Developing an analytical method for the determination and verification of cannabidiol (CBD) in recreational cannabis products against label claims

Abstract

Following the recent legalisation of cannabis for recreational use in Malta, the market has seen a surge in the availability of cannabis-based products in shops. While the level of tetrahydrocannabidiol (THC) is not supposed to be higher than 0.2% in these products, the level of cannabidiol (CBD) is not determined in the legislation. Concerns have arisen regarding the quality and consistency of cannabis products available on the market. This burgeoning interest in these products has sparked extensive research into the accuracy of labelling and quantification of these cannabis products, especially the levels of THC and CBD. This present study aimed to address this gap by developing a validated method for the determination of the CBD content of commercially available cannabis products in Malta. A gas chromatography-mass spectrometry (GC/MS) technique was thus used for the development of a method for CBD quantification in such products. Methapyrilene HCl was used as an internal standard, and calibration standards were used to establish a calibration curve for the CBD. Samples of three different commercially available products, which were labelled as containing varying CBD concentrations (<14%, <17% and <6%) were purchased from a local shop. The three samples underwent rigorous preparation steps, including homogenisation, sonication, dilution with methanol, and filtration, in order to ensure that the samples were suitably prepared for eventual analysis by GC/MS. The results of the analysis revealed that there were notable discrepancies between the CBD concentration as stated in the respective label of the sample and the measured CBD concentrations in the sampled products. Specifically, Sample 1 exhibited a CBD content of 12.78% (below the value stated on the label of <14%), while Sample 2 displayed a significantly lower CBD content of 8.25% when compared to the stated value of <17%. Sample 3, however, demonstrated an average CBD percentage of 10.25%, exceeding the labelled value of <6%. Additionally, the Certificate of Analysis (CoA) also reflected differences in CBD content for Sample 3. The CoA for Sample 3 indicated a CBD content of 10.47%, which closely aligns with the measured value from this study (10.25%). However, this CoA value was higher than the <6% CBD content stated on the product label. This discrepancy highlights potential issues in the labelling process or batch-to-batch variability, suggesting that the actual product content may not consistently match the information provided to consumers. Overall, the study underscores the urgent need for improved regulation and standardisation in the commercial cannabis product industry, particularly in terms of accurate labelling and batch-to-batch consistency of CBD content. These findings have implications for consumer safety and highlight the necessity of regulatory oversight to ensure product quality and efficacy.