A measure of the preference of a compound to dissolve in either water or an organic solvent (such as octanol) when uncharged.

More technically, it is the logarithm of the partition coefficient (P) of a molecule between an aqueous and lipophilic phase.

LogP therefore provides a measure of the lipophilicity of a molecule. Lipophilicity is a key characteristic of drug molecules, affecting their absorption, distribution, metabolism and excretion (ADME).

High lipophilicity is often preferred in drug development, particularly for intracellular targets. However, the most desirable properties for an antibiotic will depend on multiple factors, including the site of infection and location of the drug’s molecular target.

If a compound can be ionized, its logP value will vary with pH. For ionizable compounds, the related measure logD is used to characterize lipophilicity.