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.