Difference between revisions of "Journal:Quality control of cannabis inflorescence and oil products: Response factors for the cost-efficient determination of ten cannabinoids by HPLC"
Shawndouglas (talk | contribs) (Created stub; saving and adding more.) |
Shawndouglas (talk | contribs) (Saving and adding more.) |
||
| Line 41: | Line 41: | ||
==Introduction== | ==Introduction== | ||
Despite an extensive history of use as a medicinal plant spanning ancient cultures [1–3], [[cannabis]] use is contentious in many jurisdictions, as it has been considered a social drug of abuse since the mid-1930s. [4,5] Over the last two decades, meaningful legal, sociocultural, and economic change has led to the establishment of [[Cannabis (drug)|medicinal cannabis]] research programs in several countries, which have validated the therapeutic use of cannabis for indications, including chronic neuropathic pain, certain intractable epilepsies, the vomiting and spasticity of multiple sclerosis, and chemotherapy-induced nausea. [6] Further to this, the use of medicinal cannabis has expanded into pediatric and vulnerable patient groups [7–9], and regulated markets for recreational use have developed in some jurisdictions. Accordingly, [[quality control]] across the supply chain is increasingly important to ensure that cannabis products are safe and have well-defined chemical and therapeutic profiles. | |||
Critically, the complex relationship between chemical profiles and therapeutic activity requires further exploration. Presently, the activities of the three most abundant neutral cannabinoids—[[tetrahydrocannabinol]] (Δ<sup>9</sup>-THC), [[cannabidiol]] (CBD), and [[cannabigerol]] (CBG)—have been studied closely, exhibiting numerous properties, including analgesic, anticonvulsant, and anti-inflammatory characteristics. [6,10] However, the full potential of medicinal cannabis may not be realized without leveraging the full diversity of [[cannabinoid]]s. Over 140 cannabinoids have been identified, many of which have their own inherent pharmacological properties. [11,12] This includes the acidic cannabinoids, which have significant anticonvulsant activities, contrary to the historical perspective that they were inert precursors which only acquired activity after [[Decarboxylation|decarboxylating]] into the neutral cannabinoids. [13] Furthermore, the complexity of cannabis increases geometrically under the "[[entourage effect]]," which postulates that cannabinoids interact to modulate their therapeutic effects. [14,15] | |||
An experimental basis for the entourage effect is provided by [[wikipedia:Murinae|murine]] studies, which have demonstrated that binary combinations with acidic cannabinoids increase bioavailability, [[potency]], and efficacy of neutral cannabinoids in epilepsy models. [16—18] Even authors exclusively preoccupied with neutral cannabinoids have demonstrated synergistic binary combinations. [19—21] Clinical evidence is also mounting, with a recent meta-analysis on observational studies of epileptic patients concluding that crude [[Cannabis concentrate|cannabis extracts]] yielded a greater reduction in seizure frequency and had fewer side-effects than equivalent doses of purified CBD. [22] However, as most extracts were only characterized to the extent of standardizing the CBD dose, information about other cannabinoids was absent or based on inference. Consequently, the authors’ attribution of the differences between the extracts and purified CBD to the entourage effect was speculative. It was not possible to evaluate if the effects of the other cannabinoids added together, comparable to merely increasing the dose of CBD, or if they magnified the effect to surpass what CBD could achieve alone. Evidently, to progress beyond studies of binary combinations or poorly characterised extracts, routine analyses capable of quantifying panels of cannabinoids could help to better inform the design and interpretation of future studies that investigate the entourage effect. A clinical understanding of this effect might subsequently inform the extent to which cannabinoids are screened during cannabis product quality control. | |||
Several published methods are available for the separation and quantification of cannabinoids, with a variety of limitations which constrain their routine use. For the analysis of neutral cannabinoids, [[gas chromatography]] (GC) is simple, sensitive, and provides acceptable resolution. [23] However, GC is not immediately suitable for acidic cannabinoids, as they are poorly volatilised and rapidly undergo thermal decarboxylation into neutral cannabinoids. [24] Fortunately, this limitation can be surmounted by trimethylsilyl derivatisation of the labile acid group. [24,25] Alternatively, some analysts have adopted [[High-performance liquid chromatography|liquid chromatography]] (LC) for the separation of cannabinoids in medicinal cannabis. Following separation by LC, detection can be achieved by [[mass spectrometry]] (MS) or by [[Photodiode#Photodiode array|photodiode array]] (PDA). The MS detector enables the peak identity confirmation from their fragmentation patterns and relative ratios [26], and it is sufficiently specific to recognize coeluting impurities in complex matrices. [24] However, the required technical expertise, operation, and maintenance costs prohibit the use of MS for the routine analysis of cannabinoids. The [[ultraviolet–visible spectroscopy]] (UV-Vis) PDA detectors are much cheaper, require less operator expertise, and are widely available. Since cannabinoids contain UV [[chromophore]]s [27], they are amenable to PDA detection. Moreover, the UV spectra may assist with compound identity confirmation and the measurement of peak purity, which aids in quantification. | |||
Revision as of 20:21, 12 December 2022
| Full article title | Quality control of cannabis inflorescence and oil products: Response factors for the cost-efficient determination of ten cannabinoids by HPLCn |
|---|---|
| Journal | Talanta Open |
| Author(s) | Hall, Damian R.; Sinclair, Justin S.; Bhuyan, Deep J.; Khoo, Cheang; Li, Chun G.; Sarris, Jerome; Low, Mitchell |
| Author affiliation(s) | NICM Health Research Institute, Wentworth Institute, Florey Institute of Neuroscience and Mental Health |
| Primary contact | Email: Mitchell dot Low at westernsydney dot edu dot au |
| Year published | 2022 |
| Volume and issue | 5 |
| Article # | 100112 |
| DOI | 10.1016/j.talo.2022.100112 |
| ISSN | 2666-8319 |
| Distribution license | Creative Commons Attribution 4.0 International |
| Website | https://www.sciencedirect.com/science/article/pii/S2666831922000315 |
| Download | https://www.sciencedirect.com/science/article/pii/S2666831922000315/pdfft (PDF) |
 |
This article should be considered a work in progress and incomplete. Consider this article incomplete until this notice is removed. |
 |
This article contains rendered mathematical formulae. You may require the TeX All the Things plugin for Chrome or the Native MathML add-on and fonts for Firefox if they don't render properly for you. |
Abstract
The quality control of medicinal cannabis should include quantification of as many cannabinoids as practicable in a routine analytical laboratory, to accurately reflect the quality of the product. However, the cost and availability of some cannabinoid standards is an impediment to their routine use. This work seeks to overcome this obstacle by analyzing samples using relative retention times (RRT) and relative response factors (RRF), relative to cannabidiol (CBD) and cannabidiolic acid (CBDA) reference standards which are readily available. A high-performance liquid chromatography-photodiode array method was developed to quantify 10 cannabinoids—tetrahydrocannabinol (Δ9-THC), delta-8-Tetrahydrocannabinol (Δ8-THC), delta-9-Tetrahydrocannabinolic acid A (THCA-A), cannabinol (CBN), cannabidiol (CBD), cannabidiolic acid (CBDA), cannabichromene (CBC), cannabidivarin (CBDV), cannabigerol (CBG), and cannabigerolic acid (CBGA)—in dried cannabis inflorescence and cannabis oil. This method was validated according to International Conference for Harmonization (ICH) guidelines.
The proposed method has detection limits ranging from 20 to 78 µg/g, which provided sufficient sensitivity for the panel of cannabinoids. Non-cannabinoid surrogate matrices were used for spike recovery studies to determine method accuracy; analyte recoveries for the inflorescence and oil ranged from 90.1 to 109.3% (inflorescence mean, 100.9%; oil mean, 99.6%). The RRT and RRF values, determined independently by three analysts, were comparable, indicating the method is robust. The validity of analysis using RRT and RRF was further confirmed by testing six inflorescence samples, as it was found that concentrations above the order of magnitude of the limit of quantitation (LoQ) agreed satisfactorily (range, 95.0 to 111.9%; mean, 100.0%) with the concentrations obtained through the conventional approach of multipoint calibration using pure standards. The proposed method is therefore suitable for the rapid and simple determination of a panel of 10 cannabinoids without having to repeatedly purchase every expensive pure standard. Accordingly, analysts in the medicinal cannabis field may explore the use of RRF and RRT for their methods and instruments.
Keywords: liquid chromatography, cannabis, cannabinoid, response factor, relative retention time
Graphical abstract: 
Introduction
Despite an extensive history of use as a medicinal plant spanning ancient cultures [1–3], cannabis use is contentious in many jurisdictions, as it has been considered a social drug of abuse since the mid-1930s. [4,5] Over the last two decades, meaningful legal, sociocultural, and economic change has led to the establishment of medicinal cannabis research programs in several countries, which have validated the therapeutic use of cannabis for indications, including chronic neuropathic pain, certain intractable epilepsies, the vomiting and spasticity of multiple sclerosis, and chemotherapy-induced nausea. [6] Further to this, the use of medicinal cannabis has expanded into pediatric and vulnerable patient groups [7–9], and regulated markets for recreational use have developed in some jurisdictions. Accordingly, quality control across the supply chain is increasingly important to ensure that cannabis products are safe and have well-defined chemical and therapeutic profiles.
Critically, the complex relationship between chemical profiles and therapeutic activity requires further exploration. Presently, the activities of the three most abundant neutral cannabinoids—tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabigerol (CBG)—have been studied closely, exhibiting numerous properties, including analgesic, anticonvulsant, and anti-inflammatory characteristics. [6,10] However, the full potential of medicinal cannabis may not be realized without leveraging the full diversity of cannabinoids. Over 140 cannabinoids have been identified, many of which have their own inherent pharmacological properties. [11,12] This includes the acidic cannabinoids, which have significant anticonvulsant activities, contrary to the historical perspective that they were inert precursors which only acquired activity after decarboxylating into the neutral cannabinoids. [13] Furthermore, the complexity of cannabis increases geometrically under the "entourage effect," which postulates that cannabinoids interact to modulate their therapeutic effects. [14,15]
An experimental basis for the entourage effect is provided by murine studies, which have demonstrated that binary combinations with acidic cannabinoids increase bioavailability, potency, and efficacy of neutral cannabinoids in epilepsy models. [16—18] Even authors exclusively preoccupied with neutral cannabinoids have demonstrated synergistic binary combinations. [19—21] Clinical evidence is also mounting, with a recent meta-analysis on observational studies of epileptic patients concluding that crude cannabis extracts yielded a greater reduction in seizure frequency and had fewer side-effects than equivalent doses of purified CBD. [22] However, as most extracts were only characterized to the extent of standardizing the CBD dose, information about other cannabinoids was absent or based on inference. Consequently, the authors’ attribution of the differences between the extracts and purified CBD to the entourage effect was speculative. It was not possible to evaluate if the effects of the other cannabinoids added together, comparable to merely increasing the dose of CBD, or if they magnified the effect to surpass what CBD could achieve alone. Evidently, to progress beyond studies of binary combinations or poorly characterised extracts, routine analyses capable of quantifying panels of cannabinoids could help to better inform the design and interpretation of future studies that investigate the entourage effect. A clinical understanding of this effect might subsequently inform the extent to which cannabinoids are screened during cannabis product quality control.
Several published methods are available for the separation and quantification of cannabinoids, with a variety of limitations which constrain their routine use. For the analysis of neutral cannabinoids, gas chromatography (GC) is simple, sensitive, and provides acceptable resolution. [23] However, GC is not immediately suitable for acidic cannabinoids, as they are poorly volatilised and rapidly undergo thermal decarboxylation into neutral cannabinoids. [24] Fortunately, this limitation can be surmounted by trimethylsilyl derivatisation of the labile acid group. [24,25] Alternatively, some analysts have adopted liquid chromatography (LC) for the separation of cannabinoids in medicinal cannabis. Following separation by LC, detection can be achieved by mass spectrometry (MS) or by photodiode array (PDA). The MS detector enables the peak identity confirmation from their fragmentation patterns and relative ratios [26], and it is sufficiently specific to recognize coeluting impurities in complex matrices. [24] However, the required technical expertise, operation, and maintenance costs prohibit the use of MS for the routine analysis of cannabinoids. The ultraviolet–visible spectroscopy (UV-Vis) PDA detectors are much cheaper, require less operator expertise, and are widely available. Since cannabinoids contain UV chromophores [27], they are amenable to PDA detection. Moreover, the UV spectra may assist with compound identity confirmation and the measurement of peak purity, which aids in quantification.
References
Notes
This presentation is faithful to the original, with only a few minor changes to presentation. Some grammar and punctuation was cleaned up to improve readability. In some cases important information was missing from the references, and that information was added.
