Isolation and Characterization of Impurities in Commercially Marketed Δ 8 -THC Products.

Qualitative analysis of several commercial products containing Δ 8 -tetrahydrocannabinol (Δ 8 -THC) as a major component using GC-MS resulted in the identification of several impurities along with Δ 8 -THC. In an attempt to isolate and identify these impurities, a commercial Δ 8 -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 4,8 - iso -tetrahydrocannabinol ( 1 ), Δ 4 - iso -tetrahydrocannabinol ( 2 ), Δ 8 - cis - iso -tetrahydrocannabinol ( 3 ), 4,8-epoxy- iso -tetrahydrocannabinol ( 4 ), 8-hydroxy- iso -tetrahydrocannabinol ( 5 ), 9β-hydroxyhexahydrocannabinol ( 6 ), 9α-hydroxyhexa-hydrocannabinol ( 7 ), iso -tetrahydrocannabifuran ( 8 ), cannabicitran (CBT, 9 ), olivetol ( 10 ), and Δ 9 -THC ( 11 ). The chemical structures of the purified compounds were determined using several spectroscopic methods, including 1D ( 1 H, 13 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, 12 ), cannabinol (CBN, 13 ), hexahydrocannabinol (HHC, 14 ), and Δ 8 -tetrahydrocannabivarin (Δ 8 -THCV, 15 ). The chemical structure of Δ 8 -THCV ( 15 ), 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 8 -THCV as impurities in Δ 8 -THC products.