Selective liquid chromatographic method for determination of fluoxetine inplasma

A selective and sensitive liquid chromatographic method was developed for t he determination of fluoxetine (FLU) in plasma. FLU was isolated from plasm a by liquid-liquid extraction. The chromatographic separation was performed on an analytical 250 x 3.9 mm id Novapak C-18 column (4 mum particle size) with an isocratic mobile phase consisting of phosphate buffer-acetonitrile -methanol-triethylamine (58 + 30 + 10 + 2, v/v) adjusted to pH 7. Using UV detection at 226 nm, the detection limit for FLU in plasma was 3 ng/mL. No interferences were found with tricyclic antidepressant drugs, which allows this method to be used in clinical studies. The calibration curve was linea r over the concentration range of 10-200 ng/mL. The average recovery was ab out 80% for plasma. The inter- and intraday assay coefficients of variation were <8%.