Development of a dispersive liquid-liquid microextraction technique for the extraction and spectrofluorimetric determination of fluoxetine in pharmaceutical formulations and human urine.

PURPOSE Fluoxetine is the most prescribed antidepressant drug worldwide. In this work, a new dispersive liquid-liquid microextraction (DLLME) method combined with spectrofluorimetry has been developed for the extraction and determination of FLX in pharmaceutical formulations and human urine. METHODS For FLX determination, the pH of a 10 mL of sample solution containing FLX, was adjusted to 11.0. Then, 800 µL of ethanol containing 100 µL of chloroform was injected rapidly into the sample solution. A cloudy solution was formed and FLX extracted into the fine droplets of chloroform. After centrifugation, the extraction solvent was sedimented and supernatant aqueous phase was readily decanted. The remained organic phase was diluted with ethanol and its fluorescence was measured at 292±3 nm after excitation at 234±3 nm. RESULTS Some important parameters influencing microextraction efficiency were investigated. Under the optimum extraction conditions, a linear calibration curve in the range of 10 to 800 ng/mL with a correlation coefficient of r(2) = 0.9993 was obtained. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 2.78 and 9.28 ng/mL, respectively. The relative standard deviations (RSDs) were less than 4%. Average recoveries for spiked samples were 93-104%. CONCLUSION The proposed method gives a very rapid, simple, sensitive, wide dynamic range and low-cost procedure for the determination of FLX.