Postmortem changes in tissue concentrations of triazolam and diazepam in rats

Post-mortem Redistribution of Alprazolam in Rats

The post-mortem toxicological findings may be misinterpreted, if the drug undergoes substantial post-mortem redistribution. As alprazolam is one of the most frequently evaluated drug for legal/forensic reasons in drug-related fatalities, we studied possible changes in alprazolam distribution after death in a rat model. Rats were sacrificed 30 minutes after alprazolam administration. Blood and tissue samples from 8 animals per sampling time were collected at 0, 2, 6, and 24 h after death. The experimental samples were assayed for alprazolam using validated UHPLC-PDA method. Median blood alprazolam concentrations increased approximately 2 times compared with ante-mortem levels due to the redistribution during early post-mortem phase and then slowly decreased with a half-life of 60.7 h. The highest alprazolam tissue concentrations were found in fat and liver and the lowest levels were observed in lungs and brain. The median amount of alprazolam deposited in the lungs was relatively stable over the 24-h post-mortem period, while in heart, liver and kidney the deposited proportion of administered dose increased by 43-48% in comparison with ante-mortem values indicating continuous accumulation of alprazolam into these tissues. These results provide evidence needed for the interpretation of toxicological results in alprazolam-related fatalities and demonstrate modest alprazolam post-mortem redistribution.

Microsampling with cotton thread: Storage and ultra-sensitive analysis by thread spray mass Spectrometry

Storage and quantitative analysis of small volumes of biofluids are challenging, especially when low concentrations of analytes are to be detected in the presence of complex matrices. In this study, we describe an integrated thread-based approach for stabilizing small blood volumes in the dry-state at room temperature, while also offering direct analysis capabilities via thread spray mass spectrometry. The analytical merits of this novel microsampling platform was demonstrated via the direct analysis of diazepam and cocaine in dried blood samples stored for 42 days. In-situ in-capillary blood processing from hydrophobic threads enabled limits of detection as low as parts-per-quadrillion to be reached. We validated this ultra-sensitivity by analyzing small tissue-like residues collected after pushing a thread through the sample once. The implications of this sample collection, storage, and analysis platform can be extensive with direct applications in forensics and clinical studies.

A study to model the post-mortem stability of 4-MMC, MDMA and BZP in putrefying remains

There is currently limited data available on the stabilities of the three stimulants 4-methylmethcathinone (4-MMC), 3,4-methylenedioxymethamphetamine (MDMA) and N-benzylpiperazine (BZP) in a putrefying matrix. A Gas Chromatography Mass Spectrometry (GC-MS) method to determine the concentration of the three drugs in putrefying porcine liver over a three month period was developed and validated. Both 4-MMC and BZP were found to be unstable, becoming undetectable and having an average recovery of 52% respectively after one month at ambient room temperature (20°C). MDMA was found to be moderately stable, with an average recovery of 74% after three months at room temperature. This study indicated that the putrefaction process could have a significant impact on concentrations of 4-MMC and BZP in post-mortem cases involving putrefied remains.

A suicide involving intraperitoneal injection of pentobarbital

We present an unusual case of suicide by intraperitoneal injection of pentobarbital, an overdose of zolpidem and the intake of diazepam, ethanol and other psychoactive substances. The autopsy and specimen collection were conducted in a 10 to 18 h postmortem interval. The toxicological analysis revealed a significantly higher pentobarbital concentration in femoral blood compared to cardiac blood (36 vs. 15 mg/L). On the contrary, zolpidem and diazepam concentrations in cardiac blood (2700 and 590 µg/L) were found to be significantly higher than in femoral blood (1500 and 230 µg/L). These findings point to a postmortem redistribution with a distinct gradient from areas of high drug concentrations in the gastrointestinal tract (zolpidem and diazepam) and the injection site (pentobarbital) to peripheral tissue. Ethanol concentration was 0.95 ‰ which amplified the CNS depression. The choice of this unusual suicide method was associated with the deceased's former job as a veterinarian's assistant. In veterinary medicine, the intraperitoneal injection of a lethal dose of pentobarbital is quite commonly performed to euthanise small animals. Intraperitoneal injection is rare as route of administration in humans.