Cyclodextrin enhanced spectrofluorimetric determination of fluoxetine in pharmaceuticals and biological fluids

The characteristics of host–guest complexation between methyl-β-cyclodextrin and fluoxetine were investigated by fluorescence spectrometry. A 1:1 stoichiometry of the complex was established and association constant of 4.35×10−3 M−1 at 20 °C was calculated. A spectrofluorimetric method for the determination of fluoxetine, with a range of application between 40 and 1000 μg l−1 was developed. Overall least squares regression was used to find the straight line that fitted the experimental data. The detection limit, according to the error propagation theory, was 9.6 μg l−1 and the detection limit proposed by Clayton was 15.8 μg l−1. Repeatability and relative standard deviation were also determined according to this theory, with satisfactory results. The method was successfully applied to the determination of fluoxetine in pharmaceuticals and biological fluids.