Determination of selective serotonin reuptake inhibitors in plasma and urine by micellar liquid chromatography coupled to fluorescence detection

Abstract

Citalopram, paroxetine and fluoxetine are selective serotonin reuptake inhibitor (SSRIs) currently used in the treatment of psychiatric disorders. We present an analytical method using micellar liquid chromatography to quantify these three drugs in pharmaceutical formulations, plasma and urine. The resolution was performed using a mobile phase of 0.075 M SDS – 6% (v/v) butanol buffered at pH 7 running through a C18 column under isocratic mode at 1 mL/min at 25 °C. The analytes were eluted in less than 20 min. The fluorescence detection was programmed at the maximum excitation (236, 295 and 230 nm) and emission (310, 350 and 305 nm) wavelengths for citalopram, paroxetine and fluoxetine, respectively. The experimental procedure was expedited to 1/5 dilution of the sample in the micellar mobile phase and filtration, thus avoiding clean-up and extraction steps. An aliquot of 20 μL was injected after 80 min of preparation, to obtain maximum sensitivity. The method was validated according to the guidelines of the Food and Drug Administration (FDA) in terms of calibration range (20–500 ng/mL; r2 > 0.999), sensitivity, accuracy (91.3–103.2%), precision (<9.3%), and robustness (<6.1%). The suitability of the method was successfully evaluated by analyzing plasma and urine samples from patients treated with SSRIs and checking the content of the active principle in tablets. Thus, the method can be applied to pharmacokinetics studies and in forensic cases, as well as in quality control of commercial pharmaceutical formulations.