Metabolism of ibuprofen in zebrafish larvae

Abstract

1. The application of zebrafish (Danio rerio) larvae to drug discovery assays and toxicity testing, and the occurrence of pharmaceuticals in the environment, has resulted in a need to understand the extent of the metabolic capabilities in the early life stages of this species.

2. The aims of this study were to determine if zebrafish larvae absorbed, metabolized and excreted the model pharmaceutical, ibuprofen. Zebrafish larvae (72 h post fertilization) were exposed to ibuprofen (100 µg/L), ¹⁴C-ibuprofen (100 µg/L) or a solvent control (ethanol) for ≤24 h. Water samples and larval extracts were assessed for metabolites of ibuprofen using liquid chromatography mass spectrometry (LC–MS–MS). Fractions from the separation of the samples treated with ¹⁴C-ibuprofen were collected after chromatography and analysed for ¹⁴C content by scintillation counting.

3. Assessment of larval extracts and water samples by LC–MS–MS at 24 h resulted in the identification of hydroxy-ibuprofen in both water samples and larval extracts (8.2 and 0.08% of the total detected ¹⁴C, respectively). A second putative hydroxy-ibuprofen moiety was also observed in water samples at trace levels, and a third minor unknown metabolite was detected in larval extracts only by scintillation counting (0.02% of the total ¹⁴C detected).

4. This study provides evidence that zebrafish larvae can metabolize and excrete ibuprofen in a manner known to be cytochrome P450-dependent in mammals, and the similarity to the mammalian pathway supports the use of this system as a surrogate in toxicity and efficacy screening.

Keywords::

• Zebrafish
• ibuprofen
• metabolism

Acknowledgements

This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC, Award Number BBS/S/N/2006/13057) and AstraZeneca. We thank Peter Jones (The University of Birmingham, UK) for maintenance of the zebrafish, and Rosemary Parslow and Robert Harris (The University of Birmingham, UK) for their advice and assistance with the scintillation counting.

Declaration of interest

The authors reports no conflict of interest.