Review of Synthetic Cannabinoids on the Illicit Drug Market

Abstract Cannabimimetics (synthetic cannabinoids) exhibit agonistic activity on the two cannabinoid re-ceptors, CB1 and CB2 but have no structural similarity with the active compound of marijuana; tetrahydrocannabinol (THC). They are called synthetic cannabinoids due to their mechanism of pharmaceutical actions. Because these compounds have no structural similarity with THC, as expected immunoassays designed to detect marijuana metabolite THC-COOH cannot detect the presence of these drugs or metabolites in urine. These compounds have been classified into several different major classes: carbazoles, classical cannabinoids, cyclohexylphenols, endogenous cannabinoids, indoles, indazoles, pyrroles, the URB-class, and others in a miscellaneous class. Every year, new synthetic cannabinoids arise, differing by the addition or removal of a substituent group. Currently over 130 synthetic cannabinoids have been identified. Although liquid chromatography combined with mass spectrometry or tandem mass spectrometry is commonly applied for analysis of synthetic cannabinoids and their metabolites in urine or other biological fluids, other analytical methods including nuclear magnetic resonance have been described for their analysis.