A new analytical method using dispersive liquid-liquid microextraction and liquid chromatography-tandem mass spectrometry was developed to detect ketamine, its metabolites norketamine and 6-hydroxy-norketamine, and its analogues deschloroketamine and 2-fluorodeschloroketamine in oral fluid. The method showed linearity from 10 to 1,000 ng/mL, with detection and quantification limits at 10 ng/mL. Imprecision and bias were below 8.2% and 9.5%, respectively, and matrix effects did not exceed 10.6%. Recovery ranged from 24% to 42%. The method was applied to 29 authentic oral fluid samples and evaluated as environmentally friendly by three green chemistry metrics.
MDMB-4en-PINACA, a synthetic cannabinoid receptor agonist, caused severe developmental abnormalities and high embryo mortality in zebrafish at 10 µM, including pericardial edema, yolk edema, coagulation, and lack of heartbeat or somite formation. In contrast, the ketamine derivatives deschloroketamine and 2-fluorodeschloroketamine showed low embryo mortality even at higher concentrations. In larval stages, MDMB-4en-PINACA caused 8% mortality at 10 µM by eight days post-fertilization, while the ketamine derivatives led to 100% mortality at 2000 µM. MDMB-4en-PINACA was approximately 26 times more toxic than the ketamine derivatives based on LC50 values. The results support the absence of NMDA receptors in early zebrafish life stages, explaining the lower toxicity of ketamine derivatives early on.