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Substandard and falsified medical products for treating COVID-19 have spread worldwide. These medicines have entered Japan through personal importation of products purchased via the Internet. In this study, we investigated the circulation of 19 COVID-19-related medicines on the Internet in Japan and evaluated the pharmaceutical quality and authenticity of 2 medicines (dexamethasone tablets and ivermectin tablets) obtained online. We purchased 23 samples of 0.5-mg dexamethasone tablets and 13 samples of 3-mg ivermectin tablets from the Internet in December 2020 and July 2022. We investigated the quality and authenticity of the obtained samples through visual observation and tested their authenticity. We conducted pharmacopoeia compliance testing (quantitative assay, content uniformity tests, and dissolution tests) using the high-performance liquid chromatography-photodiode array detector method. No prescription was ever required at the time of purchase. Visual observation revealed that most samples lacked a package insert and some samples had packaging deficiencies. In terms of authenticity, eight ivermectin samples were genuine; the authenticity of the other samples remained uncertain. Four dexamethasone samples and three ivermectin samples failed quality testing based on pharmacopeia validation standards. Our findings illustrate that dexamethasone and ivermectin tablets of poor quality are available online. It is important to increase consumer awareness and provide information about these medicines to prevent the purchase of substandard medicines via the Internet.

Abamectin, the mixture of avermectin B1a and B1b, is widely used as a bioinsecticide and is an alternative to chemical pest control from insects. To our knowledge, its behaviour is not fully recognized, especially in herbs. Thus, the objective of this study was to investigate the environmental fate of abamectin in herbal plants belonging to the Lamiaceae family, its dissipation in open field studies laboratory processing treatments and dietary risk assessment. Three medicinally and culinary important species of herbs: Melissa officinalis L., Mentha × piperita L. and Salvia L. were treated with single and double dose than recommended on the label during their cultivation (BBCH 11-29). Residues were monitored using the QuEChERS method followed by the LC-MS/MS. The dissipation pattern of the sum of avermectin B1a and B1b and their persistence were observed 14 d after spraying. Abamectin decline was very rapid in plants and followed the first-order kinetics model. The half-life (t 1/2 ) was in the range of 0.96-1.08 d (single dose) and 0.93-1.02 d (double dose). The pre-harvest intervals (decrease to the level of 0.01 mg kg -1 ) were 7.29-7.92 d at single and 7.99-8.64 d at double dose application. Herbal infusion preparation in previously washed and dried mint, lemon balm and sage leaves was the key processing step in the removal of abamectin residues. The reduction of initial deposits after single dose treatment was noted up to 65% (PF = 0.35-0.67) and up to 79% after double dose application (PF = 0.21-0.72) in herbal tea. Acute risk assessment of children and adults for the highest residues in EFSA PRIMo model at single and double dose expressed as hazard quotients (HQ) were <1, indicating no risk to humans via consumption of the herbal products. The data provide a better understanding of abamectin behaviour in herbal plants and can help assure herbs' safety for consumers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The presence of antibiotic residues in drinking water may be a source of contamination, which could affect the diffusion of polyphenols into the wine must during the traditional fermentation process. Antibiotic residues such as ivermectin, hydroxychloroquine, ciprofloxacin, and azithromycin on the diffusion of polyphenols and anthocyanins during wine fermentation were studied. Different samples were taken at different periods (0, 48, 96, and 168 h) to analyse the total polyphenols, anthocyanin content, and antioxidant capacity, which were correlated with Peleg's equation to establish the diffusion kinetics of these compounds. The results indicated that the presence of antibiotics reduced between 40 and 50% the diffusion of the total polyphenols and monomeric anthocyanins in red wine. The use of ivermectin showed the highest kinetic parameter k 1 compared with the use of other antibiotics. This suggested that the chemical structure and molecular weight of the antibiotics could play an important role in inhibiting the metabolism of yeasts affecting the ethanol and CO 2 production. Consequently, cell membranes would be impermeable and would not allow the release of polyphenols and anthocyanins. Therefore, it is necessary to establish strategies that allow future water quality control in wine production companies.

Spin label electron paramagnetic resonance (EPR) spectroscopy was used to study the mechanisms of action of ivermectin and curcumin against Leishmania (L.) amazonensis promastigotes. EPR spectra showed that treatment of the parasites with both compounds results in plasma membrane rigidity due to oxidative processes. With the IC 50 and EPR measurements for assays using different parasite concentrations, estimations could be made for the membrane-water partition coefficient (K M/W ), and the concentration of the compound in the membrane (c m50 ) and in the aqueous phase (c w50 ), which inhibits cell growth by 50%. The K M/W values indicated that ivermectin has a greater affinity than curcumin for the parasite membrane. Therefore, the activity of ivermectin was higher for experiments with low cell concentrations, but for concentrations greater than 1.5 × 10 8 parasites/mL the compounds did not show significantly different results. The c m50 values indicated that the concentration of compound in the membrane leading to growth inhibition or membrane alteration is approximately 1 M for both ivermectin and curcumin. This high membrane concentration suggests that many ivermectin molecules per chlorine channel are needed to cause an increase in chlorine ion influx., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Combination therapy of many anthelmintic drugs has been used to achieve fast animal curing. Q-DRENCH is an oral suspension, containing four different active drugs against GIT worms in sheep, commonly used in Australia and New Zeeland. The anti-parasitic drugs are Albendazole (ALB), Levamisole HCl (LEV), Abamectin (ABA), and Closantel (CLO). The main purpose of this study is to present a new simultaneous stability-indicting HPLC-DAD method for the analysis of the four drugs. The recommended liquid system was 1 mL of Triethylamine/L water, adjusting the pH to 3.5 by glacial acetic acid: acetonitrile solvent (20:80, v / v ). Isocratic elusion achieved the desired results of separation at a 2 mL/min flow rate using Zorbax C-18 as a stationary phase. Detection was performed at 210 nm. The linearity ranges were 15.15 to 93.75 μg/mL for ALB, 25 to 150 μg/mL for LEV, 30 to 150 μg/mL for ABA, and 11.7 to 140.63 μg/mL for CLO. Moreover, the final greenness score was 0.62 using the AGREE tool, which reflects the eco-friendly nature. Moreover, the four drugs were determined successfully in the presence of their stressful degradation products. This work presents the first chromatographic method for simultaneous analysis for Q-DRENCH oral suspension drugs in the presence of their stressful degradation products.

Production of minor crop varieties often requires intensive pesticide use, which raises serious concerns over food safety and human health. Chaenomeles speciosa (Sweet) Nakai as one of the representative of this kind of crops is therefore used for investigating the residue behavior of fenpropathrin and emamectin benzoate, a synthetic pyrethroid and macrocyclic lactone widely used as an insecticide, respectively, from cultivation to C. speciosa postharvest processing. Results showed that the degradation trends of those selected insecticides in C. speciosa followed first-order kinetics with an average half-life (t 1/2 ) of 3.7-4.1 days and a dissipation rate of 97% over 14 days. The terminal residues of fenpropathrin and emamectin benzoate at 120 and 3 g a.i./ha were below the U.S Environmental Protection Agency (FAD, 1.00 mg/kg) and European Union (EU, 0.01 mg/kg) maximum residue limits (MRLs) in papaya species, respectively, when measured 14 days after the final application, which suggested that the use of these insecticides was safe for humans. Postharvest processing procedure resulted in a |90% reduction of the insecticides. Moreover, the hazard quotient (HQ) for C. speciosa decoction (with processing factors) indicated an acceptable risk for human consumption. These findings provide the scientific evidence of reasonable application and risk assessment of the selected pesticide residues in C. speciosa., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The development of detecting residual level of abamectin B 1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5'-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B 1 in apples. The TPB molecule has been characterized by ultraviolet-visible absorption spectrometry, 1 H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L -1 and 4.4 μg L -1 , respectively. The mechanism of this probe to identify abamectin B 1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B 1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B 1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B 1 in agricultural foods.

Some South African (SA) healthcare practitioners are promoting the prescription and use of products claiming to contain ivermectin for the treatment and/or prevention of COVID-19 in SA. This study qualitatively analysed seven samples of ivermectin formulations (5 tablet and 2 capsule formulations) being sold in SA for human use. The samples were analysed using a high-performance liquid chromatography instrument connected to a Sciex X500R quadrupole time-of-flight high-resolution mass spectrometer. The study found that all the samples had both the major homologues of ivermectin (B1a and B1b) and also that 4 out of the 5 tablet formulations tested had at least one additional undeclared active pharmaceutical ingredient.

Avermectins and moxidectin are antiparasitics widely used as active pharmaceutical ingredients in veterinary medicine, as well as in pesticide formulations for pest control in agriculture. Although the use of these compounds provides benefits to agribusiness, they can impact the environment, since a large part of these substances may reach the soil and water from the excreta of treated animals and following direct applications to crops. The present work had the objective of evaluating the dissipation behaviors of abamectin, doramectin, eprinomectin, ivermectin, and moxidectin in four native Brazilian soils of different textural classes (clay, sandy-clay, sandy, and sandy-clay-loam), following OECD Guideline 307. The studies were conducted in a climate chamber at 22 °C, 71% relative humidity, and protected from light. The dissipation studies were carried out with all drugs together, since no difference was verified when studies were done with each drug separately. The concentrations of the drugs in the soils were determined using an ultra-high performance liquid chromatograph coupled to a fluorescence detector or a tandem mass spectrometer. The dissipation half-life (DT 50 ) values ranged from 9 to 16 days and the calculated GUS index values were in the range from -1.10 to 0.08, indicating low mobility of the drugs in the soils evaluated and low tendency for leaching. In addition, a field study was carried out to evaluate the dissipation of abamectin after application of a foliar pesticide in an orange crop. A DT 50 of 9 days was determined, which was similar to that obtained under controlled conditions in the climate chamber (12 days), indicating that biotransformation was the primary process influencing the overall dissipation., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Spinosad (SPN) and abamectin (ABM) are used in poultry premises to control external parasites including red mites ( Dermanyssus gallinae ). This study aimed to determine levels of SPN (spinosyn A + spinosyn D) and ABM residues in egg and edible tissues of laying hens following spray application. A total of 36 laying hens were divided into four groups of nine birds each, and they were kept in individual cages. Two different concentrations of SPN (2 and 4 g/l) and ABM (0.025 and 0.033 g/l) were applied in stocked and empty cages, respectively. Eggs were collected individually for 30 days. All hens were sacrificed at day 30 post-treatment, and tissue samples (liver, breast muscle, fat and skin) were collected. The residue levels in eggs and tissues were determined by high pressure liquid chromatography. ABM residues were not detectable in egg samples. SPN residues in eggs and residues of both ABM and SPN in liver, muscle and fat were under the maximum residue limits (MRLs) following low and high concentration applications. However, although the MRLs have not been established for SPN and ABM in skin tissue of chicken, residues in the skin detected at the low and high concentrations were greater than the MRLs for other edible tissues (except fat tissue) indicating that a withdrawal period would be necessary for the skin tissue after ABM and SPN use in laying hens.

Pesticides vary in the level of poisonousness, while a conventional rapid test card only provides a general "absence or not" solution, which cannot identify the various genera of pesticides. In order to solve this problem, we proposed a seven-layer paper-based microfluidic chip, integrating the enzyme acetylcholinesterase (AChE) and chromogenic reaction. It enables on-chip pesticide identification via a reflected light intensity spectrum in time-sequence according to the different reaction efficiencies of pesticide molecules and assures the optimum temperature for enzyme activity. After pretreatment of figures of reflected light intensity during the 15 min period, the figures mainly focused on the reflected light variations aroused by the enzyme inhibition assay, and thus, the linear discriminant analysis showed satisfying discrimination of imidacloprid (Y = -1.6525X - 139.7500), phorate (Y = -3.9689X - 483.0526), and avermectin (Y = -2.3617X - 28.3082). The correlation coefficients for these linearity curves were 0.9635, 0.8093, and 0.9094, respectively, with a 95% limit of agreement. Then, the avermectin class chemicals and real-world samples (i.e., lettuce and rice) were tested, which all showed feasible graphic results to distinguish all the chemicals. Therefore, it is feasible to distinguish the three tested kinds of pesticides by the changes in the reflected light spectrum in each min (15 min) via the proposed chip with a high level of automation and integration.

Many crops are produced using soil fumigation and chemical pesticides to control soil-borne fungi and bacterial diseases, nematodes and weeds. Fumigation of soil, however, may alter its ability to adsorb, degrade and volatilize pesticides, which can then change the potential for pesticides to leach into groundwater. Soil adsorption kinetics, Freundlich isothermal adsorption and pesticide degradation techniques were used to determine the potential for pesticides to pollute groundwater in fumigated soil. The effect on soil pesticide adsorption in different types of chloropicrin (CP) fumigated soils was also examined. We observed that the equilibrium adsorption (q e ) decreased significantly at 24 h. Soil fumigation decreased the Freundlich K f and K foc values, and increased the Freundlich exponent 1 / n values, for pesticides in fumigated Beijing soil. Soil fumigation influenced the K f of pendimethalin, oxyfluorfen and abamectin the most, which themselves had a larger K f in untreated soil. This indicated that the greater the soil pesticide adsorption the greater the influence of a fumigation treatment on that pesticide. The K f was decreased more in the Heilongjiang and Beijing CP-fumigated soils that had high organic carbon content compared to Hunan soil. Fumigation of the soil with CP extended the half-life values of fosthiazate (from 34.3 to 43.1 days) and azoxystrobin (from 52.9 to 64.2 days), which increased their potential to leach into groundwater. Famers should minimize the quantity of some pesticides applied to fumigated soil, or apply some pesticides 60 days after fumigation, in order to avoid ground water pollution when crops are grown in fields or greenhouses., (Copyright © 2018. Published by Elsevier Ltd.)

Ivermectin is a veterinary pharmaceutical widely applied against parasites of livestock. Being effective against pests, it is also known to have lethal and sublethal effects on non-target organisms. While considerable research demonstrates the impact of ivermectin residues in livestock dung on the development and survival of dung feeding insect larvae, surprisingly little is known about its fitness effects on adults. We tested the impact of ivermectin on the survival of adult sepsid dung fly species (Diptera: Sepsidae) in the laboratory, using an ecologically relevant and realistic range of 69-1978 µg ivermectin/kg wet dung, and compared the sensitivities of larvae and adults in a phylogenetic framework. For one representative, relatively insensitive species, Sepsis punctum, we further investigated effects of ivermectin on female fecundity and male fertility. Moreover, we tested whether females can differentiate between ivermectin-spiked and non-contaminated dung in the wild. Adult sepsid flies exposed to ivermectin suffered increased mortality, whereby closely related species varied strongly in their sensitivity. Adult susceptibility to the drug correlated with larval susceptibility, showing a phylogenetic signal and demonstrating systemic variation in ivermectin sensitivity. Exposure of S. punctum females to even low concentrations of ivermectin lowered the number of eggs laid, while treatment of males reduced egg-to-adult offspring survival, presumably via impairment of sperm quality or quantity. The fitness impact was amplified when both parents were exposed. Lastly, sepsid flies did not discriminate against ivermectin-spiked dung in the field. Treatment of livestock with avermectins may thus have even more far-reaching sublethal ecological consequences than currently assumed via effects on adult dung-feeding insects., (Copyright © 2018. Published by Elsevier Inc.)

The active ingredients (a.i.) used as pesticides vary across regions. Diet represents the main source of chronic exposure to these chemicals. The aim of this study was to look at the pesticides applied in fruit, vegetable, and beef cattle productions in Mendoza (Argentina), to identify those that were simultaneously used by the three production systems. Local individuals (n = 160), involved in these productions, were interviewed. Glyphosate was the a.i. most often used by fruit-vegetable producers, and ivermectin by beef cattle producers. Chlorpyrifos (CPF) and cypermethrin (CYP) were the only a.i. used by the three production systems. The survey revealed that CPF, CYP, alpha CYP, and CPF+CYP were used by 22, 16, 4, and 20% of the fruit and vegetable producers, respectively. Regarding beef cattle, CYP was used by 90% of producers, CYP + CPF formulation by 8%, and alpha CYP by 2%. The second approach of this study was to search the occurrence of CYP and CPF residues in food commodities analyzed under the National Plan for Residue Control (2012-2015). CYP residues found above the LOD were reported in 4.0% and CPF in 13.4% of the vegetable samples tested, as well as in 1.2 and 28.8%, respectively, of the fruit samples tested. Regarding beef cattle, CYP residues were reported in 2.3% and organophosphates (as a general pesticide class) in 13.5% of samples tested. In conclusion, consumers may be exposed simultaneously to CPF and CYP, from fruits, vegetables, and beef intake. Accordingly, the policy for pesticide residues in food and human risk assessment should account for the combined exposure to CPF and CYP. Moreover, appropriate toxicological studies of this mixture (including genotoxicity) are warranted.

A method was established for the simultaneous determination of seven avermectin (AVMs) residues, such as avermectin, ivermectin, doramectin, selamectin, eprinomectin, moxidectin and emamectin, in aquatic products using modified QuEChERS and high-performance liquid chromatography -tandem mass spectrometry (HPLC-MS/MS). The samples were extracted with 0.2% (v/v) ammoniate acetonitrile, and then 3 g of anhydrous magnesium sulfate and 2 g of anhydrous sodium sulfate were added to remove moisture and precipitate proteins. The samples were purified with 100 mg of C 18 and 500 mg of anhydrous magnesium sulfate. The mobile phases comprised of acetonitrile (containing 0.1% (v/v) formic acid and 5 mmol/L ammonium acetate) and water (containing 0.1% (v/v) formic acid and 5 mmol/L ammonium acetate). The prepared samples were separated on a Varian Pursuit ULTRA C 8 column (100 mm×2.0 mm, 2.8 μm) and determined using heated electrospray ionization (HESI) in the positive ion multiple reaction monitoring (MRM) mode. The analytes were quantified using external standard with the matrix-matched standard calibration curve method. The results showed that the solvent and matrix-matched standard curves for avermectin, ivermectin, doramectin, selamectin, eprinomectin and moxidectin in the range of 2-200 μg/L and for emamectin in the range of 0.2-20 μg/L were all linear, and the correlation coefficients ( r ) were ≥ 0.9972. The recoveries were 71.6%-112.8% with the relative standard deviations in the range of 4.7%-13.1%. The limits of quantification (LOQs) for avermectin, ivermectin, doramectin, selamectin, eprinomectin and moxidectin were all 5 μg/kg and for emamectin was 0.25 μg/kg. The present method is simple, repeatable, and suitable for the simultaneous determination of the residues of the seven avermectins in aquatic products.

Ivermectin (IVM) is a parasiticide widely used for livestock. It is a semisynthetic derivative of avermectin, a macrocyclic lactone produced by Streptomyces avermitilis. This drug is only partly metabolized by livestock; considerable amounts of parent drug are excreted mostly via feces. To simulate exposure of aquatic invertebrates and macrophytes to direct excretion of cattle dung into surface waters, a microcosm experiment with IVM spiked in cattle dung was conducted. The objectives of this study were to characterize accumulation of IVM in water, sediment+dung, roots of the floating fern Salvinia and the zooplankton Ceriodaphnia dubia, the amphipod Hyalella and the apple snail Pomacea; to determine the effect of this drug spiked in cattle dung on life-history traits of these invertebrates; and to evaluate the influence of IVM on aquatic nutrient cycling. Dung was spiked with IVM to attain concentrations of 1150, 458, 50 and 22µgkg -1 dung fresh weight, approximating those found in cattle dung at days 3, 7, 16 and 29 following subcutaneous injection. Concentrations found in dung during the first week of excretion were lethally toxic to Ceriodaphnia dubia and Hyalella, whereas no mortality was observed in Pomacea. Concentrations of IVM in roots, sediment + dung and Pomacea increased significantly from the lowest to the highest treatment level. The effect of this drug on decomposition and release of nutrients from dung would have negative consequences for nutrient cycling in water. Increasing concentrations in sediment + dung with days of the experiment suggested that toxic concentrations would persist for an extended period in the water-sediment system. IVM represents an ecological risk for aquatic ecosystems, underscoring the need for livestock management strategies to limit its entry into water bodies., (Copyright © 2017 Elsevier Inc. All rights reserved.)

In this study, the residues of beta-cypermethrin, pyriproxyfen, avermectin, diflubenzuron and chlorothalonil in button mushrooms were investigated. The dietary risks of ingesting button mushrooms that have had these pesticides applied by two different methods under normal plant conditions were evaluated. The dissipation of these pesticides into the soil was also studied. According to the maximum residue limits (MRLs) and acceptable daily intakes (ADIs), the final residues of beta-cypermethrin, pyriproxyfen, avermectin, diflubenzuron, and chlorothalonil were safe for human consumption after these pesticides were applied by spraying 2 times at the dosages of 900, 750, 540, 562.5, and 540 g a.i.ha -1 . The dissipation experiment results demonstrated that these pesticides dissipated rapidly after spraying, and there were no residues that could be detected at harvest time when the pesticides were mixed with substrates. According to this work, the application methods of spraying and incorporation with these pesticides at 1 and 1.5 times of the recommended dosage are safe and proper in cultivating button mushrooms.

Ivermectin (IVM) is broad-spectrum compound active against endo and ecto-parasites of clinical relevance in veterinary and human medicine. It is commercially available to use in livestock animals as injectable formulations containing 1% IVM and also as a concentrated (3.15%) long-acting (LA) preparation. The potential risk of the presence of high concentrations of drug residues in muscle tissue at the injection site is therefore a concern. The aim of this study was to determine the relationship between the IVM residual concentrations at the injection site, in comparison to the untreated contralateral neck (control muscle) and in fat from cattle treated with different preparations. Healthy steers received one of the following subcutaneous treatments in the neck area: Group A: IVM-LA 3.15% preparation and Group B: IVM 1%. After a withdrawal period for each formulation the animals were sent to the slaughterhouse. IVM concentrations at the injection site were detected among animals treated with the LA formulation, with high residual concentrations of IVM (between 15 and 141 μg/kg) in the injection site of two steers. However, the residual concentrations of IVM at the injection site obtained after the subcutaneous administration of the LA preparation do not represent a toxicological risk to consumers., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A new analytical method based on solvent extraction, followed by continuous solid-phase extraction (SPE) clean-up using a polymeric sorbent, was demonstrated to be applicable for the detection of ivermectin in complex biological matrices of dung beetles (hemolymph, excreta or dry tissues) using liquid chromatography combined with positive electrospray ionization tandem mass spectrometry (LC/ESI+-MS/MS). Using a signal-to-noise ratio of 3:1, the limit of detection (LOD) in the insect matrices at trace levels was 0.01 ng g-1 and the limit of quantification (LOQ) was 0.1 ng g-1. The proposed method was successfully used to quantitatively determine the levels of ivermectin in the analysis of small samples in in vivo and post mortem samples, demonstrating the usefulness for quantitative analyses that are focused on future pharmacokinetic and bioavailability studies in insects and the establishment of a new protocol to study the impact of ivermectin on non-target arthropods such as dung beetles and other insects that are related with the "dung community". Because satisfactory precision and accuracy values were obtained in both in vivo matrices, we suggest that the method can be consistently used for quantitative determinations that are focused on future pharmacokinetic and bioavailability studies in insects. Furthermore, this new analytical method was successfully applied to biological samples of dead dung beetles from the field suggesting that the method can be used to establish a new routine analysis of ivermectin residues in insect carcasses that is applied to complement typical mortality tests.

Avermectins (AVM) are macrocyclic lactones used in livestock and agriculture. A quantitative method of high performance liquid chromatography with fluorescence detection for the determination of eprinomectin, abamectin, doramectin and ivermectin in rural water samples was developed and validated. The method was employed to study samples collected in the Pito Aceso River microbasin, located in the Bom Jardim municipality, Rio de Janeiro State, Brazil. Samples were extracted by solid phase extraction using a polymeric stationary phase, the eluted fraction was re-concentrated under a gentle N2 flow and derivatized to allow AVM determination using liquid chromatography with fluorescence detection. The excitation and emission wavelengths of the derivatives were 365 and 470nm, respectively, and a total chromatographic run of 12min was achieved. Very low limits of quantification (22-58ngL(-1)) were found after re-concentration using N2. Recovery values varied from 85.7% to 119.2% with standard deviations between 1.2% and 10.2%. The validated method was applied in the determination of AVM in 15 water samples collected in the Pito Aceso River microbasin, but most of them were free of AVM or showed only trace levels of these compounds, except for a sample that contained doramectin (9.11µgL(-1)). The method is suitable for routine analysis with satisfactory recovery, sensitivity, and selectivity., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Abamectin is a broad-spectrum antiparasitic agent that has been widely employed in veterinary medicine and has also been used as a pesticide in agriculture. Veterinary drugs may reach the soil and may be transported to surface and ground waters, posing risks to terrestrial and aquatic organisms. Sorption, transformation and transport processes are primarily responsible for the fate of these substances in the environment. In this study, the sorption and the aerobic dissipation of abamectin in Brazilian soils (sand, clay and sandy-clay) were evaluated. For sorption studies, batch equilibrium experiments were performed. Sorption and desorption isotherms were fitted to the Freundlich model. Abamectin showed a high affinity to soil particles, with Freundlich sorption and desorption coefficients ranging from 44 to 138 μg(1-1/n) (cm(3))(1/n) g(-1) and from 89 to 236 μg(1-1/n) (cm(3))(1/n) g(-1), respectively. Dissipation of abamectin was evaluated in sterile and non-sterile soils in an aerobic and dark environment under controlled temperature and humidity. The time required for a 50% reduction of the amount of abamectin present in non-sterile soils was up to 4 days, and the time period for 90% dissipation was up to 12 days. In sterilized soils, there was no reduction in the concentration of abamectin over 37 days of exposure, suggesting that aerobic microbial degradation must have been the primary mechanism responsible for the dissipation of abamectin in soils., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Avermectins, such as eprinomectin (EPM), are antiparasitic drugs widely and globally used. There is undisputed evidence that they could be a threat for the terrestrial ecosystem. Despite their global use, data for avermectins behaviour and fate in soils are scarce. The objectives of this research were to conduct adsorption experiments in the soil to determine kinetics and isotherms as well as to explore the EPM adsorption mechanism. Accordingly, various models were employed to study the adsorption behaviour and kinetics as well as the adsorption mechanism of EPM in soils. The results showed that the degree of EPM adsorption to soils is determined by the soils' physicochemical properties and the EPM initial concentration. It is possible that dissolved EPM concentration will be higher in soils that contain low amounts of clay minerals and organic matter, resulting in higher toxicity risk for the soil biota and shallow groundwater aquifers contamination. The results of this study are crucial for impact assessment of EPM and in the design of environmental fate or ecotoxicological studies., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Residue analysis of emamectin benzoate and lufenuron in cabbage matrices and soil was developed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and ultra high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with 1% acetic acid in acetonitrile (v/v) or 1% acetic acid in acetonitrile/water (5:1, v/v) and cleaned up by dispersive solid-phase extraction. Mean recoveries and relative standard deviations (RSDs) in all samples ranged 87.8-100.0 % and 3.6-12.6% for emamectin benzoate and 87.8-104.8 % and 6.2-11.5% for lufenuron, respectively. The validated method was used to evaluate the dissipation rate of emamectin benzoate and lufenuron in cabbage and soil as well as the residual levels in harvested cabbage and soil at different preharvest intervals (PHI). The half-lives of emamectin benzoate and lufenuron were 1.08-2.70 and 1.74-5.04 days in cabbage, and 1.42-4.01 and 0.94-6.18 days in soil, respectively. The terminal residues were below the China maximum residue limits (MRLs) at 3 days for emamectin benzoate (0.1 mg kg(-1)) and European Union MRLs at 5 days for lufenuron (0.5 mg kg(-1)), which suggested that 5 days could be recommended as the PHI for the commercial formulation of emamectin benzoate and lufenuron application in the Chinese cabbage field.

A method based on on-line solid-phase extraction (SPE) with hydrophobic monolithic column coupled with high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of five avermectins in bovine liver. A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was used as the sorbent. The parameters influenced on on-line SPE and separation process such as the loading mobile phase, the eluting flow rate and the solvent for the separation were investigated in detail. Blank samples, spiked samples, matrix effect and recovery experiments were investigated to evaluate the extraction efficiency and potential interfering compounds originating from the matrix. Under the optimized conditions, the method showed a linear range of 1-100 µg/L and the quantification limit of 5 µg/kg for each analyte. The presented method gave recoveries of 77.4%-98.4%. The relative standard deviations of intra-day and inter-day were 4.46%-8.03% and 4.79%-8.68%, respectively. Moreover, no significant changes were found in the extraction performance after more than 400 usages on one monolithic column, and even on the monoliths with various batches. The feasibility of the developed poly (butyl methacrylate-coethylene dimethacrylate) monolithic column based on the on-line SPE method for the determination of avermectins was further demonstrated by the analysis of real samples.

In recent years, the number of analytical methods of target compound residues (such as pharmaceuticals) has grown rapidly. Most of them are based on high performance liquid chromatography (HPLC). From the economic point of view, it is usual to apply the conditions of available HPLC methods or to design extraction and chromatographic separation conditions using HPLC and transfer them subsequently to a more sensitive technique like liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). However, if such a transfer is planned, it is important to assess the quality of the newly-designed LC-MS/MS method. The determination of parameters like matrix effects (ME), extraction efficiency (EE) and absolute recovery (AR) is mandatory. These parameters can visualise the weakest step in the analytical method and enable methods based on different techniques to be compared. The aim of this work was to show how quality assessment should be carried out in order to transfer an optimised method from one technique to another. The representative compound used in our investigation was doramectin (DOR), an anthelmintic drug used in veterinary medicine. The quality of the suggested methods for determining this drug in three environmental matrices (water, sediment and fish tissue) using HPLC-UV and LC-MS/MS was evaluated on the basis of known values of absolute recovery (HPLC-UV) and matrix effect, extraction efficiency and absolute recovery (all LC-MS/MS). Finally, the suggested methods for determining DOR in water, sediment and fish tissue based on LC-MS/MS measurements were validated and applied to the analysis of real environmental samples., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Dissipation and decontamination of the semisynthetic macrolide emamectin benzoate and the natural insecticide spinosad on cowpea pods were studied following field application at single and double doses of 11.0 and 22 and 73 and 146 g ai ha(-1), respectively. Residues of these naturalytes were estimated using LC-MS/MS. The initial deposit of 0.073 and 0.153 mg kg(-1) of emamectin benzoate dissipated below quantitation level on the fifth and seventh day at single and double dosage, respectively. For spinosad, the initial deposits of 0.94 and 1.90 mg kg(-1) reached below quantitation level on the 7th day and 15th day at single and double dosage, respectively. The half-life of emamectin benzoate and spinosad was 1.13-1.49 and 1.05-1.39 days with the calculated safe waiting period of 2.99-6.12 and 1.09-3.25 days, respectively, for single and double dosage. Processing of the harvestable pods with different decontamination techniques resulted in 33.82 to 100 % removal 2 h after the application of emamectin benzoate and 100 % removal 3 days after spraying, while the removal was 42.05 to 87.46 % 2 h after the application of spinosad and 38.05 to 68.08 % 3 days after application.

A labour- and time-effective analytical procedure for determination of ivermectin in medicated feed at recommended level of 2.0 mg kg(-1) has been developed and validated. The analyte was extracted from grinded feed samples with acetonitrile and derivatisated with N-methylimidazole and trifluoracetic anhydride. The fluorescent derivatives were analysed by liquid chromatography method using C8 column. The isocratic conditions using acetonitrile, methanol, water, and tetrahydrofuran were applied. Fluorescence detection was performed at 365 nm (excitation) and 475 nm (emission) wavelengths. The total analysis time was 10 min. The validation results of the method (within-laboratory reproducibility 4.0% CV, mean recovery 100.1%) confirm the appropriate precision and accuracy of the developed method.

The pre-harvest residue limit (PHRL) of abamectin (abamectin B1a and B1b) in Perilla frutescens leaves grown under greenhouse conditions were investigated using high-performance liquid chromatography with a fluorescence detector. Samples were extracted with acetonitrile. The extract was purified through a solid phase extraction procedure. Then the purified extract was derivatized with trifluoroacetic anhydride and N-methylimidazole to form a strong stable fluorescent derivative of abamectin. Finally, derivatized abamectins were conveyed to the detector via an Atlantis C18 column, with water and methanol as a mobile phase. Calibration curves were linear over the calibration ranges with coefficients of determinants r (2) ≥ 0.999. The limits of detection and quantification were 0.0033 and 0.01 mg kg(-1) for abamectin B1a and B1b, respectively. Recovery was assessed in a control matrix at two different fortification concentrations, with three replicates for each concentration. Good recoveries were obtained for the target analytes and ranged from 82.11 to 93.03%, with relative standard deviations of less than 8%. The rate of disappearance of total abamectin on perilla leaves for recommended and double the recommended doses was described as first-order kinetics with a half-life of 0.7 days. Using the PHRL curve, we could predict the residue level of total abamectin to be 0.92 mg kg(-1) at 7 days before harvest or 0.26 mg kg(-1) at 4 days before harvest, which would be below the provisional MRL designed by the Korea Food and Drug Administration.

Eprinomectin (EPM) is a veterinary drug currently licensed in many countries for the treatment of endo- and ecto-parasites in cattle. Despite the notable evidence for its high toxicity to the terrestrial and aquatic environment ecosystems, its environmental behavior and fate are currently unknown. In the present research, the dissipation of EPM was studied in three soils and in cattle manure by using the OECD 307 guideline and the recently developed European Medicines Agency (EMA/CVMP/ERA/430327) guideline, respectively. The procedure presented by the FOrum for Co-ordination of pesticide models and their USe (FOCUS) was adopted for estimating the EPM degradation kinetics in soil and cattle manure. The EPM dissipation in soil was best described by the SFO (Simple First Order) and the HS (Hockey Stick) models, under aerobic and anaerobic conditions, respectively. The EPM dissipation in cattle manure was best described by the FOMC (First Order Multi Compartment) model. The Dissipation Time for the 50% of the initial EPM mass (DT50) range was 38-53days under aerobic and 691-1491days under anaerobic conditions. In addition, the DT50 for EPM in cattle manure was 333days. Therefore, EPM could be characterized as moderately to highly persistent to dissipation in soil, which depends on soil type, its oxygen content (aerobic or anaerobic conditions in soil) and the microbial activity. Moreover, the EPM resists dissipation in cattle manure, resulting to a high load in soil after manure application in agricultural land (or direct defecation in grassland). Consequently, the high possibility for EPM accumulation in soil and cattle manure should be considered when assessing the environmental risk of the drug., (© 2013.)

Veterinary pharmaceuticals excreted in the dung of treated livestock can have strong non-target effects on the dung organism community. We report results of ecotoxicological tests with ivermectin for 21 species of temperate (Europe, North America) and tropical (Asia, Central America) black scavenger flies (Diptera: Sepsidae), using standardized methods developed previously for the yellow dung fly and the face fly. Our study documents great variation in ivermectin sensitivity of more than two orders of magnitude among species and even populations within species: estimated lethal effect concentrations LC(50) (at which 50% of the flies died) ranged from 0.05 to 18.55 μg/kg dung fresh weight (equivalent to 0.33-132.22 μg/kg dung dry weight). We also show that controlled laboratory tests can--within reasonable limits-be extended to the field or to laboratory settings without climate control, as obtained LC(50) were roughly similar. In addition to lethal effects, our study revealed relevant sub-lethal effects at lower ivermectin concentrations in terms of prolonged development, smaller body size and reduced juvenile growth rate. Finally, oviposition choice experiments showed that females generally do not discriminate against dung containing ivermectin residues. We conclude that sepsid flies are well suited test organisms for pharmaceutical residues in the dung of livestock due to their ease and speed of rearing and handling, particularly in the tropics, where high-tech laboratory equipment is often not available., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Due to the widespread use and potential toxicity of avermectins (AVMs), multi-residue monitoring of AVMs in edible tissues, especially in milk, has become increasingly important. With the aim of developing a broad-selective immunoassay for AVMs, a broad-specific monoclonal antibody (Mab) was raised. Based on this Mab, a homologous indirect enzyme-linked immunosorbent assay (ELISA) for the rapid detection of AVMs in milk was developed. Under the optimized conditions, the IC₅₀ values in assay buffer were estimated to be 3.05 ng/mL for abamectin, 13.10 ng/mL for ivermectin, 38.96 ng/mL for eprinomectin, 61.00 ng/mL for doramectin, 14.38 ng/mL for emamectin benzoate. Detection capability (CCβ) of the ELISA was less than 5 ng/mL and 2 ng/mL in milk samples prepared by simple dilution and solvent extraction, respectively. The optimized ELISA was used to quantify AVMs in milk samples spiked at different amounts. The mean recovery and coefficient of variation (CV) were 95.90% and 15.42%, respectively. The Mab-based ELISA achieved a great improvement in AVMs detection. Results proved this broad-selective ELISA would be useful for the multi-residue determination of AVMs in milk without purification process.

A LC-ESI-MS/MS method with QuEChERS for analysis of emamectin benzoate in cabbage, apple and soil was established. At fortification levels of 0.001, 0.01 and 0.1 mg/kg in cabbage, apple and soil, it was shown that recoveries ranged from 75.9 to 97.0 percent with relative standard deviation (RSD) of 4.4-19.0 percent. The limit of quantification (LOQ) was 0.001 mg/kg for cabbage, apple and soil. The dissipation half-lives of emamectin benzoate in cabbage, apple and soil were 1.34-1.72 day, 2.75-3.09 day and 1.89-4.89 day, respectively. The final residues of emamectin benzoate ranged from 0.001 to 0.052 mg/kg in cabbages, 0.003 to 0.090 mg/kg in apples and 0.001 to 0.089 mg/kg in soils, respectively. Therefore, it would be unlikely to cause health problems if emamectin benzoate was applied according to the use pattern suggested by the manufactures on the label., (Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.)

The potential impact of commercial salmon aquaculture along the coast of British Columbia on the health of non-target marine wildlife is of growing concern. In the current initiative, the biological effects on gene expression within spot prawn (Pandalus platyceros) exposed to the sea lice controlling agent, emamectin benzoate (EB; 0.1-4.8 mg/kg sediment), were investigated. A mean sediment/water partitioning coefficient (K(p)) was determined to be 21.81 and significant levels of EB were detected in the tail muscle tissue in all exposed animals. Animals selected for the experiment did not have eggs and were of similar weight. Significant mortality was observed within 8 days of EB treatment at concentrations between 0.1 and 0.8 mg/kg and there was no effect of EB on molting. Twelve spot prawn cDNA sequences were isolated from the tail muscle either by directed cloning or subtractive hybridization of control versus EB exposed tissues. Three of the transcripts most affected by EB exposure matched sequences encoding the 60S ribosomal protein L22, spliceosome RNA helicase WM6/UAP56, and the intracellular signal mediator histidine triad nucleotide binding protein 1 suggesting that translation, transcription regulation, and apoptosis pathways were impacted. The mRNA encoding the molting enzyme, β-N-acetylglucosaminidase, was not affected by EB treatment. However, the expression of this transcript was extremely variable making it unsuitable for effects assessment. The results suggest that short-term exposure to EB can impact biological processes within this non-target crustacean., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Abamectin is used as an acaricide and insecticide for fruits, vegetables and ornamental plants, as well as a parasiticide for animals. One of the major problems of applying pesticides to crops is the likelihood of contaminating aquatic ecosystems by drift or runoff. Therefore, toxicity tests in the laboratory are important tools to predict the effects of chemical substances in aquatic ecosystems. The aim of this study was to assess the potential hazards of abamectin to the freshwater biota and consequently the possible losses of ecological services in contaminated water bodies. For this purpose, we identified the toxicity of abamectin on daphnids, insects and fish. Abamectin was highly toxic, with an EC(50) 48 h for Daphnia similis of 5.1 ng L(-1), LC(50) 96 h for Chironomus xanthus of 2.67 μg L(-1) and LC(50) 48 h for Danio rerio of 33 μg L(-1)., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: To investigate plasma disposition, concentration in the hair, and anthelmintic efficacy of eprinomectin after topical administration in donkeys., Animals: 12 donkeys naturally infected with strongyle nematodes., Procedures: The pour-on formulation of eprinomectin approved for use in cattle was administered topically to donkeys at a dosage of 0.5 mg/kg. Heparinized blood samples and hair samples were collected at various times between 1 hour and 40 days after administration. Samples were analyzed via high-performance liquid chromatography with fluorescence detection. Fecal strongyle egg counts were performed by use of a modified McMaster technique before and at weekly intervals for 8 weeks after treatment., Results: Plasma concentration and systemic availability of eprinomectin were relatively higher in donkeys, compared with values reported for other animal species. Concerning the anthelmintic efficacy against strongyle nematodes, eprinomectin was completely effective (100%) on days 7 and 14 and highly effective (> 99%) until the end of the study at 56 days after treatment. No abnormal clinical signs or adverse reactions were observed for any donkeys after treatment., Conclusions and Clinical Relevance: Eprinomectin had excellent safety. The relatively high plasma concentration after topical administration could result in use of eprinomectin for the control and treatment of parasitic diseases in donkeys.

The purpose of the study was to develop a simple, versatile HPLC method for the identification and quantification of praziquantel and ivermectin (in Equimax) or praziquantel and abamectin (in Abamitel Plus). A satisfactory separation was obtained using the Supelcosil LC-ABZ+ column in gradient system with a mobile phase A: acetonitrile / water in 40:60 ratio and phase B: acetonitrile. The UV detection was set at 245 nm. The correlation coefficient values (> or = 0,998) for all active substances confirmed that the calibration curves (peak area vs. concentration) are linear. The results of the quantification and the statistical evaluation confirmed that the method is accurate and precise. It can also be applied to confirm the identity of benzyl alcohol, methyl p-hydroxybenzoate and propyl p-hydroxybenzoate in Abamitel Plus formulation.

A method for the determination of avermectin, ivermectin, doramectin, moxidectin, eprinomectin, diclazuril, toltrazuril and its two metabolite residues in pork was developed using QuEChERS method with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with acetonitrile and purified through QuEChERS method using ODS as the sorbent. The target compounds were separated on a Venusil ASB C18 column (150 mm x 2.1 mm, 3.0 microm) and detected by HPLC-MS/MS. The linear ranges were 0.005 - 0.2 mg/L and the correlation coefficients were all above 0.990. The average recoveries and the relative standard deviations ranged from 73.2% to 91.5% and from 12% to 17% at the spiked levels of 0.005, 0.01 and 0.02 mg/kg for the 9 analytes in pork matrix. This method is reliable, and suitable for the determination of the residues of avermectin and related compounds in pork.

Batch equilibrium studies were conducted to determine eprinomectin partitioning behavior in three Greek soils (agricultural, pastoral and riparian soil). An analytical method was developed to quantify eprinomectin in aqueous 0.01 M CaCl₂. Recovery was 95% and limits of detection and quantification were both 0.005 mgL⁻¹. An existing method for its quantification in soil was successfully tested in this study. Mass balance determinations showed that we accounted for 89-98% of the eprinomectin spiked in 5 g soil/25 mL 0.01 M CaCl₂. The concentration specific adsorption distribution coefficient (K(d)(ads)) ranged from 6.4 to 21.4 L kg⁻¹ while concentration specific desorption distribution coefficient (K(d)(des)) ranged from 23.2 to 124.6 L kg⁻¹. The Freundlich model adequately described adsorption and desorption with n values from 0.6 to 1.07. Hysteresis between adsorption and desorption was observed in two (agricultural and pastoral) soils. Moreover, eprinomectin binding to the clay mineral vermiculite and natural peat was tested. The drug binds to both materials. Hydroxyl groups and the nitrogen group present in eprinomectin are probably responsible for the binding to vermiculite. Coefficient K(d)(ads) significantly correlated with cation exchange capacity (CEC), Fe and Cu content of the soils when data for eprinomectin and data for ivermectin and abamectin were combined. These could be evidence that eprinomectin fate is related not only to organic matter (lipophilic binding) but also to clay content and other charged inorganic groups typically present in the soil environment., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Fish bioaccumulate a variety of contaminants and act as an exposure portal to the human consumer. Surfactants, known pharmaceutically to alter membrane permeability, change drug bioavailability and attenuate transporter function are also found in contaminant mixtures in the aquatic environment. The overall objective of this study was to determine if the surfactant C-12 linear alkylbenzene sulfonate (LAS) at environmentally relevant concentrations, alters the disposition and enhances bioaccumulation of co-exposed dietary xenobiotics in the catfish. Included for study were the carcinogen benzo(a)pyrene (BaP), pharmaceutical, ivermectin (IVM), and P-glycoprotein (P-gp) substrate rhodamine 123 (Rho-123), each exhibiting different dispositional footprints. Rho-123 transport into bile and membrane fluidity was examined in isolated perfused livers from control and LAS exposed catfish. Mass balance residue assessments were performed on catfish following in vivo exposure for 12 days to LAS in water at 0, 100 or 300 microg/L with 6 days of (3)H-IVM or (3)H-BaP gavage treatments. LAS at 1, 5 and 20 microM in the perfused liver, significantly decreased the transport of Rho-123 (1 microM) into bile by 18.6, 38.1 and 66.7%, respectively. Fluorescence anisotropy measurements demonstrated a 29.7% increase in fluidity at the (1 microM, 348 microg/L) LAS concentration. In vivo mass balance studies indicated that waterborne LAS (100 and 300 microg/L) increased the dietary dose remaining in fish by 39% and 78% for (3)H-IVM and 50 and 157% for (3)H-BaP. LAS at environmentally relevant concentrations altered the bioavailability and disposition of dietary xenobiotics in the catfish. Co-exposure with LAS increases xenobiotic bioaccumulation, potential toxicity of mixture components to the fish and the potential for residue transfer from fish to the consumer., ((c) 2010 Elsevier B.V. All rights reserved.)

Factors influencing fate of avermectins (abamectin, doramectin) in faeces of treated sheep were investigated under different experimental conditions. In the laboratory, concentrations of both avermectins were declined in homogenised faeces of treated animals until day 14 of exposure, regardless of experimental conditions. After that day, no significant decrease in concentrations was observed till the end of the experiment. Established DT(50) did not exceed 9 days. In the karst pasture, an average DT(50) of 27 days was established for abamectin and 23 days for doramectin in natural faeces of treated sheep. In the compost mixture, doramectin concentration was decreased by 38.9+/-2.6% during 21 days of the thermophilic phase of composting. Therefore, DT(50) was not established. A possible influence of moisture content of sheep faeces on concentrations of avermectins was observed.

Dung invertebrate colonization and degradation levels of faeces from cattle treated with endectocides were studied. Faeces of control and doramectin (DRM) (subcutaneous) and moxidectin (MXD) (subcutaneous and topical) treated animals were deposited on the field from 3 to 21 days post-treatment (pt). Pats were recovered after 6 to 42 days post-deposition (pd). Faecal weight, dry matter, arthropods number, and drugs concentrations were determined. Total arthropods number was higher in control (P<0.0001) than in the other groups from days 3 to 21 pt. Total number of insects recovered on days 3, 11, and 21 pt from control pats was significantly (P<0.001) higher than in treated-animal pats during all the trial. At day 21 pt, the insects' number in dung voided by DRM-treated cattle was (P<0.05) lower than in the other groups. Comparisons of dung degradation among treatments were inconclusive. A lower adverse effect was observed for MXD compared with DRM. No significant degradation of MXD or DRM was observed during the present trial.

A rapid method has been developed for monitoring five multiclass pesticides commonly used in citrus fruits. The determination is performed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), after extraction with a mixture of ethyl acetate and sodium sulfate. The method has been validated for orange matrix. Mean recoveries obtained were between 74-110% with a repeatability precision of < 7%, intermediate precision of < 10% and reproducibility precision of < 17%. Linearity over the range 0.010-0.150 mg/kg was demonstrated (r(2) > or = 0.99) with limits of quantification (LOQs) of < or = 0.01 mg/kg. Also, an analytical study focused on the stability of pesticide residues in orange extracts under storage was performed. The method has been applied to the analysis of 365 samples from the agricultural area of the Valencian Community (Spain). Of 103 samples that contained pesticide residues, only abamectin in 2 samples and carbendazim in 5 samples slightly exceeded the European maximum residue limits (MRLs).

Phenoloxidase (PO) is a key enzyme involved in the immune response of insects. We show that egg-to-adult exposure to residues of 0.001, but not 0.0005 mgkg(-1) ivermectin elevated PO activity in yellow dung flies (Scathophaga stercoraria) developing in cattle dung. Fly fat content was unaffected by the treatments. Therefore, the response of PO was a direct effect of ivermectin and not an indirect one caused by an alteration in body 'condition'. This supports the non-intuitive conclusion that flies surviving exposure to faecal residues may have enhanced immune function. To our knowledge, this is the first study to assess the effects on PO activity of insecticidal residues in livestock dung. The non-target effects of such residues are of wide interest, given the global use of veterinary products.

A simple and rapid analytical method for the simultaneous determination of abamectin, emamectin, eprinomectin, ivermectin, doramectin and moxidectin residues in tea by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC/ESI-MS/MS) has been developed. The avermectins were extracted from the tea with acetonitrile after the tea was infiltrated in saturated aqueous NaCl solution, then cleaned up with a C18 solid phase extraction cartridge. The linear ranges were 2.0-50 microg/L and the correlation coefficients were all above 0.9920. Several UPLC-MS/MS conditions that included the mobile phase, monitor ions and the selection of calibration of the measurement were studied. The average recoveries and the relative standard deviations ranged from 61.7% to 85.4% and from 9.37% to 17.19%, respectively, in spiked samples at the concentrations of 5, 10, 20 microg/kg for moxidectin and 2, 5, 10 microg/kg for other analytes. This method is suitable for the determination of avermeetin residues in tea.

A sensitive and reliable method for the determination of trace amounts of abamectin in muscles, kidneys and fat tissue of fallow deer is presented. Abamectin was extracted from the tissues with acetonitrile and the extract was cleaned up on a C8 solid-phase extraction cartridge. Abamectin residue was derivatised with trifluoroacetic acid anhydride and 1-methylimidazole, and determined using reversed-phase high-performance liquid chromatography under isocratic conditions and fluorescence detection. The recoveries of the method were high and consistent, ranging from 78% to 90%. The limit of detection of the method was below 1 microg/kg when analysing muscle, kidney and fat tissue. Matrix-matched calibration was used in order to obtain accurate values and to avoid matrix interference.

A method was developed for the determination of emamectin benzoate residue in cabbage and mushroom using solid-phase extraction (SPE) and high performance liquid chromatography (HPLC) with fluorescence detection. The sample was extracted with ethyl acetate. Further cleanup was performed on a propylsulfonic acid solid phase extraction cartridge, followed by the derivatization with trifluoroacetic anhydride in the presence of N-methylimidazole. The amount of derivatized emamectin benzoate was determined by fluorescence detector after separation by HPLC. The detection limit was 0.10 microg/kg for cabbage and mushroom samples. The recoveries of emamectin benzoate in cabbage and mushroom samples were 78.6%-84.9%. The inter-day relative standard deviation (RSD) and intra-day RSD were 2.7%-6.0% and 3.1%-8.9%, respectively, at the fortified levels of 1.0-20.0 microg/kg. The calibration curve of emamectin benzoate in vegetables at the concentration range of 0.002 mg/L to 0.10 mg/L was linear (r = 0.9999).

An analytical procedure has been introduced to enable study of the time profile of eprinomectin excretion in sheep faeces. Eprinomectin was extracted from sheep faeces with acetonitrile, the extract was cleaned by solid-phase extraction (SPE), and, after derivatization by reaction with N-methylimidazole, trifluoroacetic anhydride, and acetic acid, eprinomectin was analysed by high-performance liquid chromatography (HPLC) with fluorescence detection. The method has a low detection limit (1.0 ng g(-1) of moist sheep faeces), a low quantification limit (2.5 ng g(-1) of moist sheep faeces), good recovery (in the range 78.8 to 87.1%), and good reproducibility (RSD<10%). The method was used to study the time-profile of excretion of eprinomectin in sheep faeces after a single topical administration of 0.5 mg kg(-1) b.w. of the drug. Because of its good recovery, precision, and sensitivity, the method has also proved applicable to further ecotoxicological studies of eprinomectin.

According to European Union recommendations, a test method has been developed to evaluate the effects of veterinary pharmaceuticals on dung feeding insects. This test method was evaluated with the dung beetle Aphodius constans by using fecal residues of ivermectin after a pour-on administration. Dung of different age (and thus containing different concentrations of ivermectin) as well as mixtures of highly-contaminated spiked dung with untreated control dung were studied in five test runs in two laboratories. The concentration of ivermectin (active substance; a.s.) in the dung samples was verified analytically. The main test endpoint was the survival of first instar larvae. The LC50 using dung directly obtained from treated cattle ranged from 470 to 692 microg a.s. kg(-1) dung (dry weight; d.w.) and 67 to 97 microg a.s. kg(-1) dung (fresh weight; f.w.). Using mixtures, the outcome of two tests was almost identical: 770 to 781 microg a.s. kg(-1) dung (d.w.); 109 to 132 microg a.s. kg(-1) dung (f.w.). In comparison to the LC50 values obtained when ivermectin was spiked in control dung at several concentrations (LC50 880-985 microg a.s. kg(-1) dung (d.w.)), the LC50 values were again very similar. Three conclusions can be drawn from these results. The proposed test method seems to be robust and allows for the initiation of an international validation process (including ringtesting). Because of only small differences found in tests in which the test substance was spiked into control dung and those in which dung from treated cattle was applied, the use of a standard test method is proposed. The effects of ivermectin on ecologically relevant dung beetles obtained in a standardised test method reflect the results from field studies and are in the range of environmentally relevant concentrations.

We studied abamectin and doramectin excretion and their degradation in sheep faeces under field conditions on pasture after a single subcutaneous dose (0.2mg/kg body weight). In the excretion experiment, maximal abamectin concentration (1277 ng/g dry faeces) was detected on day 3, while doramectin concentration showed two peaks (2186 and 1780 ng/g dry faeces on days 2 and 5, respectively). Both avermectins were excreted at approximately the same rate (k=0.23 day(-1) for abamectin and 0.19 day(-1) for doramectin). In the field, a rapid loss of abamectin and doramectin from sheep faeces was seen during the first 32 days after which concentrations remained constant at approximately 77 ng/g and 300 ng/g, respectively. The half life values (DT(50)) for abamectin and doramectin dissipation from sheep faeces were 23 and 22 days, respectively, during the first 32 days. Dissipation of both avermectins was strongly correlated with moisture content of the faeces.

Eprinomectin (EPM) is a broad-spectrum endectocide compound approved for use in dairy cattle with a zero milk-withdrawal period, but has not been registered for use in lactating dairy sheep. The pattern of EPM excretion in milk was comparatively characterized following its pour-on administration (500 microg/kg) to lactating dairy sheep at two different stages of lactation. The relationship between milk excretion and plasma disposition kinetics of EPM was characterized. Residual EPM concentrations were assessed during cheese making (whey and curd) and ripening (cheese) by high-performance liquid chromatography and fluorescence detection. EPM was poorly distributed from the bloodstream to the mammary gland and low concentrations were excreted in milk. The level of milk production (early-mid and mid-late lactation) did not affect either the plasma-milk distribution or the pattern of residual concentrations in milk. During cheese making, the highest residual concentrations of EPM were measured in the curd, which increased during cheese ripening, reaching a maximum after 40 days. However, these residual concentrations were below the maximum residue limit of 20 ng/ml established for EPM in bovine's milk. Therefore, these dairy products could be considered safe for consumers after the EPM antiparasitic pour-on treatment (500 microg/kg) in lactating dairy sheep.