New extraction method of THC and its metabolites, 11-OH-THC and THC-COOH, in plasma/Nouvelle methode d'extraction du THC et ses metabolites, 11-OH-THC et THC-COOH dans le plasma

In this paper, a liquid/liquid extraction technique on solid support of Delta 9-tetradydrocannabinol (THC), 11-hydroxy- Delta 9-tetradydrocannabinol (11-OH-THC) and 11-nor- Delta 9-tetradydrocannabinol-9-carboxylic acid (THCCOOH) in plasma was developed in order to be assayed by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS). The samples were extracted by liquid/liquid extraction over solid support of an extraction cartridge. The extracts were thereafter dried down and injected into the HPLC-MS/MS system set with a positive electrospray mode using a Waters XTerra MS C18 3.5- mu m 2.1 x 150 mm column. The extraction recovery levels were 66%, 70% and 71% for THC, and 75%, 93% and 101% for 11-OH-THC at concentrations of 2.5, 5 and 10 ng/mL, respectively. They were 86% and 78% for THC-COOH at concentrations of 5 and 10 ng/mL. The novel extraction method for THC, 11-OH-THC and THC-COOH developed in this paper is rapid, sensitive and specific. It may be a valuable tool for predictive toxicology, high-throughput metabolism and pharmacokinetic studies of cannabinoids.