In this study, thermodynamic acidity constants ((s)(s)pK(a)) of atorvastatin, pravastatin, and rosuvastatin using chromatographic data in acetonitrile-water binary mixtures with acetonitrile percentages of 40, 45 and 50% (v/v) were determined with reverse phase liquid chromatographic method (RPLC). pH values were measured in the hydroorganic mixture, which was used as the mobile phase, taking into account the effect of the activity coefficients. The combined effect of the two factors (solvent percentage and (s)(s)pK(a) of the mobile phase) on the chromatographic behavior of these compounds was investigated.;plc values and limiting retention factors of these compounds were calculated chromatographically using equations derived. From these values, the aqueous (w)(w)pK(a) of statins was calculated by different approaches. The chromatographic determination was achieved on a Xterra RP18 (250 mm x 4.6 mm, 5 pm ID.) analytical column. (C) 2015 Elsevier B.V. All rights reserved.