The aim of this study was to determine the efficacy of atom-type electrotop
ological state indices for estimation of the octanol-water partition coeffi
cient (log P) values in a set of 345 drug compounds or related complex chem
ical structures. Multilinear regression analysis and artificial neural netw
orks were used to construct models based on molecular weights and atom-type
electrotopological state indices. Both multilinear regression and artifici
al neural networks provide reliable log P estimations. For the same set of
parameters, application of neural networks provided better prediction abili
ty for training and test sets. The present study indicates that atom-type e
lectrotopological state indices offer valuable parameters for fast evaluati
on of octanol-water partition coefficients that can be applied to screen la
rge databases of chemical compounds, such as combinatorial libraries.