Pharmacokinetics and tissue residues of enrofloxacin in the largemouth bass (Micropterus salmoides) after oral administration

Abstract

The study was carried out to evaluate the pharmacokinetic disposition of enrofloxacin (ENF) with a single dose of 20 mg/kg after oral administration in largemouth bass (Micropterus salmoides) at 28°C. The concentrations of ENF and of its metabolite ciprofloxacin (CIP) in plasma, liver, and muscle plus skin in natural proportions were determined using HPLC. The concentration–time data for ENF in plasma were best described by a two‐compartment open model. After oral administration, the maximum ENF concentration (Cmax) of 10.99 μg/ml was obtained at 0.60 hr. The absorption half‐life (T1/2Ka) of ENF was calculated to be 0.07 hr whereas the elimination half‐life (T1/2β) of the drug was 90.79 hr. The estimates of area under the plasma concentration–time curve (AUC) and apparent volume of distribution (Vd/F) were 1,185.73 μg hr/ml and 2.21 L/kg, respectively. ENF residues were slowly depleted from the liver and muscle plus skin of largemouth bass with the T1/2β of 124.73 and 115.14 hr, respectively. Very low levels of ciprofloxacin were detected in the plasma and tissues. A withdrawal time of 24 days was necessary to ensure that the residues of ENF + CIP in muscle plus skin were less than the maximal residue limit (MRL) of 100 μg/kg established by the European Union.

Pharmacokinetics and Tissue Distribution of Enrofloxacin Following Single Oral Administration in Yellow River Carp (Cyprinus carpio haematoperus)

“…Shorter T 1/2λZ values have also been reported in rainbow trout, with the values ranging from 36.48 to 71.88 h in different tissues (19). However, longer muscle plus skin T 1/2λZ value (115.14 h) has been reported in largemouth bass (22). In the present study, it should be noted that only 2-4 samples, including plasma, kidney, liver, and skin-muscle, were quantified at the last quantifiable time point (360 or 480 h), and those samples with enrofloxacin concentrations below the LOQ were omitted and not used to calculate T 1/2λZ .…”

“…The plasma pharmacokinetics of enrofloxacin has been reported in some fish species, such as crucian carp (11,12), large yellow croaker (13), tilapia (14), snakehead fish (15), brown turbot (16), and salmonids (17). In addition to those pharmacokinetics studies, the tissue distribution of enrofloxacin has also been reported in aquaculture species, including northern snakeheads (18), rainbow trout (19,20), grass carp (21), largemouth bass (22), and pacu (23). Those previous results indicated that the plasma and tissues kinetics of enrofloxacin might be strongly influenced by fish species, body conditions, routes of administration, water temperature, and other environmental factors.…”

Pharmacokinetics and Pharmacokinetic/Pharmacodynamic Integration of Enrofloxacin Following Single Oral Administration of Different Doses in Brown Trout (Salmo trutta)

“…In our study, ciprofloxacin could not be detected in plasma samples taken after enrofloxacin administration. Although ciprofloxacin was detected at a low ratio in largemouth bass [ 10 ], crucian carp [ 38 ], grass carp [ 33 ] and rainbow trout [ 35 ], it was not detected in brown trout [ 4 ], rainbow trout [ 14 ] and sea bream [ 38 ]. It has been stated that the single dose administration of enrofloxacin in sea bass strongly inhibits the hepatic P450 enzymes system [ 37 ].…”

“…In both mammalian and nonmammalian species, enrofloxacin is dealkylated to ciprofloxacin, which exhibits a potency and spectrum of activity similar to enrofloxacin [ 7 ]. Enrofloxacin is widely used in fish due to its properties such as good absorption, large volume of distribution, high bioavailability, and long terminal half-life [ 9 , 10 ]. Although enrofloxacin is included in category B (Restrict) in the classification of antibiotics for veterinary use in terms of the risk of antimicrobial resistance by the EMA, it has been stated that it can be used in fish in cases in which there are few alternative treatment options, such as Aeromonas infection [ 11 ].…”

Pharmacokinetics and Tissue Residue Profiles of Enrofloxacin in Crucian Carp (Carassius auratus gibelio) Following Single and Multiple Oral Administration

“…The determination of ENR and CIP were carried out based on our previously published HPLC methods ( 19 , 23 ). Shortly, 0.5 ml of plasma was extracted two times with 3 ml of acetonitrile.…”