Liquid chromatographic determination of lipophilicity with application to a homologous series of barbiturates.

A graphical method for determining the lipophilicity of the members of a homologous series of barbituric acids, from a consideration of their reverse-phase HPLC retention data, is described. The HPLC parameter used as the index of lipophilicity, RQ, is shown not only to form excellent correlations with the more commonly employed indices of lipophilicity, Rm and log P, but also to have a predictive capability for those log P values that had not previously been determined experimentally.