Solute descriptor

As the solute descriptors (E, S, A, B and V) represent the solute influence on various solute-solvent phase interachons, the regression coefficients e, s, a, h and V correspond to the complementary effect of the solvent phases on these interactions. As an example, consider the product aA in Eq. (4). Since A is the H-bond acidity of the solute, a is the H-bond basicity of the system. In other words, the intermolecular forces discussed in Sections 12.1.1.2 and 12.1.1.3 are present in all Abraham s log P factorization equations, with the exception of those interactions involving ions. This is the reason why Abraham s equahons are valid for neutral species only. 

Plass, M., Valko, K., Abraham, M. H., Determination of solute descriptors of tripeptide derivatives based on high-throughput gradient high-performance liquid chromatography retention data, J. Chromatogr. A. 1998, 803(1-2), 51-60. 

M. H. Abraham, New solute descriptors for linear free energy relationships and quantitative structure-activity relationships, in Quantitative Treatments of Solute/Solvent Interactions, P. Politzer and J. S. Murray, eds., Elsevier, Amsterdam (1994) pp. 83-134. 

Abraham et al. [2] published a number of papers in which they analyzed Young s data set using MLR and gave a general solvation equation in which various solvent-solute interactions were described by solute descriptors and equation coefficients (Eq. 16)... 

Abraham s solute descriptors to yield a predictive regression equation. Further, the solute dipolarity/polarizability, hydrogen bond acidity, and hydrogen bond basicity were found to favor blood and solute size favor brain. 

Iyer et al. [22] Intramolecular solute, intermolecular solute-solvation and intermolecular membrane-solute descriptors... 

Abraham, M.H., Ibrahim, A. and Zissimos, A.M. (1037) Determination of sets of solute descriptors from chromatographic measurements. Journal of Chromatography. A, 2004, 29-47. 

The solute descriptors for each analyte and the corresponding retention factor (measured at a specific temperature) are subjected to multiple linear... 

Solute descriptors are available for more than 2,000 compounds. The magnitude of the coefficients is due to a difference between mobile and stationary phase properties. According to Sny-... 

From a practical point of view, the use of Abraham descriptors appears to be preferable in cases where the experimentally derived solute descriptors of the compounds are well available for all solutes of interest. If partition coefficients between phases similar to those used for the derivation of the Abraham descriptors are considered, the Abraham approach is usually more accurate, because it only needs to predict the small differences from the experimental information intrinsically included in the descriptors, and it avoids the total prediction of the large free energy differences that often occur between different phases. On the other hand, the COSMO a-moment approach does not require experimental input for each individual solute, and hence can be applied even in cases where no experimental data are available for the solute or even when the solutes are still virtual candidates for drugs or other agents. Furthermore, the cr-moment approach is more rigorously derived from physical chemistry and provides more insight into the driving forces for partition equilibria. 

ASER relates a property of a series of drug substances in a given condition, such as solubility in water (Sw) and partition coefficient in water-octanol mixture (Kwo), to a sum of solute descriptors as given by ... 

Moreover, the only solute descriptor for ion-pair effect was the analyte charge, but it was shown that the analyte charge status did not explain (1) different experimental curves when k is plotted as a function of the stationary phase concentration of the IPR for various IPRs (2) the dependence of the ratio of the retention of two different analytes on IPR concentration (3) the dependence of the k/ ko ratio on the analyte nature if experimental conditions are the same [16,17] and (4) ion-pairing of peptides [12]. The model makers realized that the charge may have been a too-simple solute descriptor for ion-pairing because it did not exhibit the hydrophobic effect, but they did not devise a better descriptor. Section... 

Iyer et at, Molecular Pharmaceutics, 2007 Prediction and mechanistic interpretation of human oral drug absorption using MI-QSAR analysis 188 MLR n.a. 2D and 3D solute descriptors (n = 7)... 

LafTort solute descriptors Linear Solvation Energy Relationships... 

Similar equations but based on other solute descriptors were proposed in literature with the aim of better chromatographic data [Abraham, Ibrahim et al, 2004]. In particular, five solute descriptors, here called LafFort solute descriptors (Table LI), were defined by Laffort et al. using GLC retention data on five stationary phases for 240 compounds [Laffort and Patte, 1976 Patte, Etcheto et al., 1982[. These solute descriptors were used to fit a number of physico-chemical and biochemical properties. Note that in the first paper [Laffort and Patte, 1976[, the five solute descriptors were obtained by Principal Component Analysis on the data obtained from 25 stationary phases for 75 compounds, thus their numerical values differ from those obtained in the later paper. 

Other five solute descriptors, here called Wilson solute descriptors (Table LI), were proposed by Wilson et al. using ten different HPLC stationary phases, all with acetonitrile 50% as the mobile phase, initially for 67 compounds and then extended to a larger class of compounds [Wilson, Nelson et al., 2002a, 2002b Wilson, Dolan et al., 2002[. 

Weckwerth solute descriptors (Table LI) are five solute parameters based on —> Kovats retention index on seven of GC stationary phases for 53 compounds [Weckwerth, Vitha et al, 2001]. 

Table LI Laffort, Wilson, and Werkwerth solute descriptors.

Lafibrt solute descriptors Wilson solute descriptors Weckwerth solute descriptors... 

Table M7 MI-QSAR general intramolecular solute descriptors (set a).

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