The partition coefficients, log P-app(RPLC), for a series of propranolol analogues have been determined by reversed phase high performance liquid chromatography. The hydrochloride salts and free base log P-app(RPLC) show that charged and uncharged species can partition into the reversed phase. An extrathermodynamic relationship was found for log P-app(RPLC) measured in two different column stationary phases, C8 and PMOS, suggesting that the same sei of compounds experience a similar trend in these elution systems. The importance of using phosphate and/or MOPS buffer is due to the fact that the latter can avoid ion-pairing partitioning, but the former does play the same role for PMOS column when the free base is considered.53416711116