Liquid-phase microextraction and capillary electrophoresis of citalopram, an antidepressant drug

• Published in: Journal of Chromatography A 2001-02, Vol.909 (1), p.87-93
• Main Authors: Halvorsen, Trine Grønhaug, Pedersen-Bjergaard, Stig, Rasmussen, Knut E.
• Format: Article
• Language: English
• Subjects: Analysis; Antidepressive Agents, Second-Generation - blood; Biological and medical sciences; Chemistry Techniques, Analytical - methods; Citalopram; Citalopram - analogs & derivatives; Citalopram - blood; Electrophoresis, Capillary - methods; General pharmacology; Humans; Medical sciences; N-Desmethylcitalopram; Pharmacology. Drug treatments; Polypropylenes; Quality Control; Reproducibility of Results
• ISSN: 0021-9673
• DOI: 10.1016/S0021-9673(00)00868-2

A newly developed disposable device for liquid-phase microextraction (LPME) was evaluated for the capillary electrophoresis (CE) of the antidepressant drug citalopram (CIT) and its main metabolite N-desmethylcitalopram (DCIT) in human plasma. CIT and DCIT were extracted from 1 ml plasma samples through hexyl ether immobilised in the pores of a porous polypropylene hollow fibre and into 25 μl of 20 m M phosphate buffer (pH 2.75) present inside the hollow fibre (acceptor phase). Prior to extraction, the samples were made strongly alkaline in order to promote LPME of the basic drugs. Owing to the high ratio between the volumes of sample and acceptor phase, and owing to high partition coefficients, CIT and DCIT were enriched by a factor of 25 to 30. In addition, sample clean-up occurred during LPME since salts, proteins and the majority of endogenic substances were unable to penetrate the hexyl ether layer. Since the extracts were aqueous, they were injected directly into the CE instrument. Limits of quantification ( S/N=10) for CIT and DCIT in plasma were 16.5 ng/ml and 18 ng/ml respectively, while the limits of detection ( S/N=3) were 5 ng/ml and 5.5 ng/ml respectively. This enabled CIT (and DCIT) to be analysed within the therapeutic range by LPME–CE and detection limits were comparable with previously reported HPLC methods.