Detection of ADB-4en-PINACA Metabolite, 2-Methylmethcathinone and 3-Methylmethcathinone in Authentic Urine Samples

Introduction

In Singapore, new psychoactive substances (NPS) continued to be prevalent with synthetic cannabinoids (SC), synthetic cathinones and mitragynine being detected. In early 2023, ADB-4enPINACA metabolite and the positional isomers of 4-methylmethcathinone (4-MMC), i.e., 2-MMC and 3-MMC were detected in drug users’ urine samples. To the best of our knowledge, ADB-4en-PINACA metabolite was the first time being identified in authentic urine sample.

Methods

0.5 mL of urine samples were incubated with β-glucuronidase enzyme and extracted. The extracted samples were screened using LC-Orbitrap MS method followed by confirmation using LC-QToF MS method.

Results

ADB-4en-PINACA dihydrodiol metabolite was detected in two authentic urine samples, which was consistent to the result of the metabolic study.1 The identity was confirmed with the reference standard in both HRMS methods. Other SC metabolites such as MDMB-4en-PINACA metabolites, ADBBUTINACA metabolite and/or ADB-PINACA metabolite were also detected in the samples. In addition, 2-MMC and 3-MMC were recently detected in a few drug users’ urine samples. Using the sensitive and selective LC-QToF method, the three positional isomers of methylmethcathinone were chromatography separated and specifically identified with the reference standards.

Conclusions

New NPS constantly enters the drug market with structural diversity and rapid development of the new derivatives, therefore, NPS continues to pose challenge for the drug detection in urine testing. The laboratory applies various techniques to comprehensively identify the new NPS and their positional isomers to cater for the rapid change.