Pharmacokinetics of florfenicol and its metabolite, florfenicol amine, in rice field eel (Monopterus albus) after a single‐dose intramuscular or oral administration

Abstract

The pharmacokinetics of florfenicol (FF) and its metabolite, florfenicol amine (FFA), were studied in rice field eel (Monopterus albus) after a single dose (20 mg/kg) by intramuscular (i.m.) or oral gavage (p.o.) dose at 25 °C. The elimination half-lives (t1/2β ), peak concentration of FF (Cmax ), and time to reach FF peak concentration (Tmax ) in plasma were estimated as 18.39 h, 10.83 μg/mL, and 7.00 h, respectively, after i.m. injection and 13.46 h, 8.37 μg/mL, and 5 h, respectively, after p.o. administration. The Tmax values of FF in tissues (i.e., kidney, muscle, and liver) were larger for i.m. injection compared with those for p.o. administration. The t1/2β had the following order kidney>muscle>liver for i.m. administrated and kidney>liver>muscle for p.o. administrated. The largest area under the concentration-time curve (AUC) was calculated to be 384.29 mg·h/kg after i.m. dosing, and the mean residence time (MRT) was 42.46 h by oral administration in kidney. FFA was also found in all tissues with a lower concentration than FF for both i.m. and p.o. administrations throughout the study. The elimination of FFA was slow with a t1/2β between 18.19 and 47.80 h in plasma and tissues. The mean metabolic rate of FFA for i.m. and p.o. administrations was >23.30%.

Pharmacokinetic Study of Florfenicol in Healthy and Vibriosis-infectedPseudosciaena croceaafter Oral Administration

“…T 1/2β of florfenicol was estimated to be 33.85 h in healthy P. crocea and 22.92 h in vibriosis-infected fish after oral administration. These were similar to the half-life of European eel (18.39 h; Xie et al, 2012), but were longer than that of tilapia (10.03 h;Feng and Jia, 2009), Atlantic salmon (12.2 h;Horsberg et al, 1996), and chicken (1.73 h; Shen and Wu, 2002). These differences indicated that the elimination rate of florfenicol might be influenced by factors such as species, increased emunctory function, and physiological mechanism.…”

“…There are some reports of its pharmacokinetics determined in Oncorhynchus mykiss, Piaractus brachypomus, P. crocea, Gadus morhua, Salmo salar, Acipenser baeri, Anguilla anguilla, Tilapia, Silurus asotus, and Crucian carp (Horsberg et al, 1996;Lunden and Bylund, 2000;Samuelsen et al, 2003;Lewbart et al, 2005;Park et al, 2006;Feng and Jia, 2008;Bowser, 2009;Sun et al, 2010;Qin et al, 2010;Xie et al, 2012).…”

Pharmacokinetics of florfenicol in blunt‐snout bream (Megalobrama amblycephala) at two water temperatures with single‐dose oral administration

“…From the concentration–time curve in M. amblycephala plasma and tissues, we can see two distinct peak concentrations. The same result was shown in a study of FFC in rice field eel ( Monopterus albus ) (Xie et al, ). In addition, two peak concentrations have been observed in many reports on the pharmacokinetics of other drugs in other aquatic animals.…”

“…The plasma (0.2 ml), liver (0.2 g), muscle (1 g) and kidneys (0.2 g) of M. amblycephala were sampled at 0.25, 0.5, 0.75, 1, 2,4, 6, 8, 12, 16, 20, 26, 32, 40, 48, 72, 96 and 128 hr after the end of the medication period for the pharmacokinetic study. All the samples were stored at −20°C (Xie et al, ). The experiments and all of the protocols strictly followed the guidelines of the Huazhong Agricultural University for the care and utilization of laboratory animals.…”

Pharmacokinetics of florfenicol and behaviour of its metabolite florfenicol amine in orange‐spotted grouper (Epinephelus coioides) after oral administration

“…) and rice field eel (Xie et al . ). The results showed that the drug was absorbed rapidly, extensively distributed and the bioavailability of florfenicol in Atlantic salmon, cod and Korean catfish ranging from 91% to 99% was excellent.…”