Partition coefficient n-octanol/water of propranolol and atenolol at different temperatures: Experimental and theoretical studies

The n-octanol/water partition coefficients of propranolol and atenolol were experimentally determined by ultraviolet (UV) spectroscopy at T = (298.15, 310.15 and 314.15) K. All measurements were made at the maximum wavelength corresponding to maximum absorption. The results showed that the n-octanol/water partition coefficients of propranolol and atenolol increase with the increase of temperature. The experimental data of this work were also used to examine the phase equilibrium correlating capability of some liquid-phase models. The equilibrium experimental data were correlated using the NRTL and UNIQUAC activity coefficient models and the binary interaction parameters were reported. The average root-mea n-square deviations (RMSD) between the experimental and calculated mass fractions of the (n-octanol + propranolol + water) and (n-octanol + atenolol + water) systems were determined. From the partition coefficients obtained, it is concluded that propranolol (log Pow = 3.12 ± 0.14) is more hydrophobic than the atenolol (log Pow = 0.16 ± 0.01) at T = 298.15 K.

► n-Octanol/water partition coefficients of propranolol and atenolol were measured.
► The effect of temperature on the partition coefficient was studied.
► The equilibrium data were correlated using the NRTL and UNIQUAC activity models.
► The binary interaction parameters of the activity models were reported.
► It is concluded that propranolol is more hydrophobic than the atenolol at 298.15 K.