Determination of Ulifloxacin by Terbium-sensitized Fluorescence with Second-order Scattering and Its Applications

Abstract

IntroductionAs broad-spectrum antibiotics, fluoroquinolones (FQs) have gained increasing use and have become popular in clinical application thanks to their high bacteriologic and clinical cure rates and good pharmacokinetic profile. 1 Prulifloxacin (PUFX, Scheme 1), 6-fluoro-1-methyl-7-(4-[5-methyl-2-oxo-1,3-dioxolen-4-yl]-methyl-1-piprazinyl)-4-oxo-4H-(1,3)thiaceto(3,2-α)quinolone-3-carboxylic acid, is a new oral fluoroquinolone antibiotics. It is active against both gram-positive and gram-negative bacteria and several anaerobic and atypical bacteria associated with chronic bronchitis and urinary infections. 2After PUFX is administrated, it is immediately and quantitatively transformed to the active metabolite ulifloxacin (UFX, Scheme 1) which actually has antibacterial activity. Prulifloxacin is not detectable in the systemic circulation. 3 That is to say, PUFX is the prodrug of UFX. The oxodioxolenylmethyl group in the 7-piperazine ring helps PUFX to have an advantage over UFX on oral absorption.3 Thus, the main form existing in biological fluids, such as serum and urine, is UFX. It is thus necessary to develop rapid, selective and sensitive analytical methods for the determination and pharmacokinetic study of UFX.Analytical literature about the determination of UFX is seldom seen. There are a few papers that describe HPLC methods. 4-6The HPLC methods allow the separation and generally require expensive equipment and complicated procedures. The main advantages of fluorometry are simplicity and rapidity. Luminescence sensitization of lanthanide ions (especially Tb(III) and Eu(III)) allows their application as the luminescence probes. Lanthanide-sensitized luminescence provides a selective and sensitive approach that shows a large stokes shift, narrow emission bands and a long luminescence lifetime. The carboxylate and the keto oxygen atoms of FQs provide the chelated sites for Tb(III) or Eu(III) ion to form Ln(III)-FQ complex. When Tb(III)-FQ complex is excited, it gives rise to the characteristic luminescence of Tb(III) ion with maximum emission at 545 nm via intramolecular energy transfer. This terbium-sensitized method has been used in the determination of FQs. 7-11In recent years, the light scattering technique has been increasingly applied to analytical chemistry, the most common method used is resonance light scattering (RLS). In studying RLS, the strong scattering of light at double the wavelength of the incident light (λem = 2λex) is found, which is named as "second-order scattering (SOS)". 12 As it may interfere with fluorometric measurements, SOS is always minimized and if possible eliminated as a harmful phenomenon in the fluorometric determinations. 13 Since Liu et al. first studied SOS as an analytical technique and applied it in the determination of metal ions in 1995, 14,15 however, it has been used as a new analytical technique with sensitive application prospects. 16,17 We have reported some flow-injection lanthanide-sensitized chemiluminescence (CL) [18][19][20] and electrochemiluminescence ...

Flow Injection Determination of Moxifloxacin using Silver Nanoparticles with Tris(2,2-Bipyridyl)Ruthenium(III)-Ce(IV) Chemiluminescence Detection

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Direct electrodeposition of gold nanoparticles on indium tin oxide surface and its application

“…In neutral 0.05 M PBS, the voltammetric peaks positively shifted to 0.37 V and 0.29 V, respectively. The catalytic effect of the GNPs can be rationalized by considering the incipient hydrous oxide/adatom mediator model (Burke, 2004;Wang et al, 2007).…”

Gold nanoparticles‐based fluorescence enhancement of the terbium–levofloxacin system and its application in pharmaceutical preparations

“…A large number of spectrofluorimetry methods have been used for the assay of drugs and metals and for the determination of low concentrations of other analytes (11)(12)(13). The terbium-sensitized fluorescence method has been used in the determination of fluoroquinolones (14)(15)(16).…”