Abstract
In 2014, NM-2201 (CBL-2201), a novel synthetic cannabinoid (SC), was detected by Russian and United States laboratories. It was already added to the scheduled drugs list in Japan, Sweden and Germany. Unfortunately, no human metabolism data are currently available, making it challenging to confirm its intake because all previous investigated SCs were extensively metabolized. The present study aims to recommend appropriate marker metabolites by investigating NM-2201 metabolism in human hepatocytes and confirm the results in authentic human urine specimens. For the metabolic stability assay, 1 μM NM-2201 was incubated in human liver microsomes (HLMs) for up to 1 h; for metabolite profiling, 10 μM of NM-2201 was incubated in human hepatocytes for 3 h. Two authentic urine specimens from NM-2201 positive cases were analyzed after β-glucuronidase hydrolysis. Metabolite identification in hepatocyte samples and urine specimens was achieved with high-resolution mass spectrometry via information-dependent acquisition. NM-2201 was quickly metabolized in HLMs with an 8.0 min half-life. In human hepatocyte incubation samples, a total of thirteen NM-2201 metabolites were identified, generated mainly from ester hydrolysis and further hydroxylation, oxidative defluorination and subsequent glucuronidation. M13 (5-fluoro PB-22 3-carboxyindole) was the major metabolite. In the urine specimens, the parent drug NM-2201 was not detected; M13 was the predominant metabolite after β-glucuronidase hydrolysis. Therefore, based on our study, we recommend the M13 as a suitable urinary marker metabolite for confirming NM-2201 and/or 5F-PB-22 intake.