Partial molar volumes of some drug and pro-drug substances in 1-octanol at T = 298.15 K

The article deals with measuring the densities of phenol, acetanilide, benzamide, benzoic acid, phenacetin, i-(acetylamino)-benzoic acid, i-hydroxy-benzamide, and i-acetaminophen (where i = 1, 2, 3) in 1-octanol in the wide concentration interval at T = 298.15 K. It also concerns the evaluation of apparent molar volumes and partial molar volumes at infinite dilution, V20¯ as well as comparative analysis of the free volumes per molecule in the octanolic solutions, V2free, and in the crystal lattices, V2free (cr), from the nature and position of the substitutes. Also described is the evaluation of the increments of V20¯andV2free for the unsubstituted molecules and isomers and the methods to obtain partial molar volumes for various functional groups at infinite dilution in 1-octanol at T = 298.15 K. Also considered is the limiting partial molar volume of the solutes in terms of the scaled particle theory.