Measurement and Correlation of Tadalafil Solubility in Five Pure

Feb 28, 2014 - and Faiyaz Shakeel*. ,†. †. Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Sa...
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Measurement and Correlation of Tadalafil Solubility in Five Pure Solvents at (298.15 to 333.15) K Mahmoud El-Badry,†,§ Nazrul Haq,† Gihan Fetih,§ and Faiyaz Shakeel*,† †

Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia Department of Pharmaceutics, College of Pharmacy, Assiut University, Assiut, Egypt

§

ABSTRACT: The aim of this study was to measure and correlate the temperature dependent solubility data of tadalafil (TDL) in water, ethanol, propylene glycol (PG), polyethylene glycol-400 (PEG-400), and Transcutol from (298.15 to 333.15) K at atmospheric pressure using the shake flask method. The experimental solubilities were regressed by Apelblat equation with a relative deviation in the range of (1.20 to 5.74) % in all solvents investigated at (298.15 to 333.15) K. The root mean square deviation between experimental and calculated solubility was observed less than 1.10 in all solvents investigated. The correlation coefficients in water, ethanol, PG, PEG-400, and Transcutol were observed in the range of 0.997 to 0.999. The solubility of TDL was found to be increased with an increase in temperature in all solvents investigated. The mole fraction solubility of TDL was found to be higher in PEG-400 (1.86·10−2 at 298.15 K) and Transcutol (8.76·10−3 at 298.15 K) as compared to water (5.74·10−7 at 298.15 K), ethanol (1.77· 10−4 at 298.15 K) and PG (4.1·10−4 at 298.15 K).

1. INTRODUCTION The IUPAC name of tadalafil (TDL) is pyrazino[1′,2′:1,6]pyrido[3,4-b]indole-1,4-dione,6-(1,3-benzodioxol-5-yl)2,3,6,7,12,12-a-hexahydro-2-methyl-(6R-tarns)-(6R-12aR)2,3,6,7,12,12-a-hexahydro-2-methyl-6-[3,4-methylenedioxy)phenyl]-pyrazinol[1′,2′:1,6]pyrido[3,4-b]indole-1,4-dione, and its molecular structure is presented in Figure 1 (molecular

enhancing the solubility of the poorly soluble drug paracetamol in water.8 Therefore, in the present study, water, ethanol, PG, PEG-400, and Transcutol were selected as pure solvents, and the solubility of poorly soluble drug TDL was measured in these solvents. The poor aqueous solubility of TDL has also been reported as a main barrier for the development of its liquid dosage forms.2−5 The solubility of TDL has been improved via various approaches such as the cocrystal approach, solid dispersion, and cyclodextrin complexation.9−11 However, the temperature-dependent solubility data of TDL in water, ethanol, PG, PEG-400, and Transcutol are not reported in the literature so far. Various mathematical models/equations have been reported for the measurement and correlation of solubility, but the Apelblat equation is the commonly used equation among them.12−19 Therefore, the aim of this study was to measure and correlate the temperature-dependent solubility data of TDL in water, ethanol, PG, PEG-400, and Transcutol from (298.15 to 333.15) K at atmospheric pressure using the shake flask method. The Apelblat equation was selected for correlation of experimental solubility data with the calculated one.

Figure 1. Molecular/chemical structure of tadalafil.

formula-C22H19N3O4 and molecular mass-489.40 g·mol−1).1,2 It was recently approved by Food and Drug Administration (2001) for the treatment of male erectile dysfunction.1−4 TDL has been reported as practically insoluble in water (mole fraction solubility 8.42·10−7 at 305.15 K), slightly soluble in propylene glycol (PG) (mole fraction solubility 5.85·10−4 at 305.15 K) and ethyl alcohol (mole fraction solubility 2.56·10−4 at 305.15 K) and soluble in polyethylene glycol-400 (PEG-400) (mole fraction solubility 2.27·10−2 at 305.15 K).5 However, its solubility in Transcutol has not been reported in literature so far. The commonly used cosolvents for solubilization and stabilization of drugs and pharmaceuticals are ethyl alcohol, PG, and PEG-400 due to their nontoxicity and compatibility with most of the drugs and pharmaceuticals.6,7 Transcutol is also a nontoxic and safe solvent for drugs/pharmaceuticals, and most recently its potential as a cosolvent has been proven in © 2014 American Chemical Society

2. EXPERIMENTAL SYSTEM AND METHODS 2.1. Materials. TDL was purchased from Luna Pharmaceuticals (Cairo, Egypt). Tarnscutol (IUPAC name, diethylene glycol monoethyl ether) was obtained as a kind gift sample from Gattefosse (Cedex, France). PEG-400 [IUPAC name, poly(oxyethene)] and PG (IUPAC name-propane-1,2-diol) were purchased from Fluka Chemicals (Bucsh, Switzerland). Ethyl alcohol (IUPAC name, ethanol) was purchased from Received: November 11, 2013 Accepted: February 21, 2014 Published: February 28, 2014 839

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Table 1. Sample Table with General Properties of Tadalafil and Pure Solvents material

molecular formula

molecular mass (g·mol−1)

purity (mass fraction)

analysis method

CAS No.

source

tadalafil ethanol propylene glycol transcutol-HP polyethylene glycol-400

C22H19N3O4 C2H5OH C3H8O2 C6H14O3 H(OCH2CH2)nOH

489.400 46.060 76.090 134.170 400.000

0.990 0.999 0.995 0.999 0.999

HPLC GC GC GC GC

171596-29-5 64-17-5 57-55-6 111-90-0 25322-68-3

Luna Pharmaceuticals Sigma Aldrich Fluka Chemicals Gattefosse Fluka Chemicals

Table 2. Experimental Mole Fraction Solubilities (xe) for Crystalline Tadalafil in Five Different Pure Solvents (S) at Temperatures T = (298.15 to 333.15) K and Pressure p = 0.1 MPaa xe

a

S

T = 298.15 K

T = 303.15 K

T = 308.15 K

T = 313.15 K

T = 323.15 K

T = 333.15 K

water ethanol PG PEG-400 Transcutol

5.74·10−7 1.77·10−4 4.10·10−4 18.64·10−3 8.76·10−3

7.59·10−7 2.48·10−4 5.07·10−4 21.43·10−3 9.73·10−3

10.27·10−7 3.43·10−4 6.63·10−4 24.85·10−3 10.73·10−3

13.42·10−7 4.73·10−4 8.39·10−4 28.34·10−3 11.96·10−3

22.67·10−7 8.51·10−4 12.88·10−4 35.30·10−3 14.96·10−3

34.56·10−7 14.53·10−4 19.31·10−4 43.80·10−3 18.29·10−3

The standard uncertainty for the temperatures u(T) is ± 0.18 K, the relative standard uncertainty in solubility ur (xe) for crystalline tadalafil is 1.4 %.

Figure 2. The correlation of experimental mole fraction solubilities (xe) with Apelblat solubilities for tadalafil in (a) ×, PEG-400; ∗, Transcutol; and (b) ◆, water, ■, ethanol and ▲, PG from (298.15 to 333.15) K at atmospheric pressure of 0.1 MPa [solid lines represent the Apelblat solubilities (Apl)].

Axiom, Germany) at 284 nm.21 The calibration curve was plotted between UV absorbance and concentration (μg·mL−1) of TDL. The proposed analytical method was observed linear in the concentration range of 2 μg·mL−1 to 50 μg·mL−1 with correlation coefficient of 0.999. The standard uncertainty for temperatures u(T) was observed as ± 0.18 K and the relative standard uncertainty in solubility ur(xe) was 1.4 %. From the calibration plot, the solubility of TDL was determined in μg· mL−1. This solubility was then converted to g·g−1 with the help of the reported density of pure solvents. Because the densities of all solvents used were known, their measurements were not performed in the present study. The experimental mole fraction solubility (xe) of TDL in each pure solvent was calculated using eq 1:22,23

Sigma Aldrich (St. Louis, MO). Distilled water was obtained in the laboratory. All other chemicals and reagents used were of analytical reagent (AR grade). The general properties of all these materials are listed in Table 1. 2.2. Measurement of TDL Solubility. The solubility of TDL in water, ethanol, PG, PEG-400, and Transcutol was measured using shake flask method from (298.15 to 333.15) K at atmospheric pressure of 0.1 MPa.7,8 The excess amount of TDL was added in known volumes (5 mL) of pure solvents in 10 mL capacity conical flasks and these mixtures were equilibrated with continuous mixing in a water shaker bath (Julabo, PA) at 100 rpm for 72 h. All the samples were taken in triplicate. To optimize equilibrium time, the solubility of TDL was measured at 24 h, 48 h, 72 h, 96 h, and 120 h. Only negligible changes in solubility were observed after 72 h. Therefore, 72 h was selected as the optimum equilibrium time for solubility measurements.5 After the period of 72 h, all the sample mixtures were taken out from the water shaker bath, and the solute (TDL) particles were allowed to settle for 2 h at the bottom of the flasks. All the samples were filtered using 0.45 μm filter paper, supernatants were taken, and diluted suitably with respective pure solvent.7,8,18,20 The quantification of TDL was carried out by UV−visible spectrophotometer (SP1900,

xe =

m1/M1 m1/M1 + m2 /M 2

where, m1 and m2 represent the masses of TDL (g) respective pure solvent (water, ethanol, PG, PEG-400, Transcutol-HP) (g), respectively. However, M1 and represent the molecular masses of TDL (g·mol−1) respective pure solvent (water, ethanol, PG, PEG-400, Transcutol-HP), respectively. 840

(1)

and and M2 and and

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Table 3. The Apelblat Parameters (A, B, and C) for Taldalafil in Five Different Pure Solventsa S

A ± SD

B ± SD

C ± SD

R2

rmsd

water ethanol PG PEG-400 Transcutol

155.62 ± 4.89 82.74 ± 2.39 41.02 ± 1.03 109.90 ± 3.05 −96.36 ± 2.86

−12284.40 ± 46.63 −9315.76 ± 20.23 −6024.12 ± 16.02 −7359.37 ± 21.22 2500.69 ± 13.52

−22.60 ± 1.29 −10.55 ± 0.40 −5.02 ± 0.22 −15.65 ± 1.08 14.60 ± 0.95

0.997 0.999 0.999 0.997 0.999

7.68·10−5 0.02 0.02 1.05 0.63

a

Pure solvents (S), correlation coefficient (R2), standard deviation (SD), root-mean-square deviation between experimental and calculated solubility (rmsd)

3. RESULTS AND DISCUSSION 3.1. Solubility Data of TDL. The experimental mole fraction solubility data of TDL in water, PG, PEG-400, ethanol, and Transcutol from (298.15 to 333.15) K and atmospheric pressure of 0.1 MPa are presented in Table 2. The mole fraction solubility of TDL in water, ethanol, PG, and PEG-400 has been reported as 8.42·10−7, 2.56·10−4, 5.85·10−4, and 2.27· 10−2 at 305.15 K, respectively.5 However, its solubility in Transcutol is not available in the literature. In the present study, the mole fraction solubility of TDL in water, ethanol, PG, and PEG-400 were not measured directly at the reported temperature (305.15 K). These solubilities were determine by interpolation of a graph plotted between temperature and solubility (Figure 2). The mole fraction solubility of TDL in water, ethanol, PG, and PEG-400 by the interpolation method was observed as 8.35·10−7, 2.62·10−4, 6.02·10−4, and 2.29·10−2 at 305.15 K, respectively, which was in good agreement with reported values of TDL. The solubility was found to be increased with an increase in temperature in all solvents at (298.15 to 333.15) K. The mole fraction solubility of TDL was found to be highest in PEG-400 (1.86·10−2 at 298.15 K) followed by Transcutol (8.76·10−3 at 298.15 K), PG (4.10·10−4 at 298.15 K), ethanol (1.77·10−4 at 298.15 K), and water (5.74· 10−7 at 298.15 K) at (298.15 to 333.15) K (Table 2). The higher solubilities of TDL in PEG-400 and Transcutol were probably due to their lower polarities as compared to water.8 However, the lowest solubility of TDL in water was probably due to its highest polarity.7,8 The highest mole fraction solubility of TDL in PEG-400 was probably due to its higher molecular weight as compared to Transcutol, ethanol, PG, and water.18 On the basis of these results, TDL has been considered as soluble in PEG-400 and Transcutol, slightly soluble in ethanol and PG, and practically insoluble in water. 3.2. Correlation of TDL Solubility. In the present study, the experimental solubilities of TDL were correlated with the Apelblat equation.7,8,18,22,23 The mole fraction solubility of TDL can be represented by eq 2:22−27 ln x = A +

B + C ln(T ) T

(Figure 2a for higher solubility values and Figure 2a for lower solubility values). AD (%) =

(xe − xAc) 100 xe

(3)

The root-mean-square deviations (rmsd) between xe and xAc were calculated using eq 4. ⎡ 1 rmsd = ⎢ ⎢⎣ N

1/2 ⎛ xAc − xe ⎞2 ⎤ ⎥ ⎟ ∑⎜ xe ⎠ ⎥⎦ t−1 ⎝ N

(4)

Where, N denotes the number of data points in solubility measurement. The % AD was found to be (1.20 to 5.74) % in water, ethanol, PG, PEG-400, and Transcutol at (298.15 to 333.15) K. The highest % AD (5.74%) was observed in Transcutol at 323.15 K. The values of regressed parameters A, B, and C along with correlation coefficients (R2) and rmsd in water, ethanol, PG, PEG-400 and Transcutol are listed in Table 3. The rmsd values were found to be less than 1.10 in all solvents investigated. The R2 for TDL in water and PEG-400 was found to be 0.997. However, the R2 for TDL in ethanol, PG, and Transcutol was found to be 0.999 (Table 3). These results indicated good fitting of experimental solubility data in all solvents. 3.3. Thermodynamic Parameters for TDL Dissolution. The relationship between dissolution equilibrium constants and activities can be expressed as23 ai Ki = asal (5) where ai is the activity of TDL in solution and as and al represent the activity of pure solid and pure liquid, respectively. The values of as and al are believed to remain constant over the experimental range because all solids and liquids are in the standard states. Therefore, eq 5 can be represented as

Ki = (2)

γiXi a3al

(6)

where γi represents the activity coefficient of TDL in solution and Xi is mole fraction solubility of TDL in solution. Equation 7 can be obtained by taking the natural log on both sides of eq 6:28

where x and T are the experimental solubility of TDL and absolute temperature (K), respectively. The adjustable parameters A, B, and C (equation parameters) were determined by multivariate regression analysis of experimental solubility data listed in Table 2.25 The calculated/Apelblat solubilities (xAc) were back calculated with the help of these equation parameters. The experimental solubility data of TDL were correlated with calculated solubility data, and the percentage of relative deviations (% AD) were calculated using eq 3. The correlation between xe and xAc in water, ethanol, PG, PEG-400, and Transcutol at (298.15 to 333.15) K is presented in Figure 2

ln K i = ln Xi + j

(7)

where j is a temperature-independent constant which can be represented as j = ln γi − ln asal

(8)

A combination of eqs 7 and 8 allows γi to be merged into asal, hence (by assuming j = 0 and γi = 1 for ideal behavior): 841

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ln K i = ln Xi

the correlation coefficients in the range of 0.997 to 0.999. On the basis of these results, tadalafil has been considered as practically insoluble in water, slightly soluble in ethanol and propylene glycol, and soluble in polyethylene glycol-400 and Transcutol.

(9)

Combining the Gibbs−Helmholtz and the modified Van’t Hoff equations, the molar enthalpy (ΔH0) for TDL dissolution can be represented as29

ΔH 0 = −R

■

d ln ki dT −1

(10)

Corresponding Author

Substituting eq 9 into eq 10, eq 10 becomes: 0

ΔH = −R

*Tel.: +966-537507318. E-mail: [email protected].

d ln Xi

Funding

dT −1

(11)

The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding the work through the research group Project No. RGP-VPP-299.

From eq 2 obtaining the derivative and substituting it into eq 11 gives23,30 ⎛ B⎞ ΔH 0 = RT ⎜C − ⎟ ⎝ T⎠

Notes

The authors declare no competing financial interest.

(12)

■

0

The Gibb’s function (ΔG ) for TDL dissolution was calculated using eq 13: ΔG 0 = −RT ln x

with the help of ΔH and ΔG , the entropy (ΔS ) for TDL dissolution was calculated using eq 14: ΔS 0 =

ΔH 0 − ΔG 0 T

0

REFERENCES

(1) Aboul-Enein, H. Y.; Ali, I. Determination of tadalafil in pharmaceutical preparation by HPLC using monolithic silica column. Talanta 2005, 65, 276−280. (2) Reddy, B. P.; Reddy, K. A.; Reddy, M. S. Validation and stability indicating RP-HPLC method for the determination of tadalafil API in pharmaceutical formulations. Res. Pharm. Biotechnol. 2010, 2, 1−6. (3) Mehanna, M. M.; Motawwa, A. M.; Samaha, M. W. Tadalafil inclusion in microporous silica as effective dissolution enhancer: Optimization of loading procedure and molecular state characterization. J. Pharm. Sci. 2011, 100, 1805−1818. (4) Badr-Eldin, S. M.; Elkheshen, S. A.; Ghorab, M. M. Inclusion complexes of tadalafil with natural and chemically modified βcyclodextrins. I: Preparation and in-vitro evaluation. Eur. J. Pharm. Biopharm. 2008, 70, 819−827. (5) El-Maghraby, G. M.; Alanazi, F. K.; Alsarra, I. A. Transdermal delivery of tadalafil. I. Effect of vehicles on skin permeation. Drug Dev. Ind. Pharm. 2009, 35, 329−336. (6) Strickley, R. G. Solubilizing excipients in oral and injectable formulations. Pharm. Res. 2004, 21, 201−230. (7) Shakeel, F.; Alanazi, F. K.; Alsarra, I. A.; Haq, N. Solubility prediction of indomethacin in PEG 400 + water mixtures at various temperatures. J. Mol. Liq. 2013, 188, 28−32. (8) Shakeel, F.; Alanazi, F. K.; Alsarra, I. A.; Haq, N. Solubilization behavior of paracetamol in Transcutol-water mixtures at (298.15 to 333.15) K. J. Chem. Eng. Data 2013, 58, 3551−3556. (9) Vinesh, V.; Sevukarajan, M.; Rajalakshmi, R.; Chowdary, G. T.; Haritha, K. Enhancement of solubility of tadalafil by cocrystal approach. Int. Res. J. Pharm. 2013, 4, 218−223. (10) Vyas, V.; Sancheti, P.; Karekar, P.; Shah, M.; Pore, Y. Physicochemical characterization of solid dispersion systems of tadalafil with poloxamer 407. Acta Pharm. 2009, 59, 453−461. (11) Prasanna, T. V.; Rani, B. N.; Rao, A. S.; Murthy, T. E. G. K. Design and evaluation of solid dispersed tadalafil tablets. Int. J. Pharm. Sci. Res. 2012, 3, 4738−4744. (12) Delgado, D. R.; Vargas, E. F.; Martinez, F. Thermodynamic study of the solubility of procaine HCl in some ethanol + water cosolvent mixtures. J. Chem. Eng. Data 2010, 55, 2900−2904. (13) Gantiva, M.; Yurquina, A.; Martinez, F. Solution thermodynamics of ketoprofen in ethanol + water cosolvent mixtures. J. Chem. Eng. Data 2010, 55, 113−118. (14) Jouyban, A.; Shokri, J.; Barzegar-Jalali, M.; Hassanzadeh, D.; Acree, W. E.; Ghafourian, T.; Nokhodchi, A. Solubility of benzodiazepines in polyethylene glycol 200 + water cosolvent mixtures at 303.2 K. J. Chem. Eng. Data 2010, 55, 519−522. (15) Ali, H. S. M.; York, P.; Blagden, N.; Soltanpour, S.; Acree, W. E.; Jouyban, A. Solubility of budesonide, hydrocortisone and prednisolone in ethanol + water cosolvent mixtures at 298.2 K. J. Chem. Eng. Data 2010, 55, 578−582.

(13) 0

AUTHOR INFORMATION

0

(14)

where R is the universal gas constant and B and C are Apelblat parameters obtained from Table 3. The values ΔH0 and ΔS0 at saturation in water, ethanol, PG, PEG-400, and Transcutol at (298.15 to 333.15) K were calculated using eqs 12 and 14, respectively. The values of ΔH0 for TDL dissolution were found to be higher in water, ethanol, and PG as compared to PEG-400 and Transcutol at (298.15 to 333.15) K. The ΔH0 values for TDL dissolution in water, ethanol, PG, PEG-400, and Transcutol were observed in the range of (39.53 to 46.11) kJ· mol−1, (48.23 to 51.30) kJ·mol−1, (36.18 to 37.64) kJ·mol−1, (17.83 to 22.39) kJ·mol−1 and (15.40 to 19.64) kJ·mol−1 at (298.15 to 333.15) K, respectively. However, the ΔS0 values for TDL dissolution in water, ethanol, PG, PEG-400, and Transcutol were observed in the range of (14.11 to 35.17) J· mol−1·K−1, (90.44 to 100.25) J·mol−1·K−1, (56.64 to 61.41) J· mol−1·K−1, (27.53 to 42.00) J·mol−1·K−1 and (12.26 to 25.71) J·mol−1·K−1 at (298.15 to 333.15) K, respectively. The ΔH0 values for TDL dissolution in PEG-400 and Transcutol were significantly reduced as compared to water, ethanol, and PG. These results indicated that relatively low energy is required for solubilization of TDL in PEG-400 and Transcutol as compared to water, ethanol, and PG. The positive values of ΔH0 and ΔS0 indicated that TDL dissolution was endothermic and an entropy-driven process in all solvents investigated.

4. CONCLUSION In the present study, the measurement and correlation of tadalafil solubility in water, ethanol, propylene glycol, polyethylene glycol-400 and Transcutol were performed at (298.15 to 333.15) K using a shake flask method. The mole fraction solubility of tadalafil was found to be increased with an increase in temperature in all solvents investigated. The solubility of tadalafil was significantly higher in polyethylene glycol-400 and Transcutol as compared to water, ethanol and propylene glycol. The experimental solubilities were correlated well with the Apelblat equation in all solvents at (298.15 to 333.15) K with 842

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(16) Jouyban, A.; Soltanpour, S.; Acree, W. E. Solubility of acetaminophen and ibuprofen in the mixtures of polyethylene glycol 200 or 400 with ethanol or water and the density of solute-free mixed solvents at 298.2 K. J. Chem. Eng. Data 2010, 55, 5252−5257. (17) Hsieh, C. M.; Wang, S.; Lin, S. T.; Sandler, S. I. A predictive model for the solubility and octanol−water partition coefficient of pharmaceuticals. J. Chem. Eng. Data 2011, 56, 936−945. (18) Shakeel, F.; Haq, N.; Alanazi, F. K.; Alsarra, I. A. Thermodynamic modeling for solubility prediction of indomethacin in self-nanoemulsifying drug delivery system (SNEDDS) and its individual components. Drug Dev. Ind. Pharm. doi: 10.3109/ 03639045.2013.814063. (19) Sardari, F.; Jouyban, A. Solubility of nifedipine in ethanol + water and propylene glycol + water mixtures at 293.2 to 313.2 K. Ind. Eng. Chem. Res. 2013, 52, 14353−14358. (20) Soleymani, J.; Djozan, D.; Martinez, F.; Jouyban, A. Solubility of ranitidine hydrochloride in solvent mixtures of PEG 200, PEG 400, ethanol, and propylene glycol at 25 °C. J. Mol. Liq. 2013, 182, 91−94. (21) Yunoos, M.; Sankar, D. G.; Kumar, B. P.; Hameed, S. UV spectrophotometric methods for the estimation of tadalafil in bulk and tablet dosage form. E. J. Chem. 2010, 7, 833−836. (22) Wang, Q.; Chen, Y.; Deng, L.; Tang, J.; Zhang, Z. Determination of the solubility parameter of ionic liquid 1-allyl-3methylimidazolium chloride by inverse gas chromatography. J. Mol. Liq. 2013, 180, 135−138. (23) Sunsandee, N.; Hronec, M.; Stolcova, M.; Leepipatpiboon, N.; Pancharoen, U. Thermodynamics of the solubility of 4-acetyl benzoic acid in different solvents from 303.15 to 373.15 K. J. Mol. Liq. 2013, 180, 252−259. (24) Cantillo, E. A.; Delgado, D. R.; Martinez, F. Solution thermodynamics of indomethacin in ethanol + propylene glycol mixtures. J. Mol. Liq. 2013, 181, 62−67. (25) Apelblat, A.; Manzurola, E. Solubilities of o-acetylsalicylic, 4aminosalicylic, 3,5-dinitrosalicylic and p-toluic acid and magnesium-DLaspartate in water from T = (278 to 348) K. J. Chem. Thermodyn. 1999, 31, 85−91. (26) Wang, L.; Lv, T. T. Determination and modeling of the solubility and prediction of the dissolution properties of 2,4dichlorophenoxyacetic acid in toluene, tetrachloromethane, and the binary solvent mixtures of (cyclohexane+ethyl acetate). J. Mol. Liq. 2013, 181, 29−33. (27) Liu, B. S.; Gong, J. B.; Wang, J. K.; Jia, C. Y. Solubility of potassium calvulanate in ethanol, 1-propanol, 1-butanol, 2-propanol, and 2-methyl-1-propanol between 273 and 305 K. J. Chem. Eng. Data 2005, 50, 1684−1686. (28) Wang, F. A.; Wang, L. C.; Song, J. C.; Wang, L.; Chen, H. S. Solubilities of bis(2,2,6,6-tetramethyl-4-piperidinyl) maleate in hexane, heptane, octane, m-xylene and tetrahydrofuran from (253.15 to 310.15) K. J. Chem. Eng. Data 2004, 49, 1539−1541. (29) Bourgois, D.; Thomas, D.; Fanlo, J. L.; Vanderschuren, J. Solubilities at high dilution of toluene ethylbenzene, 1,2,4trymethylbenzene and hexane in di-2-ethylhexyl, diisoheptyl, and diisononyl phthalates. J. Chem. Eng. Data 2006, 51, 1212−1215. (30) Williamson, A. T. The exact calculations of heats of solutions from solubility data. Trans. Faraday Soc. 1944, 40, 421−436.

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