Optimized method for analysis of ethanolamines, hydrolysis products of nitrogen mustards, from urine samples using LC-MS/MS.

Highly polar ethanolamines (EAs), excreted in urine, are hydrolysis products of nitrogen mustards (NMs), which are prohibited by the Chemical Weapons Convention (CWC). The methods established for biological matrices are essential for verification analysis of the CWC related chemicals. This paper describes a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method developed for qualitative and quantitative analysis of EAs, N-ethyldiethanolamine (EDEA), N-methyldiethanolamine (MDEA) and triethanolamine (TEAOH) from urine samples. After optimization of sample preparation and chromatographic conditions, the method was fully validated. Silica solid-phase extraction (SPE) cartridges and a porous graphite carbon (PGC) column were selected for validation studies. The method is linear from 5 to 500, 0.5 to 250, and 0.5 to 500 ng/mL for TEAOH, EDEA, and MDEA, respectively. It is also precise and accurate. A minimum sample amount of 0.5 mL urine was used. The limit of quantification using this approach was 0.4, 5.5, and 6.3 ng/mL for MDEA, EDEA and TEAOH, respectively. The combination of the PGC column and high pH eluents in analysis retained and separated the studied EAs. Retention times were 2.11, 2.56 and 2.98 min for MDEA, EDEA and TEAOH, respectively. The method is applicable for verification analysis of the CWC.

Hypophosphatasia in Adults: Clinical Spectrum and Its Association With Genetics and Metabolic Substrates.

BACKGROUND: Hypophosphatasia (HPP) is a rare metabolic bone disorder caused by mutations in the alkaline phosphatase (ALPL) gene, and characterized by low circulating alkaline phosphatase (ALP) levels and bone, muscle, dental and systemic manifestations. In this case series we investigate the clinical spectrum, genetic and biochemical profile of adult HPP patients from the University Hospitals Leuven, Belgium. METHODOLOGY: Adults with HPP were identified through medical record review. Inclusion criteria were: (1) age ≥ 16 yr; (2) consecutively low ALP levels not explained by secondary causes; (3) one or more of the following supporting criteria: biochemical evidence of elevated enzyme substrates; subtrochanteric fractures, metatarsal fractures or other typical clinical features; family history of HPP; a known or likely pathogenic ALPL mutation. RESULTS: Nineteen patients met our inclusion criteria (n = 2 infantile, n = 6 childhood, n = 10 adult-onset HPP and one asymptomatic carrier). Fractures and dental abnormalities were the most reported symptoms. Fatigue was reported in n = 7/19 patients (37%), three of which had previously been misdiagnosed as having chronic fatigue syndrome and/or fibromyalgia. Empirical pyridoxine therapy in four patients (without seizures) did not provide symptomatic relief. N = 7/19 patients (37%) were inappropriately treated or planned to be treated with antiresorptive treatment. Two patients developed atypical femoral fractures following exposure to bisphosphonates and/or denosumab. Patients detected by screening were less severely affected, while patients with homozygous or compound heterozygous mutations had the most severe symptoms, significantly lower circulating ALP levels (p = 0.013) and significantly higher pyridoxal-5'-phosphate (p = 0.0018) and urinary phosphoethanolamine (p = 0.0001) concentrations. CONCLUSIONS: Screening may detect mainly less severely affected individuals, which may nevertheless avoid misdiagnosis and inappropriate antiresorptive drug exposure. Patients with biallelic mutations had more severe symptoms, significantly lower ALP and higher substrate levels. Whether the latter finding has implications for the classification and treatment of HPP should be investigated further in larger cohorts.

A homozygous missense variant in the alkaline phosphatase gene ALPL is associated with a severe form of canine hypophosphatasia.

Inherited skeletal disorders affect both humans and animals. In the current study, we have performed series of clinical, pathological and genetic examinations to characterize a previously unreported skeletal disease in the Karelian Bear Dog (KBD) breed. The disease was recognized in seven KBD puppies with a variable presentation of skeletal hypomineralization, growth retardation, seizures and movement difficulties. Exome sequencing of one affected dog revealed a homozygous missense variant (c.1301T > G; p.V434G) in the tissue non-specific alkaline phosphatase gene, ALPL. The identified recessive variant showed full segregation with the disease in a cohort of 509 KBDs with a carrier frequency of 0.17 and was absent from 303 dogs from control breeds. In humans, recessive and dominant ALPL mutations cause hypophosphatasia (HPP), a metabolic bone disease with highly heterogeneous clinical manifestations, ranging from lethal perinatal hypomineralization to a relatively mild dental disease. Our study reports the first naturally occurring HPP in animals, resembling the human infantile form. The canine HPP model may serve as a preclinical model while a genetic test will assist in breeding programs.

Untargeted search and identification of metabolites of antiviral agent camphecene in rat urine by liquid chromatography and mass spectrometry and studying their distribution in organs following peroral administration of the compound.

Major metabolites of camphecene, a new effective antiviral agent, formed after its oral administration to rats and excreted in the urine, were found and identified using liquid chromatography coupled to mass spectrometry as well as multivariate analysis of HPLC-MS data. The metabolites were found to be camphecene glucuronide, camphecene sulfate and the corresponding iminoacid. A study of the dynamics of accumulation of camphecene and its metabolites in the liver, kidneys, lungs and brain of animals was performed. Maximum concentration of camphecene in blood and organs was reached after 1.5-2 h of its administration, and the maximal content of the agent in the organs investigated was observed in the kidneys. The content of the substance in the lungs was comparable to that in the liver. Also, camphecene was found in brain in high concentration, thus allowing assumption of its ability to penetrate the blood-brain barrier and to exert its antiviral properties in the organ. Camphecene glucuronide and iminoacid had concentration-time profiles similar to that of their precursor, their content being maximal in kidney and liver and 2-3 orders of magnitude higher than in lungs and brain. The content of camphecene sulfate was of similar level in all organs studied. The results obtained made it possible to develop recommendations for therapy with the use of camphecene.

Pyridoxal 5'-phosphate and related metabolites in hypophosphatasia: Effects of enzyme replacement therapy.

OBJECTIVE: To investigate the utility of serum pyridoxal 5'-phosphate (PLP), pyridoxal (PL), and 4-pyridoxic acid (PA) as a diagnostic marker of hypophosphatasia (HPP) and an indicator of the effect of, and patient compliance with, enzyme replacement therapy (ERT), we measured PLP, PL, and PA concentrations in serum samples from HPP patients with and without ERT. METHODS: Blood samples were collected from HPP patients and serum was frozen as soon as possible (mostly within one hour). PLP, PL, and PA concentrations were analyzed using high-performance liquid chromatography with fluorescence detection after pre-column derivatization by semicarbazide. We investigated which metabolites are associated with clinical phenotypes and how these metabolites change with ERT. RESULTS: Serum samples from 20 HPP patients were analyzed. The PLP-to-PL ratio and PLP concentration were elevated in all HPP patients. They correlated negatively with serum alkaline phosphatase (ALP) activity and showed higher values in more severe phenotypes (perinatal severe and infantile HPP) compared with other phenotypes. PL concentration was reduced only in perinatal severe HPP. ERT reduced the PLP-to-PL ratio to mildly reduced or low-normal levels and the PLP concentration was reduced to normal or mildly elevated levels. Urine phosphoethanolamine (PEA) concentration did not return to normal levels with ERT in most patients. CONCLUSIONS: The serum PLP-to-PL ratio is a better indicator of the effect of ERT for HPP than serum PLP and urine PEA concentrations, and a PLP-to-PL ratio of <4.0 is a good indicator of the effect of, and patient compliance with, ERT.

Low serum alkaline phosphatase activity due to asymptomatic hypophosphatasia in a teenage girl.

OBJECTIVE: The case report details an unusual presentation of a teenage patient with hypophosphatasia. PATIENT AND METHODS: A 17 year-old female patient presented to endocrinology for the evaluation of fatigue and possible adrenal insufficiency. In the course of her clinical evaluation she was noted to have a low serum alkaline phosphatase activity. Relatively few conditions are associated with a low serum alkaline phosphatase including Wilson's disease, hypophosphatasia, pernicious anemia and untreated hypothyroidism. RESULTS: Laboratory testing for hypothyroidism were unrevealing, as were the results for vitamin B12 and vitamin D. Testing for Wilson's disease revealed a ceruloplasmin concentration of 165 mg/L (Reference Interval, 160-450 mg/L), however sequencing of the ATP7B gene revealed no deleterious mutations. Measurement of serum pyridoxal phosphate and urine phosphoethanolamine for the diagnosis of hypophosphatasia revealed concentrations of 541.5 nmol/L (reference interval: 29.6-295.5) and 707 mmol/mol creatinine (reference interval: <778 mmol/mol creatinine), respectively, consistent with a diagnosis of hypophosphatasia. CONCLUSIONS: Hypophosphatasia was initially considered an unlikely diagnosis for this patient given her lack of characteristic skeletal abnormalities. This diagnosis of hypophosphatasia in this case was complicated by a serum ceruloplasmin concentration at the lower end of the reference interval leading to the genetic testing for Wilson's disease.

pH detection in biological samples by 1D and 2D 1H-31P NMR.

The chemical shifts of several important endogenous phosphorus compounds under different pH conditions were explored, including adenosine-5'-triphosphate, adenosine-5'-diphosphate, adenosine-5'-monophosphate, phosphorylcholine and phosphorylethanolamine. Their 31P NMR and 1H NMR chemical shifts were all pH-sensitive in the similar pH range. Two dimensional (2D) 1H-31P NMR spectra were found helpful to identify these endogenous phosphorus markers in biological samples from rather complicated NMR spectra. Herein, for the first time, a pH sensor based on 2D 1H-31P NMR was established and applied to biological samples analysis with pH values determined in good agreement with those by potentiometric method. Apart from being simple, green, rapid and less sample-consuming, information concerning both the endogenous phosphorus markers and pH status could be attained in a single NMR run, which demonstrated the great potential of this method in rare sample analysis and even disease diagnosis.

Mutational and biochemical findings in adults with persistent hypophosphatasemia.

A majority of adults with persistently low serum alkaline phosphatase values carry a pathogenic or likely pathogenic variant in the ALPL gene and also have elevated alkaline phosphatase substrate values in serum and urine. These adults may fall within the spectrum of the adult form of hypophosphatasia. INTRODUCTION: The primary objective of this study was to determine what proportion of adults with persistently low serum alkaline phosphatase values (hypophosphatasemia) harbor mutations in the ALPL gene or have elevated alkaline phosphatase (ALP) substrates. Some adults with persistent hypophosphatasemia share clinical and radiographic features with the adult form of hypophosphatasia (HPP). In HPP, ALPL mutations result in persistent hypophosphatasemia and ALP substrate accumulation in plasma (pyridoxal-5-phosphate (PLP)) and urine (phosphoethanolamine (PEA)). METHODS: Biochemical analyses, including serum ALP activity, bone-specific ALP, plasma PLP, and urine PEA, were performed in adults with persistent hypophosphatasemia. Mutational analyses were performed using PCR and Sanger sequencing methods. Gene variants were classified as pathogenic (P), likely pathogenic (LP), variants of uncertain significance (VUS), likely benign (LB), and benign (B). P and LP variants were further grouped as "Positive ALPL variants" and LB and B grouped as "Negative ALPL variants." RESULTS: Fifty subjects completed all mutational and biochemical analyses. Sixteen percent carried only Negative ALPL variants. Of the remaining 42 subjects, 67% were heterozygous for a P variant, 19% for an LP variant, and 14% for a VUS. Biochemical results were highly inter-correlated and consistent with the expected inverse relationship between ALP and its substrates. Subjects harboring Positive ALPL variants showed lower ALP and BSAP and higher PLP and PEA values compared with subjects harboring only Negative ALPL variants. Approximately half of all subjects harboring Positive ALPL variants or ALPL VUS showed elevations in plasma PLP, and three quarters showed elevations in urine PEA. CONCLUSION: Adults with persistent hypophosphatasemia frequently harbor ALPL mutations and have elevated ALP substrates. These adults may fall within the spectrum of the adult form of hypophosphatasia. Clinicians should take note of persistent hypophosphatasemia in their patients and be cautious in prescribing bisphosphonates when present.

Clinical, biochemical and genetic spectrum of low alkaline phosphatase levels in adults.

BACKGROUND: Low serum levels of alkaline phosphatase (ALP) are a hallmark of hypophosphatasia. However, the clinical significance and the underlying genetics of low ALP in unselected populations are unclear. METHODS: In order to clarify this issue, we performed a clinical, biochemical and genetic study of 42 individuals (age range 20-77yr) with unexplained low ALP levels. RESULTS: Nine had mild hyperphosphatemia and three had mild hypercalcemia. ALP levels were inversely correlated with serum calcium (r=-0.38, p=0.012), pyridoxal phosphate (PLP; r=-0.51, p=0.001) and urine phosphoethanolamine (PEA; r=-0.49, p=0.001). Although many subjects experienced minor complaints, such as mild musculoskeletal pain, none had major health problems. Mutations in ALPL were found in 21 subjects (50%), including six novel mutations. All but one, were heterozygous mutations. Missense mutations were the most common (present in 18 subjects; 86%) and the majority were predicted to have a damaging effect on protein activity. The presence of a mutated allele was associated with tooth loss (48% versus 12%; p=0.04), slightly lower levels of serum ALP (p=0.002), higher levels of PLP (p<0.0001) and PEA (p<0.0001), as well as mildly increased serum phosphate (p=0.03). Ten individuals (24%) had PLP levels above the reference range; all carried a mutated allele. CONCLUSION: One-half of adult individuals with unexplained low serum ALP carried an ALPL mutation. Although the associated clinical manifestations are usually mild, in approximately 50% of the cases, enzyme activity is low enough to cause substrate accumulation and may predispose to defects in calcified tissues.

Development of an ultrasensitive immunochromatographic assay (ICA) strip for the rapid detection of phenylethanolamine A in urine and pork samples.

In this study a one-step immunochromatographic assay based on competitive format was developed for the rapid detection of phenylethanolamine A (PEAA) residues in urine and pork samples. A monoclonal antibody against PEAA was produced from BALB/c mice immunized with the PEAA-BSA conjugate. The results of this qualitative test strip were to be interpreted visually. The visual detection limit (VDL) and threshold level of the optimized immunochromatographic assay for PEAA were 0.1 ng/mL and 0.5 ng/mL, respectively. Cross-reactions with other ß-agonists were not significant inhibitions to the performance of the test strip assay. The results from the test strip were in a good agreement with those obtained using a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay. The immunochromatographic assay developed here was a useful on-site screening tool that is rapid to use, low in cost, and extremely convenient for the detection of PEAA in urine samples and pork samples.

Copper nanoparticles applied to the preconcentration and electrochemical determination of ß-adrenergic agonist: an efficient tool for the control of meat production.

A novel method for preconcentration and electrochemical detection of zinterol in bovine urine samples was developed. In order to improve the limit of detection, the surface of a screen-printed carbon electrode was modified with electrodeposited metal copper nanoparticles. The experimental electrodeposition optimization was performed using a central composite design (CCD), involving the variables: precursor concentration, potential and time applied. Copper nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, cyclic voltammetry, and energy dispersive X-ray spectroscopy. Mesoporous shuttle-like copper oxide nanoparticles were used for the preconcentration step to avoid interferences with many compounds present in the sample matrix. The optimal working conditions for the preconcentration approach were found by means of both two-level fractional factorial and CCD designs. The obtained enhancement factor for a sample volume of 30 mL was 35 fold. The calibration curve showed linearity between 0.5 and 45 ng mL(-1) and the limit of detection was 0.16 ng mL(-1). The intra and inter assay coefficients of variability were below 4% and 5%; respectively.

Simple quantitation of formoterol and 11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid in human urine by liquid chromatography-tandem mass spectrometry in doping control.

11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) and formoterol are newly revised prohibited threshold substances (150 ng/mL for THC-COOH and 40 ng/mL for formoterol) by the World Anti-Doping Agency (WADA). In continuation of our direct quantitation work of the prohibited threshold substances, direct LC-MS/MS methods combined with a simple sample preparation procedure have been developed and validated for the measurement of these two threshold substances in urine samples. After the enzymatic hydrolysis of urine samples, the resulting samples were diluted with acetonitrile and centrifuged. The supernatant was directly analyzed by LC-MS/MS using the selected reaction monitoring mode. The calibration curve range of the assay was ranged over 50-200% of the threshold value according to WADA guidelines. The limit of detection and limit of quantification were 6.1 and 18.4 ng/mL for THC-COOH and 2.0 and 6.2 ng/mL for formoterol, respectively. Intra- and inter-day precisions were between 2.08% and 7.28% and the accuracies ranged from 95.16% to 104.49%. The present methods were successfully applied to the analysis of the proficiency test samples.

Simultaneous ultra-high performance liquid chromathograpy-electrospray ionization-quadrupole-time of flight mass spectrometry quantification of endogenous anandamide and related N-acylethanolamides in bio-matrices.

We describe and validate a sensitive UHPLC-ESI-QTOF-MS method for the simultaneous quantification of seven endocannabinoids and non-endocannabinoids related N-acylethanolamides: N-arachidonoylethanolamide, N-palmitoylethanolamide, N-stearoylethanolamide, N-oleoylethanolamide, N-linoleoylethanolamide, N-α-linolenoylethanolamide and N-eicosapentaenoylethanolamide in several bio-matrices for the purpose of research and clinical application. We examined effects of different liquid-liquid and solid phase extraction on the recovery of endocannabinoids and N-acylethanolamides. Protein precipitation with cooled acetone and extraction with acetonitrile (1% v/v formic acid) using OASIS HLB cartridge gave better results. Separation was performed on a Waters Acquity UPLC HSST3 column using a 9min elution gradient coupled with high resolution mass spectrometry (QTOF/MS). The high sensitivity of the developed method allow its application on sample with low volumes or low levels of endocannabinoids and N-acylethanolamides and make the method suitable for routine measurement in human bio-matrices, such as plasma, serum (500µL), urine (1mL) and tissues (10-30mg). Its application in clinical research could contribute to unravel pathophysiological roles of these family of lipid mediators and disclose novel diagnostic and prognostic markers.

An improved liquid chromatography-tandem mass spectrometric method to quantify formoterol in human urine.

Formoterol is a new threshold substance in the prohibited list 2012 according to World Anti-Doping Agency. Extracted by ethyl acetate using formoterol-D6 as internal standard, formoterol underwent a constant flow rate gradient elution separation in reversed-phase liquid chromatography. Subsequently, mass spectrometry analysis was conducted by tandem mass spectrometry in the multiple reaction monitoring mode. According to the proposed method, a calibration curve was constructed in the range of 0.2-500 ng/mL (r(2) = 1) with a limit of quantification 0.2 ng/mL. The mean extracted recovery assessed at three different concentrations (1, 30 and 100 ng/mL) was more than 80%. The method was validated by the analysis of three quality control samples from World Association of Anti-Doping Scientists. In conclusion, the developed and validated method was sensitive, accurate and precise for the quantification of formoterol in human urine for doping control purposes.

A simplified procedure for the analysis of formoterol in human urine by liquid chromatography-electrospray tandem mass spectrometry: application to the characterization of the metabolic profile and stability of formoterol in urine.

Since 1992, formoterol is included in the prohibited list of doping substances and methods, presently reviewed and updated by the World Anti-Doping Agency. Recently a threshold value of 40ng/mL has been established to differentiate between the prohibited (oral) and the permitted (inhalatory) administration of formoterol to athletes. This paper considers the urinary excretion profile of formoterol and its main metabolites after inhalation of different doses of two of the most used medicaments, available in Italy, containing formoterol fumarate bihydrate (12 and 36µg twice a day of Foradil(®) or 9 and 27µg twice a day of Symbicort(®)), focusing also on the effects, on the measured levels of formoterol, of potential alteration processes (thermal and/or microbiological) that may take place after the collection of the urine samples. Urine sample preparation included an enzymatic hydrolysis and a dilution step. Detection of analytes was performed by a newly developed and validated direct LC-ESI-MS/MS procedure, using a triple quadrupole mass spectrometer under positive ion electro-spray ionization conditions and selected reaction monitoring acquisition mode. The results showed the capability and suitability of the direct LC-ESI-MS/MS analysis for the quantitative confirmation analysis of formoterol in urine samples. The data from the analysis of the urine samples obtained in the excretion studies showed that formoterol is excreted mainly as unmodified drug and to a lesser degree as O-demethylated metabolite. The urinary levels of formoterol (40-60%) and its metabolites (O-demethylated metabolite 5-25%; glucuronide metabolites 25-40%) vary significantly depending both on the administered drug formulation and the subject tested. The maximum urinary concentration reached in this study was 15ng/mL (free+glucuronide), that is significantly lower than the threshold value fixed to report an adverse analytical finding. Finally, our results also showed that formoterol is stable for at least 4 weeks in urine samples correctly collected and stored.

An online field-amplification sample stacking method for the determination of ß2-agonists in human urine by CE-ESI/MS.

Field amplified sample stacking (FASS) was combined with a simple, rapid, sensitive CE-ESI-MS method to achieve the on-line enrichment and simultaneous determination of Clenbuterol (CLE), Salbutamol (SAL), Terbutaline (TER) and Formoterol (FOR). Samples were diluted in deionized water, and electrokinetic injection (10 kV × 50 s) was employed to carry out FASS. With FASS, the four ß2-agonists had simultaneously baseline enhancement as much as 319, 332, 297 and 115 fold, respectively. Consequently, satisfactory LODs (S/N=3) of 0.08, 0.1, 0.1 and 0.5 ng/mL for CLE, SAL, TER and FOR were obtained. The separation of the four analytes was performed at 22 kV in ammonium acetate/ammonia (20 mmol/L, pH 9.0), using 7.5 mmol/L acetic acid in isopropanol/water 50/50% (v/v) as sheath liquid. In addition, an excellent linear response was obtained with RSD less than 1.3% for migration times and less than 6.7% for peak areas (n=5). The recoveries of spiked urine samples were in the range of 82.7-101% with RSD lower than 9.8%. The proposed method has been applied to analyze human urine samples successfully.

Detection of main urinary metabolites of ß2-agonists clenbuterol, salbutamol and terbutaline by liquid chromatography high resolution mass spectrometry.

Clenbuterol, terbutaline and salbutamol are B2-agonists drugs included in the list of banned substances of the World Anti Doping Agency (WADA) prohibited in and out of competition. In this article, the excretion of urinary metabolites of clenbuterol, terbutaline and salbutamol have been studied using liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS), after a single therapeutic dose administration in rats. Urine collected was processed with solid-phase extraction prior to LC-TOFMS analyses using electrospray in the positive ion mode and pseudo MS/MS experiments from in-source collision induced dissociation (CID) fragmentation (without precursor ion isolation). The strategy applied for the identification of metabolites was based on the search of typical biotransformations with their corresponding accurate mass shift and the use of common diagnostic fragment ions from the parent drugs. The approach was satisfactory applied, achieving the identification of 11 metabolites (5 from clenbuterol, 4 from salbutamol and 3 from terbutaline), 4 of them not previously reported in urine. Novel metabolites identified in rat urine included N-oxide-salbutamol, hydroxy-salbutamol, methoxy-salbutamol glucuronide and terbutaline N-oxide, which are all reported here for the first time.

Overcoming matrix effects in electrospray: quantitation of ß-agonists in complex matrices by isotope dilution liquid chromatography-mass spectrometry using singly (13)C-labeled analogues.

In this work, the implementation of isotope dilution mass spectrometry (IDMS) using minimal labeling and isotope pattern deconvolution (IPD) is evaluated as a strategy for the minimization of matrix effects during trace determination of ß2-agonists in complex matrices by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). First, the parameters affecting the measurement of isotopic composition of organic compounds by liquid chromatography electrospray ionization high resolution mass spectrometry with a time-of-flight analyzer were evaluated using as a case of study three different ß2-agonists: clenbuterol, clenproperol and brombuterol. Then, a calibration graph-free IDMS methodology was evaluated in order to overcome matrix effects in LC-ESI-MS in complex samples. In this procedure singly (13)C-labeled analogues of clenbuterol, clenproperol and brombuterol were employed in combination with IPD. Using this approach accurate and precise results were obtained in the simultaneous quantification of ß2-agonists in human urine and bovine liver, even at the sub ngg(-1) and particularly in spite of the previously reported matrix effects. Recovery rates in the range of 97-114% in fortified human urine and from 95% to 111% in fortified bovine liver were obtained with RSD (%) of independent recovery experiments always lower than 6%. These results demonstrate that the proposed methodology based on the use of (13)C1-labeled standards and IPD is a reliable approach for accurate LC-MS quantitation of small molecules and compatible with full-scan high-resolution mass spectrometry.

Evaluation of the urinary threshold concentration of formoterol in sports drug testing.

The use of formoterol in sports is allowed by inhalation at the maximum recommended therapeutic dose. Recently, a threshold concentration of 30 ng.mL(-1) was defined by the World Anti-Doping Agency (WADA) to distinguish between therapeutic and forbidden use of formoterol. The objective of this work was to evaluate that threshold concentration. Concentrations of formoterol were measured in urine samples collected after administration of 18 µg of inhaled formoterol to five healthy volunteers, and in samples collected in routine doping tests belonging to athletes having declared inhaled formoterol use. Formoterol was detected up to 8 h after administration in all volunteers with concentrations up to 19.6 ng.mL(-1) . From 28 routine samples, 27 had less than 10 ng.mL(-1) of formoterol and only in one of the samples the concentration was 25 ng.mL(-1) . Therefore, administration of formoterol by inhalation at the maximum dose allowed by WADA will not produce false positive results using a threshold concentration of 30 ng.mL(-1) , and the experience up to now in routine doping tests indicates that the probability of obtaining urines with concentrations greater than 30 ng.mL(-1) is close to nil. For this reason, sports authorities should re-evaluate the need of a threshold concentration for formoterol and its practical usefulness.

Formoterol concentrations in blood and urine: the World Anti-Doping Agency 2012 regulations.

INTRODUCTION: We examined urinary and serum concentrations of formoterol in asthmatic and healthy individuals after a single dose of 18 µg inhaled formoterol and after repeated inhaled doses in healthy individuals. Results were evaluated using the World Anti-Doping Agency (WADA) 2012 threshold for formoterol. METHODS: On the day of this open-label, crossover study, 10 asthmatic subjects who regularly used beta2-agonists and 10 healthy participants with no previous use of beta2-agonists received a single dose of 18 µg formoterol. Further, 10 nonasthmatic participants inhaled 18 µg formoterol every second hour until obtaining a total of 72 µg, which is twice the maximum daily dose (36 µg formoterol) permitted by the WADA. Blood samples were collected at baseline, 30 min, 1, 2, 3, 4, and 6 h after the first inhalation. Urine samples were collected at baseline, 0-4, 4-8, and 8-12 h after the first inhalation. RESULTS: Median urine concentration, corrected for specific gravity, after the single-dose administration peaked during 0-4 h after inhalation at a maximum of 7.4 ng·mL(-1) in asthmatic subjects and 7.9 ng·mL(-1) in healthy subjects. Median urine concentration after repeated doses peaked during 4-8 h after inhalation of a total of 72 µg formoterol at a maximum of 16.8 ng·mL(-1) in healthy participants. The maximum individual concentration of 25.6 ng·mL(-1) was found after inhalation of a total of 72 µg formoterol. CONCLUSIONS: We found no significant differences in urinary and serum concentrations of formoterol between asthmatic and healthy subjects. We found high interindividual variability in the concentrations in all groups. Our data support the WADA 2012 urinary threshold of 30 ng·mL(-1) formoterol as being an adverse analytical finding.