Cognitive Behavioral Therapies Master of Science Program
Department of Psychology & Psychotherapy; Titu Maiorescu University

HPLC-FL method for fluoxetine quantification in human plasma

Fluoxetine, a selective serotonin reuptake inhibitor (SSRI) antidepressant is proved to be safer than tricyclic antidepressants both in therapy and in overdose, although, fluoxetine and its active metabolite norfluoxetine have long half-lives and can result in potentially serious drug interactions. Therefore, clinical monitoring is justified not only for checking patients’ compliance, but also to detect the overdoses risk

The objective of the study was to develop a HPLC method with fluorescence detection (FL) applicable for quantification of fluoxetine in human plasma.

The HPLC-FL method was chosen, as it is more specific (only 15% of the active substances have native fluorescence) and the experimental conditions were simple: stationary phase - C18 – Kromasil column, the separation was achieved by reverse phase HPLC method, using as mobile phase – methanol: acetonitrile: formic acid = 25:50:25, and the method is rapid (the analysis time was only 3 minutes). Both liquid-liquid (using different solvents, such as hexane, dichloromethane) and solid phase (on the C18 and C8 cartridges) extraction procedures have been applied.

The linearity of the method has been demonstrated in the range of concentrations of 0.1 – 1 μg/mL, corresponding to both therapeutic and toxic plasma fluoxetine levels. The method is precise, accurate, with average recovery percent between 93 - 106% and has a LOD of 0.03 and a LOQ of 0.1µg/mL.

The proposed method can be used to assess fluoxetine levels in human plasma in pharmacokinetic studies, in clinical monitoring as well as and in overdose cases.

Keywords: fluoxetine, HPLC, fluorescence