Analysis of the anti-Parkinson drug pramipexole in human urine by capillary electrophoresis with laser-induced fluorescence detection Original Research Article

A sensitive method based on capillary electrophoresis with laser-induced fluorescence detection has been developed for the analysis of the non-ergoline dopamine agonist pramipexole in human urine. Separation was carried out in uncoated fused silica capillaries (75 μm internal diameter, 75.0 and 60.0 cm total and effective length, respectively), with a background electrolyte composed of borate buffer (50 mM, pH 10.3), tetrabutylammonium bromide (30 mM), and acetone (15%, v/v). Applying a 20 kV voltage, the electrophoretic run is completed within 12 min. A sample pre-treatment procedure based on liquid/liquid extraction with ethyl acetate, followed by derivatisation of pramipexole with fluorescein isothiocyanate at pH 9, allows the complete removal of biological interferences, with extraction yields always higher than 94.5%. Method validation gave good linearity (r2 = 0.9992) in the 25.0–1000 ng mL−1 range; limit of detection and limit of quantitation were 10.0 and 25.0 ng mL−1, respectively; precision was ≤6.8 R.S.D.%, accuracy expressed as recovery% was >90.0. The method was applied to the analysis of urine samples from patients undergoing therapy with pramipexole.