Measurement and Correlation of Curcumin Solubility in Supercritical

Article pubs.acs.org/jced

Measurement and Correlation of Curcumin Solubility in Supercritical Carbon Dioxide Shiping Zhan,* Shuting Li, Qicheng Zhao, Weijing Wang, and Jingchang Wang College of Environmental and Chemical Engineering, Dalian University, Dalian 116023, China ABSTRACT: Curcumin is a natural phenolic pigment extracted from turmeric and has a good pharmacological activity in anti-inflammatory, antioxidant, hypolipidemic, and antitumor. It has been frequently used in drug-loaded microspheres recently. However, the reports on its solubility in supercritical fluids have not been seen yet. In the present study, solubility of curcumin in the supercritical carbon dioxide (ScCO2) was determined using the dynamic equilibrium method. The experimental measurements were performed at temperatures of 35, 45, and 55 °C and pressure range from 8 to 20 MPa. The measured data showed that the solubilities of curcumin were between 1.82 × 10−8 and 1.97 × 10−6 (mole fractin) for the corresponding temperatures and pressures. The effects of temperature, pressure, and with and without ethanol cosolvent on the solubility were investigated. The measured solubilities were calculated and correlated by semi-empirical formulas Chrastil and Mendez-Santiago and Teja models. The results showed that the experimental values of solubility were in good agreement with the theoretical ones, and the average absolute relative deviations (AARD) were 5.88% and 11.68% without cosolvent, and the AARD of the latter was 15.50% with the ethanol cosolvent.

1. INTRODUCTION Curcumin is a polyphenol compound extracted from turmeric rhizome of zingiberaceae plants and has the extensive pharmacological activities on antitumor, anti-inflammatory, antibacterial, antiviral, antioxidant, lowering blood lipid, and so on. Especially it has enormous research value in the prevention and treatment of cancer.1,2 The physical properties and structure of curcumin are shown in Table 1. However, curcumin has poor water solubility, poor stability under neutral to alkaline condition, easy to be decomposed in light, easy to be metabolized into the body, low bioavailability and so on, so its clinical application is greatly limited.3−6 Drug loaded microparticles have many advantages, such as improving the solubility and stability of the drug, changing the distribution of drugs in the body, prolonging the time of drug action, improving the bioavailability and biocompatibility, enhancing the efficacy of drugs, reducing the toxicity of drugs, being not easy to produce the rejection and other advantages. Therefore, many researchers have focused on preparing curcumin into microspheres to improve the effective utilization of drugs and the problem of direct use.7−9 The process of preparing the polymer drug-loaded microparticles in supercritical carbon dioxide (ScCO2) has many advantages, such as using nontoxic solvents, simple post process, the easy changing particle size by the operating condition, and uniform particle size; in recent years, the process has been widely used in pharmaceutics, food, and other fields.10−13 Curcumin formulations in ScCO2 have been also developed by researchers. When the solid solute formulations are produced in ScCO2, the heat transfer and mass transfer rate © XXXX American Chemical Society

in the process are relevant with the soluble property of the solid solute in ScCO2. The solubility of the solid solute in ScCO2 is a key factor affecting the quality of the prepared microparticle. It is necessary to achieve a deep insight into the phase behavior and equilibrium property on the solid solute in ScCO2 because the solubility is also an important physicochemical data to study supercritical system. Many researchers have carried out relevant theoretical research14,15 and experimental research16−18 work and achieved certain results19,20 but the report about the solubility of curcumin in ScCO2 has not been seen yet. In this work, the solubilities of curcumin in ScCO2 with or without the ethanol cosolvent were investigated experimentally. A test technique by the dynamic equilibrium method was used. During the experiment, the pressure in the autoclave with drugs was raised to a predesigned pressure retained for a certain period of time. Under this pressure, both outlet and entrance valve of carbon dioxide were open, and carbon dioxide of a small flow was replaced until a predetermined time was reached. The solubility of curcumin in ScCO2 was determined with or without the ethanol cosolvent under temperature of 35, 45, and 55 °C and pressure range from 16 to 40 MPa. Moreover, the solubility data were calculated by using the density models of Chrastil and Mendez-Santiago and Teja. The results of both calculations demonstrate a good consistency with the experimental value. Received: September 11, 2016 Accepted: March 21, 2017

A

DOI: 10.1021/acs.jced.6b00798 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 1. Physical Properties and Structure of the Curcumin

0.01 °C. The pressures were read from the precision pressure gauge with the accuracy of 0.01 MPa. First, the experiments of air tightness and resistance to pressure for the device were conducted. Before the solubilities were determined under different temperature and pressure, an equilibrium time had to be determined. In pre-experiment, it was found that the solubility after 2 h was a constant, so that the 2 h was determined as the dissolve equilibrium time of curcumin. The specific experimental steps are as follows: (1) A specific amount of curcumin microparticles were added in the autoclave. (2) The autoclave and the corresponding pipeline were connected and heated to the set temperature. (3) The freezer was opened and a specific amount of carbon dioxide was sent into the autoclave to replace the air in the system; then the exit valve of the system was closed and the high pressure pump was opened to raise thepressure to the set value. (4) The pressure and temperature in the autoclave was maintained for 2 h so that curcumin was dissolved and reached a balance. (5) The micrometering valve (14) was opened and new carbon dioxide was added slowly with a small flow pump. The absorber and the pipeline connected with the autoclave were heated to a moderately high temperature in order to prevent the pipeline from being frozen. The system pressure was maintained constant by regulating valve 14 slightly, and the gas flow was measured through the absorber. The pump was immediately stopped and valve 14 was shut off after 1 h. (6) After the absorber was removed, the valve 14 was opened and the pressure of the system was discharged. (7) The absorbed liquid can be obtained under different temperature and pressure by repeating steps 2−6. The determination of each data was repeated 3 times, and the obtained average value was the experimental value at the corresponding temperature and pressure. (8) The content of curcumin in ethanol solution was determined in the absorber with ultraviolet spectrophotometer as original data. In the experiment of the solubility of curcumin with cosolvent, when the temperature in the autoclave reached their predetermined values CO2 and a certain amount of ethanol were pressed into the autoclave by the plunger pump 5 and constant-flux pump 12, respectively, until the pressure reached a predetermined value, and then valve 7 was closed. After it was maintained for a certain time in static balance, CO2 and ethanol were pressed into the autoclave at the same time to achieve a dynamic balance. 2.4. Standard Curve Measurement. Curcumin (100 mg) dried to constant weight weighed accurately was put in a volumetric flask (100 mL) with anhydrous ethanol. It was dissolved and diluted to certain concentration (i.e., the drug concentration was 1 mg/mL), and the solution was well shaken. Curcumin/ethanol solution (1 mL) was put in a volumetric flask (100 mL) and diluted to the certain volume with anhydrous ethanol as the standard solution (i.e., the drug concentration was 0.01 mg/mL). The standard solution of 1.0,

2. EXPERIMENT 2.1. Materials. Curcumin (98%) were purchased from Meryer Chemical Technology Co. (Xian, China). Gas chromatograph (GC) analysis ethanol was supplied by Aladdin Biochemical Technologies Co. Ltd. (Shanghai, China). Carbon dioxide used was purchased from Kelide Chemical Technology Development Co., Ltd. (Dalian, China) with a purity of 99.9%. All reagents used in the experiment are no longer further purified as shown in Table 2. Table 2. Sample Description chemical name curcumin carbon dioxide ethanol

source Meryer (Shanghai) Chemical Technology Co., Ltd. Kelide Chemical Technology Development Co., Ltd. Aladdin Biochemical Technologies Co., Ltd.

initial mole fraction purity

purification method

analysis method

98%

none

TLC

99.9%

none

99.8%

none

GC

2.2. Analysis and Testing Device. The ultraviolet spectrophotometer (752N) was supplied from Shanghai Precision Scientific Instrument Co., Ltd. (Shanghai, China). Electronic balance (BS 200S, d = 0.001 g, Max = 200 g) is from Beijing Saiduolisi balance Co. Ltd. (Beijing, China). 2.3. Experimental Apparatus and Process. The solubility of solute in supercritical carbon dioxide was determined by dynamic equilibrium method. The experimental flow is shown in Figure 1.The temperatures were measured using the platinum resistance thermometer with the accuracy of

Figure 1. Schematic drawing of the owing solubility test apparatus. 1, CO2 cylinder; 2, 6, 8, 19, pressure gauge; 3, cylinder outlet valve; 4, cooler; 5, plunger pump; 7, 11, 20, stop valves; 9, 13, temperature controller; 10, high pressure vessel; 12, constant-flux pump; 13, organic solution; 14, micrometering valve; 15, heater band; 16, primary absorber; 17, two stage absorber; 18, silica gel desiccator; 21, mass flowmeter; 22, flow totalizer. B



Article

2.0, 3.0, 5.0, 7.0, 9.0, and 10.0 mL were respectively collected in a test tube (10 mL) and diluted to the certain volume with anhydrous ethanol. The solutions of 1.0, 2.0, 3.0, 5.0, 7.0, 9.0, and 10.0 μg/mL concentration were obtained, respectively. The absorbances of the above six solutions with different concentration were measured at a wavelength of 420 nm with ultraviolet spectrophotometer and anhydrous ethanol was used as blank solution. The curcumin standard curve equation of absorbance A on the concentration C (μg/mL) in anhydrous ethanol was obtained by data regression (A = 0.13516C − 0.03254, R = 0.99872). The standard curve by the absorbance A as ordinate and concentration C as the abscissa is shown in Figure 2.

S=

y1 =

mcur VCO2

(1)

SM1 SM1 + ρM 2

(2)

where S (g·L−1) is the solubility of the curcumin, mcur (g) is the mass of curcumin, VCO2 (L) is the volume of CO2. M1 and M2 are the molecular weights of CO2 and curcumin (g·mol−1) respectively, y1 is the mole fraction solubility of the solute in pure CO2, and ρ is the density of CO2 at room temperature and normal atmospheric pressure (g·mol−1). The solubility (y2) of curcumin in ScCO2 with ethanol is calculated from eq 3 y2 =

ncur ncur + nCO2 + nEtOH

(3)

where y2 is the solubility of curcumin in mole fraction; ncur, nco2 and nEtOHr (mol) are the amounts of curcumin, carbon dioxide, and ethanol placed in the autoclave. 2.5. Correlation of Solubility Data. The solubility of curcumin was calculated and correlated by Chrastil21 and Mendez-Santiago and Teja (M-S−T) models.22 The experiment data were compared with calculation one. The fitting parameters of models were optimized by using multiple linear fitting. Chrastil model proposed in 1982 by Chrastil was an earliest molecular association model, and it has less parameters, simple form, and high accuracy. Chrastil model is based on intermolecular interaction existing between solute and solvent to form a complex molecular association model. Chrastil equation is shown as eq 4

Figure 2. Standard curve of curcumin measured by UV spectrophotometry at λ = 420 nm.

The absorbances of the sample were determined by using ultraviolet spectrophotometer. The concentrations of curcumin were calculated by using the regression equation and converted into quality. The volume of gas after decompression was measured through CO2 flow integrating instrument and the solubility S of curcumin in ScCO2 was calculated according to the following equation

ln S = k ln ρ +

α +β T

(4) −1

Here, S is the solubility (g·L ) of curcumin in ScCO2, ρ is the density (g·L−1) of ScCO2, T is temperature (K), k is association number. α is determined by the heat of solvation and vaporization heat of solute and β is a function of k. The

Table 3. Comparison between the Experimental and Calculated Solubility of Curcumin in ScCO2 without Cosolventa T (°C) 35

45

55

P (MPa)

ρ23 (g·L−1)

yexp × 108

ycal × 108 Chrastil

ycal × 108 M-S−T

8 10 13 16 20 8 10 13 16 20 8 10 13 16 20

419.09 712.81 785.70 827.17 865.72 241.05 498.25 693.65 759.98 812.69 203.64 325.07 571.33 681.12 754.61

2.07 2.51 2.68 2.85 3.11 1.82 2.31 2.69 3.12 3.52 1.86 2.03 2.62 3.25 3.70

2.04 2.65 2.78 2.86 2.92 1.72 2.47 2.91 3.05 3.15 1.75 2.21 2.93 3.19 3.36 5.88%

1.83 3.29 3.10 2.82 2.51 1.55 2.46 3.20 3.10 2.86 1.91 2.09 3.05 3.29 3.19 11.68%

AARD%

a ρ is the density of pure SCCO2. y is solubility of curcumin (mole fraction). Standard uncertainties are u(y) = 0.02 × 10 −8, u(T) = 0.01 °C, and u(P) = 0.01 MPa, and the combined expanded uncertainty is Uc(ρ) = 0.1 g·L−1 (0.95 level of confidence).

C



Article

parameters of k, α, and β are obtained by fitting the experimental data. Mendez-Santiago and Teja (M-S−T) model is the model based on dilute solution theory. The model has a relatively simple form for near critical binary mixed dilute solution. The model form is shown as eq 5 ⎛ yP ⎞ T ln⎜ std ⎟ = A + Bρ + CT + Dy3 ⎝P ⎠

(5)

Here, y is the mole fraction of curcumin in ScCO2, y3 is the mole fraction of the cosolvent in system, P is the pressure of the system (MPa), Pstd is the standard atmospheric pressure (Pstd = 0.101 MPa), and A, B, C, and D are constants from multiple linear fitting for the solubility data according to van Der Waals’ s mixing rule. The quality of the model was evaluated by the average absolute relative deviation (AARD %), which represents the average deviation of the experimentally measured solubility and the solubility given by each model, as shown in eq 6 AARD (%) =

1 N

N

∑ i=1

y cal − y exp y exp

Figure 3. Solubility of curcumin in ScCO2 under different pressures and temperatures.

× 100 i

(6)

Here, ycal is the calculated value of the solubility of solute, yexp is the experimental value of the solubility of solute, and N is the number of experimental data points.

3. RESULTS AND DISCUSSION 3.1. Solubility of Curcumin in ScCO2 without Cosolvent. The solubility values (S) of curcumin in ScCO2 at 35, 45, and 55 °C in the pressure range of 8−20 MPa of ScCO2 at each set of operating conditions are listed in Table 3. Each experimental data is the average of at least three replicate measurements. The density values of pure CO2 were obtained from the National Institute of Standards and Technology (NIST) fluid property database,23 and the density of mixed solvent was calculated24 by content of CO2 and ethanol. Each experimental point was the average of multiple measurement. As shown in Table 3, the magnitude order of curcumin solubility in ScCO2 without ethanol cosolvent is 10−8. The obtained adjustable parameters led to correlation of the solubility of curcumin with a rather good accuracy of 5.88% by Chrastil model and 11.68% (AARD %) by M-S−T model, respectively. Also, the results prove that Chrastil model is more suitable for correlation of curcumin in ScCO2. Figure 3 shows the effect of pressure and temperature on the solubility of curcumin. It can be seen that the solubility of curcumin in ScCO2 increases with the increase of pressure when the temperature is kept constant. These trends are similar to those observed for other solute such as piroxicam (a nonsteroidal anti-inflammatory drugs), caffeine,25 γ-oryzanol,26 and diuron27 observed in previous studies. This trend can be described based on the effect of the density on the intermolecular distance. As the pressure increases, the density will increase, which would lead to a reduction of the intermolecular distance and an enhancement of the intermolecular forces and solvating power. So higher density leads to the higher solubility of the curcumin in ScCO2 just as seen in Figure 4. The effect of temperature on the solubility of curcumin in ScCO2 was more complex. There is a pressure transition point (PTP) in the range of 13−13.5 MPa as shown in Figure 3.

Figure 4. Solubility of curcumin in ScCO2 under different density and temperatures.

When the operating pressure is below PTP, a high temperature was not conducive to the increase of solubility. Under the same pressure, the solubility at low temperature was higher than the solubility under high temperature. When the operating pressure is higher than PTP, under the same pressure the solubility at high temperature was significantly higher than the solubility under low one. On the one hand, under certain pressure the temperature directly affects the saturated vapor pressure of solid component; the higher the temperature, the greater the saturated vapor pressure is and the greater the solubility is. But on the other hand, the temperature affects the supercritical fluid density; the higher the temperature, the smaller the density is and the smaller solubility is. The interaction of two aspects results that the influence of the temperature on the solution is more complex. Under low pressure, density is low and saturated vapor pressure is high, so that the change of the saturated vapor pressure is a smaller factor, and the effect of temperature on fluid density is dominant. When the temperature increased, the fluid density is significantly reduced, and the increase of saturated steam pressure is offset, so that the solubility decreased. Therefore, the low temperature is beneficial to improve the solubility. Under high pressure, density is high and saturated vapor pressure is low, so that the change of saturated vapor pressure on the solubility is a main role and density changes is a smaller influence factor. But when the temperature rises, the saturated vapor pressure increase and the density D



Article

decrease are offset, so that the solubility increased. Therefore, under high pressure the high temperature is beneficial to improve the solubility of solute.28−30 Figure 5 presents the result of experimental data correlated by Chrastil model. It suggests that the plots of ln S versus ln q

Figure 6. Change of T ln(y P/Pstd) with ρ at different temperatures.

point of the solvent the solubility change of the solute with that of temperature and pressure is very sensitive. The addition of cosolvent can change the critical point of mixed solvent and increase the corresponding solubility. CO2 is a nonpolar solvent and curcumin is a polar solute. Here, ethanol as a polar cosolvent was used and its effects on the solubility of curcumin were explored. Table 5 shows the experimental solubility data at the pressure range from 8 to 16 MPa at 45 °C and the results of the correlation by using M-S−T model on the solubility of curcumin in ScCO2 and the AARD (%) is 15.50%. Each experimental data is the average of at least three replicate measurements. Table 6 shows that the experimental data with the cosolvent can be well fitted using the M-S−T model. However, the Adj. R-Square is 0.03 by Chrastil model, which shows that the regression line fitting to the experimental values has failed. This is because the mole percent of the cosolvent is a important factor except for temperature, density, and pressure for the solubility of curcumin in ScCO2 with cosolvent. These two models are multivariate regression: the M-S−T model contains the mole percent of the cosolvent whereas the Chrastil model can only consider temperature and density, so that the error of correlation is greater by the Chrastil model and the M-S−T model is more appropriate to calculate solubility of curcumin in ScCO2 with cosolvent. The effect of different mole fractions of ethanol as cosolvent on the solubility of curcumin in ScCO2 at 45 °C are presented in Figure 7. The results show that when the mole fraction of the cosolvent increases, the solubility of curcumin in ScCO2 increases as many as 2 orders of magnitude compared to the one without the cosolvent. At the same temperature and pressure, by adding 1%−5% of ethanol as the cosolvent, the solubility increases by 26.4−63.1 times those without cosolvent. This result indicates that the presence of a cosolvent is beneficial to further applying of the curcumin in ScCO2. Figure 8 shows that the solubility of curcumin in ScCO2 with ethanol as cosolvent under the different pressure at 45 °C. The same trend is shown with the addition of cosolvent as in the case without cosolvent. The solubility of curcumin in ScCO2 also slightly increases with the increase of the pressure. Figure 9 is the result correlated on the solubility of curcumin in ScCO2 with cosolvent under different concentrations by MS−T model. It can be seen that the correlation by M-S−T

Figure 5. ln S of curcumin with ln ρ at different temperatures.

for several temperatures are straight lines whose slopes are the constant k. The values of model coeffcients for k, α, and β in eq 5 obtained by multilinear regression are 0.50 ± 0.05, −1055.03 ± 260.39, and −14.49 ± 0.75, respectively, as shown in Table 4. Table 4. Values of Model Coeffcients and Adj. R-Square without Cosolventa model Chrastil model

M-S−T model

coeffcient k α β A B C D

0.50 −1055.03 −14.49 −3400.97 0.85 −3.57 0

Adj. R-Square ± ± ± ± ± ±

0.05 260.39 0.75 572.28 0.07 1.74

0.89

0.94

k, α, and β are values of Chrastil Model coeffcients, ln S = k ln ρ + α/ T + β. A, B, C, and D are values of M-S−T model coeffcients, T ln(y P/Pstd) = A + Bρ + CT + Dy3. Adj. R-Square is adjusted goodness of fit index a

The Adj. R-Square is adjusted goodness of fit index, and when the value is closer to 1 it shows that the regression line fitting to the experimental values is better. Otherwise, the values are closer to 0, which shows the regression line fitting to the experimental values is worse. The result of correlation of the experimental data by the model of Mendez- Santiago and Teja are shown in Figure 6. This correlation performs well for curcumin and ScCO2 system with Adj. R-Square of 0.94, and A to D are −3400.97 ± 572.28, 0.85 ± 0.07, −3.57 ± 1.74 and 0, as listed in Table 4. 3.2. Solubility of Curcumin in ScCO2 with the Cosolvent. Cosolvent can affect the solubility and the selectivity of the solute in ScCO2 from two aspects, namely the density of CO2 and interaction between molecules of the solute with cosolvent. Usually, the cosolvent dosage is very small, so its effect on the density is little. The main factors affecting the solubility and the selectivity are van der Waals’ force or interactions between specific molecules, such as hydrogen bonding or other forces.31 In addition, near a critical E



Article

Table 5. Comparison between the Experimental and Calculated Solubility of Curcumin in ScCO2 with Ethanol as Cosolventa T (°C)

ethanol (mol %)

P (MPa)

ρ23 (g·L−1)

yexp × 106

ycal × 106 M-S−T

1

8 10 13 16 8 10 13 16 8 10 13 16

246.53 501.16 694.60 760.27 257.49 506.97 696.51 760.85 268.45 512.79 698.42 761.43

0.48 0.53 0.54 0.57 0.87 1.08 1.28 1.61 1.24 1.35 1.57 1.97

0.45 0.60 0.69 0.64 0.76 1.02 1.15 1.07 1.30 1.72 1.93 1.79 15.50

45

3

5

AARD (%)

ρ is the density of pure SCCO2. y is solubility of curcumin (mole fraction). Standard uncertainties are u(y) = 0.02 × 10 −6, u(T) = 0.01 °C, and u(P) = 0.01 MPa, and the combined expanded uncertainty is Uc(ρ) = 0.1 g·L−1 (0.95 level of confidence). a

Table 6. Values of Model Coeffcients and Adj. R-Square with Cosolventa model Chrastil model

M-S−T model

coeffcient k α β A B C D

0.09 (2.40 (−7.54 −0.03 0.65 −11.01 8147.31

± ± ± ± ± ± ±

0.37 2.02) × 1017 6.34) × 1014 6.70 × 10−4 0.10 0.21 1187.72

Adj. R-Square 0.03

0.89

a k, α, and β are values of Chrastil Model coeffcients, ln S = k ln ρ + α/ T + β. A, B, C, and D are values of M-S−T Model coeffcients, T ln(y P/Pstd) = A + Bρ + CT + Dy3. Adj. R-Square is adjusted goodness of fit index.

Figure 8. Solubility of curcumin in ScCO2 with cosovent at different mole fractions of cosolvent.

Figure 7. Solubility of curcumin in ScCO2 with cosovent at different pressure. Figure 9. Change of T ln(y2 P/Pstd) with ρ under 45 °C at different cosolvent concentrations.

model is very consistent with the experimental results with theoretical analysis on the experimental data.

4. CONCLUSIONS The phase equilibrium behavior of curcumin-supercritical CO2 was studied experimentally and theoretically for the first time. The solubility of curcumin in ScCO2 with or without the cosolvent of ethanol under the pressure range of 8−20 MPa and the temperature of 35, 45, and 55 °C was measured. The experimental results showed that the pressure and temperature of the solution were important factors to affect the solubility of

curcumin in ScCO2, and the solubility of curcumin in supercritical mixed solvents containing cosolvent increased with the increase of the cosolvent concentration. The results showed that the experimental values of solubility were in good agreement with the theoretical ones, and the AARD was 5.88% and 11.68% without cosolvent, and the AARD of the latter was 15.50% with the ethanol cosolvent. It is expected that the F



Article

solubility data with several density-based correlations. J. Supercrit. Fluids 2007, 41, 187−194. (16) Li, J. L.; Jin, J. S.; Zhang, Z. T. Solubility of pToluenesulfonamide in Pure and Modified Supercritical Carbon Dioxide. J. Chem. Eng. Data 2009, 54, 1142−1146. (17) Su, C. S.; Chen, Y. P. Correlation for the solubilities of pharmaceutical compounds in supercritical carbon dioxide. Fluid Phase Equilib. 2007, 254, 167−173. (18) Hezave, A. Z.; Khademi, M. H.; Esmaeilzadeh, F. Measurement and modeling of mefenamic acid solubility in supercritical carbon dioxide. Fluid Phase Equilib. 2012, 313, 140−147. (19) Brunner, G. Applications of supercritical fluids. Annu. Rev. Chem. Biomol. Eng. 2010, 1, 321−342. (20) de Melo, M. M. R.; Silvestre, A. J. D.; Silva, C. M. Supercritical fluid extraction of vegetable matrices: Applications, trends and future perspectives of a convincing green technology. J. Supercrit. Fluids 2014, 92, 115−176. (21) Chrastil, J. Solubility of solids and liquids in supercritical gases. J. Phys. Chem. 1982, 86, 3016−3021. (22) Mendez-Santiago, J.; Teja, A. S. The solubility of solids in supercritical fluids. Fluid Phase Equilib. 1999, 158−160, 501−510. (23) National Institute of Standards and Technology: Thermophysical Properties of Fluid System. http://webbook.nist.gov/chemistry/ fluid/; 2016 (Accessed Apr. 5, 2016). (24) Xu, Q.; Han, B. X.; Yan, H. K. Density of supercritical CO2 -tetrahydrofuran binary mixture and the partial molar volume of the cosolvent. Chin. J. Chem. 1998, 16, 414−420. (25) Li, B.; Guo, W.; Song, W.; Ramsey, E. D. Interfacing supercritical fluid solubility apparatus with supercritical fluid chromatography operated with and without on-line post-column derivatization: Determining the solubility of caffeine and monensin in supercritical carbon dioxide. J. Supercrit. Fluids 2016, 115, 17−25. (26) Bitencourt, R. G.; Filho, W. A. R.; Paula, J. T.; Cabral, F. A. Solubility of γ-oryzanol in supercritical carbon dioxide and extraction from rice bran. J. Supercrit. Fluids 2016, 107, 196−200. (27) Ciou, J. L.; Su, C. S. Measurement of solid solubilities of diuron in supercritical carbon dioxide and analysis of recrystallization by using the rapid expansion of supercritical solutions process. J. Supercrit. Fluids 2016, 107, 753−759. (28) Li, Y.; Ning, Y.; Jin, J.; Zhang, Z. Solubility of 3-aminobenzoic acid in supercritical carbon dioxide modified by ethanol. J. Chem. Eng. Data 2013, 58, 2176−2180. (29) Coelho, J. P.; Naydenov, G. P.; Yankov, D. S.; Stateva, R. P. Experimental measurements and correlation of the solubility of three primary amides in supercritical CO2: acetanilide, propanamide, and butana- mide. J. Chem. Eng. Data 2013, 58, 2110−2115. (30) Hezave, A. Z.; Rajaei, H.; Lashkarbolooki, M. Esmaeilzadeh. Analyzing the solubility of fluoxetine hydrochloride in supercritical carbon dioxide. J. Supercrit. Fluids 2013, 73, 57−62. (31) Peña, M. A.; Reillo, A.; Escalera, B.; Bustamante, P. Solubility parameter of drugs for predicting the solubility profile type within a wide polarity range in solvent mixtures. Int. J. Pharm. 2006, 321, 155− 161.

experimental data will provide references to research the ideal condition of extraction or drug sustained release system.

■

AUTHOR INFORMATION

Corresponding Author

*Tel: +86 411 87402439. E-mail: [email protected]. ORCID

Shiping Zhan: 0000-0003-1192-4236 Funding

The authors acknowledge the funding provided by the Natural Science foundation of China (Project 21176032, 21676038). Notes

The authors declare no competing financial interest.

■

REFERENCES

(1) Witkin, J. M.; Li, X. Curcumin, an active constiuent of the ancient medicinal herb Curcuma longa L.: some uses and the establishment and biological basis of medical efficacy. CNS Neurol. Disord.: Drug Targets 2013, 12, 487−497. (2) Aggarwal, B. B.; Harikumar, K. B. Potential therapeutic effects of curcumin, the anti-inflammatory agent, against neurodegenerative, cardiovascular, pulmonary, metabolic, autoimmune and neoplastic diseases. Int. J. Biochem. Cell Biol. 2009, 41, 40−59. (3) Shen, L.; Ji, H.-F. The pharmacology of curcumin: is it the degradation products? Trends Mol. Med. 2012, 18, 138−144. (4) Mohanty, C.; Sahoo, S. K. The in vitro stability and in vivo pharmacokinetics of curcumin prepared as an aqueous nanoparticulate formulation. Biomaterials 2010, 31, 6597−6611. (5) Anand, P.; Kunnumakkara, A. B.; Newman, R. A.; Aggarwal, B. B. Bioavailability of curcumin: problems and promises. Mol. Pharmaceutics 2007, 4, 807−818. (6) Dadhaniya, P.; Patel, C.; Muchhara, J.; Bhadja, N.; Mathuria, N.; Vachhani, K.; Soni, M. G. Safety assessment of a solid lipid curcumin particle preparation: acute and subchronic toxicity studies. Food Chem. Toxicol. 2011, 49, 1834−1842. (7) Ganta, S.; Devalapally, H.; Amiji, M. Curcumin enhances oral bioavailability and anti-tumor therapeutic efficacy of paclitaxel upon administration in nanoemulsion formulation. J. Pharm. Sci. 2010, 99, 4630−4641. (8) Gupta, N. K.; Dixit, V. K. Bioavailability enhancement of curcumin by complexion with phosphatidyl choline. J. Pharm. Sci. 2011, 100, 1987−1995. (9) Bisht, S.; Mizuma, M.; Feldmann, G. Systemic administration of polymeric nanoparticle-encapsulated curcumin (NanoCurc) blocks tumor growth and metastases in preclinical models of pancreatic cancer. Mol. Cancer Ther. 2010, 9, 2255−2264. (10) Zabihi, F.; Xin, N.; Li, S. N.; Jia, J. F.; Cheng, T.; Zhao, Y. P. Polymeric coating of fluidizing nano-curcumin via anti-solvent supercritical method for sustained release. J. Supercrit. Fluids 2014, 89, 99−105. (11) Kurniawansyah, F.; Mammucari, R.; Foster, N. R. Inhalable curcumin formulations by supercritical technology. Powder Technol. 2015, 284, 289−298. (12) Yoncheva, K.; Kondevaburdina, M.; Tzankova, V.; Petrov, P.; Laouani, M.; Halacheva, S. S. Curcumin delivery from poly(acrylic acid-co-methyl methacrylate) hollow microparticles prevents dopamine-induced toxicity in rat brain synaptosomes. Int. J. Pharm. 2015, 486, 259−267. (13) Ren, J. P.; Zhan, S. P.; Zhou, J. X.; Zhang, M.M. New equilibrium autoclave for determining solubility and melting point of solid solute in supercritical fluids. 1. Determination of solubility of levonorgestrel in supercritical carbon dioxide. Ind. Eng. Chem. Res. 2012, 51, 2451−2455. (14) Ghaziaskar, H. S.; Kaboudvand, M. Solubility of trioctylamine in supercritical carbon dioxide. J. Supercrit. Fluids 2008, 44, 148−154. (15) Hojjati, M.; Yamini, Y.; Khajeh, M. Solubility of some statin drugs in supercritical carbon dioxide and representing the solute G


Measurement and Correlation of Curcumin Solubility in Supercritical

Recommend Documents