Clocapramine-related fatality. Postmortem drug levels in multiple psychoactive drug poisoning

Forensic toxicokinetics of difenidol hydrochloride in vivo verified by practical lethal cases

A gas chromatography-mass spectrometry (GC-MS) method for the determination of difenidol hydrochloride in biological specimens has been developed. The method exhibited excellent recovery (> 90%) and precision (RSD < 10%), and the LOD was 0.05 μg/mL or μg/g, which met the requirements of bioanalytical method. Through the animal model of the forensic toxicokinetics, the dynamic distribution, postmortem redistribution (PMR) and stability in specimen preservation process of difenidol in animals were studied. The experimental results showed that after intragastric administration, the difenidol's concentrations in the heart-blood and various organs increased over time except stomach, and then decreased gradually after reaching the peaks of concentration. The toxicological kinetics equation and toxicokinetic parameters were established by processing the data of the mean drug concentration of difenidol changing with time. In PMR experiment, the concentrations of difenidol in some organs closer to the gastrointestinal tract (heart-blood, heart, liver, lung, kidney, and spleen) changed significantly at different time points. But the concentration of difenidol in brain tissues which were far away from the gastrointestinal tract and muscles with larger overall mass was relatively stable. PMR of difenidol was therefore confirmed. Thus, the effect of PMR on the concentration of difenidol in the specimens should be considered in cases involving difenidol poisoning or death. Furthermore, the stability of difenidol in heart-blood samples from poisoned rats was investigated at various time points and under different preservation conditions (20 °C, 4 °C, - 20 °C and 20 °C (1% NaF)) for a period of two months. Difenidol was stable and did not decompose in the preserved blood. Therefore, this study provided the experimental basis for the forensic identification of the cases of difenidol hydrochloride poisoning (death). PMR has been verified by practical lethal cases.

An autopsy case of BRONTM overdose with multiple drug ingestion

A man in his forties was found dead in his friend's home, with moderate putrefaction. Quantitative toxicological analysis showed that concentrations of caffeine, chlorpheniramine, dihydrocodeine, and methylephedrine were 183.3 µg/mL, 0.533 µg/mL, 2.469 µg/mL and 8.336 µg/mL, respectively. Ephedrine, amitriptyline, nortriptyline, etizolam, fluvoxamine and 7-aminoflunitrazepam were detected in an aortic blood sample. Caffeine, chlorpheniramine, dihydrocodeine and methylephedrine are the main components of BRON^TM, an over-the-counter antitussive sold in Japan. Those concentrations in blood were within fatal ranges. Caffeine is classified as a methylxanthine and is mainly metabolized by cytochrome P450 (CYP)1A2. Fluvoxamine is a potent CYP1A2 inhibitor. Blood fluvoxamine concentration was within the therapeutic range, but would have increased blood caffeine level by the inhibition of caffeine metabolism. The conclusion was that his death was caused by BRON^TM overdose. Inhibition of caffeine metabolism may increase blood caffeine concentrations. This suggests that more attention should be paid to potential interactions between multiple drugs.

Quantification of clotiazepam in human plasma by gas chromatography–mass spectrometry

An analytical procedure was developed and validated for the quantification of clotiazepam in human plasma. After subjecting plasma samples to solid-phase extraction, the extract was evaporated and the residue re-constituted. An aliquot of the mixture was injected onto a gas chromatography-mass spectrometry system. The detector response was linear for clotiazepam concentrations in the range of 5-200 ng/ml. Intra- and inter-day precision for the assay over the concentration range was below 13.1 and 13.5%, and the accuracy ranged between 99.0-107.9% and 92.4-101.3%, respectively. The drug was found to be stable under various processing conditions used. The method is applicable to human pharmacokinetic studies of clotiazepam.

A fatal forensic intoxication with fenarimol: analysis by HPLC/DAD/MSD

Fenarimol (Rubigan) is a pyrimidine ergosterol biosynthesis inhibitor used as a systemic fungicide. The authors present a fatal fenarimol intoxication case analysed in the Forensic Toxicology Service of the National Institute of Legal Medicine. The results were used to compare two different HPLC techniques, regarding selectivity and sensitivity: an HPLC system with a diode array detector (DAD) and an HPLC system with a DAD and a mass spectrometry detector (MSD) with an electrospray interface. All biological samples were submitted to a solid-phase extraction procedure. The detection and quantification limits of fenarimol, linearity, precision and accuracy were evaluated. The fenarimol concentration levels determined were of 89.0 mg/ml in gastric contents, 1.9 mg/g in liver and 0.4 mg/g in kidney. Blood was not available at autopsy. No published data related to fenarimol self-poisoning were found, so it was not possible to interpret the results obtained by comparison with toxic/lethal levels.