Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Drug Test Anal ; 13(2): 348-359, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32949107

RESUMO

Betamethasone (BET) is prohibited in sports competitions when administered by systemic routes, and it is allowed by other routes for therapeutic purposes. In out-of-competition periods, there is no restriction of use. The present work aimed to assess the urinary excretion of BET and its metabolites after allowed and prohibited administrations to verify the suitability of the current reporting level of 30 ng/ml used to distinguish allowed and prohibited administrations and to establish washout periods for oral and intramuscular (IM) administrations when out-of-competition treatments are needed. BET was administered to healthy volunteers by different routes: topical (10 mg/day for 5 days, n = 6 males), intranasal (320 µg/day for 3 days, n = 4 males and 4 females), oral (0.5 mg, n = 8 males) or IM (6 mg, n = 6 males, or 12 mg, n = 4 males and 4 females). Urine and plasma samples collected before and after administration were analysed using liquid chromatography-tandem mass spectrometry. Among all studied metabolites, the parent drug was selected as the best discriminatory marker. After topical administration, BET concentrations were lower than 6.6 ng/ml. However, after intranasal treatment, some samples at concentrations close to or higher than 30 ng/ml were detected, suggesting the need to revise the current reporting level. Urinary concentrations after oral and intranasal administrations were similar, and after IM administration, concentrations were much higher. Taking into account all information, a urinary reporting level of 60 ng/ml is proposed. Washout periods of at least 48 and 96 h are recommended after oral and IM administrations, respectively.


Assuntos
Betametasona/administração & dosagem , Betametasona/urina , Glucocorticoides/administração & dosagem , Glucocorticoides/urina , Administração Intranasal , Administração Oral , Administração Tópica , Betametasona/sangue , Cromatografia Líquida/métodos , Monitoramento de Medicamentos/métodos , Feminino , Glucocorticoides/sangue , Humanos , Injeções Intramusculares , Limite de Detecção , Masculino , Espectrometria de Massas em Tandem/métodos
2.
Food Addit Contam Part B Surveill ; 11(3): 201-207, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29716443

RESUMO

The presence of corticosteroid residues was assessed in urine and liver samples from livestock of Sicily. A total of 630 bovine samples were collected from farms and slaughterhouses. The samples were analysed using solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). All the corticosteroids found were under the maximum residue limit imposed by Commission Regulation (EC) 37/2010. About 4% of liver samples showed dexamethasone levels above the limit of detection (LOD), with a mean of 1.5 ± 0.2 µg kg-1. Betamethasone was found only in seven liver samples, with a mean of 1.6 ± 0.1 µg kg-1. Furthermore, prednisolone and prednisone were found only in urine and liver samples from slaughterhouse, probably related to the high rate of stress for bovines. These results suggest good control practices adopted by Sicilian farms, able to ensure the quality of food products.


Assuntos
Corticosteroides/análise , Resíduos de Drogas/análise , Contaminação de Alimentos , Inspeção de Alimentos/métodos , Fígado/química , Matadouros , Corticosteroides/urina , Animais , Betametasona/análise , Betametasona/urina , Biomarcadores/análise , Biomarcadores/urina , Bovinos , Cromatografia Líquida de Alta Pressão , Dexametasona/análise , Dexametasona/urina , Feminino , Humanos , Limite de Detecção , Fígado/crescimento & desenvolvimento , Masculino , Prednisolona/análise , Prednisolona/urina , Prednisona/análise , Prednisona/urina , Reprodutibilidade dos Testes , Sicília , Extração em Fase Sólida , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
3.
Rapid Commun Mass Spectrom ; 32(11): 897-905, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29572989

RESUMO

RATIONALE: In addition to the development of adequate screening methods for multiple compounds, the World Anti-Doping Agency (WADA) requires anti-doping laboratories to analyze prohibited substances and their metabolites from various classes. This task presents a difficult challenge for all agencies and interests involved in the field of doping control. METHODS: A screening method is reported in which hybrid sample preparation was performed using a combination of weak cation-exchange solid-phase extraction (WCX-SPE) and the 'Dilute and Shoot' strategy in order to take advantage of both the methodologies. Target substances were extracted using a WCX cartridge and reconstituted with a diluted sample aliquot that included 20% of an untreated urine sample. The target substances were further analyzed by high-performance liquid chromatography/triple quadrupole mass spectrometry (LC/MS). RESULTS: The SPE procedure was optimized using a cartridge-washing step, elution conditions, and elution volume. The cartridge-washing step, which was performed using 10% methanol, improved the overall recovery of target substances. Since the recovery was observed to vary according to the pH of the eluting solution, we applied an elution step using both an acid and a basic organic solvent to achieve complementary recovery. Reconstitution of the diluted aliquot sample was performed to recover the polar substances. CONCLUSIONS: The method was validated and applied to real samples in accordance with the external quality assessment scheme of WADA and to the previously reported samples that had provided positive test results. This novel method using hybrid sample preparation and LC/MS could be useful to screen multiple classes of the 264 targeted substances in anti-doping analysis.


Assuntos
Dopagem Esportivo , Substâncias para Melhoria do Desempenho/análise , Extração em Fase Sólida/métodos , Betametasona/urina , Cromatografia Líquida de Alta Pressão , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Substâncias para Melhoria do Desempenho/urina , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Solventes/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Trimetazidina/urina
4.
Drug Test Anal ; 10(6): 947-955, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29278450

RESUMO

The steroid profile (SP) is a powerful tool to detect the misuse of endogenous anabolic androgenic steroids in sports, and it is included in the Athlete Biological Passport (ABP). Glucocorticoids (GCs), which are widely prescribed in sports and only prohibited in competition by systemic routes, inhibit the hypothalamic-pituitary-adrenal axis. Since the metabolites monitored in the SP have a partial adrenal origin, their excretion in urine might be altered by GCs consumption. The aim of the present work was to investigate if GCs administered by either systemic or local routes could influence the SP parameters. Three of the most frequently detected GCs in sports (prednisolone, betamethasone, and triamcinolone acetonide) were administered to healthy male and female volunteers (n=40) using different administration routes (topical, oral, and intramuscular administration at different doses). In total, 66 administrations of GCs were performed. Urine samples were collected before and after GCs administration. The SP was measured using gas chromatography-mass spectrometry. The excretion rates of the SP metabolites decreased after systemic GCs administration. This excretion decrease showed to be associated with the dose and the administration route. However, the individual evaluation of the SP ratios (T/E, A/T, A/Etio, 5αAdiol/5ßAdiol, and 5αAdiol/E) led to normal sequences for all the conditions tested. Therefore, GCs administration did not produce misinterpretations on the ABP evaluation. According to these results, GCs administration should not distort the establishment of normal ranges of the SP ratios, and does not need to be considered a confounding factor in the SP evaluation.


Assuntos
Glucocorticoides/administração & dosagem , Esteroides/urina , Detecção do Abuso de Substâncias/métodos , Administração Oral , Administração Tópica , Adulto , Betametasona/administração & dosagem , Betametasona/urina , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Glucocorticoides/urina , Humanos , Injeções Intramusculares , Masculino , Prednisolona/administração & dosagem , Prednisolona/urina , Esteroides/metabolismo , Testosterona/metabolismo , Testosterona/urina , Triancinolona/administração & dosagem , Triancinolona/urina , Adulto Jovem
5.
J Pharm Biomed Anal ; 149: 278-289, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29128828

RESUMO

Quantitative evaluation and assessment of pharmacokinetic parameters of Diprospan® (suspension for injection 7mg/mL (2mg+5mg/mL) of betamethasone) were performed in urine samples taken from patients with rheumatoid arthritis or ankylosing spondylitis for 28days after systemic intramuscular administration in routine clinical practice in an open-comparative prospective cohort study. The maximum betamethasone concentration was reached at day 4 of the follow-up; in some cases, ß-phase of elimination of the drug was appeared at day 14 or at day 21 of the follow-up. The deferred ß-phase elimination was likely a consequence of the physiological characteristics of the patients or of the influence of non-steroidal agents. The half-life of betamethasone was 8.5days. The elimination rate constant was 2.49h-1; the mean clearance was 4.72L/d. The recommended frequency of the drug administration to its complete elimination was estimated up to 48days. Mann-Whitney test showed no significant differences in pharmacokinetic characteristics between male and female subjects. The prolonged elimination phase was observed in patients with deviations in their body mass index, continual treatment by diclofenac and nimesulide or, possibly, after consuming an alcohol. The study was recorded in Clinical Trials open source with identifier NCT03119454.


Assuntos
Artrite Reumatoide/tratamento farmacológico , Betametasona/análogos & derivados , Glucocorticoides/farmacocinética , Eliminação Renal/efeitos dos fármacos , Espondilite Anquilosante/tratamento farmacológico , Adulto , Artrite Reumatoide/urina , Betametasona/administração & dosagem , Betametasona/farmacocinética , Betametasona/urina , Diclofenaco/farmacologia , Combinação de Medicamentos , Etanol/farmacologia , Feminino , Glucocorticoides/administração & dosagem , Glucocorticoides/urina , Meia-Vida , Humanos , Injeções Intramusculares , Masculino , Estudos Prospectivos , Fatores Sexuais , Espondilite Anquilosante/urina , Sulfonamidas/farmacologia
6.
J Vet Pharmacol Ther ; 39(1): 22-6, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25847081

RESUMO

To the date, no reports exist of the pharmacokinetics (PK) of betamethasone (BTM) sodium phosphate and betamethasone acetate administered intra-articular (IA) into multiple joints in exercising horses. The purpose of the study was to determine the PK of BTM and HYD concentrations in plasma and urine after IA administration of a total of 30 mg BTM. Eight 4 years old Thoroughbred mares were exercised on a treadmill and BTM was administered IA. Plasma and urine BTM and HYD were determined via high performance liquid chromatography spectrometry for 6 weeks. Concentration-time profiles of BTM and HYD in plasma and urine were used to generate PK estimates for non-compartmental analyses and comparisons among times and HYD concentrations. BTM in plasma had greater Tmax (Tmax 0.8 h) vs. urine (Tmax 7.1 h). Urine BTM concentration (ng/mL) and amount (AUClast ; h × ng/mL) were greater than plasma. HYD was suppressed for at least 3 days (<1 ng/mL) for all horses. The time of last quantifiable concentration of BTM (Tlast ; hour) was not significantly different in plasma than urine. Use of highly sensitive HPLC-MS/MS assays enabled early detection and prolonged and consistent determination of BTM in plasma and urine.


Assuntos
Betametasona/análogos & derivados , Glucocorticoides/farmacocinética , Cavalos/fisiologia , Hidrocortisona/farmacocinética , Animais , Área Sob a Curva , Betametasona/administração & dosagem , Betametasona/sangue , Betametasona/farmacocinética , Betametasona/urina , Feminino , Glucocorticoides/administração & dosagem , Meia-Vida , Cavalos/sangue , Hidrocortisona/sangue , Hidrocortisona/urina , Injeções Intra-Articulares , Metatarso , Condicionamento Físico Animal , Tarso Animal
7.
Drug Test Anal ; 7(8): 663-72, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25545348

RESUMO

Glucocorticosteroids are prohibited in sports when administered by systemic routes and allowed using other administrations for therapeutic reasons. Therefore, markers to distinguish between routes of administration through the analysis of urine samples are needed in anti-doping control. As a first step to achieve that goal, the metabolism of betamethasone (BET) was investigated in the present work. Urine samples obtained after BET intramuscular injection were hydrolyzed with ß-glucuronidase and subjected to liquid-liquid extraction with ethyl acetate in alkaline conditions. The extracts were analyzed by liquid chromatography coupled to tandem mass spectrometry. Common open screening methods for fluorine containing corticosteroids (precursor ion scan method of m/z 121, 147, 171, and neutral loss (NL) scan methods of 20 and 38 Da in positive ionization, and 46 and 76 Da in negative ionization) were applied to detect BET metabolites. Moreover, an NL method was applied to detect A-ring reduced metabolites of BET, which are ionized as [M+NH4 ](+) (NL of 55, 73, and 91 Da, corresponding to the consecutive losses of NH3 , HF and one, two and three water molecules, respectively). BET and 24 metabolites were detected. Six metabolites were identified by comparison with standards, and for ten, feasible structures were proposed based on mass spectrometric data. Eleven of the characterized metabolites had not been previously reported. Metabolites resulting from 11-oxidation, 6-hydroxylation, C20 or 4-ene-3-one reduction and combination of some of them were detected. Moreover one metabolite resulting from cleavage of the side chain with subsequent oxidation of carbon at C17 was also detected.


Assuntos
Betametasona/metabolismo , Betametasona/urina , Glucocorticoides/metabolismo , Glucocorticoides/urina , Betametasona/análise , Cromatografia Líquida/métodos , Glucocorticoides/análise , Humanos , Extração Líquido-Líquido/métodos , Masculino , Detecção do Abuso de Substâncias/métodos , Espectrometria de Massas em Tandem/métodos
8.
Ann Clin Biochem ; 48(Pt 6): 542-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21846739

RESUMO

BACKGROUND: We report a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of four commonly prescribed steroid drugs (prednisolone, dexamethasone, betamethasone and beclomethasone dipropionate) while simultaneously measuring 24-h urine free cortisol and cortisone in patients. METHODS: Two hundred and fifty microlitre aliquots of urine were spiked with internal standard and extracted with dichloromethane. The MS instrument was operated with positive electrospray and multiple reaction monitoring. Two transitions were monitored for each analyte of interest and the ratio of the intensities of the product ion fragments was established. RESULTS: The LC-MS/MS method for the measurement of urine free cortisol and cortisone was established. The assay was linear up to 788 nmol/L for cortisol and 777 nmol/L for cortisone, with a limit of quantitation of 5.0 nmol/L for both. Analysis time per sample was seven minutes. Transitions for four synthetic glucocorticoids were included, and they were identified based on the ratio of the intensities of product ion fragments. Analysis of 219 samples collected from 154 patients (55 male and 99 female) revealed the presence of prednisolone in five samples from three patients. Dexamethasone was detected in samples from four patients, and betamethasone was detected in one sample. CONCLUSION: This is the first LC-MS/MS method in routine use to combine quantification of urinary cortisol and cortisone and detection of synthetic glucocorticoids in patients being investigated for Cushing's syndrome. Since the most common quoted cause of Cushing's syndrome is steroid treatment, this is a valuable diagnostic tool.


Assuntos
Cromatografia Líquida/normas , Síndrome de Cushing/diagnóstico , Glucocorticoides/urina , Espectrometria de Massas em Tandem/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Beclometasona/uso terapêutico , Beclometasona/urina , Betametasona/uso terapêutico , Betametasona/urina , Criança , Cortisona/urina , Síndrome de Cushing/tratamento farmacológico , Dexametasona/uso terapêutico , Dexametasona/urina , Feminino , Glucocorticoides/uso terapêutico , Humanos , Hidrocortisona/urina , Limite de Detecção , Masculino , Pessoa de Meia-Idade , Prednisolona/uso terapêutico , Prednisolona/urina , Padrões de Referência , Adulto Jovem
9.
Breastfeed Med ; 4(4): 201-6, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19772378

RESUMO

BACKGROUND: Antenatal corticosteroids are given to most women at risk of preterm delivery, although many do not eventually deliver preterm. Profound disruptions of lactation have been shown in ewes after antenatal corticosteroid treatment, but little is known of the effect on lactation in women. This study aimed to investigate the effects of antenatal corticosteroid treatment on mammary secretion during pregnancy in women. METHODS: We conducted a prospective cohort study of women receiving betamethasone for anticipated preterm delivery (n = 87). Women collected 24-hour urine samples on days 1, 2, 3, 5, 7, and 14 after treatment if they remained pregnant. We measured urinary excretion of pregnanediol glucuronide (PdG), a major metabolite of progesterone and lactose, which indicates mammary secretion during pregnancy. Withdrawal of progesterone triggers the onset of mammary secretion. RESULTS: Median (range) gestational age at treatment was 28.8 (23.6-33.6) weeks. A total of 330 24-hour urine samples were collected. Median (range) excretion of PdG was 1.355 (0.139-5.069) mmol/24 hours, and lactose excretion was 0.823 (0.035-6.676) mmol/24 hours. Both PdG and lactose excretion increased with increasing gestational age (P < 0.001). After adjustment for gestational age, there were significant transient increases in lactose excretion (P < 0.001) after betamethasone treatment but no changes in PdG excretion (P = 0.435). CONCLUSIONS: Antenatal betamethasone treatment was associated with a transient premature secretory activation while women were still pregnant.


Assuntos
Corticosteroides/urina , Betametasona/urina , Lactose/urina , Gravidez/urina , Pregnanodiol/urina , Corticosteroides/administração & dosagem , Corticosteroides/efeitos adversos , Adulto , Betametasona/administração & dosagem , Betametasona/efeitos adversos , Biomarcadores/urina , Estudos de Coortes , Feminino , Idade Gestacional , Humanos , Lactação/efeitos dos fármacos , Glândulas Mamárias Humanas/efeitos dos fármacos , Glândulas Mamárias Humanas/metabolismo , Pregnanodiol/análogos & derivados , Cuidado Pré-Natal , Estudos Prospectivos
10.
J Sep Sci ; 30(18): 3137-42, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18008280

RESUMO

The effects of temperature, organic modifier and the type of acid on the retention factor, the resolution and peak shape of betamethasone and dexamethasone are described. The study is performed using narrow bore porous graphitic carbon (PGC) columns online with diode-array detector (DAD) and ESI MS/MS. The results show that temperature affects the retention behaviour of the two compounds and ACN yields the best separation while no effect is obtained by changing the type of organic acid. The developed method is applied for the confirmation of dexamethasone and betamethasone in human urine.


Assuntos
Betametasona/urina , Carbono/química , Cromatografia Líquida/métodos , Dexametasona/urina , Compostos Orgânicos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos , Ácidos/química , Humanos , Íons/química , Temperatura
11.
Anal Chem ; 79(15): 6020-6, 2007 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-17602668

RESUMO

Detection of doping agents in urine frequently requires extensive separation prior to chemical analyses. Gas or liquid chromatography coupled to mass spectrometry has produced accurate and sensitive assays, but chromatographic separations require time and, sometimes, chemical derivatization. To avoid such tedious and lengthy procedures, vacuum matrix-assisted laser desorption ionization (vMALDI) coupled with the linear ion trap mass spectrometry (LIT/MS) technique is tested for its applicability as a rapid screening technique. Commonly used doping agents like nandrolone, boldenone, trenbolone, testosterone, and betamethasone were chosen as study compounds. Different MALDI matrixes like alpha-cyano-4-hydroxycinnamic acid (CHCA), dihyroxy benzoic acid (DHB) with and without cetyl trimethyl ammonium bromide (CTAB), a surfactant, and meso-tetrakis(pentafluorophenyl) porphyrin (F20TPP) were tested. Among them, F20TPP (MW 974.57 Da) was selected as the preferred matrix owing to the lack of interfering matrix peaks at the lower mass range (m/z 100-700). Urine samples spiked with study compounds were processed by solid-phase extraction (SPE) and consistently detected through a linear range of 0.1-100 ng/mL. The limit of detection and lower limit of quantification for all five analytes have been determined to be 0.03 and 0.1 ng/mL, respectively, in urine samples. Testosterone-d3 was used as an internal standard, and the quantitative measurements were achieved by the selective reaction monitoring (SRM) mode. The method was validated and showed consistency in the results. Hence, vMALDI-LIT/MS can be used as a rapid screening method to complement the traditional GC/MS and LC/MS techniques for simultaneous identification, confirmation, and quantification of doping agents in urine.


Assuntos
Anabolizantes/urina , Dopagem Esportivo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Detecção do Abuso de Substâncias/métodos , Benzoatos/química , Betametasona/urina , Ácidos Cumáricos/química , Álcoois Graxos , Humanos , Nandrolona/urina , Porfirinas/química , Compostos de Amônio Quaternário/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tensoativos/química , Testosterona/análogos & derivados , Testosterona/urina , Acetato de Trembolona/urina , Vácuo
12.
J Chromatogr B Analyt Technol Biomed Life Sci ; 848(2): 292-302, 2007 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-17101303

RESUMO

Direct-injection LC-LC hybrid tandem MS methods have been developed for undertaking broad-based screening for acidic drugs in protein-precipitated plasma and neutral doping agents in equine urine. In both analyses, analytes present in the matrix were trapped using a HLB extraction column before being refocused and separated on a Chromolith RP-18e monolithic analytical column using a controlled differential gradient generated by proportional dilution of the first column's eluent with water. Each method has been optimised by the adoption of a mobile phase and gradient that was tailored to enhance ionisation in the MS source while maintaining good chromatographic behaviour for the majority of the target drugs. The analytical column eluent was fed into the heated nebulizer (HN) part of the Duospray interface attached to a 4000 QTRAP mass spectrometer. Information dependent acquisition (IDA) with dynamic background subtraction (DBS) was configured to trigger a sensitive enhanced product ion (EPI) scan when a multiple reaction monitoring (MRM) survey scan signal exceeded the defined criteria. Ninety-one percent of acidic drugs in protein-precipitated plasma and 80% of the neutral compounds in equine urine were detected when spiked at 10 ng/ml.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Preparações Farmacêuticas/sangue , Preparações Farmacêuticas/urina , Espectrometria de Massas em Tandem/métodos , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/sangue , Betametasona/administração & dosagem , Betametasona/urina , Glucocorticoides/administração & dosagem , Glucocorticoides/sangue , Cavalos , Preparações Farmacêuticas/química , Fenilbutazona/administração & dosagem , Fenilbutazona/sangue , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/instrumentação
13.
Luminescence ; 20(3): 197-204, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15924320

RESUMO

The development of a black market of chemical cocktails for illegal growth promotion in food-producing animals includes substances that are potentially dangerous for human health, such as synthetic corticosteroids. The potential presence of these residues in food makes it necessary to develop rapid and sensitive analytical methodologies to detect such substances, preferably in live animals before they arrive at the market. A chemiluminescence (CL) detection method for the determination of four synthetic corticosteroids (prednisolone, betamethasone, dexamethasone and flumethasone) in bovine urine has been developed. The proposed system, which does not need any derivatization procedure, offers an easy method well suited for routine research. Urine samples were homogenized with methanol:water (50:50, v/v) and centrifuged. The upper layer was collected and Strata X cartridges were used for cleaning up. The purified residues were evaporated to dryness and then redissolved in the mobile phase. Analysis of the extracts was performed using high-performance liquid chromatography with chemiluminescence detection, employing luminol as the CL reagent. The recovery curves, obtained at four spiking levels (different for each corticosteroid), showed that recoveries of at least 70% could be obtained for urine. The chemiluminescence detection procedure afforded satisfactory results with respect to sensitivity and the LOD and LOQ, taken as the first point of the regression curve, ranged from 4 ppb to 65 ppb. The maximum mean RSD was below 13% and below 15% for intra- and inter-day assay, respectively, in all cases.


Assuntos
Corticosteroides/urina , Cromatografia Líquida de Alta Pressão/métodos , Animais , Betametasona/urina , Bovinos , Dexametasona/urina , Flumetasona/urina , Contaminação de Alimentos/análise , Medições Luminescentes/métodos , Medições Luminescentes/normas , Luminol , Prednisolona/urina
15.
J Mass Spectrom ; 37(1): 69-75, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11813313

RESUMO

Betamethasone and dexamethasone are two corticosteroids differing in the stereoisomery of their C-16 methyl group. These two compounds are imperfectly separated by reversed-phase liquid chromatography and their mass spectra are very similar, leading to a difficult unambiguous identification according to European criteria. A method is proposed for differentiating betamethasone and dexamethasone using liquid chromatography/tandem mass spectrometry and multivariate statistical analysis. Multiple analysis of variance was used for the justification and the selection of diagnostic ions. Principal component analysis permitted the suitability of the approach to be tested on a large number of samples. Discriminant factorial analysis was finally performed to build a decisional model based on the six most significant ions. This novel utilization of mass spectrometric data appeared efficient for the unambiguous identification of the target analytes in urine samples.


Assuntos
Betametasona/análise , Dexametasona/análise , Animais , Betametasona/urina , Bovinos , Cromatografia Líquida , Dexametasona/urina , Indicadores e Reagentes , Análise Multivariada , Espectrometria de Massas por Ionização por Electrospray
16.
J Chromatogr B Biomed Sci Appl ; 713(2): 339-52, 1998 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-9746249

RESUMO

Different hyphenated liquid chromatographic (LC) and mass spectrometric (MS) techniques were investigated in order to set-up a method for the fast, direct analysis of betamethasone in hydrolysed and non-hydrolysed urine using large-volume sample injection. After the optimisation of the LC parameters using a traditional UV detector and of the thermospray and mass spectrometric parameters by flow injection, urine samples (0.5 ml) were submitted to analysis by either LC combined with tandem mass spectrometry (MS-MS), coupled-column LC (LC-LC) combined with single quadrupole MS, and LC-LC-MS-MS. Both the three-step configurations (LC-MS-MS and LC-LC-MS) did not provide satisfactory results: loss of sensitivity was noted in the case of LC-MS-MS (likely due to reduced efficiency in the ionisation of betamethasone in the thermospray owing to the presence of large amounts of matrix interference), while in the case of LC-LC-MS a high chemical noise resulting in insufficient selectivity of detection was observed. On the contrary, LC-LC-MS-MS analysis proved to meet the demand of high speed of analysis (sample throughput, 4.5 h(-1)), selectivity, and sensitivity (LOQ, 1 ng/ml; LOD, 0.2 ng/ml). Notwithstanding the complex analytical system adopted, the developed procedure was manageable and very robust, provided that at the beginning of each analytical session the performance of the system was controlled by checking the retention time of the analytes on the first analytical column with UV detection and by optimising vaporiser temperature of the thermospray by flow injection.


Assuntos
Betametasona/urina , Glucocorticoides/urina , Cromatografia Líquida , Humanos , Hidrólise , Espectrometria de Massas , Sensibilidade e Especificidade
17.
Anal Biochem ; 235(2): 119-26, 1996 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-8833319

RESUMO

A method for the immunoaffinity extraction of dexamethasone and betamethasone in bovine urine, followed by high-pressure liquid chromatography (HPLC) fractionation and gas chromatography-mass spectrometry determination, is described. A commercial immunoaffinity gel, containing antibodies raised against dexamethasone, was used to prepare an immunoaffinity cartridge which was inserted in an automatic HPLC system for on-line extraction and purification. By injecting urine samples (spiked with flumethasone as internal standard) directly into the system, it was possible to collect purified fractions, containing the analytes of interest. The fractions were dried and derivatized to yield the tetra-trimethylsilyl derivatives of the three corticosteroids, which were analyzed by selected ion monitoring gas chromatography-mass spectrometry. The method allowed a very good purification of samples and reached a detection limit of 0.1 ng/ml for dexamethasone and 0.2 ng/ml for betamethasone. Several samples, coming from a steer treated with dexamethasone and from other bovines coming from breedings in northern Italy, were analyzed with the method described. Dexamethasone levels ranged from 0.12 to 146 ng/ml.


Assuntos
Betametasona/urina , Dexametasona/urina , Animais , Bovinos , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectrofotometria Ultravioleta
18.
Analyst ; 119(12): 2631-4, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7879866

RESUMO

A generic, rapid and sensitive enzyme linked immunosorbent assay (ELISA) test has been developed which allows large-scale simultaneous testing of synthetic corticosteroids viz., flumethasone, dexamethasone and betamethasone. This assay can be directly applied to diluted urine samples (1 + 9) without hydrolysis of glucuronide or sulfate conjugates or any other treatment of samples. The polyclonal antibody was obtained by immunizing sheep with a flumethasone derivative linked to human serum albumin. This polyclonal antibody displayed high-reactivity with several synthetic corticosteroids whilst endogenous corticosteroids such as cortisol gave very low cross-reactivity (< 0.5%). Sensitivities obtained in this assay were 2.5, 3.1 and 12.5 ng ml-1 for flumethasone, dexamethasone and betamethasone, respectively. The ability of this assay to detect several synthetic corticosteroids was demonstrated by testing urine samples from horses to which the drugs had been administered.


Assuntos
Corticosteroides/urina , Animais , Betametasona/urina , Bovinos , Dexametasona/urina , Ensaio de Imunoadsorção Enzimática/métodos , Flumetasona/urina , Glucuronatos , Cavalos , Humanos , Sensibilidade e Especificidade , Albumina Sérica/imunologia , Ovinos/imunologia
20.
J Chromatogr ; 341(2): 261-9, 1985 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-4030978

RESUMO

Micro-liquid chromatography-mass spectrometry (micro-LC-MS) was utilized to quantitatively determine betamethasone and its major unconjugated metabolite, 6 beta-hydroxybetamethasone, in equine plasma and urine. The advantage of micro-LC-MS over conventional gas chromatography-mass spectrometry in corticosteroid determination is illustrated and the reliable, steadfast nature of micro-LC-MS is demonstrated through example.


Assuntos
Betametasona/análogos & derivados , Betametasona/urina , Cavalos/urina , Animais , Betametasona/sangue , Cromatografia Líquida/métodos , Cromatografia em Camada Fina , Cavalos/sangue , Espectrometria de Massas/métodos , Plasma/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...