APPLICATION OF TERBIUM SENSITIZED FLUORESCENCE FOR THE DETERMINATION OF FLUOROQUINOLONE ANTIBIOTICS PEFLOXACIN, CIPROFLOXACIN AND NORFLOXACIN IS SERUM

A simple, rapid and sensitive spectrofluorimetric method for the deter mination of fluoroquinolone antibiotics, norfloxacin (NOR), ciprofloxa cin (CIP) and pefloxacin (PEF) is described. The method is based on th e radiative energy transfer from fluoroquinolones to terbium ions (Tb3 +) in the presence of tri-n-octylphosphine oxide (TOPO) in weakly acid ic (pH 5.5) micellar solution of cetylpyridinium chloride (CPCl). Opti mum conditions for the formation of the fluoroquinolone-Tb3+-TOPO tern ary complexes have been investigated. Under optimized conditions the d etection limits are 1.7, 1.2 and 4.4 nM for NOR, CIP and PEF, respecti vely, while the range of application for all three drugs is 0.05-10 mu M. The method has been successfully applied to the determination of N OR, CIP and PEF in serum samples after deproteinization with acetonitr ile (serum-acetonitrile; 1:2, v/v) The mean recoveries from serum samp les spiked with NOR, CIP and PEF (5.0-50.0 mu M) were (90.3 +/- 4.9), (105.0 +/- 3.6) and (95.3 +/- 1.5)%, respectively. Within-run and day- to-day s, values for 5.0, 25.0 and 50.0 mu M of each fluoroquinolone v aried from 1.7 to 5.4% and from 3.3 to 12.8%, respectively. The influe nce of several usually coadministered drugs on the determination of fl uoroquinolones in serum has been investigated. (C) 1997 Elsevier Scien ce B.V.