DETECTION OF FLUOROQUINOLONES IN URINARY SPECIMENS FROM PATIENTS UNDERGOING ANTI-TUBERCULOUS THERAPY

A paper strip impregnated with ferric chloride has been developed for visual detection of fluoroquinolones in urine based on a change of col our due to the chelation of the transition metal ion to the p-oxo acid array in the 4-oxo-1,4-dihydropyridine-3-carboxylic acid moiety of th e fluoroquinolone molecule. In urine specimens, the detection limit of the strip was 100 mg/l for pefloxacin, 200 mg/l for ciprofloxacin, fl eroxacin, levofloxacin, norfloxacin, ofloxacin and sparfloxacin, and 3 00 mg/l for trovafloxacin. In 193 urine specimens taken from 138 patie nts on ofloxacin therapy and 55 controls preliminary evaluation of the strip showed that all the 55 specimens from control patients were neg ative, while 112 out of the 138 ofloxacin-treated patients were positi ve. Quantitative analysis by high-performance liquid chromatography of the 26 strip-test-negative specimens taken from patients with ofloxac in treatment indicated that these urinary specimens contained less tha n 200 mg/l of the antimicrobial, mostly because of poor renal function and in some occasions, non-compliance. This strip method would provid e a convenient way of monitoring drug compliance in patients who recei ve fluoroquinolone therapy for tuberculosis.