GB/SA-based continuum solvation model for octanol

A continuum solvation model has been developed for octanol on the basis of the generalized Born/surface area (GB/SA) formalism. This model was parameterized to fit experimental octanol free energies of solvation for a training set of 66 diverse organic solutes. The resulting model is able to reproduce experimental octanol free energies of solution with an unsigned average error of 0.50 kcal/mol when using the recently developed Merck molecular force field (MMFF). Results are poorer when the model is applied to other force fields such as OPLS, where the atomic charges vary significantly from MMFF. The GB/SA octanol model can be used in conjunction with computed or experimental aqueous free energies of solvation to calculate log P-ow directly. The average unsigned error in calculated log P-ow values for the same set of compounds is 0.37.