Pharmacokinetics of florfenicol and its metabolite florfenicol amine in crucian carp (<i>Carassius auratus</i>) at three temperatures after one single intramuscular injection

The pharmacokinetics and residue elimination of florfenicol (FFC) and its metabolite florfenicol amine (FFA) were studied in healthy blunt‐snout bream (Megalobrama amblycephala, 50 ± 10 g). The study was conducted with a single‐dose (25 mg/kg) oral administration at a water temperature of 18 or 28°C, while in the residue elimination study, fish were administered at 25 mg/kg daily for three consecutive days by oral gavage to determine the withdrawal period (WDT) at 28°C. The FFC and FFA levels in plasma and tissues (liver, kidneys and muscle) were analysed using high‐performance liquid chromatography (HPLC). A no‐compartment model was used to analyse the concentration versus time data of M. amblycephala. In the two groups at 18 and 28°C, the maximum plasma concentration (Cmax) of FFC was 5.89 and 6.21 μg/ml, while the time to reach Cmax (Tmax) was 5.97 and 2.84 hr, respectively. These suggested that higher temperature absorbed more drug and more quickly at M. amblycephala. And the elimination half‐life (T1/2kβ) of FFC was calculated as 26.75 and 16.14 hr, while the total body clearance (CL) was 0.09 and 0.15 L kg−1 hr−1, and the areas under the concentration–time curves (AUCs) were 265.87 and 163.31 μg hr/ml, respectively. The difference demonstrated that the elimination rate of FFC in M. amblycephala at 28°C was more quickly than that at 18°C. The results of FFA showed the same trend in tissues of M. amblycephala. After multiple oral doses (25 mg/kg daily for 3 days), the k (eliminate rate constant) of FFA in M. amblycephala muscle was 0.017, the C0 (initial concentration) was 3.07 mg/kg, and the WDT was 10 days (water temperature 28°C).

Section: Discussionsupporting

confidence: 88%

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

Huang

Chen

Wang

et al. 2019

“…It indicates the elimination rate in vivo. In this study, the t 1/2(ke) was 75.13 hr, which was far higher than that in crucian (31.66 hr) (Yang et al., ; Yang et al., ). The MRT of FF in plasma was also long (100.6 hr).…”

Section: Resultscontrasting

confidence: 54%

Tissue distribution and elimination features of florfenicol in hybrid sturgeon cultured in cool water

Yang

Shang

et al. 2018

In order to understand pharmacokinetics in vivo and tissue residues of florfenicol in Hybrid sturgeon cultured in cold water, changes in concentration of florfenicol in plasma, muscle, liver and kidney of sturgeon after administration were measured by high performance liquid chromatography mass spectrometry. The results show that after 15.0 mg/kg dose administration, the concentration change in plasma and liver, kidney and muscle of sturgeon are suitable for the one compartment open model. Florfenicol pharmacokinetic parameters in plasma, liver, kidney and sturgeon muscle showed that the peak concentration (C ) were 549.7, 551.8, 958.2 and 405.4 μg/kg, respectively. The peak time (T ) was 17.5, 14.2, 14.0 and 20.8 hr, respectively. The elimination half-life (T ) was 75.1, 99.8, 68.8 and 75.5 hr, respectively. Area under the curve were 70,048.9, 63,850.6, 109,579.9 and 53,437.3 μg/kg hr, respectively. Mean residence time was 100.6, 96.4, 96.5 and 104.6 hr, respectively. The absorption speed and elimination of florfenicol in cold water cultured sturgeon is slow, and the peak concentration is low, but the florfenicol was widely distributed in the body of sturgeon. The results provide a theoretical basis for formulation of medication and withdrawal period of florfenicol used in sturgeon cultured in cold water.

“…There are many factors affecting the pharmacokinetics and residue elimination times in aquatic animals including species and physiological differences, dosage, route of administration, temperature, salinity, and pH. Among these factors, water temperature is the most influential (Yang et al, ; Yang, Yang, Wang, Kong, & Liu, ). Therefore, the clinical withdrawal period should be determined according to the specific fish species and the actual breeding environment.…”

Section: Discussionmentioning

confidence: 99%

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

Qi¹,

Wang

Zheng³

et al. 2019

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.