Stability of cannabidiol (CBD) in solvents and formulations: A GC–MS approach

The stability of cannabidiol (CBD) under thermal (heating, microwave irradiation, presence of Bronsted and Lewis acids) and photochemical conditions has been tested in organic solvents, including glycerol and propylene glycol that are traditionally employed in the preparation of CBD-containing formulation (e-liquid) for e-cigarettes. The results obtained in the present investigation point out the instability of CBD in the realistic scenario of pharmaceutical preparations and commercial products (e.g., e-liquids). In simulated e-liquid, among the by-products, the psychotropic THCs were found in negligible amounts (<5% added CBD) unless acidic catalysts are used (i.e., 40 mg/L strong acid). Cannabielsoin, Δ8-iso-THC and Δ8-THC were commonly found both as photochemical and thermal degradation products in methanol, acetonitrile and n-hexane. In the experiments performed in methanol, differently from acetonitrile and n-hexane, the solvent tends to be incorporated in the cannabinoids obtained as final products.