High performance liquid chromatography with ultraviolet detection used for laboratory routine determination of fluvoxamine in human plasma.

Fluvoxamine is an antidepressant drug introduced into the clinic in 1986. It acts by selectively inhibiting neuronal serotonin recapture. It can be quantified by several methods, including high performance liquid chromatography. The HPLC method used so far needs special equipment and has poor sensitivity. The technique is difficult and time consuming. An easier, quicker and more sensitive HPLC assay for the routine determination of fluvoxamine in human plasma has therefore been developed. After alkalinisation and direct extraction by a mixture of n-hexane-isoamylic alcohol 985: 15 (v/v) of plasma samples, the organic phases were further extracted by HCl 0.1 N. Thirty microL of the final extract (with loxapine as internal standard) were injected directly into a C-8 column with a mobile phase consisting of 370 mL acetonitrile, 0.4 mL diethylamine, 630 mL of distilled water, 25 mL pic B5. UV detection at 254 nm was used. The whole process was completed in 40 min. The detection limit was 10 ng mL-1. No interference was found either with several benzodiazepines or with antidepressant drugs commonly associated during treatments.