Determination of ∆-9-Tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-9-carboxy-THC and Cannabidiol in Human Plasma using Gas Chromatography–Tandem Mass Spectrometry

Abstract

Two marijuana compounds of particular medical interest are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). A gas chromatography-tandem mass spectrometry (GC-MS-MS) method was developed to test for CBD, THC, hydroxy-THC (OH-THC) and carboxy-THC (COOH-THC) in human plasma. Calibrators (THC and OH-THC, 0.1 to 100; CBD, 0.25 to 100; COOH-THC, 0.5-500 ng/mL) and controls (0.3, 5 and 80 ng/mL, except COOH-THC at 1.5, 25 and 400 ng/mL) were prepared in blank matrix. Deuterated (d 3 ) internal standards were added to 1-mL samples. Preparation involved acetonitrile precipitation, liquid-liquid extraction (hexane:ethyl acetate, 9:1), and MSTFA derivatization. An Agilent 7890 A GC was interfaced with an Agilent 7000 MS Triple Quadrupole. Selected reaction monitoring was employed. Blood samples were provided from a marijuana smoking study (two participants) and a CBD ingestion study (eight participants). Three analytes with the same transitions (THC, OH-THC and COOH-THC) were chromatographically separated. Matrix selectivity studies showed endogenous chromatographic peak area ratios (PAR) at the analyte retention times were <20% of the analyte limit of quantitation PAR. The intra-assay accuracy ranged from 83.5% to 118% of target and the intra-run imprecision ranged from 2.0% to 19.1%. The inter-assay accuracy ranged from 90.3% to 104% of target and the inter-run imprecision ranged from 6.5% to 12.0%. Stability was established for 25 hours at room temperature, 207 days at −20°C, after three freeze-thaw cycles and for 26 days for rederivatized processed samples. After smoking marijuana predictable concentrations of THC, OH-THC and COOH-THC were seen; low concentrations of CBD were detected at early time points. In moderate users who had not smoked for at least 9 hours before ingesting an 800 mg oral dose of CBD, the method was sensitive enough to follow residual concentrations of THC and OH-THC; sustained COOH-THC concentrations over 50 ng/mL validated its higher analytical range.

Development of a Liquid Chromatography–Tandem Mass Spectrometry Method for the Simultaneous Determination of Four Cannabinoids in Umbilical Cord Tissue

“…The average recoveries observed for THC, THC-COOH, 11-OH-THC and CBN were 74, 82, 58 and 86%, respectively. The presented method was able to achieve higher recoveries (58-86%) compared to the previously published study that reported 34-73% recoveries for cannabinoids in urine (21), while our results were found to be similar to the recoveries for cannabinoids in oral fluid (75.9-86.1%) reported by Huestis et al (22) as well as those in plasma (61.3-91.6%) reported by Andrenyak et al (20). The sample loss during the extraction process typically results from the complexity of specimen extraction procedure, and hydrophobicity of analytes; particularly, hydrophobic analytes tend to adhere to collagen of cord tissue as well as HPLC vials during the sample handling process.…”

“…Validation experiments were carried out as previously described (20). Within-and between-run precision, accuracy, linearity, sensitivity, carryover, analytical recovery, matrix effect, hydrolysis efficiency and on-board stability of extracts were evaluated using drug-free blank umbilical cord spiked with non-deuterated and deuterated standards.…”

Cannabidiol in Pharmacoresistant Epilepsy: Clinical Pharmacokinetic Data From an Expanded Access Program

“…Blood samples were transferred into heparinized tubes and immediately centrifuged at 1,500 × g for 10 min, at 4°C. Plasma was separated and stored at −80°C until analysis, within 6 months from the collection ( Andrenyak et al, 2017 ). Plasma concentrations of CBD were measured by ultra-high-pressure liquid chromatography-mass spectrometry ( Dulaurent et al, 2014 ).…”

The nephrologistʼs guide to cannabis and cannabinoids

“…▪ gas chromatography mass spectrometry (GC-MS) detection of CBD in hair [21,22], oral [23] and plasma [24] samples; ▪ 2-dimensional-GC-MS methods for detection in oral fluid [25], plasma [26] and post mortem blood samples [27].…”