Chrastil Model Research Articles

Measurement and correlation of solubilities of the poorly water-soluble pharmaceutical compound etodolac by addition of co-solvents

The purpose of this study is to measure the solubilities of poorly water-soluble drugs, and to enhance their solubilities by adding co-solvents. Etodolac, a cyclooxygenase-2 (cox-2) inhibitor in non-steroid anti-inflammatory drugs (NSAIDs), was selected as a model pharmaceutical compound. The solubilities of etodolac were determined at 298.15K in mixtures of water and the following six cyclodextrins (CDs) using high-performance liquid chromatography: α-CD, β-CD, γ-CD, 2-hydroxypropyl-β-CD, 2-hydroxyethyl-β-CD, and methyl-β-CD. With the exception of γ-CD, the experimental solubility data were correlated using a modified Chrastil model. Additionally, the solubilization power of each correlated co-solvent–solute system was evaluated using a log-linear model. Finally, the stability constants were determined using the Takeru Higuchi–Connors solubility method.

Extraction of protocatechuic acid from Scutellaria barbata D. Don using supercritical carbon dioxide

The use of supercritical carbon dioxide (SC⿿CO2), with water as a modifier, was evaluated in this study as a method to extract protocatechuic acid (PA) from Scutellaria barbata D. Don. The highest extraction yield of PA, 64.094±2.756μg/g of dry plant, was achieved at 75°C and 27.5MPa, with the addition of 15.6% (v/v) water as a modifier. The mean particle size was 0.355mm, the CO2 flow rate was 2.2mL/min (STP) and the dynamic extraction time was 100min. At pressures of 16.2⿿30.0MPa and temperatures of 45⿿75°C, the mole fraction solubilities of PA in SC⿿CO2 ranged from 2.829ÿ10⿿7 to 9.631ÿ10⿿7. The solubility data for PA fit well in the Chrastil model. It is evident that the SC⿿CO2 extraction uses less solvent, saves both energy and time and is an environmentally friendly extract technology that can be used in the food, cosmetic and pharmaceutical industries.

Liquid and supercritical CO2 extraction of fat from rendered materials

The separation of fat from rendered materials has potential for value-added products, fuels and feed sources for animals. Current industrial processes utilize continuous screw pressing to extract fat from rendered materials, but the ability to minimize residual fat content is limited. In this work, liquid and supercritical CO2 were used to extract the remaining fat from rendered poultry meal. CO2 extraction offers high extraction yields with potential ecological and economic benefits for the rendering industry. A semi-batch extraction unit was used to investigate the effect of pressure (69–345bar), temperature (25°C, 40°C and 50°C), flow rate, and mass of CO2 on the extraction yield and the fat solubility. Maximum extraction yields between 87% and 97% were obtained which produced a remaining fat content of 1.0±0.3wt% in the extracted poultry meal. Fat solubility increased with pressure but decreased with temperature, providing liquid CO2 with the highest fat solubility (6.47g/L) at 25°C and 345bar. The Chrastil model successfully correlated the solubility data as a function of density and temperature, obtaining an AARD value of 5.56%. Gas chromatography was used to analyze the composition of fatty acids, obtaining similar results with those reported in the literature. It can be concluded that high fat extraction yields can be obtained using CO2 and that liquid CO2 is more effective than supercritical CO2 for the extraction of rendered fats under the conditions tested.

Density estimation of pure carbon dioxide at supercritical region and estimation solubility of solid compounds in supercritical carbon dioxide: Correlation approach based on sensitivity analysis

Nowadays due to wide applications of supercritical fluids (SCFs) technology in different industrial fields, solubility estimation of solid species in SCF is so important. In this work, two new correlations for the prediction of supercritical carbon dioxide (SC-CO2) density and solubility of 31 well known industrial compounds in the SC-CO2 are proposed. These correlations have been developed based on the sensitivity analysis and mathematically regression using 1240 SC-CO2 density data and 1012 solubility data of 31 solid compounds for the temperature range of 308–523K and pressure between 75 and 468bar. The proposed density and solubility models have been compared with the literature experimental data and also different models. The proposed SC-CO2 density correlation has better performance (lower AARD%) and higher density prediction ability at wider range of temperature and pressure respect to Jouyban et al. and Bahadori et al. density models. Also, more precisely prediction results of proposed solubility model respect to K–J and Chrastil models showed that the proposed model can be used as a reliable solubility model in industrial applications.

Solubility and micronisation of phenacetin in supercritical carbon dioxide

AbstractThe rapid expansion of a supercritical solution (RESS) process represents an attractive prospect for producing sub-micron and nano-particles of medical compounds with low solubility. The solubility of phenacetin in supercritical carbon dioxide was measured by the analytical-isothermal method at pressures ranging from 9.0 MPa to 30.0 MPa and temperatures ranging from 308.0 K to 328.0 K. The results show that the mole fraction solubility of phenacetin in supercritical carbon dioxide is up to 10−5. Four density-based semi-empirical models were introduced to correlate the experimental data. Agreement between the model predictions and experimental data is greater with the Adachi-Lu-modified Chrastil model than with the Chrastil model, Méndez-Santiago-Teja model, and the Bartle model and the average absolute relative deviation (AARD) observed is 0.0483. The preparation of fine phenacetin particles by the RESS process under different conditions of extraction temperatures (308.0–328.0 K), extraction pressures (9.0–30.0 MPa), nozzle temperatures (373.0–393.0 K), nozzle diameters (0.1–0.8 mm), and collection distance (20.0–40.0 mm) was investigated. The size and morphology of the resultant particles were analysed by SEM. A remarkable modification in size and morphology can be obtained by condition-optimisation.

Supercritical Carbon Dioxide Extraction of Corn Distiller’s Dried Grains with Solubles: Experiments and Mathematical Modeling

Corn distiller's dried grains with solubles (DDGS) is a byproduct of the ethanol industry and has potential as a source of valuable compounds. In this study, corn DDGS was extracted using supercritical carbon dioxide (SC-CO(2)) at 50-70 °C, 34.5-49.6 MPa, and constant CO(2) flow rate of 1 L/min (measured at ambient conditions). The highest yield of total lipids (9.2%, w/w) was obtained at 49.6 MPa/70 °C. Apparent solubility of corn DDGS lipids ranged between 0.010 kg/kg CO(2) at 34.5 MPa/50 °C and 0.026 kg/kg CO(2) at 49.6 MPa/70 °C. The extract contained 107 mg/kg carotenoids, 1538 mg/kg tocochromanols, and 15904 mg/kg phytosterols at 49.6 MPa/70 °C. The Sovova model and Chrastil model were successfully used to describe the extraction of total lipids and apparent solubility of total and minor lipids, respectively. The study revealed that DDGS is a good inexpensive source of lipids and valuable minor lipid components and that SC-CO(2) extraction can be used as a "green" process to add value to corn DDGS by recovering such high-value lipids.

Measurements and modeling of the solubility of ergosterol in supercritical carbon dioxide

In this work, the solubility of ergosterol, which is a natural phytosterol exhibiting cholesterol-lowering properties and is of particular interest to the food and nutraceutical industries, in supercritical carbon dioxide was measured with a semi-flow type phase equilibrium apparatus. The solubility experiment was performed at pressures in the range of 120–240bar and at temperatures of 318.15, 323.15, and 333.15K, and the measured solubility ranged from 2.9×10−6 to 3.0×10−5. The high-pressure solubility data for each isotherm were correlated by the Schmitt–Reid and Giddings models with average absolute relative deviations (AARD) ranging from 4.1 to 9.7% and 2.2 to 5.5%, respectively. The Chrastil model and the Méndez-Santiago and Teja model were also used to fit the entire data set yielding AARDs of 7.6% and 8.5%, respectively. Furthermore, the Peng–Robinson equation of state (EOS) using one-parameter and two-parameter van der Waals mixing rules was employed to fit the experimental solubility data with the latter giving a significantly smaller AARD of 6.4%. Retrograde behavior of the solute's solubility in the supercritical fluid was observed and was also predicted by the equation of state.

Measurement and correlation solubility of cefixime trihydrate and oxymetholone in supercritical carbon dioxide (CO2)

The equilibrium solubilities of cefixime trihydrate and oxymetholone in supercritical carbon dioxide (CO2) were measured using a “static method”. Cefixime trihydrate is a cephalosporin antibiotic drug and Oxymetholone is a 17alpha-alkylated anabolic-androgenic steroid drug. The experimental measurements for cefixime trihydrate were performed at temperatures of 308, 318 and 328K as well as pressure range from 183 to 335bar. The solubility of oxymetholone was determined at 308, 318 and 328K and pressure range from 121 to 305bar. The experimental solubility data (mole fraction) for cefixime trihydrate and oxymetholone was greater than 1.6×10−7 and 1.6×10−5 and less than 3.02×10−7 and 1.49×10−4, respectively. The solubilities for two drugs in CO2 were correlated by using four semi-empirical models such as Bartle, Kumar and Johnstone (K–J), Mendez-Santiago and Teja (M–T) and Chrastil models. The results obtained from the semi-empirical models show that there is good agreement between the experimental data and the results of semi-empirical models. By using the correlation results, the heat of drug–CO2 solvation and heat of drug vaporization for cefixime–CO2 and oxymetholone–CO2 systems may be approximately estimated. Also, the Peng–Robinson (PR) cubic equation of state (CEOS) along with the van der Waals combining rule was applied to correlate the drugs solubilities in supercritical CO2. The average absolute deviation between the experimental data and the results of PR equation for cefixime trihydrate and oxymetholone was 11.92% and 11.74%, respectively.

Solubility comparison and partial molar volumes of 1,2-hexanediol before and after end-group modification by methyl oxalyl chloride and ethyl oxalyl monochloride in supercritical CO2

Bis(methoxy oxalic)-1,2-haxenediester and bis(ethoxy oxalic)-1,2-haxenediester were synthesized by modifying the end groups of 1,2-hexanediol with methyl oxalyl chloride and ethyl oxalyl monochloride. The solubilities of all three compounds in supercritical carbon dioxide were determined at different conditions of pressures (8.8 to 18.8)MPa and temperatures (313, 333, and 353)K. Then, the solubility data were correlated with the Bartle model and the Chrastil model. The average absolute relative deviation (AARD) for the Bartle model was in the range of (3.89 to 25.46)% which is within a good approximation. The Chrastil model also showed satisfactory agreement and the AARD was in the range of (3.70 to 16.92)%. Furthermore, the partial molar volumes of those compounds were estimated following the theory developed by Kumar and Johnston.

Solubilities and partial molar volumes of 1-methypropanedioate derivatives in supercritical carbon dioxide

In present study, five new CO2-philic 1-methypropanedioate derivatives containing nonfluorous alkyl groups had been designed and synthesized. The solubilities of these compounds in supercritical carbon dioxide (scCO2) were investigated with a static analytical method at the temperature from 323K to 343K and in the pressure range of 9.3–13.7MPa. All compounds showed high solubilities in supercritical CO2 at easily accessible temperatures and pressures. To correlate the experimental data, two density-based models proposed by Bartle and Chrastil were investigated. The correlation results showed good self-consistency between the calculated and the measured values, which were in the range of 7.79–21.99% by Bartle model and 4.09–11.15% by Chrastil model. Additionally, according to the Kumar and Johnston theory, the partial molar volume V¯2 of each compound in scCO2 was also calculated and the results were between −10788.4 and −1585.84.

Determination on Solubility and RESS of Risocaine

To prepare ultra-fine particles and offer correlative applications such as the micronization of drugs with rapid expansion of supercritical solution (RESS), the first work in measuring the solubility of risocaine has been carried out at different operation conditions in this paper. The trend of solubility due to changes in specific operational parameters has been examined. The results of pressure (9-30 MPa) and temperature (308-328K) effecting on solubility show that the solubility increases mainly along with the increasing density. With applying different models to correlate the solubility data, we found Chrastil models had better correlation effects than the Peng Robinson EOS model, Mendez-Santiago and Teja equation model, with providing a nearly perfect average absolute relative deviation (AARD) of 0.0596. In the second part of work, RESS was applied to prepare risocaine particles at five different process conditions, including extraction temperature (308-328K), extraction pressure (9-30MPa), nozzle temperature (100-120°C), nozzle diameter (0.1-0.4nm) and spray distance (2-4cm).The size and morphology were determined by scanning electron microscopy (SEM). On the basis of the different experimental operation conditions, granular, filmily and threadlike particles with diameter (1-100nm) were obtained, it was also demonstrated that a successful size reduction of risocaine particles.

Solubilities and partial molar volumes of N,N′-dibutyl-oxalamide, N,N′-dihexyl-oxalamide, N,N′-dioctyl-oxalamide in supercritical carbon dioxide

Three new potent CO2-philic compounds were synthesized and their structures were characterized by FT-IR, NMR, and elemental analysis. The solubility of the three compounds in supercritical CO2 was determined at T=(313 to 353)K from 9.1MPa to 15.0MPa. The experimental data were correlated with two density-based models proposed by Bartle and Chrastil, and the calculated results showed good agreement with the tested data. The calculated data by Bartle model differed from the measured values by (6.76 to 9.60)%, and the average value of absolute relative deviations (AARD) with Chrastil model were observed to be between (7.42 to 12.27)%. Furthermore, solubility data were also utilized to estimate the partial molar volume V¯2 for each compound in the supercritical phase using the theory developed by Kumar and Johnston.

Modeling Oil Extraction from Green and Roasted Coffee by Means of Supercritical CO2

Green and roasted coffee oil was extracted using supercritical CO2 at temperatures of (333, 343, 353 and 363) K and pressures from (235 to 380) bar, providing a CO2 densities range from (680 to 880) kg.m-3. The mathematical models of Del Valle-Aguilera and Chrastil were applied to predict the oil solubility. The Del Valle-Aguilera led to elevated deviations between the predict solubility values and those observed experimentally. The Chrastil model provided better results, with better fitting being observed. With this procedure, the mean percentage deviation was 0.16 and 0.19, respectively, for green and roasted coffee oil, showing a good correlation between the observed and predicted values.

Solubility Measurement of Diclofenac Acid in the Supercritical CO2

The equilibrium solubility of the diclofenac acid in supercritical carbon dioxide was determined with a static method. The measurements were performed at pressures ranging from (120 to 400) bar and temperatures from (308.15 to 338.15) K. The results show that diclofenac acid solubility was increased by increasing pressure. The experimental solubility data were well correlated with enhanced density-based models including the Chrastil model, Mendez-Santiago and Teja model, Kumar and Johnston model, and the Bartle and co-workers model with an average absolute relative deviation (AARD) of 8.7 %, 6.6 %, 7.2 %, and 9.7 %, respectively. In addition, the solubility data satisfied the self-consistency test, proposed by Mendez-Santiago and Teja.

Solubility and Micronization of DL-2-Phenoxypropionic Acid in Supercritical CO2

To understand the process of DL-2-phenoxypropionic acid fine particles formation with rapid expansion of supercritical solution (RESS), it is vital to determine the solubility of DL-2-phenoxypropionic acid at different operation conditions and to detect an empirical model to correlate the solubility data. In this investigation, solubility in supercritical carbon dioxide (SC-CO2) was measured by a static method with the pressure ranged from (10 to 30) MPa and temperature from (308 to 323) K. Chrastil and its modified models have better correlation effects than the Mendez-Santiago and Teja model, especially the Adachi and Lu modified Chrastil model, provides a nearly perfect average absolute relative deviation (AARD) of 0.0532. Then, RESS was applied to prepare DL-2-phenoxypropionic acid microstructures. The effects of the extraction temperature ((308 to 328) K), extraction pressure ((10 to 30) MPa), spray distance ((10 to 30) mm), nozzle temperature ((343 to 383) K), and nozzle diameter ((0.1 to 0.4) mm) w...

The effect of the end group, molecular weight and size on the solubility of compounds in supercritical carbon dioxide

End groups of bis(2-hydroxyethyl)ether (compound 1) and tetraethylene glycol (compound 2) were modified with methyl malonyl chloride to produce two new compounds: malonic acid 2-[2-(2-methoxycarbonyl-acetoxy)-ethoxy]-ethyl ester methyl ester (compound 3) and Malonic acid 2-(2-{2-[2-(2-methoxycarbonyl-acetoxy)-ethoxy]-ethoxy}-ethoxy)-ethyl ester methyl ester (compound 4). And then the solubility of compounds 1–4 were investigated and compared in supercritical carbon dioxide (scCO2) at a temperature range of 313–363K and in the pressure range of 9.2–25.7MPa. The effect of the end group, molecular weight and size for the solubility of the compounds were discussed. In addition, the tested solubility data were calculated and correlated with a semiempirical model at different pressures and temperatures, which showed satisfactory agreement with each other and the average absolute relative deviation was in the range of 2.61% and 33.25%. The Chrastil model also showed satisfactory agreement with each other and the average absolute relative deviation was in the range of 1.69% and 11.53%.

Solubility of red pepper (Capsicum annum) oil in near- and supercritical carbon dioxide and quantification of capsaicin

Red pepper oil was extracted using near- and supercritical carbon dioxide. Extraction was carried out at pressures ranging from 10 to 35 MPa and temperatures from 30 to 60 °C, with a CO2 flow rate of 24.01 g/min using a semi-continuous high-pressure extraction apparatus. The duration for extraction was 2 h. The highest oil yield was found at high pressure and temperature. The highest solubility of oil (1.18 mg/g of CO2) was found at 35 MPa and 60 °C. The solubility data of red pepper oil in near- and supercritical CO2 were fitted in Chrastil model. The fatty acid composition of red pepper oil was analyzed by gas chromatography (GC). Linoleic acid was found to be the major fatty acid in the oil. Capsaicin was quantified in different extracts by high performance liquid chromatography (HPLC). The highest capsaicin yield was found at 35 MPa and 60 °C.

Solubility of Azadirachtin in Supercritical Carbon Dioxide at Several Temperatures

The solubility data of azadirachtin in supercritical carbon dioxide were measured at several temperatures (308.15, 313.15, 318.15, 323.15, 328.15, and 333.15 K) and at pressure between (10 and 26) MPa. The measurement of solubility data was conducted in static mode. The experimental results were correlated by Chrastil model and Del valle and Aguilera equation. Chrastil model can represent the experimental data well and give a reasonable value for fitting parameters.

High Solubility and Partial Molar Volume of 2,2′-Oxybis(N,N-bis(2-methoxyethyl)acetamide) in Supercritical Carbon Dioxide

2,2′-Oxybis(N,N-bis(2-methoxyethyl)acetamide) was synthesized and confirmed by IR, NMR, and elemental analysis. The solubility of this compound was measured at temperatures ranging from (313 to 333) K and pressures from (9.2 to 15.2) MPa in supercritical carbon dioxide. The synthesized compound showed high solubility in supercritical CO2 at easily accessible temperatures and pressures (e.g., 1.84 × 10−3 mol·L−1 at 9.2 MPa and 313 K). To confirm the tested solubility, the density-based correlations proposed by Bartle and Chrastil were investigated for the synthesized compound. The results showed good self-consistency of the data calculated using the Bartle semiempirical equation, which differed from the measured values by between (0.96 and 41.22) %. Better agreement with the experimental solubility data was obtained with the Chrastil model, for which average absolute relative deviations of less than 6 % were observed. The solubility data were also used to estimate the partial molar volume V2 for the compo...

Equilibrium solubility of pure and mixed 3,5-dinitrobenzoic acid and 3-nitrobenzoic acid in supercritical carbon dioxide

The solid solubility of pure 3,5-dinitrobenzoic acid (3,5-DNBA) and 3-nitrobenzoic acid ( m-NBA) and their equal-weight mixture in supercritical carbon dioxide (SCCO 2) was measured using a flow-type apparatus at 308, 318, and 328 K and in the pressure range of 10.0–21.0 MPa. The solubility enhancement SE of mixed 3,5-DNBA and m-NBA in the ternary system has been observed. The mixture separation factor μ and the separation efficiency HE were investigated. A modified Kumar–Johnston (K–J) model was proposed for correlating the solubility of solid compounds in SCCO 2. The experimental solubility data of pure and mixed solutes in SCCO 2 were successful to be correlated by Chrastil model, the modified Adachi–Lu model, K–J model and new proposed model. Solubility data from 23 different solid compounds were taken from literature. The accuracy of the proposed model was evaluated by correlating 13 binary systems, 13 ternary systems, and 1 quaternary system. The modified K–J model satisfactorily correlated the experimental results for the solubility of all these compounds in SCCO 2 within 5.11% AARD.