Evaluation of Postmortem Drug Concentrations in Bile Compared with Blood and Urine in Forensic Autopsy Cases

For drug screening and pharmaco-/toxicokinetic analysis, bile as a major drug excretion route in addition to urine may be used in forensic autopsy cases; however, there are limited published data on correlations between bile and blood or urine drug concentrations. The present study retrospectively investigated drug concentrations in bile, compared with blood and urine concentrations, reviewing forensic autopsy cases during 6 years (January 2009-December 2014). Drugs were analyzed using automated gas chromatography-mass spectrometry following solid-liquid phase extraction. Compared with peripheral blood concentrations, bile concentrations were higher for most drugs; however, caffeine concentrations were similar. Bile concentrations were mostly lower than urine concentrations for amphetamines, caffeine and methylephedrine, but were usually similar to or higher for other drugs. Significant correlations were detected between bile and peripheral blood concentrations for amphetamines, several cold remedies, phenobarbital, phenothiazine derivatives and diazepam, as well as between bile and urine concentrations for amphetamines, caffeine, diphenhydramine, phenobarbital and promethazine derivatives. These findings suggest that bile can provide supplemental data useful in routine forensic toxicology, for the spectrum of drugs mentioned above, as well as for investigating pharmaco-/toxicokinetics and postmortem redistribution when analyzed in combination with drug concentrations at other sites.