α-Benzyl-N-Methylphenethylamine (BNMPA), an Impurity of Illicit Methamphetamine Synthesis: III. Detection of BNMPA and Metabolites in Urine of Methamphetamine Users

Abstract

Eighty urine specimens collected from drug rehabilitation programs, which had been screened by immunoassay and confirmed positive by gas chromatography-mass spectrometry (GC-MS) for methamphetamine, were further analyzed for alpha-benzyl-N-methylphenethylamine (BNMPA) and its urinary metabolites, N-demethyl-BNMPA, diphenyl-2-propanone (DP2P), diphenyl-2-propanol, p-OH-N-demethyl-BNMPA, and p-OH-BNMPA. BNMPA is an impurity of illicit methamphetamine synthesis. Analysis of BNMPA and its metabolites was performed by quantitative GC-MS following beta-glucuronidase hydrolysis, liquid-liquid extraction, and derivatization with heptafluorobutyric anhydride. Two urine specimens contained detectable amounts of BNMPA and/or its metabolites. One contained trace amounts (greater than the limit of detection but less than the limit of quantitation) of N-demethyl-BNMPA and DP2P, as well as 0.04 mg/L p-OH-N-demethyl-BNMPA. The other contained trace amounts of BNMPA, p-OH-BNMPA, and p-OH-N-demethyl-BNMPA, as well as 0.03 mg/L N-demethyl-BNMPA. Prior to analyzing these urine specimens, pure reference material of p-OH-BNMPA was made available, and analysis confirmed our previous tentative identification of p-OH-BNMPA as a major metabolite of BNMPA. Detection of BNMPA or its metabolites in biological samples may serve as a marker of illicit methamphetamine administration.