1177–1186. [20] R.W. Taft, J.L.M. Abboud, M.J. Kamlet, M.H. Abraham, Linear solvation energy relations, J. Solution Chem. 14 (1985) 153–186. [21] M.J. Kamlet, R.W. Taft, The solvatochromic comparison method. I. The beta scale of solvent hydrogen-bond acceptor (HBA) basicities, J. Am. Chem. Soc. 98 (1976) 377–383. [22] R.W. Taft, M.J. Kamlet, The solvatochromic comparison method. 2. The alphascale of solvent hydrogen-bond donor (HBD) acidities, J. Am. Chem. Soc. 98 (1976) 2886–2894. [23] M.J. Kamlet, J.L. Abboud, R.W. Taft, The solvatochromic comparison method. 6. The pi.* scale of solvent polarities, J. Am. Chem. Soc. 99 (1977) 6027–6038. [24] M.J. Kamlet, R.M. Doherty, J.L.M. Abboud, M.H. Abraham, R.W. Taft, Linear solvation energy relationships: 36. Molecular properties governing solubilities of organic nonelectrolytes in water, J. Pharm. Sci. 75 (1986) 338–349. [25] A. Farajtabar, F. Gharib, Spectral analysis of naringenin deprotonation in aqueous ethanol solutions, Chem. Pap. 67 (2013) 538–545. [26] F. Naderi, A. Farajtabar, Solvatochromism of fluorescein in aqueous aprotic solvents, J. Mol. Liq. 221 (2016) 102–107. [27] M.J. Kamlet, J.L.M. Abboud, M.H. Abraham, R.W. Taft, Linear solvation energy relationships. 23. A comprehensive collection of the solvatochromic parameters, pi.*, alpha., and beta., and some methods for simplifying the generalized solvatochromic equation, J. Org. Chem. 48 (1983) 2877–2887. [28] G.D. Maia, M. Giulietti, Solubility of acetylsalicylic acid in ethanol, acetone, propylene glycol, and 2-propanol, J. Chem. Eng. Data 53 (2008) 256–258. [29] M. Mohammadzade, M. Barzegar-Jalali, A. Jouyban, Solubility of naproxen in 2propanol + water mixtures at various temperatures, J. Mol. Liq. 206 (2015) 110–113. [30] P.B. Rathi, V.K. Mourya, Solubility prediction of satranidazole in aqueous N, Ndimethylformamide mixtures using extended Hildebrand solubility approach, Indian J. Pharm. Sci. 74 (2012) 254–258. [31] R.J. Sindreu, M.L. Moya, B.F. Sanchez, A.G. Gonzalez, Solvent effects on the dissociation of aliphatic carboxylic acids in water-N, N-dimethylformamide mixtures: correlation between acidity constants and solvatochromic parameters, J. Solution Chem. 23 (1994) 1101–1109. [32] K. Gekko, E. Ohmae, K. Kameyama, T. Takagi, Acetonitrile-protein interactions: amino acid solubility and preferential solvation, BBA 1387 (1998) 195–205.

[33] A. Jouyban, J. Shokri, M. Barzegar-Jalali, D. Hassanzadeh, W.E. Acree Jr., T. Ghafourian, A. Nokhodchi, Solubility of chlordiazepoxide, diazepam, and lorazepam in ethanol + water mixtures at 303.2 K, J. Chem. Eng. Data 54 (2009) 2142–2145. [34] G.B. Yao, Q.C. Yao, Z.X. Xia, Z.H. Li, Solubility determination and correlation for o-phenylenediamine in (methanol, ethanol, acetonitrile and water) and their binary solvents from T = (283.15–318.15) K, J. Chem. Thermodyn. 105 (2017) 179–186. [35] J. Wang, A.L. Xu, R.J. Xu, Determination and correlation of terephthaldialdehyde solubility in (ethanol, isopropanol, ethyl acetate, isopentanol) + N, N-dimethylformamide mixed solvents at temperatures from 273.15 K to 318.15 K, J. Chem. Thermodyn. 105 (2017) 327–336. [36] J. Chen, G.Q. Chen, Y. Cong, C.B. Du, H.K. Zhao, Solubility modelling and preferential solvation of paclobutrazol in co-solvent mixtures of (ethanol, npropanol and 1,4-dioxane) + water, J. Chem. Thermodyn. 112 (2017) 249–258. [37] S. Han, L. Meng, C.B. Du, R.J. Xu, C. Cheng, J. Wang, H.K. Zhao, Solubility measurement and thermodynamic modelling of 4-nitrophthalimide in twelve pure solvents at elevated temperatures ranging from (273.15 to 323.15) K, J. Chem. Eng. Data 61 (2016) 2525–2535. [38] C. Cheng, Y. Cong, C.B. Du, J. Wang, G.B. Yao, H.K. Zhao, Solubility determination and thermodynamic models for dehydroepiandrosterone acetate in mixed solvents of (ethyl acetate + methanol), (ethyl acetate + ethanol) and (ethyl acetate + isopropanol), J. Chem. Thermodyn. 101 (2016) 372–379. [39] U. Buhvestov, F. Rived, C. Rafols, E. Bosch, M. Roses, Solute–solvent and solvent–solvent interactions in binary solvent mixtures. Part 7. Comparison of the enhancement of the water structure in alcohol–water mixtures measured by solvatochromic indicators, J. Phys. Org. Chem. 11 (1998) 185–192. [40] M. Roses, U. Buhvestov, C. Ràfols, F. Rived, E. Bosch, Solute–solvent and solvent–solvent interactions in binary solvent mixtures. Part 6. A quantitative measurement of the enhancement of the water structure in 2-methylpropan2-ol–water and propan-2-ol–water mixtures by solvatochromic indicators, J. Chem. Soc. Perkin Trans. 2 (1997) 1341–1348. [41] Y. Migron, Y. Marcus, Polarity and hydrogen-bonding ability of some binary aqueous–organic mixtures, J. Chem. Soc., Faraday Trans. 87 (1991) 1339–1343. [42] Y. Marcus, Y. Migron, Polarity, hydrogen bonding, and structure of mixtures of water and cyanomethane, J. Phys. Chem. 95 (1991) 400–406. [43] W.J. Cheong, S.H. Chun, G.Y. Lee, Determination of solvent basicity scale, b, of mixed solvents for three chromatographic solvent systems: 2-propanol/ hexane, ethyl acetate/hexane, and methanol/water, J. Liq. Chromatogr. Relat. Technol. 19 (1996) 277–291. [44] M. Zheng, A. Farajtabar, H.K. Zhao, Solute-solvent and solvent-solvent interactions and preferential solvation of hesperidin in aqueous co-solvent mixtures of ethanol, isopropanol, propylene glycol and n-propanol, J. Mol. Liq. 264 (2018) 285–291. [45] Y. Marcus, The properties of organic liquids that are relevant to their use as solvating solvents, Chem. Soc. Rev. 22 (1993) 409–416. [46] C.M. Hansen, Hansen Solubility Parameters: A User’s Handbook, CRC Press, 2007. [47] Y. Marcus, The Properties of Solvents, John Wiley & Sons, Chichester, 1998. [48] J.M. Bernal-García, A. Guzmán-López, A. Cabrales-Torres, A. Estrada-Baltazar, G.A. Iglesias-Silva, Densities and viscosities of (N, N-dimethylformamide + water) at atmospheric pressure from (283.15 to 353.15) K, J. Chem. Eng. Data 53 (2008) 1024–1027. [49] F.M. Pang, C.E. Seng, T.T. Teng, M.H. Ibrahim, Densities and viscosities of aqueous solutions of 1-propanol and 2-propanol at temperatures from 293.15 K to 333.15 K, J. Mol. Liq. 136 (2007) 71–78. [50] M.A. Saleh, S. Akhtar, M.S. Ahmed, Density, viscosity and thermodynamic activation of viscous flow of water + acetonitrile, J. Mol. Liq. 44 (2006) 551– 562. [51] Y.P. Handa, G.C. Benson, Thermodynamics of aqueous mixtures of nonelectrolytes. IV. Excess volumes of water-acetonitrile mixtures from 15 to 35 , J. Solution Chem. 10 (1981) 291–300. [52] W.E. Acree Jr., A.M. Ramirez, S. Cheeran, F. Martinez, Determination of Abraham model solute descriptors and preferential solvation from measured solubilities for 4-nitropyrazole dissolved in binary aqueous-organic solvent mixtures, Phys. Chem. Liq. 55 (2017) 605–616. [53] F. Martínez, A. Jouyban, W.E. Acree Jr, Solubility of phenobarbital in aqueous cosolvent mixtures revisited: IKBI preferential solvation analysis, Phys. Chem. Liq. 55 (2016) 432–443.

JCT 2019-351