Application of SCAP to drug design. 1. Prediction of octanol-water partition coefficients using solvent-dependent conformational analyses.

The solvent-dependent conformational analysis procedure (SCAP) has been used to predict the octanol-water partition coefficients of 20 different compounds with an average absolute error of 9%. SCAP predicts partition coefficients almost as well as the Hansch procedure using pi constants where the absolute error for the 20 compounds is 5%. In addition to estimating partition coefficients, SCAP allows direct calculation of the corresponding solute-solvent interaction free energies. Moreover, binding free energies, based upon hydrophobic and polar interactions, may also be computed. Such free energies are not calculable using other available methods. SCAP also allows solvation free energies to be compared to, or analyzed with, the various intramolecular free energies of the solute molecule as well as all other associated conformational properties.