Metabolite patterns in human urine after oral administration of highly purified Δ8-THCV.

INTRODUCTION

The interest in therapeutic applications of tetrahydrocannabivarin (THCV) recently increased. For this reason, we validated an online extraction liquid chromatography- tandem mass spectrometry (LC-MS/MS) method to investigate the formation of urinary metabolites and understand potential cross-reactivity of THCV metabolites in cannabinoid immunoassays.

METHOD: Urine samples were obtained after oral administration of Δ8-THCV to healthy participants. The protocol was approved by the Advarra Institutional Review Board (Pro00059879; approved December 20, 2021) and the trial was registered on clinicaltrials.gov (NCT05210634). Urine samples were collected pre-dose and pooled 0-8 hours post-dose. Urine samples were extracted using a simple one-step protein precipitation procedure and the extracts analyzed using online trapping LC-MS/MS in positive multiple reaction monitoring mode.

RESULTS AND DISCUSSION: All compounds passed validation criteria in urine. In the clinical samples, 11-nor-9-carboxy-Δ8-THCV (Δ8-THCV-COOH) was the main metabolite detected before and after incubation with glucuronidases. Of the urine pooled 0-8 hours post-dose, 70 out of 80 were reported positive by a cannabinoid immunoassay targeting Δ9-THC-COOH, despite being negative for Δ9-THC-COOH and positive mainly for Δ8-THCV-COOH in the LC-MS/MS analysis.

CONCLUSIONS

The major metabolites of Δ8-THCV in urine were Δ8-THCV-COOH, 11-hydroxy-Δ8-THCV and Δ9-THCV-COOH that were extensively glucuronidated and cross-react with immunoassay routinely used for toxicology testing resulting in false positive results for Δ9-THC exposure.