[Practical aspects of partition measurements according to GLP rules]

Experimental methods for octanol/water partition coefficient (logP) determination are surveyed. The terminology used in the literature, the lipophilicity/pH profile and the most important factors influencing the logP values have been discussed. Several new, recently developed direct logP determination methods are introduced including their advantages and limits of application. Some aspects of good laboratory practice of the shake-flask method are described and results of a validation study of pH-metric logP determination technique used PCA 101 pKa and logP analyser (Sirius, UK) are also shown. Questions have to be answered in method selection for logP measurement are summarized in flow chart (Fig. 8). The author based on her own experiences in lipophilicity measurements over decades, suggests the shake-flask method and the automated dual-phase potentiometric technique, as approaches fulfilling the GLP rules.