Determination of Fluoroquinolone Antibiotic Levofloxacin in Urine by Fluorescence Polarization Immunoassay

A method of fluorescence polarization immunoassay (FPIA) has been developed for the determination of levofloxacin in urine. Fluorescein-tagged antigens (tracers) with various fluoroquinolones and fluorescent tags have been synthesized. The tracer based on garenoxacin labeled with 4-aminomethylfluorescein and polyclonal antibodies to levofloxacin was the most sensitive for the determination of fluoroquinolones. A FPIA method has been developed for the determination of levofloxacin with the limit of detection 1.0 ng/mL and analytical range from 2.5 to 50 ng/mL. A one-reagent FPIA method has been developed for the determination of levofloxacin with the limit of detection 0.5 ng/mL and analytical range from 1 to 10 ng/mL. The methods have been tested in the determination of levofloxacin in urine.