Abraham Model Solute Descriptors Research Articles

Experiment-based Abraham model solute descriptors for 2,3-dimethoxybenzoic acid from measured solubility data

ABSTRACT Mole fraction solubilities have been experimentally determined for 2,3-dimethoxybenzoic acid dissolved in propanenitrile and diisopropyl ether, in two more alkyl alkanoates (tert-butyl acetate, methyl butanoate), and in ten more alcohols (1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-methyl-1-propanol, 2-butanol, 2-pentanol, 3-methyl-1-butanol, 4-methyl-2-pentanol, cyclopentanol) at 298.15 K using a spectrophotometric method of chemical analysis based on the Beer-Lambert law. Experiment-based solute descriptors for the monomeric form of the dissolved carboxylic acid solute have been calculated using the results from our solubility measurements, combined with published solubility data taken from the chemical literature. The calculated solute descriptors provide a reasonably accurate mathematical description of the observed solubility data, with the overall standard deviation between the observed and back-calculated values being 0.074 log units. The solute descriptors further suggest that the carboxylic acid solute does not undergo intramolecular hydrogen bonding in the 28 organic solvents considered in the current study.

Abraham solvation parameter model: determination of experiment-based solute descriptor values for 3,5-dimethoxybenzoic acid based on measured solubility data

ABSTRACT A spectroscopic method of chemical analysis is used to determine the mole fraction solubilities of 3,5-dimethoxybenzoic acid dissolved in propanenitrile, in eleven additional alkanol solvents (1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-methyl-1-propanol, 2-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 4-methyl-2-pentanol, 2-ethyl-1-hexanol, cyclopentanol) and in three additional alkyl alkanoate solvents (isopropyl acetate, tert-butyl acetate, methyl butyrate) at 298.15 K. Results from our experimental measurements, combined with published partition coefficient and solubility data, are used to calculate the Abraham model solute descriptors of the monomeric form of 3,5-dimethoxybenzoic acid. In total 62 experimental data points were used in the computation. The calculated solute descriptors describe the experimental solubility and partition coefficient data to within an overall standard deviation of 0.064 log units.

Abraham general solvation parameter model: intramolecular hydrogen bond formation and its effect on the A- and B-descriptor values of select tetracycline derivatives

ABSTRACT Experiment-based Abraham model solute descriptors are calculated from published solubility data for sancycline dissolved in methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 1-octanol, cyclohexane, acetonitrile, ethyl acetate and 1,4-dioxane at 298.15 K. The calculated descriptor values suggest that sancycline engages in strong intramolecular hydrogen formation. The hydrogen-bond acidity and basicity solute descriptor values obtained from the experimental solubility data are considerably smaller than what would be expected based on the four hydroxyl, one amide, one dimethylamino and two carbonyl functional groups contained in the molecule. Our study further shows that existing group contribution and machine learning methods provide rather poor estimates of the experiment-based solute descriptors of sancycline.

Abraham model solute descriptors for two additional α-amino acids: D-Tryptophan and L-Tyrosine

ABSTRACT Abraham model solute descriptors have been determined for the zwitterionic forms of D-tryptophan and L-tyrosine based on published mole fraction solubility data. The calculated solute descriptors describe the observed solubility data to within standard errors of 0.122 log units (or less). Treatment of each amino acid as a non-zwitterionic molecular compound led to significantly larger standard errors than were observed for the zwitterion form.

Abraham Model Solute Descriptors for Favipiravir: Case of Tautomeric Equilibrium and Intramolecular Hydrogen-Bond Formation

Experiment-based Abraham model solute descriptors are calculated based on recently published solubility data for favipiravir dissolved in 12 chemically diverse organic mono-solvents. The calculated descriptor values indicate that favipiravir engages in intramolecular hydrogen formation that renders the hydroxyl functional group on the pyrazine ring system unable to form intermolecular hydrogen bonds with the surrounding solvent molecules. Our study further shows that the existing group contribution and machine learning methods provide rather poor estimates of the experiment-based solute descriptors of favipiravir. Poor estimation likely occurs, in part, because the methods fail to account for the intramolecular hydrogen-bonds that are believed to be formed. In the current study, it was found that the solute descriptors estimated using three different methods provided rather poor estimates of the observed solubility behavior of favipiravir, with the overall average standard errors between the experimental and predicted molar solubilities exceeding 0.40 log units.

Determination of Abraham Model Solute Descriptors for N-Hydroxyphthalimide: An Organic Compound Having a N-Hydroxy (N–OH) Functional Group

Determination of Abraham Model Solute Descriptors for N-Hydroxyphthalimide: An Organic Compound Having a N-Hydroxy (N–OH) Functional Group

Calculation of Abraham model solute descriptors for 2-naphthoxyacetic acid

ABSTRACT Mole fraction solubilities are reported for 2-naphthoxyacetic acid dissolved in three alkanol (3-methyl-1-butanol, 2-pentanol, 1-octanol), two alkyl alkanoate (tert-butyl acetate, methyl butyrate), three alkanone (butanone, 2-pentanone, cyclopentanone) and six alkoxyalcohol (2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 3-methoxy-1-butanol) mono-solvents at 298.15 K. Results from our experimental measurements, combined with the published solubility data, are used to calculate the solute descriptors of the carboxylic acid solute. The calculated descriptor values reported in the current study back-calculate the observed solubility data to within an approximate standard error of 0.05 log units.

Determination of Abraham Model Solute Descriptors for 62 Additional C10 through C13 Methyl- and Ethyl-Branched Alkanes

Abraham model solute descriptors are reported for the first time for 62 additional C10 through C13 methyl- and ethyl-branched alkanes. The numerical values were determined using published gas chromatographic retention Kováts retention indices for 157 alkane solutes eluted from a squalane stationary phase column. The 95 alkane solutes that have known descriptor values were used to construct the Abraham model KRI versus L-solute descriptor correlation needed in our calculations. The calculated solute descriptors can be used in conjunction with previously published Abraham model correlations to predict a wide range of important physico-chemical and biological properties. The predictive computations are illustrated by estimating the air-to-polydimethylsiloxane partition coefficient for each of the 157 alkane solutes.

Abraham Solvation Parameter Model: Examination of Possible Intramolecular Hydrogen-Bonding Using Calculated Solute Descriptors

Published solubility data for 4,5-dihydroxyanthraquinone-2-carboxylic acid dissolved in several organic solvents of varying polarity and hydrogen-bonding character are used to calculate the Abraham model solute descriptors. Calculated descriptor values suggest that 4,5-dihydroxyanthraquinone-2-carboxylic acid engages in intramolecular hydrogen formation between the two phenolic hydrogens and the proton acceptor sites (the lone electron pairs) on the neighboring quinone oxygen atom. Our study further shows that existing group contribution and machine learning methods provide rather poor estimates of the experimental-based solute descriptors of 4,5-dihydroxyanthraquinone-2-carboxylic acid, in part because the estimation methods to not account for the likely intramolecular hydrogen-bonds. The predictive aspect of the Abraham model is illustrated by predicting the solubility of 4,5-dihydroxyanthraquinone-2-carboxylic acid in 28 additional organic mono-solvents for which experimental data does not exist.

Descriptors for some compounds with pharmacological activity; calculation of properties

Abraham model solute descriptors have been determined for nisoldipine, nizatidine, loratadine, zonisamide, oxaprozin, rebamipide, domperidone, temozolomide, ‘florfenicol’, florfenicol A, dapsone, chrysin, benorilate, β-lapachone, and Ipriflavone based on published partition coefficients, molar solubilities and gas chromatographic retention indices. The calculated solute descriptors, combined with our previously published Abraham model correlations, are used to predict several important physicochemical and biological properties, such as air–water, air-blood, air-lung, air-fat, air-skin, water–lipid, water-membrane and water-skin partition coefficients, as well as permeation from water through skin.

Abraham model solute descriptors: effect of structural features on the calculated numerical descriptor values for vanillin and select derivatives

ABSTRACT Abraham model solute descriptors are determined for vanillin and five select derivatives (o-vanillin, isovanillin, vanillic acid, vanillyl alcohol and ethylvanillin) based on experimental solubility and partition coefficient data that we were able to find in the published literature. The solute descriptor values reported in the current communication back-calculate the observed experimental data to within standard errors of 0.12 log units (or less). The calculated solute descriptors can be used to predict the solubility of the vanillin and the five select derivatives in additional organic mono-solvents and binary aqueous-ethanol solvent mixtures using published Abraham model correlations.

Determination of Abraham model solute descriptors for hippuric acid from measured molar solubilities in several organic mono-solvents of varying polarity and hydrogen-bonding ability

ABSTRACT Mole fraction solubilities are reported for hippuric acid dissolved in 2-propanol, 2-methyl-1-propanol, 1-pentanol, cyclopentanol, 2-ethoxyethanol, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, pentyl acetate and methyl butyrate at 298.15 K. Results of experimental measurements, combined with published solubility data taken from the published chemical literature, were used to calculate the Abraham model solute descriptors for the monomeric molecular form of hippuric acid. The derived solute descriptors back-calculate the observed molar solubility data to within a standard error of 0.10 log units.

Descriptors for fluorotelomere alcohols. Calculation of physicochemical properties

ABSTRACT Abraham model solute descriptors are calculated for several environmentally important fluorotelomer alcohols from published partition coefficient and solubility data. The various descriptors all show a gradual trend from 1:2FTOH to 8:2FTOH. The maximum deviation from self-consistent values is 0.19 log units in the calculations on vapour pressure (concentration in air) and solubility in water (concentration in water).

Solubility of 4-methyl-3-nitrobenzoic acid in organic mono-solvents: calculation of Abraham model solute descriptors

ABSTRACT Spectroscopic methods have been used to determine the mole fraction solubilities of 4-methyl-3-nitrobenzoic acid dissolved in 17 different alcohols (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-decanol, 2-propanol, 2-butanol, 2-methyl-1-propanol, 2-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 4-methyl-2-pentanol, 2-ethyl-1-hexanol), two dialkyl ether (diethyl ether, diisopropyl ether) and two cyclic ether (tetrahydrofuran, 1,4-dioxane), four alkyl alkanoate (methyl acetate, ethyl acetate, butyl acetate, pentyl acetate) and one alkanenitrile (acetonitrile) solvents at 298.15 K. Results of experimental measurements are used to calculate the Abraham model solute descriptors of 4-methyl-3-nitrobenzoic acid. The calculated Abraham model solute descriptors describe the observed solubility behaviour of 4-methyl-3-nitrobenzoic acid to within 0.05 log units.

Applications of Abraham solvation parameter model: estimation of the lethal median molar concentration of the antiepileptic drug levetiracetam towards aquatic organisms from measured solubility data

ABSTRACTAbraham model solute descriptors are calculated for the pharmaceutical compound levetiracetam based on experimental solubility data retrieved from the published literature. The calculated solute descriptors mathematically describe the solubility behaviour of levetiracetam in methanol, ethanol, 1-propanol, 2-propanol, acetone, acetonitrile, ethyl acetate, toluene and cyclohexane to within a standard error of 0.102 log units. Once calculated the Abraham model solute descriptors can be used to estimate the solubility of levetiracetam in more than 100 different organic solvents, as well as several important environmental and pharmaceutical properties, such as the lethal median molar concentration of levetiracetam towards various aquatic organisms and blood-to-body organ (or tissue) partition coefficients.

Determination of Abraham model solute descriptors for xanthone based on experimental solubility measurements at 298.2 K

ABSTRACTExperimental solubilities have been determined for xanthone dissolved in 15 different alcohol solvents (ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-ethyl-1-hexanol, 2-propanol, 2-butanol, 4-methyl-2-pentanol, 2-methyl-2-propanol and 2-methyl-2-butanol), in five alkyl acetate solvents (methyl acetate, ethyl acetate, propyl acetate, butyl acetate and pentyl acetate), in diisopropyl ether and in 2-ethoxyethanol at 298.2 K. In total, solubility measurements were performed in 22 organic solvents of varying polarity and hydrogen-bonding character. Results of the experimental measurements were used to calculate the Abraham model solute descriptors for xanthone. The calculated solute descriptors describe the experimental solubility data to within 0.096 log units.

Determination of Abraham model solute descriptors for o-acetoacetanisidide based on experimental solubility data in organic mono-solvents

ABSTRACTSpectrophotometric methods were used to measure the mole fraction solubility of o-acetoacetanisidide dissolved in 13 alcohol solvents (ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 2-propanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 2-methyl-2-butanol, 3-methyl-1-butanol and 4-methyl-2-pentanol), in 3 dialkyl ether solvents (diisopropyl ether, dibutyl ether and methyl tert-butyl ether), in 6 alkyl alkanoate solvents (methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate and methyl butyrate) and in 1 alkanenitrile solvent (propanenitrile) at 298.15 K. Solute descriptors were calculated for o-acetoacetanisidide by analysing the measured solubility data in accordance with the Abraham solvation parameter model. The calculated solute descriptors describe the observed solubility data to within 0.099 log units.

Determination of Abraham model solute descriptors for 4-tert-butylbenzoic acid from experimental solubility data in organic mono-solvents

ABSTRACTMole fraction solubilities are determined at 298 K for 4-tert-butylbenzoic acid dissolved in 11 different alcohols (1-butanol, 2-butanol, ethanol, 1-heptanol, 1-hexanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 3-methyl-1-butanol, 1-pentanol, 1-propanol, and 2-propanol), in three different alkoxyalcohols (2-butoxyethanol, 2-ethoxyethanol, and 2-methoxyethanol), in five different alkyl alkanoates (butyl acetate, ethyl acetate, methyl acetate, pentyl acetate, and propyl acetate), in one cyclic ether (1,4-dioxane) and in two different alkanenitriles (acetonitrile and propanenitrile). Results of the experimental solubilities are used to calculate Abraham model solute descriptors for the monomeric form of 4-tert-butylbenzoic acid. The calculated Abraham model solute descriptors back-calculated the observed solubility data to within 0.079 log units.

Calculation of the Abraham model solute descriptors for the pharmaceutical compound acipimox based on experimental solubility data

ABSTRACTAbraham model solute descriptors are calculated for the pharmaceutical compound acipimox based on experimental solubility data retrieved from the published literature. The calculated solute descriptors mathematically describe the solubility behaviour of acipimox in methanol, acetone, acetonitrile mono-solvents and in binary aqueous-methanol solvent mixtures, to within a standard error of 0.06 log units. The calculated solute descriptors can be used to predict the solubility of acipimox in additional alcohol, alkyl ether, alkyl alkanoates, alkanenitrile and alkoxyalcohol solvents.

Determination of Abraham Model Correlations for Solute Transfer into Propyl Acetate Based on Experimental Activity Coefficient and Solubility Data

Experimental infinite dilution activity coefficients, gas-to-liquid partition coefficients, and molar solubility data have been measured for numerous organic solutes dissolved in propyl acetate. Results of our experimental measurements, combined with published solubility data retrieved from the published literature, have been used to derive Abraham model correlations for describing solute transfer into propyl acetate. The derived Abraham model correlations describe the experimental data to within 0.11 log10 units. Calculation of Abraham model solute descriptors for boscalid was illustrated using our derived solute transfer correlations into propyl acetate. Predictions using the calculated solute descriptors indicate that boscalid would show significant partitioning into the skin and fat tissues in the body, and would exhibit considerable baseline toxicity towards the eight aquatic organisms (five fish species and three water flea species).