Development and validation of an LC-MS/MS method for the quantification of mescaline and major metabolites in human plasma

A bioanalytical method using ultra-high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and validated to rapidly quantify mescaline and its metabolites (TMPAA, NAM, and 4-desmethyl mescaline) in human plasma. The single-step protein precipitation extraction achieved complete recovery (≥98.3%) with minor matrix effects (≤7.58%). Intra-assay accuracy ranged from 84.9% to 106%, and precision was ≤7.33%. The method's sensitivity allowed lower limits of quantification of 12.5 ng/mL for mescaline and TMPAA, and 1.25 ng/mL for NAM, sufficient for clinical pharmacokinetic studies. However, 4-desmethyl mescaline could not be selectively quantified due to interference from another metabolite. The method is reliable and easy-to-use for forensic and clinical pharmacokinetic applications.

Study at a glance

Abstract

Mescaline is a psychedelic phenethylamine found in different species of cacti. Currently, mescaline's acute subjective effects and pharmacokinetics are investigated in several modern clinical studies. Therefore, we developed a bioanalytical method for the rapid quantification of mescaline and its metabolites in human plasma. Mescaline and its metabolites 3,4,5-trimethoxyphenylacetic acid (TMPAA), N-acetyl mescaline (NAM), and 3,5-dimethoxy-4-hydroxyphenethylamine (4-desmethyl mescaline) were simultaneously analyzed by ultra-high performance liquid chromatography tandem mass spectrometry (LC-MS/MS). Optimal chromatographic separation was achieved with an Acquity Premier HSS T3 C18 column. The analytes were detected in positive ionization mode using scheduled multiple reaction monitoring. A single step extraction method was implemented to enable fast and automatable plasma sample preparation. An intra-assay accuracy between 84.9% and 106% and a precision of ≤ 7.33% was observed in three validation runs. Plasma was extracted by simple protein precipitation, resulting in a complete recovery (≥ 98.3%) and minor matrix effects (≤ 7.58%). No interference with endogenous matrix components could be detected in human plasma samples (n = 7). Importantly, method sensitivity sufficed for assessing pharmacokinetic parameters of mescaline in clinical study samples with lower limits of quantification of 12.5, 12.5, and 1.25 ng/mL for mescaline, TMPAA, and NAM, respectively. Nonetheless, 4-desmethyl mescaline could not be selectively quantified in pharmacokinetic samples due to interference with another mescaline metabolite. Overall, we developed and validated a reliable and very easy-to-use method for forensic applications as well as investigating the clinical pharmacokinetics of mescaline.