Thermodynamic investigation of the effect of the mutual miscibility of some higher alkanols and water on the partitioning and solubility of some guanine derivatives

Abstract

The values for partition coefficients and solubilities determined in some higher alkanols (heptanol, octanol and nonanol), water and mutually saturated alkanol–water phases for eight antivirus guanine derivatives have been compared and considered in terms of the effect of mutual saturation of the aqueous and alkanol phases on the partitioning and solubility of the corresponding solutes. Using the solubility data, enthalpies of fusion (Δ_fH) and melting temperatures (T_m), determined by differential scanning calorimetry (DSC), the activity coefficients of the solutes in the aqueous and organic phases were calculated. It was shown that the mutual saturation of organic and aqueous phases plays an important role in the partitioning of semipolar substances, such as the guanine derivatives. It was also confirmed that heptanol, octanol and nonanol possess similar properties regarding partitioning and, owing to the hydrophilic character of the guanine derivatives and the different solubilities of water in the alkanols, the values for the partition coefficient between solvent and water decrease in the order from log P_heptanol > log P_octanol > log P_nonanol.