A multi-residue method for 17 anticoccidial drugs and ractopamine in animal tissues by liquid chromatography-tandem mass spectrometry and time-of-flight mass spectrometry

Veterinary Drug Residues in the Food Chain as an Emerging Public Health Threat: Sources, Analytical Methods, Health Impacts, and Preventive Measures

Veterinary medications are necessary for both contemporary animal husbandry and food production, but their residues can linger in foods obtained from animals and pose a dangerous human risk. In this review, we aim to highlight the sources, occurrence, human exposure pathways, and human health effects of drug residues in food-animal products. Following the usage of veterinary medications, pharmacologically active compounds known as drug residues can be found in food, the environment, or animals. They can cause major health concerns to people, including antibiotic resistance development, the development of cancer, teratogenic effects, hypersensitivity, and disruption of normal intestinal flora. Drug residues in animal products can originate from variety of sources, including water or food contamination, extra-label drug use, and ignoring drug withdrawal periods. This review also examines how humans can be exposed to drug residues through drinking water, food, air, and dust, and discusses various analytical techniques for identifying these residues in food. Furthermore, we suggest some potential solutions to prevent or reduce drug residues in animal products and human exposure pathways, such as implementing withdrawal periods, monitoring programs, education campaigns, and new technologies that are crucial for safeguarding public health. This review underscores the urgency of addressing veterinary drug residues as a significant and emerging public health threat, calling for collaborative efforts from researchers, policymakers, and industry stakeholders to develop sustainable solutions that ensure the safety of the global food supply chain.

Simultaneous determination of selected ionophoric coccidiostats and amino acids in feed premixes using high-performance liquid chromatography-ultraviolet detection method

The combination of ionophoric coccidiostats and amino acids (AAs) is important in poultry feeding to enhance immunity and improve the growth and feed efficiency of birds suffering from coccidiosis. A simple, rapid, and economical high-performance liquid chromatography-ultraviolet detection (HPLC-UV) method for the simultaneous determination of three ionophoric coccidiostats, namely salinomycin (SAL), maduramicin (MAD), and monensin (MON) in addition to three AAs; L-tryptophan (L-TRP), alpha-ketoleucin (KLEU), and L-valine (L-VAL) in feed premixes was developed and validated. Chromatographic separation was achieved in less than 12 min using a phenyl hexyl column with a mobile phase consisting of acetonitrile/methanol/water (25:20:55, v/v/v) adjusted to pH 3 using phosphoric acid. Isocratic elution was performed at a flow rate of 1 mL/min with UV detection at 210 nm. The method showed good linearity in the ranges 0.50-5.0 mg/mL for MON, 0.20-2.0 mg/mL for MAD and SAL, 10.0-100.0 μg/mL for L-TRP and KLEU, and 50.0-500.0 μg/mL for VAL. The developed method was successfully applied to determine the studied analytes in feed premixes with good recoveries and precision. The good validation criteria of the proposed method allow its utilization in quality control laboratories.

LC-MS/MS analysis of coccidiostats in meat supply chain safety

The presence of coccidiostats in meat products represents an important topic because of the animal administration of these substances, authorized as feed additives for targeted species, in order to prevent and inhibit coccidiosis. Coccidiostats include both ionophores and synthetic molecules characterized by different chemical-physical properties such as polarity. Meat is a matrix characterized by many interfering compound groups, such as proteins, phospholipids, and fats. High-performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) analysis allows the required selectivity and sensitivity for discriminating analytes and matrix interferences. For these reasons, an LC-MS/MS method for the analysis of coccidiostats in meat products was developed without SPE purification steps. The correct analyte quantification is allowed by matrix-matched calibration. The method validation was performed by the replicated analysis of spiked meat samples at two different concentration levels (limit of quantification-LOQ-and a 10 times LOQ) in order to evaluate method recovery and repeatability, plus spiked samples at higher concentrations up to 10,000 μg/kg. Moreover, the metrological approach was used for the calculation of method uncertainty. The application of the developed method to real samples evidenced the presence of some non-ionophores coccidiostats in the meat and liver of chicken and rabbit species. Although, the determined concentration was below the established MRLs, the monitoring of coccidiostats in the meat supply chain is confirmed as a good strategy in order to safeguard consumer health.

Quantitative Analysis of Decoquinate Residues in Hen Eggs through Derivatization-Gas Chromatography Tandem Mass Spectrometry

A novel precolumn derivatization-gas chromatography tandem mass spectrometry (GC-MS/MS) method was developed to detect and confirm the presence of decoquinate residues in eggs (whole egg, albumen and yolk). Liquid-liquid extraction (LLE) and solid phase extraction (SPE) were used to extract and purify samples. The derivatization reagents were pyridine and acetic anhydride, and the derivatives were subjected to GC-MS/MS detection. After the experimental conditions were optimized, satisfactory sensitivity was obtained. The limits of detection (LODs) and limits of quantification (LOQs) for the decoquinate in eggs (whole egg, albumen and yolk) were 1.4-2.4 μg/kg and 2.1-4.9 μg/kg, respectively. At four spiked concentration levels, the average recoveries were 74.3-89.8%, the intraday RSDs ranged from 1.22% to 4.78%, and the inter-day RSDs ranged from 1.61% to 7.54%. The feasibility and practicality of the method were confirmed by testing egg samples from a local supermarket.

Analysis of authorized coccidiostats in chicken feces and environmental water by ultra-performance liquid chromatography-tandem mass spectrometry based on dispersive solid-phase extraction and lyophilization

A simple, sensitive, and efficient method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of 8 coccidiostats in chicken feces and environmental water (including sewage, pond water, and lake water) surrounding the farm. Target analytes in chicken feces were extracted with 2% acetic acid in acetonitrile solution, followed by a dispersive solid-phase extraction (DSPE) cleanup step using the mixture of PSA and C18 adsorbents. Environmental water samples were pretreated using a lyophilization approach. Analysis was carried out on a UPLC-MS/MS with the combination of methanol and 0.1% formic acid aqueous solution as the mobile phase under multiple reaction monitoring in positive and negative ionization modes. Results showed that 8 coccidiostats were linear with correlation coefficients higher than 0.99. Method validation was performed using fortified samples, reaching satisfactory recoveries of 75.9%-97.8% in chicken feces and 71.9%-108.2% in environmental water. Limits of detection for 8 analytes in chicken feces and environmental water were 0.03∼2 µg/kg and 0.005∼1 µg/L, respectively. Matrix effects were calculated and strong signal suppression (>50%) for some coccidiostats was observed. The developed method was successfully applied to analyze coccidiostats in chicken feces and environmental water collected from local chicken farms.

Multiclass Method for the Determination of Anthelmintic and Antiprotozoal Drugs in Livestock Products by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

The objective of this study was to establish a multi-residue quantitative method for the analysis of anthelmintic and antiprotozoal drugs in various livestock products (beef, pork, and chicken) using ultra-high-performance liquid chromatography-tandem mass spectrometry. Each compound performed validation at three different levels i.e., 0.5, 1, and 2× the maximum residue limit according to the CODEX guidelines (CAC/GL 71-2009). This study was conducted according to the modified quick, easy, cheap, effective, rugged, and safe procedure. The matrix-matched calibrations gave correlation coefficients >0.98, and the obtained recoveries were in the range of 60.2%-119.9%, with coefficients of variation ≤32.0%. Furthermore, the detection and quantification limits of the method were in the ranges of 0.03-3.2 and 0.1-9.7 μg/kg, respectively. Moreover, a survey of residual anthelmintic and antiprotozoal drugs was also carried out in 30 samples of beef, pork, and chicken collected in Korea. Toltrazuril sulfone was detected in all three samples. Thus, our results indicated that the developed method is suitable for determining the anthelmintic and antiprotozoal drug contents in livestock products.

A Review on Pretreatment and Analysis Methods of Polyether Antibiotics in Complex Samples

Polyether antibiotics (PAs) are the anti-coccidiosis drugs used for treating and preventing coccidiosis. Studies show the residues of these antibiotics in food cause adversities and threaten human health. PAs thus need robust, rugged, and accurate methods for their analysis. This review encompasses pretreatment and detection methods of PAs in diverse matrices since 2010. Both conventional and developed methods are part of the pretreatments, such as dispersive liquid-liquid microextraction, solid-phase extraction, solid-phase microextraction, solvent front position extraction, QuEChERS (Quick Easy Cheap Effective Rugged and Safe), supercritical fluid extraction, and others. The analysis methods involve liquid chromatography coupled with detectors, sensors, etc. The pros and cons of various techniques for PAs have been discussed and future tendencies are proposed.

Qualitative and Quantitative Determination of Decoquinate in Chicken Tissues by Gas Chromatography Tandem Mass Spectrometry

A novel precolumn derivatization-GC-MS/MS method was developed for the determination of decoquinate residues in chicken tissues (muscle, liver, and kidney). The samples were extracted and purified by liquid-liquid extraction combined with solid-phase extraction and derivatized with acetic anhydride and pyridine. The recovery rates for decoquinate were 77.38~89.65%, and the intra-day and inter-day RSDs were 1.63~5.74% and 2.27~8.06%, respectively. The technique parameters meet the necessities for veterinary drug residue detection in China, the US, and the EU. Finally, the method was applied to analyze tissues of 60 chickens bought from a neighborhood supermarket, and solely one sample of chicken muscle contained 15.6 μg/kg decoquinate residue.

A Europium Nanosphere-Based Time-Resolved Fluorescent Immunochromatographic Assay for the Rapid Screening of 4,4'-Dinitrocarbanilide: Aiming at Improving Strip Method Performance

Considering that the strip method is simple and convenient for users, a Europium nanosphere-based time-resolved fluorescent immunochromatographic assay (TRFICA) for the rapid screening of 4,4'-dinitrocarbanilide (DNC) was developed to improve the performance of strip assays. After optimization, TRFICA showed IC₅₀, the limit of detection, and cut-off values of 0.4, 0.07, and 5.0 ng mL^-1, respectively. No significant cross-reactivity (CR < 0.1%) with 15 DNC analogs was observed in the developed method. TRFICA was validated for DNC detection in spiked chicken homogenates, and recoveries ranged from 77.3% to 92.7%, with coefficients of variation of <14.9%. Moreover, the time needed for the detection procedure, including the sample pre-treatment, was less than 30 min for TRFICA, which had never been achieved before in other immunoassays. The newly developed strip test is a rapid, sensitive, quantitative, and cost-effective on-site screening technique for DNC analysis in chicken muscle.

Development and Validation of a Confirmatory Method for the Determination of 12 Coccidiostat Residues in Eggs and Muscle by Means of Liquid Chromatography Coupled to Hybrid High Resolution Mass Spectrometry

A confirmatory, highly selective multi-residue method based on liquid chromatography coupled to hybrid high resolution mass spectrometry (LC-Q-Orbitrap) was developed and validated for the determination of 12 regulated coccidiostats in eggs and muscle. Particularly, ionophore antibiotics (lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin) and synthetic coccidiostats (diclazuril, halofuginone, nicarbazin as 4,4′-dinitrocarbanilide fraction, robenidine and toltrazuril as toltrazuril-sulphone) were included in the method. The sample preparation consisted in the extraction of the analytes from the matrix with acetonitrile, followed by a clean-up step with Oasis® PRiME HLB SPE and a defatting procedure with n-hexane. Validation was successfully performed according to Commission Implementing Regulation (EU) 2021/808, starting from 1 µg kg−1. The procedure was verified through the analysis of a certified reference material (CRM) and the occurrence of the residues was assessed in the context of the Italian National Residue Control Plan (NRCP).

Coccidiostats and Poultry: A Comprehensive Review and Current Legislation

Coccidiosis remains one of the major problems of the poultry industry. Caused by Eimeria species, Coccidiosis is a contagious parasitic disease affecting poultry with great economic significance. Currently, in order to prevent health problems caused by this disease, broiler farmers make extensive use of coccidiostats in poultry feed, maintaining animal health and, in some cases, enhancing feed conversion. The presence of unauthorized substances, residues of veterinary products and chemical contaminants in the food industry is of concern, since they may pose a risk to public health. As the use of coccidiostats has been increasing without any requirements for veterinary prescription, research and surveillance of coccidiostat residues in poultry meat is becoming imperative. This review presents an up-to-date comprehensive discussion of the state of the art regarding coccidiosis, the most used anticoccidials in poultry production, their mode of action, their prophylactic use, occurrence and the European Union (EU) applicable legislation.

Halofuginone micelle nanoparticles eradicate Nrf2-activated lung adenocarcinoma without systemic toxicity

The Keap1-Nrf2 system is the master regulator of the cellular response against oxidative and xenobiotic stresses. Constitutive activation of Nrf2 is frequently observed in various types of cancers. Nrf2 hyperactivation induces metabolic reprogramming in cancer cells, which supports the increased energy demand required for rapid proliferation and confers high-level resistance against anticancer radio/chemotherapy. Hence, Nrf2 inhibition has emerged as an attractive therapeutic strategy to counter such acquired resistance in Nrf2-activated tumors. We previously identified Halofuginone (HF) as a promising Nrf2 inhibitor. In this study, we pursued preclinical characterization of HF and found that while HF markedly reduced the viability of cancer cells, it also caused severe hematopoietic and immune cell suppression in a dose-dependent manner. Hence, to overcome this toxicity, we decided to employ a nanomedicine approach to HF. We found that encapsulation of HF into a polymeric micelle (HF micelle; HFm) largely relieved the systemic toxicity exhibited by free HF while maintaining the tumor-suppressive properties of HF. LC-MS/MS analysis revealed that the reduction in the magnitude of adverse effects was the result of the ability to release HF from the HFm core in a slow and sustained manner. These results thus support the contention that HFm will potentially counteract Nrf2-activated cancers in the clinical settings.

Halofuginone Sensitizes Lung Cancer Organoids to Cisplatin via Suppressing PI3K/AKT and MAPK Signaling Pathways

Lung cancer is the leading cause of cancer death worldwide. Cisplatin is the major DNA-damaging anticancer drug that cross-links the DNA in cancer cells, but many patients inevitably develop resistance with treatment. Identification of a cisplatin sensitizer might postpone or even reverse the development of cisplatin resistance. Halofuginone (HF), a natural small molecule isolated from Dichroa febrifuga, has been found to play an antitumor role. In this study, we found that HF inhibited the proliferation, induced G0/G1 phase arrest, and promoted apoptosis in lung cancer cells in a dose-dependent manner. To explore the underlying mechanism of this antitumor effect of halofuginone, we performed RNA sequencing to profile transcriptomes of NSCLC cells treated with or without halofuginone. Gene expression profiling and KEGG analysis indicated that PI3K/AKT and MAPK signaling pathways were top-ranked pathways affected by halofuginone. Moreover, combination of cisplatin and HF revealed that HF could sensitize the cisplatin-resistant patient-derived lung cancer organoids and lung cancer cells to cisplatin treatment. Taken together, this study identified HF as a cisplatin sensitizer and a dual pathway inhibitor, which might provide a new strategy to improve prognosis of patients with cisplatin-resistant lung cancer.

Risk Assessment of Nine Coccidiostats in Commercial and Home Raised Poultry

For the first time, this paper aimed to evaluate nine ionophore and synthetic coccidiostat residues in poultry muscle samples, obtained from different production types, by solid-liquid extraction followed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The fully validated methodology was successfully applied to a total of 101 chicken and turkey samples obtained from canteens, supermarkets, and home productions in Portugal. Halofuginone, diclazuril, decoquinate, narasin, lasalocid, and salinomycin were detected in 20.8% of the samples. Home raised samples showed a greater frequency, 47.1%. The synthetic coccidiostats halofuginone, diclazuril, and decoquinate were found in averages of 0.7 μg kg^-1,2.9 μg kg^-1, and 3.7 μg kg^-1, respectively, while averages of 1.2 μg kg^-1, 1.6 μg kg^-1, and 1.3 μg kg^-1 were found regarding the ionophores narasin, lasalocid, and salinomycin. As for the risk assessment, values lower than 8.06% of the acceptable daily intake (ADI) were observed, indicating that exposure to coccidiostats through consumption of poultry meat does not represent risk to consumers.

Assessment of various veterinary drug residues in animal originated food products

The veterinary drugs are broad-spectrum antibacterial antibiotics; it uses to cure the animal disease. Many countries have banned veterinary drug residues like nitrofurans metabolites, chloramphenicol. However, the people were administrated veterinary drugs to animals as illegal to increase the milk production in animals for economic benefit. The results of illegally use of veterinary drugs remain as a residue in animal product like milk and it is very harmful to whom consume it cause cancer and allergic for human being which has entered the concern among milk consumers. To control illegal use of veterinary drugs, the government of India has restricted its use in animals. For the identification and confirmation of veterinary drug residues in animal products, analytical techniques such as liquid chromatography and mass spectrometry are available. These are very sophisticated equipments which are available nowadays and their methodologies for the analytical method validation are described by European commission 2002/657/EC. The use of veterinary drugs is a big challenge to effectively identify and authorization of their use. There are so many analytical techniques are using very effectively and taking very less time to protect the consumers from their adverse effects. These techniques take very less time to identify more groups of compounds such as tetracycline, sulfonamides, anthelmintic, and macrolides in single multi-residue method. These methods having validation parameters include system precision, calibration curve, accuracy, limit of detection, and quantification. Therefore, improvement in the existing technologies and accessibility of new screening methodologies will give opportunities for automation that helps in obtaining the results in very less time and improved sensitivity and specificity which contribute to better safety assurance, standard, and quality of various food products of animal origin.

Novel spectrofluorimetric technique for determination of amoxicillin and ethopabate in chicken tissues, liver, kidney, eggs, and feed premix

A new smart spectrofluorometric method was developed for the quantitation of amoxicillin and ethopabate simultaneously for the first time. The method is based on measuring their first derivative synchronous amplitudes in water at Δλ = 80 nm. The peak amplitudes were recorded at their crossing points; 240 nm for amoxicillin and 280 nm for ethopabate. The method is linear over the concentration ranges of 100.0-1,000.0 ng/ml for amoxicillin and 2.0-20.0 ng/ml for ethopabate. The limits of detection were 20.0 ng/ml and 0.58 ng/ml and limits of quantitation were 60.0 ng/ml and 1.92 ng/ml for amoxicillin and ethopabate, respectively. The method sensitivity permitted the determination of the two drugs below their maximum residue limit stated by the federal regulations. The developed method was applicable to the analysis of both drugs in the veterinary powders, feed premix, chicken tissues, liver, kidney, and eggs samples with percentage recoveries ranging 93.72-104.71%.

Occurrence and Concentrations of Residues of Tetracyclines, Polyether Ionophores, and Anthelmintics in Livers of Chickens Sold in the Informal Market in Gauteng Province, South Africa

ABSTRACT

The occurrence, concentrations, and variables associated with tetracycline, polyether ionophore, and anthelmintic residues in the livers of chickens sold in the informal market in South Africa were determined. Ultrahigh-performance liquid chromatography-tandem mass spectrometry was used to simultaneously analyze for four tetracyclines, five polyether ionophores, and six anthelmintic residues. The study determined the presence of residues in liver samples at both the limit of quantifications (LOQ) and concentrations over the maximum residue limit (MRL), i.e., noncompliant. Doxycycline (tetracycline group) was detected in 24 (24.5%) of 98 chicken livers, and 15 (15.3%) of the 98 were noncompliant. Mean ± standard deviation (SD) concentrations of 919.04 ± 1,081.30 ppb (LOQ) and 1,410.57 ± 108.89 ppb (MRL) were obtained. Maduramicin was detected in 27 (27.6%) of 98 chicken livers, and 19 (19.4%) of 98 were noncompliant. The mean ± SD for LOQ was 117.96 ± 84.56 ppb, and MRL was 153.21 ± 76.29 ppb. The concentrations of residues of doxycycline and maduramicin in chicken livers varied significantly across townships. Lasalocid was found in 31 (31.6%) of 98 samples, of which 5 (5.1%) had concentrations above the MRL. The mean ± SD concentration of lasalocid was 62.90 ± 170.84 ppb for samples in which lasalocid was quantified and 310.16 ± 356.68 ppb for noncompliant samples. Detectable concentrations of praziquantel, closantel, and rafoxanide (anthelmintics) residues were found in 3 (3.1%), 1 (1.0%), and 2 (2.0%) of 98 chicken livers, respectively. The presence of residues of three classes of veterinary drugs in chicken livers poses food safety implications to consumers and indicates a need for enhanced regulatory enforcement in controlling these drugs in South Africa.

Determination of robenidine in shrimp and chicken samples using the indirect competitive enzyme-linked immunosorbent assay and immunochromatographic strip assay

In this study, the monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip assay were developed for the rapid screening of robenidine hydrochloride (ROBH) in samples.

A new sample treatment strategy based on simultaneous supramolecular solvent and dispersive solid-phase extraction for the determination of ionophore coccidiostats in all legislated foodstuffs

A single-step sample treatment, for the simultaneous extraction and clean-up for the determination of ionophore coccidiostats in EU legislated foodstuffs, is here proposed. The treatment is based on the combination of: (i) a supramolecular solvent with restricted access properties (SUPRAS-RAM), spontaneously formed by the addition of hexanol, water and THF to the sample; and (ii) dispersive solid phase extraction (dSPE). The SUPRAS-RAM extract was directly compatible with LC-MS/MS and no further re-extraction, evaporation or cleanup procedures were necessary. SUPRAS-RAM efficiently extracted the ionophores (recoveries in milk, eggs, fat, liver, kidney, and chicken and beef muscle were in the range 71-112%) and removed proteins and carbohydrates, whereas dSPE removed fats and other lipophilic compounds. The method was validated following the European Commission Decision 2002/657/EC. Detection limits (0.004-0.07 µg kg^-1) were far below the maximum residue limits (1-150 µg kg^-1). Method analytical and operational characteristics were suitable for routine determination of ionophores.

Simultaneous determination of multi-class antibiotics and steroid hormones drugs in livestock and poultry faeces using liquid chromatography-quadrupole time-of-flight mass spectrometry

A method for simultaneous determination of multi-class antibiotics and steroid hormone analysis in faeces of livestock and poultry was developed using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF MS). An in-house database was built for 156 detected drugs using Personal Compound Database Library software (PCDL) including compound name, monoisotopic mass, chemical formula, RT, chemical structure and three CID MS/MS spectra. The linearity result showed that all the drugs exhibited good linearity with determination coefficients (R²) higher than 0.99. The drug recoveries and their RSDs for all three faeces samples (pig, cattle and chicken) were tested and 81, 96 and 92 drugs were chosen for analysis in pig, cattle and chicken faeces, respectively. Further validation showed that 73 veterinary drugs in all three kinds of faeces samples can be quantified in one analytical run. This work shows that qualitative and quantitative analysis using LC-QTOF MS represents a simple, sensitive, low-cost and high-throughput methodology in routine laboratory analyses.

Determination of Eight Coccidiostats in Eggs by Liquid-Liquid Extraction-Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry

A method for the simultaneous determination of robenidine, halofuginone, lasalocid, monensin, nigericin, salinomycin, narasin, and maduramicin residues in eggs by liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed. The sample preparation method used a combination of liquid–liquid extraction (LLE) and solid-phase extraction (SPE) technology to extract and purify these target compounds from eggs. The target compounds were separated by gradient elution using high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC). Tandem mass spectrometry was used to quantitatively and qualitatively analyze the target compounds via electrospray ionization (ESI⁺) and multiple reaction monitoring mode. The HPLC–MS/MS and UPLC–MS/MS methods were validated according to the requirements defined by the European Union and the Food and Drug Administration. The limits of detection and limits of quantification of the eight coccidiostats in eggs were 0.23–0.52 µg/kg and 0.82–1.73 µg/kg for HPLC–MS/MS, and 0.16-0.42 µg/kg and 0.81-1.25 µg/kg for UPLC–MS/MS, respectively. The eggs were spiked with four concentrations of the eight coccidiostats, and the HPLC–MS/MS and UPLC–MS/MS average recoveries were all higher than 71.69% and 72.26%, respectively. Compared with the HPLC–MS/MS method, utilizing UPLC–MS/MS had the advantages of low reagent consumption, a short detection time, and high recovery and precision. Finally, the HPLC–MS/MS and UPLC–MS/MS methods were successfully applied to detect eight coccidiostats in 40 eggs.

Reducing Veterinary Drug Residues in Animal Products: A Review

A survey we conducted suggests that the ingestion of veterinary drug residues in edible animal parts constitutes a potential health hazard for its consumers, including, specifically, the possibility of developing multidrug resistance, carcinogenicity, and disruption of intestinal normal microflora. The survey results indicated that antibiotics, parasitic drugs, anticoccidial, or nonsteroidal anti-inflammatory drugs (NSAIDs) are broadly used, and this use in livestock is associated with the appearance of residues in various animal products such as milk, meat, and eggs. We observed that different cooking procedures, heating temperatures, storage times, fermentation, and pH have the potential to decrease drug residues in animal products. Several studies have reported the use of thermal treatments and sterilization to decrease the quantity of antibiotics such as tetracycline, oxytetracycline, macrolides, and sulfonamides, in animal products. Fermentation treatments also decreased levels of penicillin and pesticides such as dimethoate, malathion, Dichlorodiphenyldichloroethylene, and lindane. pH, known to influence decreases in cloxacillin and oxacillin levels, reportedly enhanced the dissolution of antimicrobial drug residues. Pressure cooking also reduced aldrin, dieldrin, and endosulfan in animal products. Therefore, this review provides updated information on the control of drug residues in animal products, which is of significance to veterinarians, livestock producers, and consumer health.

Comprehensive stability-indicating high-performance liquid chromatography coupled with diode array detection method for simultaneous determination of amprolium hydrochloride and ethopabate in powder dosage form for veterinary use

This research deals with the development of a stability-indicating high-performance liquid chromatography method for simultaneous determination of amprolium hydrochloride and ethopabate. To the best of our knowledge, no comprehensive stability-indicating method has been reported for analysis of this mixture. Separation was achieved using Kromasil cyano column with gradient elution of the mobile phase composed of sodium hexane sulfonate solution and methanol. Quantification was based on measuring peak areas at 266 nm. Amprolium and ethopabate peaks eluted at retention times 10.42 and 18.53 min, respectively. The proposed procedure was validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Linearity ranges for amprolium and ethopabate were 1.5-240 and 1-160 μg/mL, respectively. Analytes were subjected to stress conditions of hydrolysis, oxidation and thermal degradation. The proposed method enabled resolution of drugs from their forced-degradation products and amprolium related substance (2-picoline). Moreover, specificity was verified by resolution of the analytes from about 22 drugs used in antimicrobial veterinary products. The validated method was successfully applied to assay of the combined veterinary powder dosage form, additionally it was implemented in the accelerated stability study of the dosage form when stored for six months at 40°C and 75% relative humidity.

Assessment of veterinary drugs present in pork kidney from a Midwest US retail market

A total of 1040 pork kidneys were purchased from 4 retail stores located in a Midwestern US town and screened for antibiotics with the Charm-KIS™ screening test. Six samples (0.6%) tested positive with the Charm-KIS™. Sixty-five samples from each retail location and the 18 Charm-KIS™ positive or 'caution' samples were also subjected to ELISA to determine the presence of commonly used veterinary drugs including flunixin, ractopamine, sulfamethazine, and/or tetracycline of the 278 samples assessed by ELISA, flunixin, ractopamine, sulfamethazine, and tetracycline residues were found to be 0%, 22%, 4%, and 10% ELISA positive respectively, and had greater than limit of quantitation concentrations as measured by LC-MS/MS.  All residue levels determined by LC-MS/MS were well below US tolerances, regardless of analyte.  These findings suggest that veterinary drugs are being used in accordance with US regulations and that veterinary drug residues in pork do not pose a health concern to US consumers.

Multi-residue methodology for the determination of 16 coccidiostats in animal tissues and eggs by hydrophilic interaction liquid chromatography - Tandem mass spectrometry

A simple, sensitive and efficient confirmatory method was developed and validated for the determination of 16 coccidiostats in animal tissues and eggs using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). The sample preparation consisted of a solid-liquid extraction with ACN and dispersive SPE cleanup with MgSO₄ and C₁₈. Analysis was realized in an Acquity BEH HILIC silica column, in SRM mode. Both positive and negative ionization was performed, using polarity switching. Isocratic elution was used with a mobile phase of ACN: aqueous ammonium formate 1 mM with 0.1% formic acid (80:20, v/v). Method validation was performed in eggs, poultry, bovine, ovine, porcine and rabbit tissue and exceptionally low LODs were achieved, varying from 0.004 μg kg^-1 (decoquinate in porcine tissue) to 0.560 μg kg^-1 (halofuginone in eggs). The developed methodology was applied in 82 muscle and egg samples through the Greek National Residue Control Plan for coccidiostats.

Current research, regulation, risk, analytical methods and monitoring results for nicarbazin in chicken meat: A perspective review

This review presents up-to-date information about current research on nicarbazin, one of the most used anticoccidials in poultry production. The focus is to elucidate regulation concerning nicarbazin, limits for its residues in food, how maximum residue limits in different countries are calculated regarding edible chicken tissues and the possible implications in human health. Analytical methods to extract and quantify this residue, expressed as dinitrocarbanilide (DNC) are presented and discussed, including qualitative screening and quantitative/confirmatory analytical methods. Monitoring results and occurrence of DNC residues in chicken meat are discussed. Additionally, the causes of eventual chicken meat contamination and possible solutions to reduce or eliminate DNC residue in tissues are also presented. The paper concludes with perspectives, the current state of DNC residue analysis and suggestions for future research, especially considering the gap in the study of residue recycling effect due to continuous chicken litter use.

Development of an indirect competitive enzyme-linked immunosorbent assay for screening ethopabate residue in chicken muscle and liver

Development of an indirect competitive enzyme-linked immunosorbent assay for screening ethopabate residue in chicken muscle and liver.