A thorough investigation on the dependence of octanol/water distribution coeffs. (log D) of basic and amphiprotic β-blocker drugs on pH and pKa values was carried out. An attempt was made to clarify the factors which govern the chromatog. parameters (log k') in reversed-phase HPLC in terms of chem. structure and of distribution coeffs. The correlations between log D and log k' of different compds. show that the bulkiness and the branching of nitrogen substituent are controlling factors in HPLC measurements. Finally, an ion pair chromatog. system is considered for the prediction of octanol/water partition coeffs
