Consumption and quantitation of Δ9-tetrahydrocannabinol in commercially available hemp seed oil products

There has been a recent and significant increase in the use and availability of hemp seed oil products. These products are being marketed as a healthy source of essential omega fatty acids when taken orally. Although the health aspects of these oils is open to debate, the probability that oils derived from the hemp seed will contain Δ9-tetrahyrdocannabinol (THC) is noteworthy. Recent additions to the literature cite a number of studies illustrating that the ingestion of these products results in urinary level of the THC metabolite, Δ9-tetrahyrdocannabinol carboxylic acid (THCA), well above the administrative cutoff (50 ng/mL) used during random drug screens. Testing performed by our laboratory found that the concentration of THC in hemp oil products has been reduced considerably since the publication of earlier studies. The purpose of this study is to quantitate the THC levels in commercially available hemp oils and to administer those oils tested to THC-free volunteers to determine urine metabolite levels following several 15-g doses. Two extraction protocols were evaluated for removing THC from the oil matrix: a single step liquid-liquid extraction was compared to a two-phase process using both liquid-liquid and solid-phase techniques. Gas chromatography-mass spectrometry was used to determine THC levels in several products: four from Spectrum Essentials® (3 bottled oils and 1-g capsules), two from Health from the Sun® (1-g capsules and bottled oil) oils, and single samples of both Hempstead® and Hempola® hemp oils. These hemp oil products contained THC concentrations of 36.0, 36.4, 117.5, 79.5, 48.6, 45.7, 21.0, and 11.5 mg/g, respectively. The Abbott AxSYM® FPIA and Roche On-Line® KIMS immunoassays were used to screen the urine samples, and GC-MS was used to determine the amount of THC in each oil as well as confirm and quantitate THCA in the urine of study participants immediately before and 6 h after each dose. Peak THCA levels in the participants' urine ranged from 1 to 49 ng/mL. All volunteers were below positive screen and confirmation cutoffs within 48 h after cessation of ingestion.