Flumequine

A new magnetic dispersive solid-phase extraction approach based on Eu- and Tb-coated magnetic nanocomposites, combined with ultra-high performance liquid chromatography with fluorometric detection, is reported for the extraction and simultaneous determination of veterinary antibiotics. The method is aimed at monitoring of potential residues of three tetracyclines, namely oxytetracycline, tetracycline, chlortetracycline and three acidic quinolones, such as oxolinic acid, nalidixic acid and flumequine, chosen as model analytes, in animal muscle samples. The nanocomposites were obtained by synthesizing magnetic nanoparticles by a co-precipitation method and their coating with terbium and europium ions. The limits of detection obtained using standard solutions were: 1.0, 1.5, 3.8, 0.25, 0.7 and 1.2ngmL(-1), which corresponds to 3.3, 5.0, 12.7, 0.8, 2.3 and 4.0μgkg(-1) for oxytetracycline, tetracycline, chlortetracycline, oxolinic acid, nalidixic acid and flumequine, respectively, in meat samples.

A liquid chromatography - diode array detector (HPLC-DAD) procedure has been developed for the determination of oxytetracycline (OTC), tetracycline (TC), chlorotetracycline (CTC), doxycycline (DC), enrofloxacin (ENR), ciprofloxacin (CIP), sarafloxacin (SAR) and flumequine (FLU) residues in animal drinking water. This method was applied to animal drinking water. Solid-phase extraction (SPE) clean-up on an Oasis HLB cartridge allowed an extract suitable for liquid chromatographic analysis to be obtained. Chromatographic separation was carried out on a C18 analytical column, using gradient elution with 0.1% trifluoroacetic acid - acetonitrile - methanol at 30°C. The flow-rate was 0.7 mL/min and the eluate was analysed at 330 nm. The whole procedure was evaluated according to the requirements of the Commission Decision 2002/657/EC, determining specificity, decision limit (CCα), detection capacity (CCβ), limit of detection (LOD), limit of quantification (LOQ), precision and accuracy during validation of the method.

In this study, the pharmacokinetic profile of flumequine (FMQ) was investigated in blunt snout bream (Megalobrama amblycephala) after intravascular (3 mg/kg body weight (b.w.)) and oral (50 mg/kg b.w.) administrations. The plasma samples were determinedby ultra-performance liquid chromatography (UPLC) with fluorescence detection. After intravascular administration, plasma concentration-time curves were best described by a two-compartment open model. The distribution half-life (t1/2α ), elimination half-life (t1/2β ), and area under the concentration-time curve (AUC) of blunt snout bream were 0.6 h, 25.0 h, and 10612.7 h·μg/L, respectively. After oral administration, a two-compartment open model with first-order absorption was also best fit the data of plasma. The t1/2α , t1/2β , peak concentration (Cmax ), time-to-peak concentration (Tmax ), and AUC of blunt snout bream were estimated to be 2.5 h, 19.7 h, 3946.5 μg/L, 1.4 h, and 56618.1 h.