Partial molar volumes and heat capacities of some analogs of acyclovir

We have investigated acyclovir and eleven of its analogs modified in the ba se moiety (bicyclic and tricyclic) and ganciclovir, an analog modified in t he acyclic chain. Partial molar volumes and heat capacities of aqueous solu tions of five of these compounds were determined from acyclovir; density me asurements are reported here. The dependence of the partial molar quantitie s on the number of substituted CH2 groups were determined. For all compound s, the values of V-2(o) were evaluated by using a simple scheme of group co ntributions. The structural parameters of these compounds were determined b y the SYBYL (Tripos, USA) package. Molecular volumes, volumes of solvation shell, as well as molecular surface areas and their atomic partition were c alculated with the aid of GEPOL Version 12.1. From these data, the relative densities of the solvation shells characterizing the structure of the solv ent 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 t he total molecular surface of the molecule studied, was evaluated. Linear d ependencies were found between the densities of solvation shells and the po larity which permitted the relative densities of solvation shell is to be f ound.