LAUSR

&NA; In the present study three different procedures have been compared for the determination of the lipophilicity of the unionized species (log Po/w) of neutral, acidic, basic, amphoteric, and zwitterionic drugs. Shake‐flask, potentiometric and chromatographic approaches have been assayed in a set of 66 representative compounds in different phases of advanced development. An excellent equivalence has been found between log Po/w values obtained by shake‐flask and potentiometry, while the chromatographic approach is less accurate but very convenient for screening purposes when a high‐throughput is required. In the case of zwitterionic and amphoteric compounds, either for shake‐flask and chromatographic methods, the pH has to be accurately selected in order to ensure the compound to be in its neutral form. Graphical abstract Figure. No caption available.