A novel and innovative hair test to determine glucocorticoid levels in racing camels for use in assessment of doping, health, and disease.

The aim of this project was to develop and validate a new test for the analysis of glucocorticoids in camel hair and to use the new test to analyse hair samples from a variety of camel breeds in sports and racing applications. These findings could be of importance when evaluating racing camels for suspected doping offenses or for injury and disease control. Camel hair samples were collected from 30 non-racing dromedary camels along with 3 racing camels in Al Ain, UAE and were decontaminated, pulverised, sonicated, and extracted prior to analysis. A liquid chromatographic-mass spectrometric method was employed to determine the levels of glucocorticoids in the hair samples. The 4 drugs of interest, namely hydrocortisone, dexamethasone, flumethasone and methylprednisolone, and an internal standard were quantified in camel hair samples. All 4 of the glucocorticoids were detected in camel hair samples with concentrations ranging between 31 and 935 pg/mg for hydrocortisone, 8-59 pg/mg for dexamethasone, 0.7-1034 pg/mg for flumethasone and 5-66 pg/mg for methylprednisolone in non-racing camels. One of the racing camels displayed high concentrations of hydrocortisone (1130 pg/mg), flumethasone (2576 pg/mg), methylprednisone (1156 pg/mg) and dexamethasone (29 pg/mg). The authors believe this is the first report of a test for corticosteroids in camel hair. The new test has been validated according to Food and Drug Administration (FDA) guidelines. This new hair test could be useful for further studies in doping control, toxicological studies, pharmacological studies and other clinical applications in camel health, injury, and disease.

Simultaneous detection of flumethasone, dl-methylephedrine, and 2-hydroxy-4,6-dimethylpyrimidine in porcine muscle and pasteurized cow milk using liquid chromatography coupled with triple-quadrupole mass spectrometry.

A simple analytical method based on liquid chromatography coupled with triple-quadrupole mass spectrometry was developed for detection of the veterinary drugs flumethasone, dl-methylephedrine, and 2-hydroxy-4,6-dimethylpyrimidine in porcine muscle and pasteurized cow milk. The target drugs were extracted from samples using 10mM ammonium formate in acetonitrile followed by clean-up with n-hexane and primary secondary amine sorbent (PSA). The analytes were separated on an XBridge™ hydrophilic interaction liquid chromatography (HILIC) column using 10mM ammonium formate in ultrapure water and acetonitrile. Good linearity was achieved over the tested concentrations in matrix-fortified calibrations with correlation coefficients (R(2))≥0.9686. Recovery at two spiking levels ranged between 73.62-112.70% with intra- and inter-day precisions of ≤20.33%. The limits of quantification ranged from 2-10ng/g in porcine muscle and pasteurized cow milk. A survey of market samples showed that none of them contained any of the target analytes. Liquid-liquid purification using n-hexane in combination with PSA efficiently removed the interferences during porcine and milk sample extraction. The developed method is sensitive and reliable for detection of the three target drugs in a single chromatographic run. Furthermore, it exhibits high selectivity and low quantification limits for animal-derived food products destined for human consumption.

Novel spectrophotometric determination of flumethasone pivalate and clioquinol in their binary mixture and pharmaceutical formulation.

This work is concerned with development and validation of three simple, specific, accurate and precise spectrophotometric methods for determination of flumethasone pivalate (FP) and clioquinol (CL) in their binary mixture and ear drops. Method A is a ratio subtraction spectrophotometric one (RSM). Method B is a ratio difference spectrophotometric one (RDSM), while method C is a mean center spectrophotometric one (MCR). The calibration curves are linear over the concentration range of 3-45 µg/mL for FP, and 2-25 µg/mL for CL. The specificity of the developed methods was assessed by analyzing different laboratory prepared mixtures of the FP and CL. The three methods were validated as per ICH guidelines; accuracy, precision and repeatability are found to be within the acceptable limits.

Development of QuEChERS-based extraction and liquid chromatography-tandem mass spectrometry method for quantifying flumethasone residues in beef muscle.

A rapid, specific, and sensitive method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM) was developed and validated to quantify flumethasone residues in beef muscle. Methods were compared between the original as well as the EN quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction. Good linearity was achieved at concentration levels of 5-30 µg/kg. Estimated recovery rates at spiking levels of 5 and 10 µg/kg ranged from 72.1 to 84.6%, with relative standard deviations (RSDs)<7%. The results of the inter-day study, which was performed by fortifying beef muscle samples (n=18) on 3 separate days, showed an accuracy of 93.4-94.4%. The precision (expressed as relative standard deviation values) for the inter-day variation at two levels of fortification (10 and 20 µg/kg) was 1.9-5.2%. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.7 and 5 µg/kg, at signal-to-noise ratios (S/Ns) of 3 and 10, respectively. The method was successfully applied to analyze real samples obtained from large markets throughout the Korean Peninsula. The method proved to be sensitive and reliable and, thus, rendered an appropriate means for residue analysis studies.

Determination of dexamethasone and dexamethasone sodium phosphate in human plasma and cochlear perilymph by liquid chromatography/tandem mass spectrometry.

A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of dexamethasone (Dex) and dexamethasone sodium phosphate (Dex SP) in plasma and human cochlear perilymph. After proteins were precipitated with a mixture of acetonitrile and methanol, Dex, Dex SP and flumethasone, the internal standard, were resolved on a C18 column using gradient elution of 5 mM ammonium acetate and methanol. The three compounds were detected using electrospray ionisation in the positive mode. Standard curves were linear over the concentration range 0.5-500 µg/L (r>0.99), bias was <±10%, intra- and inter-day coefficients of variation (imprecision) were <10%, and the limit of quantification was 0.5 µg/L for both Dex and Dex SP. The assay has been used successfully in a clinical pharmacokinetics study of Dex and Dex SP in cochlear perilymph and plasma.

A liquid chromatography method using a monolithic column for the determination of corticoids in animal feed and animal feeding water.

An HPLC-DAD method for determining corticoids in calf feed and in animal feeding water samples using a monolithic column has been developed and validated. The method optimization included the study of binary mobile phases of water and acetonitrile. The optimum separation was achieved at 40 degrees C, with acetonitrile:H(2)O 29:71 v/v used as mobile phase and a 3 ml/min flow-rate, which resulted in their separation in about 5 min. Two reported sample procedures were applied to feed and for animal feeding water samples prior to HPLC. Method validation was carried out according to the EU criteria established for quantitative screening methods. The results indicate that this method is highly specific, reproducible and accurate. The proposed method was found to be robust and unaffected by small variations in the extraction procedure and in HPLC conditions. The developed method for the determination of corticoids in feed and water samples was also found to be suitable for different kinds of feeds and waters.

Rapid multi-residue method for the quantitative determination and confirmation of glucocorticosteroids in bovine milk using liquid chromatography-electrospray ionization-tandem mass spectrometry.

Dexamethasone, betamethasone and prednisolone are synthetic glucocorticosteroids authorized for therapeutic use in bovine animals within the European Union. Dexamethasone and betamethasone are used mainly for the treatment of metabolic and inflammatory diseases. Prednisolone is used to treat bovine mastitis. Maximum residue limits (MRLs) of 0.3 microg kg(-1) for both dexamethasone and betamethasone and 6.0 microg kg(-1) for prednisolone in bovine milk have been established. 6alpha-Methylprednisolone and flumethasone are not authorized for use in bovine animals and are completely banned in bovine milk. The proposed method is based on deprotenisation of milk using 20% (w/v) trichloroacetic acid. Samples are filtered using glass microfiber filters and subject to clean-up using OASIS HLB solid phase extraction. Separation was achieved on a Hypercarb 100 mm x 2.1 mm x 5 microm column. Mobile phase was: 90/10 acetonitrile/0.1% formic acid in water; flow rate was 600 microL min(-1). The method allowed the rapid identification and confirmation of the five glucocorticosteroids according to the criteria laid down in Commission Decision 2002/657/EC. Matrix calibration curves for all compounds were linear in the interval 0.0 MRL to 2.0 MRL with a correlation coefficient (r(2)) higher than 0.96. Relative recoveries ranged from 97% for betamethasone to 111% for prednisolone. Precision at the MRL ranged from 3.8% for prednisolone to 13.8% for betamethasone. Decision limits, CCalpha, and detection capability, CCbeta have been calculated for all compounds.

Confirmation of synthetic glucocorticoids with liquid chromatography/mass spectrometry: organization and results of an international interlaboratory comparison test.

Within the framework of a European Union (EU) research project entitled "Food Safety Screening: Synthetic Glucocorticoids (QLK1-1999-00122)," an international interlaboratory ring test was organized to compare and evaluate different liquid chromatography/mass spectrometry (LC/MS) confirmatory methods that are applied in European monitoring programs for detecting the use of synthetic glucocorticoids. Liver and urine samples of bovines treated with synthetic glucocorticoids were collected and sent to the participants of the study for analysis. Participants received 3 liver and 3 urine samples and were free to use either their own LC/MS method or an LC/MS-based method developed during the EU research project. The residue concentrations in the samples were calculated as the mean of the concentrations reported by each laboratory. The mean dexamethasone concentration of liver sample L1 was calculated as 2.27 microg/kg [relative standard deviation (RSD) 43%, n = 9], which exceeds the maximum residue level (MRL) of 2 microg/kg. Three of the 9 laboratories (33%) reported concentration levels less than 2 microg/kg, resulting in obviously false compliant results. The overall mean concentration of flumethasone in liver sample L2 was calculated as 3.27 microg/kg (RSD 33%, n = 8). Applying a comparable limit for flumethasone of 2 microg/kg, 8 of the 9 laboratories would have obtained a correct noncompliant result. As for the blank liver sample, 1 participant found a false noncompliant result. The urine sample U1 contained prednisolone residues at a mean concentration of 1.58 microg/kg (RSD 43%, n = 9). Four out of 9 results were less than a theoretical minimum required performance level (MRPL) of 2 microg/kg. The calculated concentration of dexamethasone in urine sample U3 was 5.21 microg/kg (RSD 62%, n = 9). One of the 9 results was lower than 2 microg/kg. Urine sample U2 was correctly reported as blank by all participants.

Immunochemical screening and liquid chromatographic-tandem mass spectrometric confirmation of drug residues in edible tissues of calves injected with a therapeutic dose of the synthetic glucocorticoids dexamethasone and flumethasone.

A field study was performed to assess the drug residue level in edible tissues after a therapeutic application of the synthetic glucocorticoids dexamethasone and flumethasone. Three diseased calves were injected intramuscularly with a commercial batch of dexamethasone esters and slaughtered 72 h after treatment. Another three calves were injected intramuscularly with an aqueous flumethasone preparation and slaughtered 24 h later. Residues of synthetic glucocorticoids in liver, muscle, kidney, and urine were assessed by competitive enzyme immunoassay. All dexamethasone concentrations exceeded the maximal residue level of 0.75 microg/kg in muscle and kidney and 2 microg/kg in the liver. The presence of both dexamethasone and flumethasone in the liver was confirmed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). These results indicate that liver tissue provides a suitable matrix to monitor the presence of illegal residues of synthetic glucocorticoids in slaughtered animals.

A high-performance liquid chromatography/tandem mass spectrometric screening method for eight synthetic corticosteroids in bovine feces and the simultaneous differentiation between dexamethasone and betamethasone.

A screening method was developed to monitor the illegal use of synthetic corticosteroids in cattle. Diethyl ether extracts from spiked feces samples were cleaned-up by solid phase extraction followed by semipreparative reversed-phase chromatography (RPC). The fraction containing the corticosteroids was derivatized with ethoxyamine hydrochloride. The corresponding ethoximes were separated using silica-based C18 RPC and analyzed on-line in an ion trap mass spectrometer using atmospheric pressure positive chemical ionization. Ethoxime derivatives of dexamethasone and betamethasone were baseline resolved, allowing for the simultaneous mass spectrometric differentiation of both epimers in bovine feces by conventional non-chiral chromatography. At the lowest level tested (1 micro g/kg), corticosteroids (except triamcinolone) could be identified in compliance with the recent European criteria for residue identification. The quantitative performance of the method was best at residue levels > or = 2 micro g/kg.

Determination of flumethasone in calf urine and serum by liquid chromatography-tandem mass spectrometry.

Corticosteroids can be illegally administered to cattle as growth promoting agents to improve meat production. We developed a liquid chromatography-atmospheric pressure ionization mass spectrometry-mass spectrometry (LC-MS-MS) method able to identify and quantify flumethasone, one of the most potent fluorinated synthetic corticosteroid, in serum and urine from treated calves. The analyte was purified from urine (conjugated and free, following enzymatic hydrolysis) and from serum by C18 solid-phase and liquid-liquid extractions, then analyzed by LC-MS-MS monitoring the product ions of an abundant precursor (SRM in negative ionization mode). Results on flumethasone residues in biological fluids in three calves treated at different levels are presented. This method allowed the detection of flumethasone in bovine urine and serum at the 30-pg/ml level.

Accelerated solvent extraction and liquid chromatography-tandem mass spectrometry quantitation of corticosteroid residues in bovine liver.

A new method for the rapid extraction and unequivocal confirmation of two highly potent fluorinated synthetic corticosteroids, dexamethasone and its beta-epimer betamethasone, in bovine liver was developed. Flumethasone was used as internal standard. An extraction procedure using an accelerated solvent extraction system was employed for the isolation of the analytes in liver samples. The procedure was highly automated, including defatting and extraction steps, sequentially carried out under 1.0 x 10(4) kPa in about 35 min. The extracts were then directly analysed by tandem mass spectrometry with on-line liquid chromatography. The analytes were ionised in a heated nebulizer interface operating in the negative ion mode where the molecular related ions [M-H-CH2O]- were generated for each analyte, at m/z 361 for betamethasone and dexamethasone and at m/z 379 for flumethasone. They served as precursor ions for collision-induced dissociation and three diagnostic product ions for the drugs were identified to carry out analyte confirmation by selected reaction monitoring. Assessment of recovery, specificity and precision for betamethasone, dexamethasone and flumethasone proved the method suitable for confirmatory purposes. The limit of quantification of betamethasone and dexamethasone in liver tissue was 1.0 microg/kg.

Collision-induced dissociation of corticosteroids in electrospray tandem mass spectrometry and development of a screening method by high performance liquid chromatography/tandem mass spectrometry.

A screening method based on liquid chromatography/electrospray tandem mass spectrometry was developed in order to control the illegal use of corticosteroids as growth promoters in cattle. The objective was the detection of low residue levels of corticosteroids or metabolites in biological matrices. Relative to other studies published on this subject, the present work focused on enhancing specificity and sensitivity. Firstly, fragmentation of corticosteroids by collision-induced dissociation was studied. In positive mode, the losses of H(2)O for each hydroxyl group fixed on the molecule, as well as the loss of HF or HCl for halogenated compounds, were observed. For higher collision energy, fragmentations in the B, C and D rings were induced. The negative mode was found to be more specific, inducing a cleavage of the C(20)-C(21) bond with concomitant loss of formaldehyde (CH(2)O). Secondly, three acquisition methods in the negative mode were studied and evaluated, recorded signals being the parent ion [M + acetate](-) and the two daughter ions, [M - H](-) and [M - H - CH(2)O](-). For dexamethasone, MS/MS instrumental detection limits of fragment ion and neutral loss scans, and of multiple reaction monitoring (MRM), were 250, 20 and 5 pg injected, respectively. The MRM method was then evaluated with the objective of use for the detection of corticosteroid residues in biological samples (urine, hair, muscle) and for a metabolism study.

Immunoaffinity chromatography combined on-line with high-performance liquid chromatography-mass spectrometry for the determination of corticosteroids.

On-line coupled immunoaffinity chromatography-reversed-phase high-performance liquid chromatography (IAC-HPLC) with detection by quadrupole ion trap mass spectrometry using a particle beam interface has been developed for the determination of the steroids, dexamethasone and flumethasone. HEMA (polyhydroxyethylmethacrylate) was evaluated as a support material for the anti-dexamethasone antibodies used in IAC. Antibody cross-reactivity and non-specific binding have been investigated for the HEMA bound anti-dexamethasone IAC column. The on-line IAC-HPLC-MS determination of dexamethasone and flumethasone in post-administration equine urine samples showed precisions (R.S.D.) of 8.0 and 7.1%, respectively, with limits of detection in the range 3-4 ng/ml.

Dexamethasone and flumethasone residues in milk of intramuscularly dosed cows.

A field study was performed to assess the level of drug residues in milk after therapeutic application of highly potent synthetic glucocorticoids. Dexamethasone was tested either as a crystalline suspension or as a combination of sodium phosphate and phenylpropionate esters. Intramuscular injection of these preparations in lactating dairy cows (60 micrograms dexamethasone/kg body wt) yielded drug residues in milk of up to 8.4 ng/mL 12 h after treatment. These dexamethasone residues fell to below 1.0 ng/mL within 3 days after treatment. Intramuscular injection of an aqueous flumethasone preparation (13.5 micrograms/kg body wt) produced drug residues in milk in the range of 0.7-1.2 ng/mL 12 h after treatment, whereas flumethasone was below the detection limit of 0.23 ng/mL 2 days after administration. These results indicate that toxicologically significant residues may arise transiently in the milk during the first 2-3 days after intramuscular injection of synthetic glucocorticoids. Urine from the same animals contained 5- to 50-fold higher glucocorticoid concentrations than the corresponding milk samples. Thus, urine analysis appears to be an effective method to monitor the use of synthetic glucocorticoids in food producing animals.