Pharmacokinetics and tissue distribution of bronopol in grass carp, Ctenopharyngodon Idella, at 15 and 20°C

This study explored the pharmacokinetic characteristics of bronopol in grass carp (Ctenopharyngodon idella) under different temperatures. The concentrations of bronopol in the plasma and tissues (kidney, liver and muscle) of grass carp after soaking in bronopol (6.75 µg/ml) at 15 and 20°C were determined using liquid chromatography–mass spectrometry. The concentrations of bronopol in both plasma and tissue first increased and then decreased with soaking time at both tested temperatures. The peak bronopol concentrations at 15°C (plasma: 8.934 µg/ml; kidney: 9.23 µg/g; liver: 9.47 µg/g; and muscle: 7.98 µg/g) were slightly lower than those at 20°C (plasma: 9.654 µg/ml; kidney: 10.83 µg/g; liver: 13.40 µg/g; and muscle: 8.68 µg/g). In an analysis of pharmacokinetic parameters, the bronopol concentration–time profiles for plasma were best described by a two‐compartment, open pharmacokinetic model with first‐order absorption. The t₁/₂ᵦ for plasma at 15 and 20°C was 82.933 and 92.041 hr, respectively, indicating that the elimination of bronopol was faster at 15°C than at 20°C. In addition, AUC₀‐ₜ and AUC₀‐∞ values of bronopol were 477.892 and 495.809 µg/L hr at 15°C and 495.809 and 589.859 µg/L hr at 20°C, indicating that the content of bronopol in the organism was higher at higher temperature.