alpha-benzyl-N-methylphenethylamine (BNMPA), an impurity of illicit methamphetamine synthesis: III. Detection of BNMPA and metabolites in urine of methamphetamine users.

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.