Identification and quantification method of spiramycin and tylosin in feedingstuffs with HPLC-UV/DAD at 1 ppm level

A liquid chromatography coupled to tandem mass spectrometry method for the quantification of spiramycin and its active metabolite neospiramycin in milk of major and minor species: Validation using the accuracy profile

A liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantification of residues of spiramycin, a macrolide antibiotic, and its active metabolite neospiramycin in cow's milk as well as in minor species 'milk, goat and ewe. Spiramycin-d3 was used as internal standard for quantification of both analytes. This analytical method was validated using a global accuracy profile as a graphical decision tool built according to the trueness and the precision of the method. A unique and optimal linear model with logarithm transformation (with a determination coefficient of 0.9991) allowed the measurement of both analytes in the milks of the three animal species, in a wide range from 0.2 to 10 times the Maximal Residue Limit (MRL) (40-2000 µg.kg^-1). The limits of detection and quantification were 13 µg.kg^-1 and 40 µg.kg^-1, respectively. The accuracy profile was established to get 80% of future measurements in routine assays that will fall within the acceptance limits. Trueness of the method, expressed as relative bias, was comprised between -1.6% and 5.7% over the whole range of concentrations. The mean relative standard deviation for repeatability and intermediate precision were comprised between 1.1% and 2.7%; 2.5 and 4.2%, respectively, in all levels of concentration for the three milks. Moreover, a two-order polynomial function was used to model the relative expanded uncertainty with a determination coefficient of 0.834. This function aimed to determine the uncertainty of the future quantifications within the validated dosing range. Overall, the global accuracy profile highlighted the reliability of the method for the routine assays of spiramycin and neospiramycin even in milk from minor species (goat, ewe) by using the most accessible milk (often from cow), while guaranteeing a very high proportion of samples within the fixed acceptance limits. The applicability of this method was tested during a depletion study of spiramycin and neospiramycin in the milk of cow, goat and ewe. The developed analytical method will be useful to assess the distribution profile of the antibiotic and its metabolite in milk of minor species where few studies are available.

A Review: Effects of Macrolides on CYP450 Enzymes

As a kind of haemoglobin, cytochrome P450 enzymes (CYP450) participate in the metabolism of many substances, including endogenous substances, exogenous substances and drugs. It is estimated that 60% of common prescription drugs require bioconversion through CYP450. The influence of macrolides on CYP450 contributes to the metabolism and drug-drug interactions (DDIs) of macrolides. At present, most studies on the effects of macrolides on CYP450 are focused on CYP3A, but a few exist on other enzymes and drug combinations, such as telithromycin, which can decrease the activity of hepatic CYP1A2 and CYP3A2. This article summarizes some published applications of the influence of macrolides on CYP450 and the DDIs of macrolides caused by CYP450. And the article may subsequently guide the rational use of drugs in clinical trials. To a certain extent, poisoning caused by adverse drug interactions can be avoided. Unreasonable use of macrolide antibiotics may enable the presence of residue of macrolide antibiotics in animal-origin food. It is unhealthy for people to eat food with macrolide antibiotic residues. So it is of great significance to guarantee food safety and protect the health of consumers by the rational use of macrolides. This review gives a detailed description of the influence of macrolides on CYP450 and the DDIs of macrolides caused by CYP450. Moreover, it offers a perspective for researchers to further explore in this area.

Directly assembled electrochemical sensor by combining self-supported CoN nanoarray platform grown on carbon cloth with molecularly imprinted polymers for the detection of Tylosin

Molecularly imprinted polymers (MIPs) based on electrochemical sensors (MIP-EC sensors) have obtained ideal achievements in recent years. However, some challenges are still need to be addressed, such as adjustable preparation, unstable sensing interface and great signal-to-noise ratio. Here, based on the ingenious combination of the MIP and the self-supported CoN nanowire arrays grown on carbon cloth (CoN NWs/CC), a robust MIP-EC sensor was developed, in which the MIP film was uniformly coated on the CoN NWs/CC via a bulk polymerization crosslinking process. Especially, CoN NWs/CC were prepared via in-situ transformation of their oxide precursors and then directly as a candidate of EC electrode. Under the optimal conditions, the MIP-EC sensor can detect Tylosin (TS) in the concentration range from 8.6 × 10^-11 to 6.7 × 10^-5 mol L^-1, and the low detection limit (LOD) is 5.5 × 10^-12 mol L^-1 (S/N = 3). Furthermore, the MIP-EC sensor showed high selectivity, reproducibility and stability. The practicability of the MIP-EC sensor was tested in the actual samples of surface water and soil with the comparison of the traditional ELISA method. The developed MIP-EC sensor with simple and fabrication process can provide a versatile and reliable method, which has great potential application value for the detection of small hazardous molecules.

Identification and Quantification of Tylosin in Animal Feed by Liquid Chromatography Combined with Electrospray Ionisation Mass Spectrometry

Introduction

The authorisation of tylosin as feed additive was withdrawn for reasons of human health concerning resistance of pathogenic bacteria. An analytical method for the identification and quantification of tylosin in animal feed was developed and validated.

Material and Methods

The samples were extracted using an acidified methanol:water mixture and solid-phase extraction was employed for the isolation of the antibiotic from diluted feed samples. Tylosin was analysed by liquid chromatography with electrospray ionisation mass spectrometric detection. The method's performance was evaluated in adherence to the Commission Decision 2002/657/EC.

Results

The recovery of the analyte from spiked samples was determined to be in the range from 78.9% to 108.3% depending on tylosin concentrations. The CCα and CCβ values for tylosin in feeds were determined at 0.085 mg kg^-1 and 0.091 mg kg^-1, respectively. The method detection limit was found to be 0.035 mg kg^-1 and the quantification limit 0.05 mg kg^-1. The applicability of the developed method was tested by analysing real feed samples.

Conclusion

A reliable LC-MS method was developed to identify and quantify tylosin in animal feed with a good repeatability and a high specificity and sensitivity. Because of these characteristics, the proposed method is applicable and could be deemed necessary within the field of feed control and safety.

Macrolide antibiotics removal using a circulating TiO2-coated paper photoreactor: parametric study and hydrodynamic flow characterization

The present work investigates the photocatalytic degradation efficiency of biorecalcitrant macrolide antibiotics in a circulating tubular photoreactor. As target pollutants, spiramycin (SPM) and tylosin (TYL) were considered in this study. The photoreactor leads to the use of an immobilized titanium dioxide on non-woven paper under artificial UV-lamp irradiation. Maximum removal efficiency was achieved at the optimum conditions of natural pH, low pollutant concentration and a 0.35 L min(-1) flow rate. A Langmuir-Hinshelwood model was used to fit experimental results and the model constants were determined. Moreover, the total organic carbon analysis reveals that SPM and TYL mineralization is not complete. In addition, the study of the residence time distribution allowed us to investigate the flow regime of the reactor. Electrical energy consumption for photocatalytic degradation of macrolides using circulating TiO2-coated paper photoreactor was lower compared with some reported photoreactors used for the elimination of pharmaceutic compounds. A repetitive reuse of the immobilized catalyst was also studied in order to check its photoactivity performance.

Simultaneous determination of ten macrolides drugs in feeds by high performance liquid chromatography with evaporation light scattering detection

Simultaneous determination of ten macrolides drugs using HPLC-ELSD.

Withdrawal times of oxytetracycline and tylosin in eggs of laying hens after oral administration

Antimicrobials administered to laying hens may be distributed into egg white or yolk, indicating the importance of evaluating withdrawal times (WDTs) of the pharmaceutical formulations. In the present study, oxytetracycline and tylosin's WDTs were estimated. The concentration and depletion of these molecules in eggs were linked to their pharmacokinetic and physicochemical properties. Twenty-seven Leghorn hens were used: 12 treated with oxytetracycline, 12 treated with tylosin, and 3 remained as an untreated control group. After completion of therapies, eggs were collected daily and drug concentrations in egg white and yolk were assessed. The yolk was used as the target tissue to evaluate the WDT; the results were 9 and 3 days for oxytetracycline and tylosin, respectively. In particular, oxytetracycline has a good oral bioavailability, a moderate apparent volume of distribution, a molecular weight of 460 g/mol, and is lightly liposoluble. Tylosin, a hydrosoluble compound, with a molecular weight of 916 g/mol, has a low oral bioavailability and a low apparent volume of distribution, too. Present results suggest that the WDTs of the studied antimicrobials are strongly influenced by their oral bioavailability, the distribution, and the molecular weight and solubility, and that these properties also influence the distribution between the egg yolk and white.

Simultaneous immunochemical detection of four banned antibiotic growth promoters in raw and cooked poultry tissue

Spiramycin, tylosin, bacitracin and virginiamycin are among a group of antibiotic growth promoters that have been banned in the European Union since the 1999 Council. This was due to concerns over the development of resistant bacteria emerging between humans and animals with the threat of antibiotics no longer being able to be used effectively to treat human infections. A sensitive and fast immunochemical method is presented for the determination of these four antibiotic growth promoters simultaneously in poultry tissue. The method employs methanol extraction followed by sample clean-up by solid-phase extraction (SPE) with determination by enzyme-linked immunoabsorbant assay (ELISA). The limit of detection (LOD) was less than 1 ng g(-1) and the detection capability (CCβ) was 3 ng g(-1) or less for all four antibiotic growth promoters. Validation was completed with both raw and cooked chicken, therefore either matrix could be used for the monitoring of these banned drugs. In a feeding trial no residues of either bacitracin or virginiamycin were found in medicated birds even without a withdrawal period. In the case of tylosin and spiramycin much higher residues level were detected immunochemically than was the case by mass spectrometry.

A novel green chemistry method for nonaqueous extraction and high-performance liquid chromatography detection of first-, second-, and third-generation tetracyclines, 4-epitetracycline, and tylosin in animal feeds

Although tetracyclines and macrolides are common additives for animal nutrition, methods for their simultaneous determination in animal feeds are nonexistent. By coupling an organic extraction and solid-phase extraction cleanup to a high-performance liquid chromatography separation and a nonaqueous postcolumn derivatization, we succeeded in detecting from 0.2 to 24.0 μg kg(-1) of tetracycline, oxytetracycline, chlortetracycline, doxycycline, tigecycline, and 4-epitetracycline in this complex and heterogeneous matrix. Minocycline and tylosin could also be detected with our procedure, but using UV spectrophotometry (1.5 ≤ LOD ≤ 1.9 mg kg(-1)). Linear responses with correlation coefficients between 0.996 and 0.999 were obtained for all analytes in the 0.5-10 mg kg(-1) concentration range. Average recoveries between 59 and 97% and between 98 and 102% were obtained for the tetracyclines and tylosin, respectively. Replicate standard deviations were typically below 5%. When this method was applied to 20 feeds marketed in Costa Rica, we detected labeling inconsistencies, banned mixtures of tetracyclines, and tetracycline concentrations that contravene international regulation.

Development and validation of a rapid multi-class method for the confirmation of fourteen prohibited medicinal additives in pig and poultry compound feed by liquid chromatography-tandem mass spectrometry

A confirmatory method has been developed to allow for the analysis of fourteen prohibited medicinal additives in pig and poultry compound feed. These compounds are prohibited for use as feed additives although some are still authorised for use in medicated feed. Feed samples are extracted by acetonitrile with addition of sodium sulfate. The extracts undergo a hexane wash to aid with sample purification. The extracts are then evaporated to dryness and reconstituted in initial mobile phase. The samples undergo an ultracentrifugation step prior to injection onto the LC-MS/MS system and are analysed in a run time of 26 min. The LC-MS/MS system is run in MRM mode with both positive and negative electrospray ionisation. The method was validated over three days and is capable of quantitatively analysing for metronidazole, dimetridazole, ronidazole, ipronidazole, chloramphenicol, sulfamethazine, dinitolimide, ethopabate, carbadox and clopidol. The method is also capable of qualitatively analysing for sulfadiazine, tylosin, virginiamycin and avilamycin. A level of 100 microg kg(-1) was used for validation purposes and the method is capable of analysing to this level for all the compounds. Validation criteria of trueness, precision, repeatability and reproducibility along with measurement uncertainty are calculated for all analytes.

Chromatographic analysis of banned antibacterial growth promoters in animal feed

The issue of antimicrobial use in animals used as food is of global concern. Antimicrobials are used in animal agriculture to improve health and welfare of animals, meat quality, the economic efficiency of growth and production and public health by decreasing shedding of zoonotic pathogens. However, large quantities are often used without professional supervision. The growth-promotant (now reclassified as zootechnical feed additives) effect of low levels of antibiotics in animal feeds was first described in the late 1940s. Already in 1969 the Swann Committee recommended that use of antibiotics as a supplement in animal feedstuff should be restricted to those with little or no application as therapeutic agents for humans and animals, which would not impair the efficacy of therapeutic antibiotics through the development of resistant strains of organisms. Antimicrobials like avoparcin, ardacin, zinc bacitracin, virginiamycin, tylosin, spriramycin, carbadox and olaquindox were withdrawn within the period 1997-1999. Four others (monensin sodium, salinomycin sodium, avilamycin and flavophospholipol) were still permitted for use as growth promoters in animal feed to animals marketed in the European Union (EU). Since January 2006, they have been banned as well. This review focuses on the analytical methods developed to be an effective tool for monitoring compliance with the ban.

Sample preparation strategy for the simultaneous determination of macrolide antibiotics in animal feedingstuffs by liquid chromatography with electrochemical detection (HPLC-ECD)

A novel and suitable clean-up method that allows, for the first time, the simultaneous determination of a rather large number of macrolide antibiotics (erythromycin, rosamicin, spiramycin, tylosin, kitasamycin and josamycin in feedingstuffs by high performance liquid chromatography with electrochemical detection (HPLC-ECD) is presented in this work. The effectiveness of the developed clean-up method allows the quantification of the target macrolides in poultry feed using standard calibration curves instead of matrix matched standards, which overcomes the general problem of finding representative blanks. Furthermore an additional back extraction included in the sample preparation procedure allows the determination of an additional macrolide (oleandomycin) with detection limits, expressed as apparent concentration in poultry feed, ranging from 0.04 to 0.22 mg kg(-1) and relative standard deviation values ranging from 3.6 to 10.1% depending on the target analyte. Moreover, this additional step has been proven to enlarge the scope of the method by the extension of its applicability, at the target level of concentration, to other animal feedingstuffs such as pig and cattle. The analysis of real feedingstuffs containing macrolides demonstrated the fitness for purpose of the whole analytical procedure as well as a good fitting between real and spiked samples. The proposed methods appeared therefore as a sound alternative in the frame of control (e.g. for post-screening purposes) and/or monitoring surveillance programmes at the target level of 1.0 mg kg(-1) established according to the reported lowest dosage of additive needed to lead a growth promoting effect.

Liquid chromatography–UV diode-array detection method for multi-residue determination of macrolide antibiotics in sheep's milk

A rapid, simple and sensitive liquid chromatography-UV diode-array detection method was developed for the simultaneous determination of seven macrolides (erythromycin, oleandomycin, roxithromycin, josamycin, spiramycin, tylosin and ivermectin) in sheep's milk. The column, mobile phase, temperature and flow rate were optimised to provide the best resolution of these analytes. The extraction of the antibiotic residues involves the treatment of protein-free samples with a combination of concentrated sodium hydroxide and ethyl acetate. Necessary defatting is achieved by alkaline hydrolysis. The recovery of each antibiotic was between 55% and 77%, with relative standard deviations ranging from 1% to 6.5%. The limit of quantification was 72.4 microg/kg for ivermectin, 48.3 microg/kg for roxithromycin, and 24.1 microg/kg for erythromycin, oleandomycin, spiramycin, josamycin and tylosin. The procedure was successfully used in the multi-residue determination of these macrolides at levels below the maximum concentrations legally allowed in milk samples.