The distribution of compounds between blood or the gas phase and various biological tissues
Distribution coefficients, Kbi00d and KtiSSues (or biophase), from the gas phase to blood and gas phase to tissues (plasma, brain, fat, heart, liver, lung, kidney, muscle, urine, saline and olive oil) have been collected for large number of volatile organic compounds (VOCs). For these datasets of VOCs, linear free energy relationships (LFERs) have been established and Abraham equations have successfully been constructed to predict these distributions. It has also been shown that human and rat data for the air to blood and air to tissue distribution of VOCs can be combined. The differences in the two data sets, for the common compounds are smaller than the estimated inter-laboratory experimental error. The combination of the log KtiSSue values with values for air to blood yields distribution coefficients from blood to tissue, as log PtiSSue-Equations have successfully been constructed to predict these distributions. From a large amount of collected data on the distribution of drugs from blood, plasma or serum to tissue (brain, fat, heart, kidney, lung, liver, muscle and skin) at steady-state concentration in rats, it is shown that the three datasets of data can be combined. Predictive LFER equations for blood/plasma/serum to tissue for a large number of drugs, has been achieved and their predictive capability has been assessed. Finally, it has been shown that the in vitro data on VOCs and the in vivo data on drugs can be combined LFERs on the total data yield correlative and predictive Abraham equations. Because the descriptors used in the LFERs can be calculated from structure, distribution coefficients for air to blood or tissue for VOCs and for blood/plasma/serum to tissue for VOCs and drugs can be predicted directly from the molecular structures of the VOCs and drugs.