Detection Time of Oxazepam and Zopiclone in Urine and Oral Fluid after Experimental Oral Dosing.

Data from previous experimental studies on the detection time of oxazepam and zopiclone in biological matrices are limited. The aim of this study was to examine the detection time in urine and oral fluid after single oral doses of oxazepam and zopiclone. Ten healthy volunteers received 25 mg of oxazepam in the evening of Day 1 and 7.5 mg of zopiclone in the evening of Day 3. Urine and oral fluid samples were collected twice daily for 9 days, with an additional sampling the day after ingestion of zopiclone. A total of 19 samples of both urine and oral fluid from each participant were analyzed using fully validated chromatographic methods. The median detection time for oxazepam was 91 h (range 73-108) in urine and 67 h (range 50-98) in oral fluid. The median detection time for zopiclone in urine was 49 h (range 25-98) and 59 h (range 48-146) in oral fluid. The metabolite zopiclone N-oxide showed a detection time of 36 h (range 25-84) in urine. The area under the concentration-time curve (AUCTotal) in urine corrected for creatinine was 150 µmol/L/mmol/L*h (range 105-216) for oxazepam and 1.60 µmol/L/mmol/L*h (range 0.79-4.53) for zopiclone. In oral fluid, the AUCtotal was 673 nmol/L*h (range 339-1,316) for oxazepam and 2,150 nmol/L*h (range 493-4,240) for zopiclone. In conclusion, oxazepam can be detected longer in urine than in oral fluid, while zopiclone can be detected longer in oral fluid than in urine. The high AUCTotal for zopiclone in oral fluid shows that the transfer into oral fluid is significant. In certain individuals the detection time of zopiclone in oral fluid is long. These results can be helpful when interpreting drug testing analyzes.

Comparison of zopiclone concentrations in oral fluid sampled with Intercept(®) oral specimen collection device and Statsure Saliva Sampler™ and concentrations in blood.

A clinical study of zopiclone was performed using doses of 5 and 10 mg. Samples of oral fluid were collected using the Statsure and Intercept devices, and blood samples were collected simultaneously. Concentrations of zopiclone in samples of oral fluid and blood were determined with liquid chromatography-mass spectrometry, and concentrations in undiluted oral fluid were calculated. The concentrations of zopiclone in oral fluid were generally higher when using the Intercept compared to the Statsure device; the median oral fluid/whole blood concentration ratios were 3.8 (range 1.5-15.9) and 1.9 (range 1.2-4.6), respectively (n = 21). The correlation between zopiclone concentrations in oral fluid collected with the two devices was fairly poor, r(2) = 0.35. The results indicate that the type of sampling device may significantly affect the analytical result for zopiclone in sampled oral fluid.

Determination of gallium in soil by slurry-sampling graphite-furnace atomic-absorption spectrometry.

A graphite-furnace atomic-absorption spectrometric method, utilizing ultrasonic slurry-sampling has been developed for the determination of Ga in soils. Calibration with aqueous standards and with slurries prepared from a certified soil reference material were both employed. When calibration with soil slurries was used no modifier was needed. Because lower and more variable sensitivity was obtained for Ga in aqueous standards than for Ga in slurry soil samples, external calibration with aqueous Ga standards required a suitable chemical modifier to level out the sensitivity difference. Of the many potential modifiers tested, i.e. Al, As, Co, Mg, Mo, Ni, Pd, Pd+Mg, Se, and Te, Ni was found to be best. When Ni (1.0 mg mL(-1), 10 micro L) was injected to the graphite tube with the aqueous standards or slurry samples (10 micro L) accurate results were obtained. Both methods of calibration gave acceptable accuracy and precision. The repeatability was