A highly sensitive spectrofluorimetric method was developed for the first time, for the analysis of ten fluoroquinolones (FQs) antibacterials, namely amifloxacin (AMI), ciprofloxacin (CIP), difloxacin (DIF), enoxacin (ENO), enrofloxacin (ENR), lomefloxacin (LOM), levofloxacin (LEV), norfloxacin (NOR), ofloxacin (OFL) and pefloxacin (PEF) in their pharmaceutical dosage forms or in biological fluids through charge transfer (CT) complex formation with bromanil (BRO). The BRO was found to react with these drugs to produce stable complexes and the fluorescence intensity of the complexes was greatly enhanced. The formation of such complexes was also confirmed by ultravioletvisible measurements. The different experimental parameters that affect the fluorescence intensity were carefully studied. At the optimum reaction conditions, the drug-BRO complexes showed excitation maxima ranging from 275 to 290 nm and emission maxima ranging from 450 to 470 nm. Rectilinear calibration graphs were obtained in the concentration range 0.02 to 3.1 µg.mL -1 for the studied drugs. The method has been successfully applied to determine their pharmaceutical dosage forms with good precision and accuracy compared to official and reported methods as revealed by tand F-tests. They are also applied for the determination of studied drugs in human urine samples.

Simple, accurate, sensitive and selective methods are described for the quantitative determination of ten fluoroquinolones (amifloxacin, ciprofloxacin hydrochloride, difloxacin hydrochloride, enoxacin, enrofloxacin, lomefloxacin hydrochloride, levofloxacin, norfloxacin, ofloxacin and pefloxacin mesylate). The methods are based on precipitation of the ion associates formed from the reaction of the cited drugs with silver nitrate, copper acetate and ferric chloride. The formation and solubility of the solid complexes at the optimum conditions of pH and ionic strength values have been studied. The methods depend on direct determination of the ions in the precipitate or indirect determination of the ions in the filtrate by atomic absorption spectroscopy. The optimum conditions for precipitation were carefully studied. Rectilinear calibration graphs were obtained in the range of 10-100 ng.ml-1 for each of the investigated drugs and the limits of detection and quantitation ranged from 1.125 to 2.260, o.937 to 2.754 and from 3.425 to 5.986 ng.ml-1 , respectively. The molar ratios of the formed chelats were determined by Job's method and their association constants were also calculated. The developed methods were applied successfully for the determination of the studied drugs in their pharmaceutical dosage forms with good precision and accuracy compared to official and reported methods as revealed by t-and F-tests. They were also applied for the determination of studied drugs in spiked urine and plasma samples.