1,720,992 research outputs found
Prevalence of illicit drug use among the Italian athlete population with special attention on drugs of abuse: a 10-year review.
No full textThe objective of this study was to assess the prevalence of illicit drugs use among young adults, in particular elite athletes. This study considers the data obtained from anti-doping analyses performed on nearly 100,000 urine samples from 2000 to 2009 by the World Anti-Doping Agency accredited Italian Anti-Doping Laboratory. The percentage of adverse analytical findings varies on a yearly basis, but it is in the range 1.0-1.8% (not considering atypical findings, such as an altered endogenous steroid profile). Among positive results, there is a high prevalence of stimulants and drugs of abuse. The drug of abuse found most frequently is the tetrahydrocannabinol (cannabis) metabolite, accounting for 0.2-0.4% of the total samples analysed (18% of the positive results). The second most frequently encountered drug is cocaine, as detected from cocaine metabolites, accounting for 0.1% of the total samples analysed (7% of positive results). Other stimulants found included amphetamines, ephedrines, carphedon, modafinil, and anorexic compounds. No amphetamine-like designer drugs were detected. These data are indicative of the widespread prevalence of cocaine and cannabis use among the young adult population. However, due to the particular population studied, it must be considered an underestimation of the phenomenon among elite athletes with respect to the general population
Rapid screening of drugs of abuse and their metabolites by gas chromatography/mass spectrometry: application to urinalysis
No full textThis paper describes a rapid gas chromatographic/mass spectrometric (GC/MS) screening method
for the detection of drugs of abuse and/or their metabolites in urine. Synthetic stimulants, opiates,
cocaine metabolites, cannabinoids—and specifically the acid metabolite of tetrahydrocannabinol
(THC-COOH)—can be simultaneously extracted by a single liquid/liquid separation step, at alkaline
pH, and assayed as trimethylsilyl derivatives by GC/MS in SIM (selected ion monitoring)
mode. All the analytes show a good linearity (R2>0.99 for most of the considered substances) in
the range 25–1000 ng/mL, with a good reproducibility of both the retention times (CV% <0.7) and
the relative abundances of the characteristic diagnostic ions (CV% <13). The limit of detection
(LOD) of the method is 25 ng/mL of target compound in human urine for most of the substances
investigated, 3 ng/mL for THC-COOH, and 10 ng/mL for norbuprenorphine. Validation of the
method allows its application to different fields of forensic analytical toxicology, including antidoping
analysi
Toxicological determination and in vitro metabolism of the designer drug methylenedioxypyrovalerone (MDPV) by gas chromatography/mass spectrometry and liquid chromatography/quadrupole time-of-flight mass spectrometry.
No full textA method for the toxicological screening of the new designer drug methylenedioxypyrovalerone (MDPV) is described; with an emphasis on its application for anti-doping analysis. The metabolism of MDPV was evaluated in vitro using human liver microsomes and S9 cellular fractions for CYP450 phase I and uridine 5'-diphosphoglucuronosyltransferase (UGT) and sulfotransferase (SULT) phase II metabolism studies. The resulting metabolites were subsequently liquid/liquid extracted and analyzed using gas chromatography/mass spectrometry (GC/MS) as trimethylsilyl (TMS) derivatives. The structures of the metabolites were further confirmed by accurate mass measurement using a liquid chromatography/quadrupole time-of-flight (LC/QTOF) mass spectrometer. The studies demonstrated that the main metabolites of MDPV are catechol and methyl catechol pyrovalerone, which are in turn sulfated and glucuronated. The method for the determination of MDPV in urine has been fully validated by assessing the limits of detection and quantification, linearity, repeatability, and accuracy. This validation demonstrates the suitability for screening of this stimulant substance for anti-doping and forensic toxicology purposes
A GC-MS method for the determination of sildenafil, vardenafil and tadalafil and their metabolites in human urine
No full textSildenafil (SDF), vardenafil (VDF) and tadalafil (TDF) are phosphodiesterase type 5 enzyme inhibitors (PDE5Is), used in the treatment of erectile disorders and to improve breathing efficiency in pulmonary hypertension. The increasing incidence of their use among young athletes has drawn the attention of the anti-doping authorities to the possible abuse of PDE5Is by athletes due to their pharmacological activities. This paper describes a method for the determination in urine of PDE5Is and their metabolites by gas chromatography/mass spectrometry (GC/MS) after liquid/liquid extraction of the analytes from urine and derivatisation to obtain trimethylsilyl derivatives. The metabolic profile was studied on real samples collected from subjects taking PDE5Is (Viagra, Levitra or Cialis); the main urinary metabolites were identified and their MS fragmentation characterized. The sample pre-treatment and GC/MS conditions for the detection of the metabolites have been optimised. A method for their preliminary screening and subsequent confirmation is described that takes into account the general requirements of a routine doping analysis to be used for the screening of large numbers of samples. The main metabolites identified can be included in a general purpose screening method and all the metabolites in a more specific confirmation method. The method developed has been applied for the screening of PDE5Is in 5000 urine samples. Based on the obtained results, the proposed method appears to be of practical use in analytical and forensic toxicology, including doping analysis
A fast gas chromatography/mass spectrometry method for the determination of stimulants and narcotics in urine.
No full textA fast method has been developed for the simultaneous determination of 52 stimulants and narcotics excreted unconjugated in urine by gas chromatography/mass spectrometry (GC/MS). The procedure involves the liquid/liquid extraction of the analytes from urine at strong alkaline pH and the injection of the extract into a GC/MS instrument with a fast GC column (10 m x 0.18 mm i.d.); the short column allows the complete separation of the 52 analytes in a chromatographic run of 8 min. The method has been fully validated giving lower limits of detection (LLODs) satisfactory for its application to antidoping analysis as well as to forensic toxicology. The repeatability of the concentrations and the retention times are good both for intra- and for inter-day experiments (%CV of concentrations always lower than 15 and %CV of retention times lower than 0.6). In addition, the analytical bias is satisfactory (A% always >15%). The method proposed here would be particularly useful whenever there are time constraints and the analyses have to be completed in the shortest possible time
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Metabolism of JWH-015, JWH-098, JWH-251, and JWH-307 in silico and in vitro: a pilot study for the detection of unknown synthetic cannabinoids metabolites
No full textThis pilot study was performed to study the main metabolic reactions of four synthetic cannabinoids: JWH-015, JWH-098, JWH-251, and JWH-307 in order to setup a screening method for the detection of main metabolites in biological fluids. In silico prediction of main metabolic reactions was performed using MetaSiteTM software. To evaluate the agreement between software prediction and experimental reactions, we performed in vitro experiments on the same JWHs using rat liver slices. The obtained samples were analyzed by liquid chromatography-quadrupole time-of-flight and the identification of metabolites was executed using Mass-MetaSiteTM software that automatically assigned the metabolite structures to the peaks detected based on their accurate masses and fragmentation. A comparison between the experimental findings and the in silico metabolism prediction using MetaSiteTM software showed a good accordance between experimental and in silico data. Thus, the use of in silico metabolism prediction might represent a useful tool for the forensic and clinical toxicologist to identify possible main biomarkers for synthetic cannabinoids in biological fluids, especially urine, following their administration
The relevance of the urinary concentration of ephedrines in anti-doping analysis: determination of pseudoephedrine, cathine, and ephedrine after administration of over-the-counter medicaments.
No full textThis article describes a method for the detection and quantitation of cathine, pseudoephedrine, ephedrine, and methylephedrine in urine, using their deuterated analogues as internal standards and derivatization to form the corresponding trimethylsilyl derivatives after a simple liquid-liquid extraction. The study was designed to evaluate whether the urinary cutoff values set by the World Anti-Doping Agency for the banned ephedrines (cathine >5 microg/mL, ephedrine and methylephedrine >10 microg/mL) can be exceeded after the normal self-administration of common over-the-counter medicaments containing nonbanned ephedrines. The present method, after validation, has been applied on real urine samples obtained from 9 healthy volunteers taking different doses of over-the-counter preparations containing ephedrines. Results obtained from excretion studies show high interindividual differences in the urinary concentrations of both pseudoephedrine and cathine, not dependent on body weight or sex nor, in some instances, on the administered dose. The same typical therapeutic dose of pseudoephedrine (60 mg) produced a urinary concentration of more than 5 microg/mL for cathine and of more than 100 microg/mL for pseudoephedrine in 2 of 9 subjects only. When a dose of 120 mg was administered, cathine concentration exceeded 5 microg/mL in 4 of 7 subject, and also concentrations of pseudoephedrine above 100 microg/mL. After administration of 5 x 120 mg of pseudoephedrine (120 mg administered every 7 days for 5 weeks) to one of the subjects exceeding the urinary threshold values, the urinary concentration of cathine and pseudoephedrine exceeded 5 microg/mL (peak concentration 14.8 microg/mL) and 100 microg/mL (peak concentration 275 microg/mL), respectively. When the same subject took 180 mg of pseudoephedrine, the urinary concentration values were below 5 microg/mL for ephedrine and 100 microg/mL for pseudoephedrine. In the case of ephedrine administration in a sustained-release formulation containing 12 mg of ephedrine, 2 of 3 subjects exceeded the urinary cutoff value of 10 microg/mL. The high interindividual variability is still significant even if the urinary concentration values are adjusted by specific gravity and/or creatinine. These results confirm a high interindividual variability in the urinary concentration of ephedrines after the administration of the same therapeutic dose of a preparation
Fast GC-MS method for the simultaneous screening of THC-COOH, cocaine, opiates and analogues including buprenorphine and fentanyl, and their metabolites in urine.
No full textA fast GC-MS method has been developed and validated for the simultaneous screening of different classes of drugs of abuse in urine. Tetrahydrocannabinol metabolite (THC-COOH), cocaine, opiates such as morphine, monoacetylmorphine (O-6-MAM), codeine, opioids such as buprenorphine, methadone, pentazocine, fentanyl and analogues, and their main metabolites can be detected and quantified after a simple liquid-liquid extraction in alkaline conditions and derivatisation to obtain the corresponding trimethyl-silyl derivatives. The chromatographic separation is performed in a total time of 6 minutes, using a short GC column (5% phenyl methyl silicone, 10m length x 0.18mm internal diameter). The Limits of Detection are satisfactory for forensic purposes for all the substances; the repeatability of concentrations (% coefficients of variation %CVs) are always lower than 15% at a high and a low concentration levels, and accuracy, intended as % error on the true value, is always lower than 15% for all the analytes. The method can successfully be applied for screening analyses in many fields of forensic toxicology
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