Analysis of Algorithms Predicting Blood:Air and Tissue:Blood Partition Coefficients from Solvent Partition Coefficients for Prevalent Components of JP-8 Jet Fuel

Abstract

Algorithms predicting tissue and blood partition coefficients (PCs) from solvent properties were compared to assess their usefulness in a petroleum mixture physiologically based pharmacokinetic/pharmacodynamic model. Measured blood:air and tissue:blood PCs for rat and human tissues were sought from literature resources for 14 prevalent jet fuel (JP-8) components. Average experimental PCs were compared with predicted PCs calculated using algorithms from 9 published sources. Algorithms chosen used solvent PCs (octanol:water, saline or water:air, oil:air coefficients) due to the relative accessibility of these parameters. Tissue:blood PCs were calculated from ratios of predicted tissue:air and experimental blood:air values (PC_EB). Of the 231 calculated values, 27% performed within ± 20% of the experimental PC values. Physiologically based equations (based on water and lipid components of a tissue type) did not perform as well as empirical equations (derived from linear regression of experimental PC data) and hybrid equations (physiological parameters and empirical factors combined) for the jet fuel components. The major limitation encountered in this analysis was the lack of experimental data for the selected JP-8 constituents. PC_EB values were compared with tissue:blood PCs calculated from ratios of predicted tissue:air and predicted blood:air values (PC_PB). Overall, 68% of PC_EB values had smaller absolute % errors than PC_PB values. If calculated PC values must be used in models, a comparison of experimental and predicted PCs for chemically similar compounds would estimate the expected error level in calculated values.

Notes

Fisher, J.W. 2005 Environmental Health Science Department Head, The University of Georgia, Athens, GA. Personal communication.