Partial Molar Volumes and Heat Capacities of Some Analogs of Acyclovir

We have investigated acyclovir and eleven of its analogs modified in the base moiety (bicyclic and tricyclic) and ganciclovir, an analog modified in the acyclic chain. Partial molar volumes and heat capacities of aqueous solutions of five of these compounds were determined from acyclovir; density measurements are reported here. The dependence of the partial molar quantities on the number of substituted CH2 groups were determined. For all compounds, the values of Vo2 were evaluated by using a simple scheme of group contributions. The structural parameters of these compounds were determined by the SYBYL (Tripos, USA) package. Molecular volumes, volumes of solvation shell, as well as molecular surface areas and their atomic partition were calculated with the aid of GEPOL Version 12.1. From these data, the relative densities of the solvation shells characterizing the structure of the solvent around the solute molecules were obtained. The polarity, defined as the ratio of the surface of polar groups and atoms exposed to the solvent to the total molecular surface of the molecule studied, was evaluated. Linear dependencies were found between the densities of solvation shells and the polarity which permitted the relative densities of solvation shell is to be found.