Determination of methylphenethylamine and Its Metabolites in Whole Blood of Rats Using MMSPE and UPLC-qTOF-MS

Abstract ID 22744 Poster Board 258 β-methylphenethylamine (BMPEA) is a positional isomer of amphetamine that is used for doping and weight loss. The purpose of this study was to determine BMPEA concentrations and investigate its metabolic pathway in rats. Twelve adult male Sprague-Dawley rats were randomly assigned to four groups (n = 3 each): a control group that received no BMPEA; a low-dose group that received 10 mg/kg of BMPEA (i.p. ); and two high-dose groups that received 30 mg/kg of BMPEA (i.p). Within 20 minutes, the rats in the low-dose and one of the two high-dose groups were euthanized by CO2 asphyxiation. The other high-dose group was euthanized by CO2 asphyxiation 90 minutes post-injection. Perimortem blood samples were collected in sodium fluoride vacutainer tubes from the rat heart (cardiac puncture). In this study, the validated UPLC-qTOF-MS analytical method using MMSPE extraction method was used to determine BMPEA concentrations and identify its metabolite in rat cardiac blood. The highest determined concentration of BMPEA was 899 ng/mL in a high-dose group sample, whereas the lowest determined concentration was 22 ng/mL in a high delayed dose group sample. All determined concentrations were within the validated working range of the assay (20-1,000 ng/mL). The high delayed-dose samples (collected 90 min post-injection) showed a sharp decline in the concentration levels of BMPEA (31 ng/mL ± 9 ng/mL) when compared to the high-dose samples (collected within 20 min of injection), which showed very high concentration levels of BMPEA (869 ng/mL ± 29 ng/mL). This finding demonstrated that BMPEA has a short half-life of elimination from the rat blood. More research is needed to precisely estimate the half-life of BMPEA. This study was demonstrated that the validated UPLC-qTOF-MS analytical method was able to differentiate between BMPEA and amphetamine at the level of baseline and metabolite. The study9s analytical method was able to distinguish between the positional isomers BMPEA and amphetamine by separating them at the baseline level and identifying their metabolite. There was a newly discovered BMPEA metabolite, which was identified as 1-amino-2-phenylpropan-2-ol. The discovery of the BMPEA metabolite was accomplished through comparison with drug-free samples. The fragmentation pattern of this proposed metabolite was obtained utilizing the MS E acquisition mode of qTOF-MS. The study utilized UPLC-qTOF-MS to determine BMPEA concentrations and identified its metabolite in rat cardiac blood. It was capable of distinguishing between BMPEA and amphetamine at the baseline and metabolite levels and can be used in forensic laboratories to precisely identify them in doping and criminal investigations. 1-amino-2-phenylpropan-2-ol, a novel BMPEA metabolite, was discovered.