Synthetic cannabinoids emerged on the designer drug market in recent years due to their ability to produce cannabis-like effects without the risk of detection by traditional drug testing techniques such as immunoassay and gas chromatography-mass spectrometry. As government agencies work to schedule existing synthetic cannabinoids, new, unregulated and structurally diverse compounds continue to be developed and sold. Synthetic cannabinoids undergo extensive metabolic conversion. Consequently, both blood and urine specimens may play an important role in the forensic analysis of synthetic cannabinoids. It has been observed that structurally similar synthetic cannabinoids follow common metabolic pathways, which often produce metabolites with similar metabolic transformations. Presented are two validated quantitative methods for extracting and identifying 15 parent synthetic cannabinoids in blood, 17 synthetic cannabinoid metabolites in urine and the qualitative identification of 2 additional parent compounds. The linear range for most synthetic cannabinoid compounds monitored was 0.1-10 ng/mL with the limit of detection between 0.01 and 0.5 ng/mL. Selectivity, specificity, accuracy, precision, recovery and matrix effect were also examined and determined to be acceptable for each compound. The validated methods were used to analyze a compilation of synthetic cannabinoid investigative cases where both blood and urine specimens were submitted. The study suggests a strong correlation between the metabolites detected in urine and the parent compounds found in blood.

A case is presented of a 19-year-old white male who was found dead in bed by a friend. While no anatomic cause of death was observed at autopsy, toxicological analysis of his blood identified AH-7921, a synthetic opioid. AH-7921 was isolated by liquid-liquid extraction into n-butyl chloride from alkalinized samples. Extracts were analyzed and quantified by gas chromatography mass spectrometry in selected ion monitoring mode. The heart blood had an AH-7921 concentration of 3.9 mg/L and the peripheral blood concentration was 9.1 mg/L. In addition to the blood, all submitted postmortem specimens including urine, liver, kidney, spleen, heart, lung, brain, bile and stomach content were quantified. The following concentrations of AH-7921 were reported: 6.0 mg/L in urine, 26 mg/kg in liver, 7.2 mg/kg in kidney, 8.0 mg/kg in spleen, 5.1 mg/kg in heart, 21 mg/kg in lung, 7.7 mg/kg in brain, 17 mg/L in bile and 120 mg/125 mL in the stomach content. The medical examiner reported that the cause of death was opioid intoxication and the manner of death was accident.

Vitreous humor may serve as a useful alternative specimen for oxycodone analysis in death investigations where blood samples are not available or are of poor quality or limited quantity. The purpose of this study was to investigate the relationship between immunoassay results and gas chromatography-mass spectrometry (GC-MS) quantitation of oxycodone in postmortem vitreous humor and blood. When used with vitreous humor calibrators, the Microgenics DRI Oxycodone (EMIT) Assay was found to be linear from 25 to 500 ng/mL with an limit of detection of 25 ng/mL. Vitreous humor and postmortem blood precipitate immunoassay responses in 57 oxycodone-positive cases were found to be correlated (r(2) = 0.69, p < 0.01). Confirmation and quantitation of oxycodone in vitreous humor by GC-MS was linear from 50 to 1000 ng/mL with a limit of detection of 10 ng/mL and a limit of quantitation of 50 ng/mL. In 30 cases, oxycodone vitreous humor concentrations ranged from less than 50 to 945 ng/mL, and blood concentrations ranged from 103 to 768 ng/mL. The average vitreous humor/blood ratio was 1.16 and ranged from 0.12 to 3.26. Disparities between vitreous fluid and blood oxycodone concentrations were seen in a few cases.

Among the abundance of cannabinoids identified in cannabis, the active parent drug, Δ9-tetrahydrocannabinol (Δ9-THC), and its oxidized metabolite, 11-nor-9-carboxy-Δ9-THC (Δ9-THCCOOH), are attractive analytical targets to detect cannabis use. More recently, confirmation of these analytes may be hindered by a related interfering compound. Forensic toxicology laboratories attribute this phenomenon to an increase in cases containing Δ8-tetrahydrocannabinol (Δ8-THC) and 11-nor-9-carboxy-Δ8-THC (Δ8-THCCOOH). It is technically challenging to chromatographically resolve and accurately quantify Δ8- and Δ9-THC and THCCOOH in toxicology specimens due to their structural resemblance. This study describes a validated method to resolve and quantify active Δ8-THC and Δ9-THC in blood while qualitatively confirming the inactive metabolites Δ8-THCCOOH and Δ9-THCCOOH in blood and urine. Analytes are extracted and concentrated by solid-phase extraction and analyzed by liquid chromatography electrospray ionization tandem mass spectrometry, which is amenable to modern toxicology laboratory routine workflows. This procedure offers a clear solution to untangling mixtures of these isomers, particularly in cases where Δ8-THC and its metabolite are the sole or dominant form.

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