Application of Terbium‐Sensitized Luminescence for the Determination of Grepafloxacin in Human Urine and Serum

ABSTRACT Analytical performance and applications of a selective and sensitive lanthanide‐sensitized luminescence method for the determination of grepafloxacin is described. The method is based in the time‐resolved luminescence signal from a terbium (III)–grepafloxacin complex in a micellar solution of sodium dodecyl sulfate. The optimized method allows the determination of 10–500 ng mL −1 of grepafloxacin in 7.5 mM sodium dodecyl sulfate solution containing 0.16 M acetic acid–sodium acetate buffer (pH 6.0) and 7.5 mM Na 2 SO 3 (chemical deoxygenation agent), with λ exc  = 275 nm and λ em  = 546 nm. Grepafloxacin was determined in human serum (by external calibration method) and urine (by standard additions method), spiked at levels found after drug administration at normal clinical doses. Average recoveries found were 89.6 (relative standard deviation 0.9%) and 102 (relative standard deviation 2%), respectively. © 2001 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1553–1557, 2001