Quick Multi-Class Determination of Residues of Antimicrobial Veterinary Drugs in Animal Muscle by LC-MS/MS

Development of a Quantitative Method for Detection of Multiclass Veterinary Drugs in Feed Using Modified QuPPe Extraction and LC–MS/MS

A method was developed for the rapid and quantitative analysis of 30 veterinary drugs belonging to 17 classes (amphenicols (1), anthelmintics (1), cephalosporins (4), coccidiostats (1), lincosamides (1), macrolide (1), nitroimidazole (1), penicillins (3), phenylhydrazines (1), polypeptides (1), pyrethrins (1), quinolones (5), sulfonamides (3), tetracycline (3), neuroleptic agents (1), triazene trypanocidal agents (1), other. (1)) in feeds. The proposed method with a modified Quick Polar Pesticides (QuPPe) sample preparation was validated for the determination of 30 veterinary drugs in feed samples by liquid chromatography triple-quadrupole mass spectrometry (LC–MS/MS). The sample was extracted with methanol containing 1% acetic acid and purified by dispersive solid-phase extraction (d-SPE) with C18. Good linearity (r² ≥ 0.98) was observed, and the LOQ values ranged from 10 to 200 µg/kg. Average recoveries ranged from 70.8 to 118.4%, and the relative standard deviation was ≤ 18.7%. This validated method was used in the determination of 30 veterinary drugs in 142 feed samples obtained from South Korea. The results show that lincomycin was present in only one of the tested feed samples, although it was detected at a value lower than the LOQ. In conclusion, this multi-residue method can be used for screening through the detection and quantitation of residual multiclass veterinary drugs in feed samples.

Pharmacokinetics, bioavailability, and tissue disposal profiles of Tiamulin fumarate in Nile tilapia (Oreochromis niloticus) following oral and intravenous administrations

Tiamulin fumarate (TIF) is a pleuromutilin antibiotic and has high activity against animal bacterial pathogens including aquatic bacterial pathogens. However, its pharmacokinetic profiles, tissue distribution characteristics and bioavailability in aquatic animals remain unknown. The objective of this study was to investigate the pharmacokinetics and tissue distribution regularities of TIF in tilapia (Oreochromis niloticus) following a single oral (PO) dose of 20 mg/kg body weight (bw) and a single intravenous (IV) dose of 5 mg/kg bw at 22 ± 1°C, respectively. TIF concentrations in tilapia plasma and tissues were determined using the isotope dilution HPLC-HESI-MS/MS procedure, which was validated according to the guidelines defined by US Food and Drug Administration. TIF was well distributed throughout the body compartments of tilapia judged by the apparent volume of distribution (V_d ) >1 L/kg (6.69 L/kg PO and 1.78 L/kg IV). TIF had a short mean residence time (MRT; 22.82 h PO and 14.61 h IV) and quick total body clearance (CL_b ) (0.62 L kg^-1  h^-1 PO and 0.60 L kg^-1  h^-1 IV). The total area under the curve (AUC_tot ) of plasma were 32.25 μg h^-1  ml^-1 (PO) and 8.30 μg h^-1  ml (IV), respectively, and the oral absolute bioavailability (F%) of TIF was calculated to be approximately 97.1%. For tissue distribution, high concentrations of TIF were found in kidney, and the longest MRT was recorded in bile. The withdrawal time (WT) of TIF in muscle, skin, liver, kidney, gill, and bile was 3.75 (4) and 1.79 (2), 1.77 (2) and 2.06 (3), 6.41 (7) and 1.97 (2), 6.95 (7) and 3.98 (4), 4.92 (5) and 2.36 (3), and 7.06 (8) and 6.16 (7) days after PO and IV administration, respectively. The present investigations indicated that TIF was quickly absorbed, well distributed, rapidly eliminated in tilapia, and it could serve as reference data for establishing use regimen and provide useful information for the further development of TIF in aquaculture.

Determination of antibiotics in meat samples using analytical methodologies: A review

Antibiotics are widely used to prevent or treat some diseases in human and veterinary medicine and also as animal growth promoters. The presence of these compounds in foods derived from food-producing animals can be a risk for human health. Consequently, regulatory agencies have set maximum residue limits for antibiotics in food samples. Therefore, the development of novel methodologies for its determination in food samples is required. Specifically, the analysis and quantification of these substances in meat tissues is a challenge for the analytical chemistry research community. This is due to the complexity of the matrix and the low detection limits required by the regulatory agencies. In this sense, a comprehensive review on the development of new sample preparation treatments involving extraction, cleanup, and enrichment steps of antibiotics in meat samples in combination with sensitive and sophisticated determination techniques that have been carry out in the last years is necessary. Therefore, the aim of this work is to summarize the published methodologies for the determination of antibiotics from 2016 until the beginning of the second semester of 2020. The first part of this review includes an introduction about antibiotic families, followed by sample preparation and determination techniques applied to the different families. Finally, a detailed discussion of the current trends and the future possible perspectives in this field are also included.

Determination of residual enantiomers of diclazuril in chicken edible tissues by high performance liquid chromatography

A convenient, simple, selective and reliable method was established for separating diclazuril enantiomers and detecting their residues in chicken edible tissues by using high-performance liquid chromatography. The potential effects of chiral column, mobile phase and column temperature on chiral separation of racemic diclazuril were evaluated. Average recovery rates of R-diclazuril and S-diclazuril in three spiking levels ranged from 84.3% to 109.5%, and the relative standard deviations were <15.8%. The limits of quantification of two enantiomers were all 25 ng g^-1 in all chicken tissues. The method proposed was successfully applied to monitor distributions and residue elimination of diclazuril enantiomers in chicken muscle, liver, kidney and fat following oral administration. There are no obvious differences (p > 0.05) between R-diclazuril and S-diclazuril in the same tissue for each sampling time. The elimination rates in liver were the fastest and the residual time in kidney was the longest. These results can help further evaluate pharmokinetics, pharmodynamics and toxicity of each enantiomer of diclazuril in food-producing animals.

Tetracycline Residues in Bovine Muscle and Liver Samples from Sicily (Southern Italy) by LC-MS/MS Method: A Six-Year Study

We examined a total of 369 bovine liver and muscle samples for the detection of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX) residues by implementation and validation of a LC-MS/MS method. The method showed good recovery values between 86% and 92% at three levels of concentrations. The linearity tests revealed r² > 0.996 for all the tetracyclines examined. Furthermore, the Youden test revealed that the method was robust. Only 14.4% of the samples showed OTC and TC residues in a concentration range of 10.4⁻40.2 µg kg^-1. No CTC and DOX residues were found in all the samples analyzed. Liver samples showed the highest average values (31.5 ± 20.6 and 21.8 ± 18.9 for OTC and TC, respectively). The results showed a low incidence of TCs in all the samples examined, in comparison with other studies reported in the literature. A significant decrease in TC residues frequency was found from 2013 (p < 0.05). This work reports for the first time epidemiological data on the presence of TC residues in liver and muscle samples of cattle farmed in Sicily (Southern Italy). The very low incidence of TC residues indicates a continuous improvement in farming techniques in Southern Italy, which is essential to ensure consumers' protection.