Forensic laboratories are challenged with backlogs that produce turnaround times that vary from days to months. Therefore, drug stability is important for interpretation in both antemortem (blood and urine) and postmortem (blood, brain, liver, stomach contents) cases. In this study, 23 benzodiazepines (2-hydroxyethylflurazepam, 7-aminoclonazepam, 7-aminoflunitrazepam, α-hydroxyalprazolam, α-hydroxytriazolam, alprazolam, bromazepam, chlordiazepoxide, clonazepam, demoxepam, desalkylflurazepam, diazepam, estazolam, flunitrazepam, flurazepam, lorazepam, midazolam, nitrazepam, nordiazepam, oxazepam, phenazepam, temazepam and triazolam) and three sedative hypnotics (zaleplon, zopiclone and zolpidem) were spiked into the six matrices at two different concentrations for each drug. The samples were stored in either a refrigerator (4°C) or freezer (-20°C) and analyzed in triplicate at various time intervals over an 8-month period using an SWGTOX validated method. The concentrations decreased over time regardless of the initial spiked concentration, and the storage conditions had little effect on the decrease of most drugs. Conversion from drug to metabolite was difficult to determine since all 26 drugs were present in each sample. Zopiclone and phenazepam were the least stable drugs; zopiclone was the only drug that completely disappeared in any matrix (both antemortem and postmortem blood). Urine was the most stable matrix with only phenazepam, 7-aminoclonazepam, 7-aminoflunitrazepam, 2-hydroxyethylflurazepam, and zopiclone decreasing >20% over the 8 months in either storage condition. Postmortem blood, the least stable matrix, had only two drugs, zolpidem and bromazepam, decreasing <20% in the 8-month time period. Further experiments on stability of these drugs should be undertaken to remove the freeze-thaw cycle effect and more thoroughly examining drug-metabolite conversion.

No abstract

In recent years, fentanyl is increasingly detected in overdose cases as well as human performance cases due to the current opioid epidemic. The comparison of fentanyl concentrations in deaths to recreational fentanyl use found in driving under the influence of drugs (DUID) cases is important to show how increased availability effects the historical knowledge of fentanyl. A two-year review of fentanyl cases from Orange County, CA, USA is presented to highlight fentanyl concentrations in these two case types. Any non-urine sample with fentanyl detected above the limit of detection of 0.5 ng/mL was reviewed in DUID and postmortem cases. The mean and median fentanyl concentrations in 199 antemortem blood samples from DUID cases were 14.2 ng/mL and 5.3 ng/mL, respectively, with a range of 0.5–303 ng/mL. In 285 central blood samples from postmortem cases the mean was 29.1 ng/mL, the median was 16.9 ng/mL and the range was 0.6–636 ng/mL. In a total of 58 postmortem peripheral blood samples, the mean, median and range were 14.0 ng/mL, 10.0 ng/mL and 0.9–78.0 ng/mL, respectively. Of the 55 brain samples analyzed, the fentanyl mean, median and range of fentanyl concentrations were 50.0 ng/g, 31.4 ng/g and 1.9–441 ng/g, respectively. Fentanyl concentrations in 16 liver samples had a mean of 82.0 ng/g, a median of 69.4 ng/g and a range of 11.6–226 ng/g. The overlap of fentanyl concentrations from the antemortem and postmortem samples highlights the importance of evaluating case circumstances when providing an interpretation in postmortem cases. Additional information such as age, gender, polydrug use, and postmortem redistribution is presented for the cases included in the study.

No abstract

In toxicological testing, drug stability is important when providing quantitative results and interpretation of findings, as well as when collecting correlation data. The goal of this study was to expand on previous stability studies and to evaluate other cannabinoids encountered in forensic toxicology. In this 6-month study, the stability of Δ-9-tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-9-carboxy-THC, Cannabinol and Cannabidiol in antemortem and postmortem blood was evaluated in refrigerated (4°C) and frozen (−4°C) storage conditions. Pooled antemortem and postmortem bloods were fortified at low and high concentrations and stored in untreated glassware. Over 6 months, samples were analyzed by automated extraction and liquid chromatography-mass spectrometry/mass spectrometry to evaluate the change in concentration over time. Samples in each storage condition were analyzed in triplicate 12 times over the 6-month period. Cannabinoids in antemortem blood were more stable in the refrigerated condition than in the frozen condition, with 11-hydroxy-THC, 11-nor-9-carboxy-THC and Cannabinol having more than 80% of the original concentration remaining at the end of the study. Cannabinoids in postmortem blood had improved stability in the frozen storage condition with THC, 11-hydroxy-THC, 11-nor-9-carboxy-THC and Cannabinol in the low concentration pool with more than 80% of the original concentration remaining. These data demonstrated that cannabinoids may decrease in concentration over time when stored in untreated glass vials. To ensure the most accurate determination of drug concentration, samples containing cannabinoids should be analyzed as soon as possible.