AUTHOR=Bettiol Alessandra , Lombardi Niccolò , Crescioli Giada , Maggini Valentina , Gallo Eugenia , Mugelli Alessandro , Firenzuoli Fabio , Baronti Roberto , Vannacci Alfredo TITLE=Galenic Preparations of Therapeutic Cannabis sativa Differ in Cannabinoids Concentration: A Quantitative Analysis of Variability and Possible Clinical Implications JOURNAL=Frontiers in Pharmacology VOLUME=Volume 9 - 2018 YEAR=2019 URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2018.01543 DOI=10.3389/fphar.2018.01543 ISSN=1663-9812 ABSTRACT=Introduction: Magistral preparations of therapeutic cannabis are extracted from standardized products imported from Holland or from the Florence Military Pharmaceutical Chemical Works, but extraction protocols differ among galenic laboratories. This study assessed the inter-laboratory variability in concentrations of cannabidiol (CBD), cannabinol (CBN), tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA) among different magistral oil preparations. Methods: 219 samples of Bediol, Bedrobinol, Bedrolite or FM-2 70 or 100mg/ml in oil were collected from 3 laboratories. Concentrations of CBD, CBN, THC and THCA were quantified by high-pressure liquid chromatography; inter-laboratories variability was assessed using the Kruskal Wallis test. Results: A significant variability in CBD and THC concentrations was found for Bediol 70mg/ml samples from 2 laboratories (for CBD: median 5.4 (range 4.8 – 6.6) vs 6.1 (4.9 – 7.2) mg/ml, p=0.033; for THC: 3.6 (3.1 – 3.9) vs 4.0 (2.6 – 5.1) mg/ml, p=0.020). As for Bediol 100 mg/ml, a significant variability emerged in THC concentrations among the three considered laboratories (5.7 (-) vs 4.2 (1.5 – 4.8) vs 5.2 (4.2 – 6.9), p=0.030). No significant inter-laboratory variability emerged for Bedrocan and Bedrolite. Concentrations of CBD, CBN and THC were