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Biomedical subjects

W E Acree

Publications and source records attributed to W E Acree.

At least 19 recordsLinked to original sources
PubMed2006

Solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model.

To show the applicability of a solution model, i.e. the Jouyban-Acree model, for predicting the solubility of a solute in ternary solvent systems based on model constants computed using solubility data of the solute in binary solvent systems, the solubility of salicylic acid in water-ethanol, water-propylene glycol, ethanol-propylene glycol mixtures was determined. A minimum number of three data points from each binary system was used to calculate the binary interaction parameters of the model. Then the solubility in other binary solvent compositions and also in a number of ternary solvents was predicted, and the mean percentage deviation (MPD) was calculated as an accuracy criterion. The overall MPD (+/-SD) was 7.3 (+/-7.3)% and those of a similar predictive model was 15.7 (+/-11.5)%. The mean difference between the proposed and a previous model was statistically significant (paired t-test, p < 0.004).

Algorithms↗
PubMed2006

Correlation of retention factor of analytes in quaternary solvent mobile phases using the Jouyban-Acree model.

The Jouyban-Acree model has been used for the mathematical representation of retention factors of phenobarbital, phenytoin and carbamazepine in quaternary aqueous-organic solvent mobile phases. The accuracy of the proposed model is evaluated using average percentage deviation (APD) of experimental and calculated values as an accuracy criterion. The obtained mean and standard deviation of APDs of the model is 4.2 +/- 0.5%. The results showed that the Jouyban-Acree model provided accurate calculations and could be used in practice to speed up the method development process in which quaternary solvent mobile phases are required.

Algorithms↗
PubMed2006

In silico prediction of drug solubility in water-ethanol mixtures using Jouyban-Acree model.

PURPOSE: A predictive method was proposed to predict solubility of drugs in water-ethanol mixtures at various temperatures based on the Jouyban-Acree model. The model requires the experimental solubility data of the drug in mono-solvent systems. METHODS: The accuracy of the proposed prediction method was evaluated using collected experimental solubility data from the literature. The proposed method is: log Xm,T = fc log Xc,T + fw log Xw,T + fcfw[724.21/T + 485.17(fc-fw)/T + 194.41(fc-fw)2/T] Where Xm,T, Xc,T and Xw,T are the solute solubility at temperature (T) in mixed solvent and neat cosolvent and water, respectively, fc and fw denote the solute free fraction of cosolvent (ethanol) and water. The average absolute error (AAE) of the experimental and the predicted solubilities was computed as an accuracy criterion and compared with that of a well-established log-linear model. RESULTS: The AAE (+/-SD) of the Jouyban-Acree and log-linear models were 0.19 (+/-0.13) and 0.48 (+/-0.28), respectively. The mean difference of AAEs was statistically significant (p < 0.0005) revealing that the Jouyban-Acree model was provided more accurate predictions. Although the log-linear model was used to predict solubility at a fixed temperature (25 or 23 degrees C), the results also showed that the model could be employed to predict the solubility in solvent mixtures at various temperatures. CONCLUSION: More accurate predictions were provided using the Jouyban-Acree model in comparison with a previously established log-linear model of Yalkowsky. The prediction methods were successfully extended to predict the solubility in water-ethanol mixtures at various temperatures.

Ethanol↗
PubMed2006

Mathematical representation of solubility of amino acids in binary aqueous-organic solvent mixtures at various temperatures using the Jouyban-Acree model.

Applicability of a solution model for calculating solubility of amino acids in binary aqueous-organic solvent mixtures at various temperatures was shown. The accuracy of the proposed model was evaluated by computing mean percentage deviation (MPD) employing available solubility data of amino acids in binary solvents at various temperatures from the literature. The overall MPD (+/- SD) for correlation of solubility data was 16.5 +/- 8.8%. In addition, the equations calculating solubility of amino acids in binary solvent mixtures at a fixed temperature was revisited.

Algorithms↗
PubMed2005

Mathematical representation of solute solubility in binary mixture of supercritical fluids by the Jouyban-Acree model.

Applicability of a solution model for calculating the solute solubility in binary mixtures of supercritical fluids at different SCF compositions and pressures was shown using phenanthrene solubility data in supercritical carbon dioxide and supercritical ethane at 313 K and a pressure range of 100-350 bar. The correlation ability of the proposed model was evaluated by fitting all data points and computing error term employing back-calculated solubilities. The prediction capability of the model was assessed by dividing each data set to two subsets, namely training and test subsets. The predicted solubilities using trained models were used to calculate the prediction error term. The results show that both correlative and predictive error terms were less than the experimentally obtained RSD values.

Algorithms↗
PubMed2004

Correlation of surface tension of mixed solvents with solvent composition.

A simple computational method for calculating surface tension of solvent mixtures based on the Redlich-Kister extension was proposed. The model was applied to the experimental surface tension of binary solvent mixtures and showed accurate results. Overall average percentage deviation (APD) between calculated and experimental surface tensions was calculated as an accuracy criterion. The overall APD for correlating surface tensions in binary solvents was 4.30%. The accuracy of the proposed model has also been compared with those of previously published models and the results showed that the proposed model was superior and capable of providing more accurate results. An extension of the model was also proposed to correlate surface tension of ternary solvents and the overall APD for ternary solvent data was 2.06%.

Algorithms↗
PubMed2002

A model to represent solvent effects on the chemical stability of solutes in mixed solvent systems.

The applicability of the combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation for quantification of solvent effects on the stability of a solute is shown employing the experimental data of three solutes in different aqueous binary solvents. The proposed model provides a simple computational method to correlate/predict the instability rate constant of a drug in mixed solvent systems. The accuracy of the model is compared with that of a model proposed by Connors and co-workers employing various methods including mean percentage deviation (MPD) as comparison criteria. The obtained overall MPD values for the proposed model to correlate and predict the instability rate constants are 2.05 +/- 1.44 and 4.41 +/- 3.21%, respectively, where the corresponding values for Connors' model are 4.34 +/- 3.28 and 10.74 +/- 9.86%. The results suggest that by using only five experimental instability rate constants at different concentrations of the cosolvent in a binary mixture, it is possible to predict unmeasured values falling between data points within an acceptable error range.

Algorithms↗
PubMed2001

The solubility of gases and vapours in dry octan-1-ol at 298 K.

Ostwald solubility coefficients of 74 compounds in dry octan-1-ol at 298 K have been determined, and have been combined with literature values and additional values we have calculated from solubilities in dry octan-1-ol and vapour pressures to yield a total of 161 log L(OctOH) values at 298 K. These L(OctOH) values are identical to gas-to-dry octan-1-ol partition coefficients, often denoted as K(OA). Application of the solvation equation of Abraham to 124 values as a training set yielded a correlation equation with n = 124, S.D. = 0.125, r2 = 0.9970 and F = 7731. This equation was then used to predict 32 values of log L(OctOH) as a test set, giving a standard deviation, S.D. of 0.131, an average absolute deviation of 0.085 and an average deviation of -0.009 log units. The solvation equation for the combined 156 log L(OctOH) values was log L(OctOH) = -0.120 - 0.203R2 + 0.560pi2(H) + 3.560 sum(alpha2(H)) + 0.702 sum(beta2(H)) + 0.939 logL16, n =156, r2 = 0.9972, S.D. = 0.125, F = 10573, where, n is the number of data points (solutes), r the correlation coefficient, S.D. the standard deviation and F is the F-statistic. The independent variables are solute descriptors as follows: R2 is an excess molar refraction, pi2(H) the dipolarity/polarisability, sum(alpha2(H)) the overall or summation hydrogen-bond acidity, sum(beta2(H)) the overall or summation hydrogen-bond basicity and L16 is the Ostwald solubility coefficient on hexadecane at 298 K. The equation is consistent with similar equations for the solubility of gases and vapours into methanol, ethanol and propan-1-ol. It is suggested that the equation can be used to predict further values of log L(OctOH), for which the solute descriptors are known, to within 0.13 log units.

1-Octanol↗
PubMed2000

Prediction of drug solubility in ternary solvent mixture.

Applicability of the combined, nearly ideal, binary solvent/Redlich-Kister equation for calculating drug solubility in ternary mixtures is presented. The advantages of the proposed model are discussed and compared with a recently published equation that calculates the solute solubility in ternary solvent mixtures based on the mixture response methodology.

Chemistry, Pharmaceutical↗
PubMed2000

Models to predict solubility in ternary solvents based on sub-binary experimental data.

The capability of the extended forms, of two well established cosolvency models, i.e. the combined nearly ideal binary solvent/Redlich-Kister equation and the modified Wilson model, used to predict the solute solubility in non-aqueous ternary solvent mixtures is presented. These predictions are based on the measured solubilities of anthracene in binary solvent mixtures. As a result the values of average percent deviations were less than 2% for the anthracene solubility in ternary mixtures. This work was also extended to other cosolvency models, ie. the extended Hildebrand solubility approach and the mixture response surface method, which are also commonly used for correlating solubility data in ternary solvents. The accuracy of the models is compared with each other and also with a published solubility model for ternary mixtures. The results illustrate that all models produced comparable accuracy.

Anthracenes↗
PubMed1999

Comparison of various cosolvency models for calculating solute solubility in water-cosolvent mixtures.

Previously published cosolvency models are critically evaluated in terms of their ability to mathematically correlate solute solubility in binary solvent mixtures as a function of solvent composition. Computational results show that the accuracy of the models is improved by increasing the number of curve-fit parameters. However, the curve-fit parameters of several models are limited. The combined nearly ideal binary solvent/Redlich-Kister, CNIBS/R-K, was found to be the best solution model in terms of its ability to describe the experimental solubility in mixed solvents. Also resented is an extension of the mixture response surface model. The extension was found to improve the correlational ability of the original model.

Drug Incompatibility↗
PubMed1997

Spectrochemical investigations of fluorescence quenching agents. Part 5. Effect of surfactants of the ability of nitromethane to selectively quench fluorescence emission of alternant PAHs.

Applicability of the nitromethane selective quenching rule for discriminating between alternant vs. nonalternant polycyclic aromatic hydrocarbons (PAHs) is examined for 18 representative PAH solutes dissolved in micellar cetyltrimethylammonium chloride (CTACl), micellar dodecyltrimethylammonium bromide (DTAB), micellar Brij-35 and micellar sodium octanoate (SO) solvent media. Experimental results show that nitromethane quenched fluorescence emission of only the 10 alternant PAHs in the two cationic (CTACl and DTAB) and nonionic Brij-35 surfactant solvent media as expected. Emission intensities of nonalternant PAHs, except for the few exceptions noted previously, were unaffected by nitromethane addition. Unexpected quenching behavior was observed, however, in the case of nonalternant PAHs dissolved in micellar sodium octanoate solvent media. Nitromethane quenched fluorescence emission of all nonalternant PAHs studied in the SO solvent media, which is contrary to the selective quenching rule.

Fluorescent Dyes↗
PubMed1989

Polycyclic aromatic hydrocarbon solute probes. Part II. Effect of solvent polarity on the fluorescence emission fine structures of coronene derivatives.

The fluorescence properties of coronene (Co), benzo[a]coronene (BCo), naphtho[2,3-a]coronene (NCo), dibenzo[a,j]coronene (DCo), naphtho[1,2,3,4-ghi]perylene, benzo[pqr]naphtho[8,1,2-bcd]perylene and dibenzo[cd,lm]perylene dissolved in solvents of varying polarity are reported. Measurements indicated that the emission intensities of the four coronene derivatives depended on solvent polarity. The Co, BCo and NCo scales have been defined as the ratio of the fluorescence intensities of bands I and III of the vibronic spectra. Band III of dibenzo[a,j]coronene was not clearly identifiable in all the solvents studied, and the DCo scale was therefore defined as the intensity ratio of band I and IV. Emission intensity ratios of the three perylene derivatives remained nearly constant, irrespective of solvent polarity.

Chemical Phenomena↗
PubMed1987

Thermochemical investigations of associated solutions: 4. Calculation of carbazole-dibutyl ether association constants from measured solubility in binary solvent mixtures.

Experimental solubilities are reported for anthracene and carbazole in binary dibutyl ether plus n-hexadecane and dibutyl ether plus squalane solvent mixtures at 25 degrees C. Results of these measurements, used in conjunction with the extended nearly ideal binary solvent (NIBS) model, enabled calculation of the carbazole-dibutyl ether association constant. The numerical value obtained was independent of the hydrocarbon cosolvent, and compared favorably with previously reported values based on carbazole solubilities in solvent mixtures containing much smaller alkane cosolvents.

Carbazoles↗
PubMed1987

Thermochemical investigations of associated solutions: 5. Calculation of solute-solvent equilibrium constants from solubility in mixtures containing two complexing solvents.

Solubilities are reported for carbazole in binary dibutyl ether plus 1-chlorohexane mixtures at 25 degrees C. Results of these measurements are compared with solution models developed for solubility in systems containing specific solute-solvent interactions. A simple stoichiometric complexation model based on a 1:1 carbazole:dibutyl ether complex could describe the measured solubility to within an average absolute deviation of 1.7%. The calculated equilibrium constant, though, was about one-half of values previously determined from carbazole solubilities in several binary dibutyl ether plus alkane mixtures. A more sophisticated solution model, derived by assuming both 1:1 carbazole: dibutyl ether and carbazole:chlorohexane complexes, could describe the solubilities to within 2.4%. This latter model enables the carbazole-chlorohexane association constant to be calculated from experimental carbazole solubilities and a priori knowledge of the carbazole-dibutyl ether equilibrium constant.

Carbazoles↗