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T-2 toxin, one of the most toxic trichothecene mycotoxins, causes economic losses in animal production. Little information is available on the toxicokinetic parameters of T-2 toxin and its major metabolites (i.e., HT-2 toxin and T-2 triol) in broiler chickens. In this study, toxicokinetics of T-2 toxin and its major metabolites were evaluated in broiler chickens after a single intravenous (0.5 mg/kg b.w.) and multiple oral administrations (2.0 mg/kg b.w., every 12 h for 2 days). Plasma concentration profiles of T-2 toxin and its metabolites were analyzed by a noncompartmental model method. Following intravenous administration, the terminal elimination half-lives (t(1/2λz)) of T-2 toxin, HT-2 toxin, and T-2 triol were 17.33 ± 1.07 min, 33.62 ± 3.08 min, and 9.60 ± 0.50 min, respectively. Following multiple oral administrations, no plasma levels above the limit of quantification were observed for HT-2 toxin. The t(1/2λz) of T-2 toxin and T-2 triol was 23.40 ± 2.94 min and 87.60 ± 29.40 min, respectively. Peak plasma concentrations (Cmax ) of 53.10 ± 10.42 ng/mL (T-2 toxin) and 47.64 ± 9.19 ng/mL (T-2 triol) were observed at Tmax of 13.20 ± 4.80 min and 38.40 ± 15.00 min, respectively. T-2 toxin had a low absolute oral bioavailability (17.07%). Results showed that the T-2 toxin was rapidly absorbed and most of the T-2 toxin was extensively transformed to metabolites in broiler chickens.

Yang, F., Sun, N., Sun, Y. X., Shan, Q., Zhao, H. Y., Zeng, D. P., Zeng, Z. L. A physiologically based pharmacokinetics model for florfenicol in crucian carp and oral-to-intramuscular extrapolation. J. vet. Pharmacol. Therap. 36, 192–200. In this study, an oral physiologically based pharmacokinetics (PBPK) model was developed for florfenicol in crucian carp (Carassius auratus). Subsequently, oral-to-intramuscular extrapolation was performed and the two models were used to predict florfenicol concentrations in the edible tissues of crucian carp. The oral model gave good predictions in most tissues, except for kidney and liver in which the florfenicol concentrations were underestimated at the later time points. In contrast, using the intramuscular model, the concentrations in the kidney were overestimated at the later time points. Both models had the best predictive ability in the main edible tissue, the muscle. The oral model also accurately predicted the florfenicol concentrations in the muscle after multiple doses. The present study demonstrated the feasibility of predicting florfenicol concentrations in the edible tissues of crucian carp using a route-to-route extrapolation method.

The pharmacokinetics of florfenicol (FF) was studied in plasma after a single dose (40 mg/kg) of intramuscular (i.m.) or oral gavage (p.o.) administration to crucian carp (Carassius auratus cuvieri) in freshwater at 25 °C. Ten fish per sampling point were examined after treatment. The data were fitted to two-compartment open models follow both routes of administration. The estimates of total body clearance (CL(b) ), volume of distribution (V(d) /F), and absorption half-life (T(1/2(ka)) ) were 0.067 L/h/kg and 0.145 L/h/kg, 2.21 L/kg and 1.04 L/kg, 2.75 and 1.54/h following i.m. and p.o. administration, respectively. After i.m. injection, the elimination half-life (T(1/2(β)) ) was calculated to be 38.2h, the maximum plasma concentration (C(max) ) to be 16.82 μg/mL, the time to peak plasma FF concentration (T(max) ) to be 1.50 h, and the area under the plasma concentration-time curve (AUC) to be 597.4 μg/mL·h. Following p.o. administration, the corresponding estimates were 2.17 h, 29.32 μg/mL, 1.61 h, and 276.1 μg/mL·h.