Critical Assessment of pH-Dependent Lipophilicity Profiles of Small Molecules: Which One Should We Use and In Which Cases?

The front cover artwork is provided by CBio Laboratory and Computational Toxicology and Artificial Intelligence Laboratory (LaToxCIA) both at the University of Costa Rica. The image shows the formalisms commonly used to determine the pH-dependent lipophilicity profile of ionizable compounds. Herein, for 4-phenylbutylamine it is accurately predicted when the apparent ion pair partitioning is considered.

Critical Assessment of pH-Dependent Lipophilicity Profiles of Small Molecules: Which One Should We Use and In Which Cases?

Lipophilicity is a physicochemical property with wide relevance in drug design, computational biology, food, environmental and medicinal chemistry. Lipophilicity is commonly expressed as the partition coefficient for neutral molecules, whereas for molecules with ionizable groups, the distribution coefficient (D) at a given pH is used. The logD is usually predicted using a pH correction over the logP using the pK of ionizable molecules, while often ignoring the apparent ion pair partitioning .