Decarboxylation Study of Acidic Cannabinoids: A Novel Approach Using Ultra-High-Performance Supercritical Fluid Chromatography/Photodiode Array-Mass Spectrometry

Summary & key facts

Researchers heated cannabis extracts at several temperatures and used a sensitive lab method to track how the main acidic cannabinoids turned into their active forms. They found that the acids broke down in a predictable, exponential way over time, and that the acid that turns into THC changed about twice as fast as the acids that become CBD and CBG. The study gives useful numbers and a reliable measurement method that can help people who make cannabis extracts or medical products understand how heating changes the amounts of active compounds, while also showing that some acids do not convert as cleanly as others.

Key facts:

• The team heated Cannabis sativa extracts at 80, 95, 110, 130, and 145 degrees Celsius for up to 60 minutes in a vacuum oven to study how acidic cannabinoids convert when heated.
• They used an advanced chromatography and mass-detection method called UHPSFC/PDA-MS, which separates and measures many acidic and neutral cannabinoids at once, and found the method gave consistent and sensitive results.
• Across temperatures, the loss of acidic cannabinoids followed an exponential pattern over time, which means the reaction behaved like a first-order process where the rate depends on how much of the acid is left.
• The acid that becomes THC (called THCA-A) converted about twice as fast as the acids that become CBD (CBDA) and CBG (CBGA).
• Decarboxylation of THCA-A was clean, with no detected side reactions or extra by-products in these tests.
• Decarboxylation of CBDA and CBGA was less straightforward: the researchers saw unexplained losses of reactants or products, which means those conversions may involve other changes or degradations.
• By measuring how the rate constants changed with temperature, the researchers calculated values related to the reaction energy, which helps predict how fast conversion happens at different temperatures.

Abstract

Introduction: Decarboxylation is an important step for efficient production of the major active components in cannabis, for example, Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabigerol (CBG). These cannabinoids do not occur in significant concentrations in cannabis but can be formed by decarboxylation of their corresponding acids, the predominant cannabinoids in the plant. Study of the kinetics of decarboxylation is of importance for phytocannabinoid isolation and dosage formulation for medical use. Efficient analytical methods are essential for simultaneous detection of both neutral and acidic cannabinoids. Methods:C. sativa extracts were used for the studies. Decarboxylation conditions were examined at 80°C, 95°C, 110°C, 130°C, and 145°C for different times up to 60 min in a vacuum oven. An ultra-high performance supercritical fluid chromatography/photodiode array-mass spectrometry (UHPSFC/PDA-MS) method was used for the analysis of acidic and neutral cannabinoids before and after decarboxylation. Results: Decarboxylation at different temperatures displayed an exponential relationship between concentration and time indicating a first-order or pseudo-first-order reaction. The rate constants for Δ9-tetrahydrocannabinolic acid-A (THCA-A) were twice those of the cannabidiolic acid (CBDA) and cannabigerolic acid (CBGA). Decarboxylation of THCA-A was forthright with no side reactions or by-products. Decarboxylation of CBDA and CBGA was not as straightforward due to the unexplained loss of reactants or products. Conclusion: The reported UHPSFC/PDA-MS method provided consistent and sensitive analysis of phytocannabinoids and their decarboxylation products and degradants. The rate of change of acidic cannabinoid concentrations over time allowed for determination of rate constants. Variations of rate constants with temperature yielded values for reaction energy.

Topics

Cannabis and Cannabinoid Research Forensic Toxicology and Drug Analysis Psychedelics and Drug Studies

Categories

Health Sciences Medicine Pharmacology

Tags

Cannabidiol Cannabis Catalysis Chemistry Chromatography Decarboxylation Mass spectrometry Organic chemistry Psychiatry Psychology Supercritical fluid

Substances

Cannabis