Quality control of cannabis inflorescence and oil products: response factors for the cost-efficient determination of ten cannabinoids by HPLC

Progress in the analysis of phytocannabinoids by HPLC and UPLC (or UHPLC) during 2020-2023

INTRODUCTION

Organic molecules that bind to cannabinoid receptors are known as cannabinoids. These molecules possess pharmacological properties similar to those produced by Cannabis sativa L. High-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC, also known as ultra-high-performance liquid chromatography, UHPLC) have become the most widely used analytical tools for detection and quantification of phytocannabinoids in various matrices. HPLC and UPLC (or UHPLC) are usually coupled to an ultraviolet (UV), photodiode array (PDA), or mass spectrometric (MS) detector.

OBJECTIVE

To critically appraise the literature on the application of HPLC and UPLC (or UHPLC) methods for the analysis of phytocannabinoids published from January 2020 to December 2023.

METHODOLOGY

An extensive literature search was conducted using Web of Science, PubMed, and Google Scholar and published materials including relevant books. In various combinations, using cannabinoid in all combinations, cannabis, hemp, hashish, C. sativa, marijuana, analysis, HPLC, UHPLC, UPLC, and quantitative, qualitative, and quality control were used as the keywords for the literature search.

RESULTS

Several HPLC- and UPLC (or UHPLC)-based methods for the analysis of phytocannabinoids were reported. While simple HPLC-UV or HPLC-PDA-based methods were common, the use of HPLC-MS, HPLC-MS/MS, UPLC (or UHPLC)-PDA, UPLC (or UHPLC)-MS, and UPLC (or UHPLC)-MS/MS was also reported. Applications of mathematical and computational models for optimization of protocols were noted. Pre-analyses included various environmentally friendly extraction protocols.

CONCLUSION

During the last 4 years, HPLC and UPLC (or UHPLC) remained the main analytical tools for phytocannabinoid analysis in different matrices.

Extraction solvent selection for Cannabis sativa L. by efficient exploration of cannabinoid selectivity and phytochemical diversity

INTRODUCTION

Cannabis sativa L. is attracting worldwide attention due to various health-promoting effects. Extraction solvent type is critical for the recovery of bioactive compounds from the plant, especially cannabinoids. However, the choice of solvent is varied and not adequately warranted elsewhere, causing confusion in involved fields.

OBJECTIVE

The present work aimed to investigate the effect of extraction solvent on C. sativa (hemp) with regard to cannabinoid recovery and phytochemical profile of the extracts, considering most of the related solvents.

METHODOLOGY

The majority of solvents reported for C. sativa (n = 14) were compared using a representative hemp pool. Quantitative results for major and minor cannabinoids were rapidly and reliably obtained using ultrahigh-performance liquid chromatography coupled with photodiode array detection (UPLC-PDA). In parallel, high-performance thin-layer chromatographic (HPTLC) fingerprinting was employed, involving less toxic mobile phase than in relevant reports. Various derivatisation schemes were applied for more comprehensive comparison of extracts.

RESULTS

Differential selectivity towards cannabinoids was observed among solvents. MeOH was found particularly efficient for most cannabinoids, in addition to solvent systems such as n-Hex/EtOH 70:30 and ACN/EtOH 80:20, while EtOH was generally inferior. For tetrahydrocannabinol (THC)-type compounds, EtOAc and n-Hex/EtOAc 60:40 outperformed n-Hex, despite its use in the official EU method. Solvents that tend to extract more lipids or more polar compounds were revealed based on HPTLC results.

CONCLUSION

Combining the observations from UPLC quantitation and HPTLC fingerprinting, this work allowed comprehensive evaluation of extraction solvents, in view of robust quality assessment and maximised utilisation of C. sativa.

Recent challenges and trends in forensic analysis: Δ9-THC isomers pharmacology, toxicology and analysis

Δ9-tetrahydrocannabinol (Δ9-THC) isomers, especially Δ8-tetrahydrocannabinol (Δ8-THC), are increasing in foods, beverages, and e-cigarettes liquids. A major factor is passage of the Agriculture Improvement Act (AIA) that removed hemp containing less than 0.3 % Δ9-THC from the definition of "marijuana" or cannabis. CBD-rich hemp flooded the market resulting in excess product that could be subjected to CBD cyclization to produce Δ8-THC. This process utilizes strong acid and yields toxic byproducts that frequently are not removed prior to sale and are currently inadequately studied. Pharmacological activity is qualitatively similar for Δ8-THC and Δ9-THC, but most preclinical studies in mice, rats, and monkeys documented greater ∆9-THC potency. Both isomers caused graded dose-response effects on euphoria, blurred vision, mental confusion and lethargy, although Δ8-THC was at least 25 % less potent. The most common analytical methodologies providing baseline resolution of ∆8-THC and ∆9-THC in non-biological matrices are liquid-chromatography coupled to diode-array detection (LC-DAD or LC-PDA), while liquid chromatography coupled to mass spectrometry is preferred for biological matrices. Other available analytical methods are gas-chromatography-mass spectrometry (GC-MS) and quantitative nuclear magnetic resonance (QNMR). Current knowledge on the pharmacology of ∆8-THC and other ∆9-THC isomers are reviewed to raise awareness of the activity of these isomers in cannabis products, as well as analytical methods to discriminate ∆9-THC qualitatively, and quantitatively and ∆8-THC in biological and non-biological matrices.