# Accurate Transferable Model for Water, *n*-Octanol, and *n*-Hexadecane Solvation Free
Energies

dataset

posted on 2002-10-02, 00:00 authored by A. J. Bordner, C. N. Cavasotto, R. A. AbagyanWe present a fast continuum method for the calculation of solvation free energies. It is based on a continuum
electrostatics model with MMFF94 atomic charges combined with a nonelectrostatic term, which is a linear
function of the solvent-accessible surface area. The model's parameters have been optimized using sets of
410, 382, and 2116 molecules for gas−water, gas−hexadecane, and water−octanol transfer, respectively.
These are the largest, most diverse sets of molecules used to date for a similar solvation model. The model's
predictive power was verified by using 90% of the molecule set for training and the remainder as a test set.
The average test set errors differed by only about 1% from the average training set error, thus demonstrating
the transferability of the parameters. The root-mean-square error for gas−water, gas−hexadecane, and water−octanol transfer are 0.53, 0.38, and 0.58 log

*P*units, respectively. Because the solvation calculation takes on average only about 0.34 s per molecule on a 700 MHz Pentium CPU and contains atom types for essentially all drug molecules, it is suitable for real-time calculations of the ADME properties of molecules in virtual ligand screening libraries.