On-Line Solid Phase Extraction High Performance Liquid Chromatography Method Coupled With Tandem Mass Spectrometry for the Therapeutic Monitoring of Cannabidiol and 7-Hydroxy-cannabidiol in Human Serum and Saliva.

Cannabidiol is a novel antiseizure medication approved in Europe and the US for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome and tuberous sclerosis complex. We describe in this article a new and simple liquid chromatography-mass spectrometry method (LC-MS/MS) for the determination of cannabidiol and its active metabolite 7-hydroxy-cannabidiol in microvolumes of serum and saliva (50 μl), to be used as a tool for therapeutic drug monitoring (TDM) and pharmacokinetic studies. After on-line solid phase extraction cannabidiol, 7-hydroxy-cannabidiol and the internal standard cannabidiol- d3 are separated on a monolithic C18 column under gradient conditions. Calibration curves are linear within the validated concentration range (10-1,000 ng/ml for cannabidiol and 5-500 ng/ml for 7-hydroxy-cannabidiol). The method is accurate (intraday and interday accuracy within 94-112% for cannabidiol, 91-109% for 7-hydroxy-cannabidiol), precise (intraday and interday precision <11.6% for cannabidiol and <11.7% for 7- hydroxy-cannabidiol) and sensitive, with a LOQ of 2.5 ng/ml for cannabidiol and 5 ng/ml for 7-hydroxy-cannabidiol. The stability of the analytes was confirmed under different storage conditions. Extraction recoveries were in the range of 81-129% for cannabidiol and 100-113% for 7-hydroxy-cannabidiol. The applicability of the method to TDM was demonstrated by analysis of human serum and saliva samples obtained from patients with epilepsy treated with cannabidiol.
Competing Interests: EP received speaker and/or consultancy fees from Angelini, Arvelle, Biogen, Biopas, Eisai, GW Pharma, Sanofi group of companies, SKL Life Science, Takeda, UCB Pharma, Xenon Pharma, and Zogenix, and royalties from Wiley, Elsevier, and Wolters Kluwers. VDG received speaker and/or consultancy fees from GW Pharma, Neuraxpharm, Dr. Schar, Nutricia. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2022 Franco, Palmisani, Marchiselli, Crema, Fattore, De Giorgis, Varesio, Rota, Dibari and Perucca.)