HYDROGEN-BONDING .30. SOLUBILITY OF GASES AND VAPORS IN BIOLOGICAL LIQUIDS AND TISSUES

The general solvation equation log L = c + rR(2) + s pi(2)(H) + a alpha(2)(H) + b beta(2)(H) + I logL(16) has been used to analyze the solubility of solute gases and vapors, as log L values, in water, blood, and a variety of other biological fluids and tissues. The explanatory variables are R(2), the solute excess molar refraction; pi(2)(H), the solute dipolarity/polarizability; alpha(2)(H) and beta(2)(H), the solute hydrogen-bond acidity and basicity; and log L(16), where L(16) is the solute Ostwald solubility coefficient of hexadecane. The obtained coefficients then serve to characterize the biological phase as follows: r + s is the phase dipolarity/polarizability, a is the phase hydrogen-bond basicity, b is the phase hydrogen-bond acidity, and I is the phase lipophilicity. In addition to characterization of phases, the equation can be used to determine quantitatively solute/phase interactions and predict further log L values. A similar equation in which McGowan's characteristic volume, V-X, replaces the log L(16) descriptor can be used to analyze partitions between phases. For example, water/phase and blood/phase partition coefficients are analyzed, and the analysis leads again to coefficients that characterize phases and to the prediction of partition coefficients.