Isolation and Characterization of Impurities in Commercially Marketed Δ-THC Products.

Qualitative analysis of several commercial products containing Δ-tetrahydrocannabinol (Δ-THC) as a major component using GC-MS resulted in the identification of several impurities along with Δ-THC. In an attempt to isolate and identify these impurities, a commercial Δ-THC distillate was selected for the isolation work. Eleven impurities were isolated using a variety of chromatographic techniques, and their chemical structures were determined. These include Δ--tetrahydrocannabinol (), Δ--tetrahydrocannabinol (), Δ---tetrahydrocannabinol (), 4,8-epoxy--tetrahydrocannabinol (), 8-hydroxy--tetrahydrocannabinol (), 9β-hydroxyhexahydrocannabinol (), 9α-hydroxyhexa-hydrocannabinol (), -tetrahydrocannabifuran (), cannabicitran (CBT, ), olivetol (), and Δ-THC (). The chemical structures of the purified compounds were determined using several spectroscopic methods, including 1D (H, C, and DEPT-135) and 2D (COSY, HMQC, HMBC, and NOESY) NMR, LC-MS, and GC-MS. Other naturally occurring cannabinoids and impurities were also identified in GC-MS chromatograms but were not isolated. These were cannabidiol (CBD, ), cannabinol (CBN, ), hexahydrocannabinol (HHC, ), and Δ-tetrahydrocannabivarin (Δ-THCV, ). The chemical structure of Δ-THCV (), for which a standard was not available, was confirmed by partial synthesis and NMR analysis. This is the first report for many of the above compounds as well as Δ-THCV as impurities in Δ-THC products.