A cannabinoid refers to any natural or synthetic compound that interacts with the CB1 and CB2 receptors. There are currently three different groups of cannabinoids: endogenous cannabinoids, phytocannabinoids and synthetic cannabinoids. The most common phytocannabinoid is delta-9-tetrahydrocannabinol (THC), which is the active component in the Cannabis sativa or marihuana plant1–3. Two examples of synthetic cannabinoids that are present in case reports from 2012 to 2018 are AB-FUBINACA and AB-PINACA4–7.
THC and synthetic cannabinoids are commonly encountered drugs in forensic toxicology cases, therefore, being able to extract these compounds and their metabolites is imperative for toxicological interpretation. There are a variety of commercially available sample preparation techniques for these analytes. Companies such as UCT, Biotage, Millipore-Sigma, Tecan, and Thermo Fisher Scientific manufacture these products. The focus of this research was to evaluate these techniques for their cleanliness, efficiency and cost effectiveness. Sample preparation techniques are designed to remove the different components of the matrix and other prescription or illicit substances present in the sample that could interfere with the assay, increase the analyte recovery, extraction efficiency, decrease variability, and clean-up the sample to allow for less instrument downtime and longer column life8. This study focused on comparing a liquid-liquid extraction (LLE), solid phase extraction (SPE), and supported liquid extraction (SLE).
The primary purpose of this study was to develop and validate the three above mentioned sample preparation techniques for the analysis of THC, 11-hydroxy-THC, 11-nor-9-carboxy-THC (THCCOOH), AB-FUBINACA, AB-FUBINACA metabolite 3, and AB-PINACA in blood and urine.
Parameters assessed followed Academy Standards Board (ASB) Standard 036, Standard Practices for Method Validation in Forensic Toxicology, including recovery, suppression, and matrix effects.
For urine and blood analysis, the calibration range was determined to be 1 ng/mL to 50 ng/mL for all three techniques. Urine recovery was highest for the LLE method, with all compounds having a recovery greater than 50%. The SLE method had the lowest LOQ results for urine, with 0.5 ng/mL for 11-hydroxy-THC and THCCOOH, 0.75 ng/mL for THC, AB-FUBINCA and AB-FUBINACA metabolite 3, and 1 ng/mL for AB-PINACA. Ion suppression was reduced using the SLE method for urine along with having the shortest sample preparation time of 1 hr for up to 48 samples.
For blood analysis, the LLE method had the greatest recovery of all analytes. The LLE method also had reduced suppression and matrix effects compared to the SPE method. Sample preparation was shorter for the SPE method, consuming 2 hrs for an average sample batch, compared to 4 hrs for the LLE method, which included a 2 hr freezing step.
In conclusion, for urine analysis, all three sample preparation techniques were acceptable for the analysis of THC, synthetic cannabinoids, and their metabolites, with the SLE method being the preferred method. For blood analysis a LLE and SPE method were developed and are adequate for the analysis of THC, synthetic cannabinoids, and their metabolites, with the LLE method being the preferred method.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/38625 |
| Date | 09 October 2019 |
| Creators | Boyle, Sarah |
| Contributors | Botch-Jones, Sabra |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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