Spectrophotometric determination of fluoxetine by batch and flow injection methods

Abstract

A rapid, simple, and accurate spectrophotometric method is presented for the determination of fluoxetine by batch and flow injection analysis methods. The method is based on fluoxetine competitive complexation reaction with phenolphthalein-β-cyclodextrin (PHP-β-CD) inclusion complex. The increase in the absorbance of the solution at 554 nm by the addition of fluoxetine was measured. The formation constant for fluoxetin-β-CD was calculated by non-linear least squares fitting. Fluoxetine can be determined in the range 7.0×10-6-2.4×10-4 mol l-1 and 5.0×10-5-1.0×10-2 mol l-1 by batch and flow methods, respectively. The limit of detection and limit of quantification were respectively 4.13×10-6 mol l-1 and 1.38×10-5 mol l-1 for batch and 2.46×10-5 mol l-1 and 8.22×10-5 mol l-1 for flow method. The sampling rate in flow injection analysis method was 80±5 samples h-1. The method was applied to the determination of fluoxetine in pharmaceutical formulations and after addition to human urine samples. © 2006 Pharmaceutical Society of Japan.