An assessment of solvent residue contaminants related to cannabis-based products in the South African market

Organic solvents are used for manufacturing herbal medicines and can be detected as residues of such processing in the final products. It is important for the safety of consumers to control these solvent residues. South African cannabis-based product samples were analysed for solvent residue contaminants as classified by the United States Pharmacopeia (USP), chapter 467. The origin of these samples ranged anywhere from crude extract, product development samples, and market ready final products. Samples were submitted to a contract laboratory over a period of 2 years from 2019 to 2021. To date, no data of this kind exist in South Africa specifically relating to cannabis-based medicinal, recreational, or complementary products. A total of 279 samples were analysed in duplicate by full evaporation headspace gas-chromatography mass-spectrometry and the results are reported in an anonymised format. The results showed an alarming 37% sample solvent residue failure rate with respect to adherence to USP 467 specification. It is important to ensure regulation is enforced to control product quality. The South African public need to be educated about the risks associated with cannabis-based products.