Elimination profile of low-dose chlortalidone and its detection in hair for doping analysis-Implication for unintentional non-therapeutic exposure.

Chlortalidone (CLT) is a thiazide-type diuretic with high affinity for the erythrocyte carbonic anhydrase. Therapeutically, it is mostly used to treat edema and hypertension due to liver cirrhosis, heart insufficiency, or renal dysfunction. Although diuretics and masking agents are prohibited by the World Anti-Doping Agency (WADA) at all times in sports, substances belonging to this category are constantly detected in athlete samples, according to WADA's annual testing figures. Within this group of structurally diverse compounds, a threshold of 20 ng/mL has been introduced for six substances solely due to their presence as contaminants in other permitted drugs because of pharmaceutical production processes. In a recent presumptive doping case with a low urinary CLT concentration, the question of unintentional doping, for example, by contaminated non-steroidal anti-inflammatory drug intake, arose. To examine this potential scenario, a co-elimination of low-dose CLT and hydrochlorothiazide (HCTA; 20 × 50 μg, 0.2 mg/day each) was conducted on five consecutive days in two volunteers. Urine samples were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). Moreover, we examined the incorporation of CLT in scalp hair. HCTA is rapidly excreted renally in comparatively high concentrations. In contrast, the elimination of CLT is considerably slower (terminal elimination half-life extended by a factor of 12) and, consequently, much less concentrated in corresponding urine samples (45 and 53 ng/mL, respectively). Conversely, a higher hair incorporation of chlorthalidone was observed with simultaneous dosing of both. The results suggest that an unintentional intake of sub-therapeutic CLT doses due to contamination might result in an adverse analytical finding

Erratum: High energy-resolution zero-degree facility for light-ion scattering and reactions at iTHEMBA LABS (Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment (2011) 654:1 (29-39))

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High energy-resolution zero-degree facility for light-ion scattering and reactions at iThemba LABS

The setup and experimental techniques for measurements of zero-degree inelastic scattering and reactions involving light ions with the K=600 magnetic spectrometer at iThemba LABS are described. Measurements were performed for inelastic proton scattering at an incident energy of 200 MeV for targets ranging from 27Al to 208Pb. An energy-resolution of 45 keV (FWHM) was achieved by utilizing the faint-beam dispersion-matching technique. A background subtraction procedure was applied and allowed for the extraction of excitation energy spectra with low background. Measurements of the (p,t) reaction at zero degrees for Ep=100 and 200 MeV benefited from the difference in magnetic rigidity between the reaction products and the beam particles, resulting in background-free spectra with an excitation energy-resolution of 32 and 48 keV (FWHM), respectively, and a scattering angle resolution of 0.55° (FWHM). The addition of Double Sided Silicon Strip Detectors (DSSSD) at backward scattering angles allowed for coincident measurements of particle-decay of states excited in the (p,t) reaction at Ep=200MeV. © 2011 Elsevier B.V. All right reserved.Articl