Absolv

Overview

The Absolv module is a product of cooperation between Pharma Algorithms and Prof. M. H. Abraham. It is used for calculating various solvation-associated properties from Abraham type equations and predicting Abraham solvation parameters necessary for those calculations. These and various other useful features of this module are all wrapped up in a straightforward ADME Suite style interface.

Features

• Calculates the following properties of a solute: A, B, Bo, E, A, L, and V.
• Lists up to 5 most similar structures from the Absolv database along with their experimental values of Abraham parameters and literature references.
• Visualizes the contributions of each atom in the structure to the currently selected Abraham parameter in terms of color intensity of highlighted atoms.
• Absolv Equations panel enables the user to calculate various solvent-solvent or gas-solvent partition coefficients from more than 100 predefined Abraham type equations may be calculated. Alternatively, any custom equations using predicted Abraham solvation parameters of a solute may be entered.
• Provides access to Absolv DB – a fully browsable and searchable database containing experimental data that was used for development of predictive models together with corresponding literature references.
• All predictive algorithms available in the single molecule mode (including a set of solvation parameters and a set of Abraham type equations using these parameters as inputs) are also available in batch mode, enabling automatic calculations for large compounds libraries, processing thousands of molecules per minute without any user intervention.

Module interface

1. Contributions of each atom to the currently selected Abraham parameter are color-mapped onto the structure, with intensity of the color indicating the degree of contribution of each atom or substructure to the selected parameter
2. Calculated Abraham solvation parameters for a solute
3. Up to 5 most similar structures from the training set with experimental values

Technical information

Calculated quantitative parameters

Parameters calculated by Absolv module represent the following properties of a solute:

• H-Bonding acidity - α₂^H (A)
• H-Bonding basicity - β₂^H (B) and β₂^O (Bo)
• Partitioning coefficient between gaseous phase and hexadecane - log L¹⁶ (L)
• Polarity / polarizability - π₂^H (S)
• Excessive molar refraction - R₂ (E)
• McGowan characteristic volume - V_x (V)

Reference database

Absolv\Absolv DB module contains a browsable database of human intestinal absorption & bioavailability. The database consists of 5004 compounds with experimental values of solvation parameters determined by Prof. M. H. Abraham and coworkers. The main literature references where the values comprising the Absolv DB were presented include:

• Abraham, M. H., Grellier, P. L., Prior, D. V., Duce, P. P., Morris, J. J., and Taylor, P. J., J. Chem. Soc. Perkin Trans 2, 1989, 699.
• Abraham, M. H., Grellier, P. L., Prior, D. V., Morris, J. J., and Taylor, P. J., J. Chem. Soc. Perkin Trans 2, 1990, 521.
• Abraham, M. H., Whiting, G. S., Doherty, R. M., and Shuely, W. J., J. Chromatogr., 1991 (587), 213-228.

Absolv DB module provides powerful searching and filtering capabilities, enabling the user to search compounds by name, by structural similarity, as well as limit the output to molecules possessing parameter values in the specified range or described in a particular publication.