Development of a fluorescence polarization immunoassay for the routine detection of N-desmethylzopiclone in urine samples.
A polarization fluoroimmunoassay was developed for the detected of N-desmethylzopiclone in urine and the reagents were adapted for use on the Vitalab Eclair analyser. Therefore, N-fluoresceinthiocarbamyldesmethylzopiclone was synthesized as a fluorescent tracer and used in combination with an existing pool of antibodies, raised against the hemisuccinyl derivative of N-desmethylzopiclone. The optimization of the assay was performed on a semi-quantitative basis, relative to a cut-off value of 300 ng ml-1. No significant interference was observed from a selection of existing drugs and endogenous compounds. The minimum detectable dose of the immunoassay was calculated to be 30 ng ml-1 (pooled-variance t-distribution, p = 0.01, degrees of freedom = 10). Intra- and inter-assay relative standard deviations were < 10 and < 12%, respectively. For the confirmation of positive samples, an established reverse-phase HPLC technique, in combination with fluorescence detection, was used. The combined screening/confirmation procedure was applied to cumulative excretion samples, after ingestion of one tablet of Imovane (zopiclone, 7.5 mg).
Mannaert
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Laboratory of Toxicology, Katholieke Universiteit Leuven, Belgium.
Daenens
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D053961:Azabicyclo Compounds; D002851:Chromatography, High Pressure Liquid; D016650:Fluorescein-5-isothiocyanate; D016231:Fluorescence Polarization Immunoassay; D005456:Fluorescent Dyes; D006801:Humans; D006993:Hypnotics and Sedatives / Q000652:urine*; D010879:Piperazines / Q000493:pharmacokinetics* / Q000652:urine*
D053961:Azabicyclo Compounds; D005456:Fluorescent Dyes; D006993:Hypnotics and Sedatives; D010879:Piperazines; C515050:zopiclone; C053229:N-desmethylzopiclone; D016650:Fluorescein-5-isothiocyanate