Analytical and Bioanalytical Chemistry
December 11, 2015
Kateřina Hájková, Bronislav Jurásek, David Sýkora et al.
26 citations
A new sample preparation and detection method for the designer drug methoxetamine (MXE) and five of its metabolites in rat brain, liver, and lung tissues was developed. The procedure uses salting-out-assisted liquid-liquid extraction followed by liquid chromatography-tandem mass spectrometry. Calibration curves were linear from 2.5 to 250 ng/g, with limits of quantification of 2.5 and 5 ng/g. Recovery ranged from 80% to 117% and matrix effects from 94% to 110%. The method was successfully applied to real samples from toxicological trials on rats.
Drug Testing and Analysis
October 31, 2019
Kateřina Hájková, Bronislav Jurásek, Jan Čejka et al.
12 citations
Deschloroketamine, a ketamine analog sold illicitly since 2015 and sometimes misrepresented as ketamine, has potential antidepressant properties. A metabolomics study used liquid chromatography–high-resolution mass spectrometry and a validated multiple reaction monitoring method to track its metabolites in urine, serum, and brain tissue. Key metabolites—trans-dihydrodeschloroketamine, cis- and trans-dihydronordeschloroketamine, and nordeschloroketamine—were synthesized and used as standards. In serum, nordeschloroketamine and deschloroketamine concentrations ranged from 0.5 to 860 ng/mL; in brain tissue, they ranged from 0.5 to 4700 ng/g. The quantification methods showed intra-day accuracy of 80–125% and precision averaging 3–7%.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences
June 1, 2025
Natalie Paškanová, Magdaléna Vágnerová, Bronislav Jurásek et al.
1 citation
Methoxphenidine (MXP), a dissociative anaesthetic derivative, is increasingly abused, but forensic and clinical data on its metabolism and enantiomers are limited. Researchers developed and validated achiral LC-MS/MS and chiral SFC-MS methods to quantify MXP and its primary metabolite, O-desmethyl-methoxphenidine (dmMXP), in rat serum and brain after a single subcutaneous dose of racemic MXP. Serum MXP peaked at 1600 ng/mL at 0.5 hours and decreased to 5.87 ng/mL at 24 hours; brain MXP peaked at 13200 ng/g at 0.5 hours and fell to 36.1 ng/g at 24 hours. (S)-MXP concentrations in brain appeared higher than (R)-enantiomer concentrations. The methods enable pharmacokinetic studies and provide tools for forensic and clinical toxicology.
Journal of pharmaceutical and biomedical analysis
August 1, 2026
Magdaléna Vágnerová, Petr Palivec, Monika Mrňavá et al.
The metabolism of the recreational drug 25E-NBOH was investigated in human liver microsomes, rat urine, and Cunninghamella elegans fungus. Using untargeted LC-HRMS/MS, 56 metabolites were annotated, many as isomers. Primary metabolic pathways included hydroxylation, O-demethylation, and N-debenzylation, followed by conjugation. Ten reference substances were synthesized; seven matched detected metabolites by retention time and MS/MS spectra, enabling structural assignment. The known psychoactive substance 2C-E was confirmed as a metabolite. Three main biomarkers are proposed. This work provides the first comprehensive metabolic profile of 25E-NBOH, supporting future pharmacological and toxicological studies and aiding clinical diagnosis of intoxication.