Metabolism of synthetic cathinones through the zebrafish water tank model: a promising tool for forensic toxicology laboratories

• DOI: 10.1007/s11419-020-00543-w
• Publication Date: 2020-07-22T10:04:04Z
• Authors: Estefany Prado; Rebecca Rodrigues...; Geovana Maria de ...; Clarisse Baptista...; Isabelle Karine d...; Carina de Souza A...; Adriana Sousa de ...; Luciana Silva do ...; Denilson Soares d...; Marco Antônio Mar...; João Carlos Laboi...; Gabriela Vanini C...; Francisco Radler ...; Monica Costa Padilha; Henrique Marcelo ...
• Keywords: Cathinone; Designer drug; Hydroxylation

Abstract Purpose The aim of this study was to identify in vivo phase I metabolites of five psychoactive substances: N-ethylpentylone, ethylone, methylone, α-PVP and 4-CDC, using the in house developed experimental set-up zebrafish (Danio rerio) water tank (ZWT). High-resolution mass spectrometry allowed for metabolite identification. A pilot study of reference standard collection of N-ethylpentylone from the water tank was conducted.

Methods ZWT consisted in 8 fish placed in a 200 mL recipient-containing water for a single cathinone. Experiments were performed in triplicate. Water tank samples were collected after 8 h and pretreated through solid-phase extraction. Separation and accurate-mass spectra of metabolites were obtained using liquid chromatography–high resolution tandem mass spectrometry.

Results Phase I metabolites of α-PVP were identified, which were formed involving ketone reduction, hydroxylation, and 2″-oxo-pyrrolidine formation. The lactam derivative was the major metabolite observed for α-PVP in ZWT. N-Ethylpentylone and ethylone were transformed into phase I metabolites involving reduction, hydroxylation, and dealkylation. 4-CDC was transformed into phase I metabolites, reported for the first time, involving N-dealkylation, N,N-bis-dealkylation and reduction of the ketone group, the last one being the most intense after 8 h of the experiment.

Conclusions ZWT model indicated to be very useful to study the metabolism of the synthetic cathinones, such as N-ethylpentylone, ethylone, α-PVP and 4-CDC. Methylone seems to be a potent CYP450 inhibitor in zebrafish. More experiments are needed to better evaluate this issue. Finally, this approach was quite simple, straightforward, extremely low cost, and fast for “human-like” metabolic studies of synthetic cathinones.