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Quantitation of zopiclone and desmethylzopiclone in human plasma by high‐performance liquid chromatography using fluorescence detection
Author(s) -
Nirogi Ramakrishna V. S.,
Kandikere Vishwottam N.,
Mudigonda Koteshwara
Publication year - 2006
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.601
Subject(s) - chemistry , chromatography , zopiclone , analyte , high performance liquid chromatography , detection limit , metabolite , pharmacokinetics , analytical chemistry (journal) , hypnotic , pharmacology , biochemistry , medicine
A simple, reliable HPLC method using fluorescence detection (excitation 307 and emission 483 nm) was developed and validated for simultaneous quantitation of zopiclone and its metabolite desmethylzopiclone in human plasma. Following a single‐step liquid–liquid extraction, the analytes and internal standard (zaleplon) were separated using an isocratic mobile phase on a reversed‐phase C 18 column. The lower limit of quantitation was 3 ng/mL for zopiclone and 6 ng/mL for desmethylzopiclone with a relative standard deviation of less than 5%. A linear dynamic range of 3–300 ng/mL for zopiclone and of 6–500 ng/mL for desmethylzopiclone was established. This HPLC method was validated with between‐batch precision of 1.7–4.2% and 3.2–7.5% for zopiclone and desmethylzopiclone respectively. The between‐batch accuracy was 99.4–111.5% and 101.6–104.8% for zopiclone and desmethylzopiclone, respectively. Frequently coadministered drugs did not interfere with the described methodology. Stability of zopiclone and desmethylzopiclone in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days' storage in a freezer. This validated method is simple and repeatable enough to be used in pharmacokinetic studies. Copyright © 2005 John Wiley & Sons, Ltd.