A reversed-phase thin-layer chromotographic method for the determination of relative partition coefficients of very lipophilic compounds.

A reversed-phase thin-layer chromatographic method has been developed for the determination of partition coefficients. A support phase has been chosen, following investigation of the lack of adsorptive properties, which has a minimal effect on the pH of the buffer system. A stationary phase has been chosen to give deltaRm values of the same magnitude as Hansch pi values for a series of phenothiazines. The method can be applied to molecules of a wide range of lipophilicity following preliminary investigations of suitable phase-volume ratios and of the pH and composition of the binary mobile phase, providing adsorption on the support phase is excluded.