Determination of fluvoxamine in human plasma by high-performance liquid chromatography with fluorescence detection

Fluvoxamine and nortriptyline, the assay internal standard, were extracted from plasma with ethyl acetate, then reacted with dansyl chloride. The derivatives were quantitated by isocratic reversed-phase high-performance liquid chromatography with fluorescence detection. The assay calibration range for fluvoxamine was 10-1000 ng/ml using a 1-ml plasma sample. Pooled plasma quality control sample relative recoveries at 25 and 250 ng/ml were 103 and 105%, respectively. Estimates of quality control inter-day precision during validation were less than or equal to 3% relative standard deviation. The assay was cross-validated with a gas chromatographic method and has been employed in therapeutic drug level monitoring.