DETERMINATION OF FLUOXETINE HYDROCHLORIDE VIA ION PAIR COMPLEXATION WITH ALIZARIN RED S
Acta Poloniae Pharmaceutica - Drug Research
Two UV-Vis spectrophotometric methods and one fluorimetric method have been developed for the quantitative determination of fluoxetine hydrochloride in bulk and pharmaceutical formulations. These methods are based on the ion-pair complex formation between alizarin red S and fluoxetine hydrochloride. In the first method (method A), the yellow-colored complex obtained in acidic medium was extracted with chloroform and the absorbance of the chloroformic solution was measured at 425 nm. Beerís law
... 425 nm. Beerís law limits (9.5 ñ 48 µg/mL), the molar absorptivity (5256 L ∑ mol -1 ∑ cm -1 ), and the complex composition (1 : 1) were determined. In the second method (method B), the yellow complex fluoxetine ñ alizarin red S extracted in chloroform was broken in alkaline medium, and the absorbance of the resulting violet-colored free dye was measured at 524 nm. A linear relationship was observed in the range of 9.0 ñ 54 µg/mL. In the third method (method C) the fluorescence intensity of the fluoxetine ñ alizarin red S complex, obtained in the same manner as for method A, was measured at 594 nm after excitation at 425 nm. The fluorescence intensity was proportional to the drug concentration in the linear range of 2.7-10.2 µg/mL. The limits of detection and quantification have also been calculated. Furthermore, the proposed methods have been successfully applied for the assay of the drug in pharmaceutical dosage forms.