An extended version of a novel method for the estimation of partition coefficients

Using the semi-empirical AM1 method, 302 compounds have been studied and equilibrium properties calculated. Functions based on linear combinations of subsets of calculated properties have been fit to the 1-octanol-water partition coefficients. The best such semi-empirical approach function has 18 parameters, has a standard deviation of 0.306, and seems to describe the partition coefficients of the 302 compounds. The predictive power of the function was tested and found to be good. Since this new version is based on a much larger number of, and structurally more varied, compounds and uses an improved, new function, we expect it to be a very useful method to predict partition properties of a wide variety of compounds.