European Journal of Medicinal Chemistry 2008-03-01

Air to lung partition coefficients for volatile organic compounds and blood to lung partition coefficients for volatile organic compounds and drugs.

Michael H Abraham, Adam Ibrahim, William E Acree

Index: Eur. J. Med. Chem. 43 , 478-85, (2008)

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Abstract

Values of in vitro gas to lung partition coefficients, K(lung), of VOCs have been collected from the literature. For 44 VOCs, application of the Abraham solvation equation to log K(lung) yielded a correlation with R(2)=0.968 and S.D.=0.25 log units. Combination of the log K(lung) values with log K(blood) values leads to in vitro blood to lung partition coefficients, log P(lung) for 43 VOCs; an Abraham solvation equation correlated these values with a very poor R(2)=0.262 but with a very good S.D.=0.190 log units. Values of in vivo log P(lung) for 80 drugs were collected, and were correlated with R(2)=0.647 and S.D.=0.51 log units. When the log P(lung) values for VOCs and drugs were combined, an Abraham solvation equation could correlate the 123 compounds with R(2)=0.676 and S.D.=0.43 log units. Division of the 123 compounds into a training set and a test set, showed that the training equation could predict log P(lung) values with an average error of 0.001 and a standard deviation of 0.44 log units; for drugs in the combined test set the average error was 0.02 and the standard deviation 0.43 log units.