Does the Quantification of Δ9-Tetrahydrocannabinolic Acid A in Serum/Plasma Provide Any Additional Information About Consumption Pattern from Drivers Under the Influence of Cannabis?

Introduction: Δ9-tetrahydrocannabinolic acid A (THCA-A) is one of the main ingredients of cannabis plants and is converted to the psychoactive substance Δ9-tetrahydrocannabinol (THC) by decarboxylation during heating above ∼90°C. During the consumption of cannabis, a varying proportion of THCA-A is absorbed into the body. Therefore, the quantification of THCA-A in serum/plasma might provide additional information on consumption behavior in driving under the influence of cannabis cases. Materials and Methods: In this study, an already established gas-chromatography mass-spectrometry (GC-MS) method for the quantification of THC, 11-OH-THC, and THC-COOH in serum and plasma samples was extended to include THCA-A. This validated method was then applied to 1228 routinely achieved serum/plasma samples from drivers suspected of cannabis consumption in Western Saxony. Two different grouping systems for chronic/occasional consumption, one system for acute/subacute consumption, Huestis formulas, and the cannabis influence factor (CIF) were used for evaluation. Results: Method validation showed appropriate results for forensic toxicological routine analysis. Limit of detection and lower limit of quantification (LLOQ) for THCA-A were 0.3 and 1.0 ng/mL, respectively. Reproducibility was <11% and accuracy ranged between 104% and 107%. THCA-A was stable in native samples at least for 2 weeks at room temperature or 4°C as well as 1 month at -20°C. Freeze-thaw stability for three cycles and processed sample stability over 3 days was proven. A total of 865 cases with a THC concentration above the German analytical cutoff of 1 ng/mL as well as the analytical LLOQs of 0.9 and 2.5 ng/mL for 11-OH-THC and THC-COOH, respectively, were included in further statistical analysis. In 407 (47.1%) of these samples, THCA-A was quantifiable. Different statistical analyses indicated a correlation between THCA-A and THC concentrations in cases of chronic and acute consumption. In addition, an increase of chronic and acute cases with increasing THCA-A concentrations was observed. However, no correlation between THCA-A and CIF was found. Discussion: These data show that THCA-A might be an additional indicative marker to provide information about consumption frequency and acuteness. Additional studies with known consumption frequencies and times are required to verify these findings.

Quantification of (9R)- and (9S)-hexahydrocannabinol (HHC) via GC-MS in serum/plasma samples from drivers suspected of cannabis consumption and immunological detection of HHC and related substances in serum, urine, and saliva.

The semisynthetic cannabinoid hexahydrocannabinol (HHC) is currently getting a lot of media attention because the legal status in many countries is not clearly specified. In this study, a GC-MS method for the quantification of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) was extended to (9R)- and (9S)-HHC. The applicability was proven by serum/plasma samples from drivers suspected of cannabis consumption. Limit of detection (LOD) and lower limit of quantification (LLOQ) were 0.15 and 0.25 ng/mL, respectively. Within-run imprecision was <6.5% and between-run imprecision was <10.0%. Inter-injection stability, processed sample stability (3 days), freeze-thaw stability (three cycles), and storage stability (1 week room temperature; 1 month 4°C, -20°C) could be proven. Both HHC diastereomers could be detected in 17 (5.3%) out of 321 analyzed samples from traffic controls in Western Saxony. The mean ratio between (9R)- and (9S)-HHC was 1.99 (CV = 14.6%). Quantification resulted in concentrations between