Determination of trovafloxacin in human serum by time resolved terbium-sensitised luminescence.

A sensitive time-resolved luminescence method for the determination of trovafloxacin is described. The method is based on the time-resolved luminescence signal from the terbium(III)-trovafloxacin complex, in a micellar solution of sodium dodecyl sulfate (SDS), using a chemical deoxygenation agent (Na(2)SO(3)). The method allows the determination of 20-450 ng ml(-1) of trovafloxacin in 7.5 mM SDS solution containing 0.16 M acetic acid-sodium acetate buffer (pH 6.0) and 7.5 mM Na(2)SO(3) with lambda(exc)=270 nm and lambda(em)=546 nm. In these experimental conditions luminescence signal for trovafloxacin increases 20-fold with respect to native fluorescence of the compound in aqueous solution at pH 6.5. Terbium-sensitised luminescence was applied to trovafloxacin determination in human serum, spiked at levels found after drug administration at normal clinical doses. Recovery is 90+/-1% and day-to-day precision is 3.5%. The proposed method tolerates high concentrations of other co-administrated drugs and excipients.