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Fabian Frankenfeld

Department of Experimental and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, 66421 Homburg, Germany.

2 papers in the library · 5 citations · publishing 2024-2025

Papers

In Vivo and In Vitro Metabolic Fate and Urinary Detectability of Five Deschloroketamine Derivatives Studied by Means of Hyphenated Mass Spectrometry.

Metabolites May 8, 2024 Fabian Frankenfeld, Lea Wagmann, Anush Abelian et al. 3 citations

Five deschloroketamine derivatives—deschloro-N-cyclopropyl-ketamine, deschloro-N-ethyl-ketamine, deschloro-N-isopropyl-ketamine, deschloro-N-propyl-ketamine, and deschloroketamine—are primarily metabolized through N-dealkylation, hydroxylation, multiple oxidations, and combinations, plus glucuronidation and N-acetylation. In total, 29 phase I and 10 phase II metabolites were detected in rat urine after a 2 mg/kg body weight dose, using liquid chromatography high-resolution tandem mass spectrometry and gas chromatography-mass spectrometry. For the LC-HRMS/MS standard urine screening approach, compound-specific metabolites were identified and confirmed in pooled human liver microsomes for all derivatives except deschloro-N-cyclopropyl-ketamine. The GC-MS approach detected only non-specific acetylated N-dealkylation metabolites.

Studies on the Stability and Microbial Biotransformation of Five Deschloroketamine Derivatives as Prerequisite for Wastewater-Based Epidemiology Screening.

Drug testing and analysis August 1, 2025 Fabian Frankenfeld, Lea Wagmann, Markus R Meyer 2 citations

Five deschloroketamine derivatives and most of their metabolites remain sufficiently stable in raw wastewater to serve as analytical targets for wastewater-based epidemiology. After incubating the parent compounds, rat urine, or rat feces in untreated influent wastewater for 24 hours, all parent compounds, seven Phase I metabolites, and one Phase II metabolite were detected in rat feces. Peak areas of Phase II N- and O-glucuronides decreased markedly, consistent with earlier findings that Phase II conjugates are unstable in wastewater and unsuitable as biomarkers. The results indicate that the parent drugs and their Phase I metabolites can be used for wastewater surveillance of these new psychoactive substances.