One hundred fifteen Americans die every day from opioid overdose. These overdose fatalities have been augmented by the increased availability of potent synthetic opioids, such as fentanyl and its derivatives. The death rate of synthetic opioids, other than methadone, increased by 72.2% from 2014 to 2015, and doubled from 2015 to 2016, situating the USA in the midst of an opioid overdose epidemic. The analytical identification of these opioids in postmortem samples and the correct toxicological data interpretation is critical to identify and implement preventive strategies. This article reviews the current knowledge of postmortem toxicology of synthetic opioids and the chemical and pharmacological factors that may affect drug concentrations in the different postmortem matrices and therefore, their interpretation. These factors include key chemical properties, essential pharmacokinetics parameters (metabolism), postmortem redistribution and stability data in postmortem samples. Range and ratios of concentrations reported in traditional and non-traditional postmortem specimens, blood, urine, vitreous humor, liver and brain, are summarized in tables. The review is focused on fentanyl and derivatives (e.g., acetyl fentanyl, butyryl fentanyl, carfentanil, furanyl fentanyl, 4-methoxybutyrylfentanyl, 4-fluorobutyrylfentanyl, ocfentanil) and non-traditional opioid agonists (e.g., AH-7921, MT-45, U-47700). All of these data are critically compared to postmortem data, and chemical and pharmacological properties of natural opioids (morphine), semi-synthetic (oxycodone, hydrocodone, hydromorphone, and oxymorphone), and synthetic opioids (methadone and buprenorphine). The interpretation of drug intoxication in death investigation is based on the available published literature. This review serves to facilitate the evaluation of cases where synthetic opioids may be implicated in a fatality through the critical review of peer reviewed published case reports and research articles.
The misuse of designer benzodiazepines, as an alternative to prescription benzodiazepines and for drug-facilitated sexual assaults, has emerged as a growing threat, due in part to the ease of purchasing these drugs on the internet at low prices. Causing concern for safety is the lack of dosage information resulting in users self-medicating, often leading to unintended overdoses, coma or death at higher doses. With limited published data regarding the quantification of designer benzodiazepines in forensic cases, a method was validated for the determination of 13 designer benzodiazepines in postmortem blood, to add to the in-house method that already included a limited number of common designer benzodiazepines. The developed method included 3-hydroxyphenazepam, clobazam, clonazolam, delorazepam, deschloroetizolam, diclazepam, flualprazolam, flubromazepam, flubromazolam, flunitrazolam, meclonazepam, nifoxipam and pyrazolam in 0.5 mL postmortem blood using liquid chromatography-tandem mass spectrometry. The analytes were treated with solid phase extraction before undergoing separation on a C18 column and analyzed on the mass spectrometer in electrospray positive mode using multiple reaction monitoring. The linear range of the calibration curve was 1–200 ng/mL and up to 500 ng/mL for 3-hydroxyphenazepam, clobazam, flubromazepam and pyrazolam. The limits of detection and quantitation were 0.5 ng/mL (signal-to-noise ratio >3) and 1 ng/mL, respectively. The calculated bias, intra-day imprecision, relative standard deviation (RSD) and inter-day imprecision RSD were ±12%, 3–20% and 4–21%. Matrix effects ranged from −52% to 33% with RSD values ranging from 3–20%, indicating consistent effects throughout multiple sources. Recovery ranged from 35 to 90%, where only two compounds were <50%. Other parameters tested included carryover, stability, interference and dilution integrity, which all yielded acceptable results. With the application of this method to blood specimens from the New York City Office of Chief Medical Examiner, this validated method proved to be simple, reproducible, sensitive and robust.
The detection of novel fentanyl analogs in both seized drugs and toxicological specimens has presented a significant challenge to laboratories with respect to identification, sourcing reference drug standards, time required for method development and ensuring sufficient method sensitivity. The New York City Office of Chief Medical Examiner (NYC OCME) has included testing for valerylfentanyl as part of a panel of synthetic opioids since May 2017 but did not identify the first valerylfentanyl positive case until July 2018. Unlike many other illicit fentanyl analogs that were briefly identified before being replaced with a new analog, valerylfentanyl has persisted over time and continues to be identified in New York City acute polydrug intoxications. Since July 2018, a total of 69 cases were identified with valerylfentanyl present, but there were no cases where it was the sole intoxicant. 84% of decedents were male, with the majority between the ages of 50 and 59 years (39%) and were predominantly Hispanic (49%). The cause of death in all 69 cases involved acute polydrug intoxication, while the manner of death was deemed an accident in 68 cases and undetermined in one case. Concentrations of valerylfentanyl in postmortem blood ranged from < 0.10 to 21 ng/mL with 44.9% (N = 31) of the concentrations at or below the lower limit of quantification (0.10 ng/mL) but above the limit of detection (0.05 ng/mL). Fentanyl was present in 100% of the cases and in higher concentrations (1.6–116 ng/mL). The most common drug classes detected with valerylfentanyl were other opiates (76.8%), cocaine/metabolites (50.7%), benzodiazepines (29%), and ethanol (21.7%). Valerylfentanyl is a relatively unknown fentanyl analog with limited information in the scientific literature. This study presents the first publication detailing a series of postmortem cases involving valerylfentanyl in acute intoxications and includes key demographic information and femoral blood concentrations for improved interpretation and analysis.
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