ABSTRACT
Lipophilic and hydrophilic regions in the surrounding space of a molecule are revealed thanks to the concept. It is easier to compare different drugs even if they do not have the same framework. If a molecule is considered as the sum of n independent fragments, the logarithmic partition coefficient value can be broken down into a sum of hydrophobic fragmental constants. The spatial conformations of drugs are those obtained either by radiocrystallography determination or by minimization of molecular energy using the molecular mechanism program of CHEMX. If molecules have to show an affinity for the receptor of the platelet-activating factor acether, they must possess at least two areas of different lipophilicity separated by a distance of 6 to 8 Å.
