Spectrofluorometric determination of certain quinolone through charge transfer complex formation

A spectrofluorimetric method was developed for the determination of three fluoroquinolones antibacterials, namely, ofloxacin (OFL), levofloxacin (LEV), lomefloxacin (LOM), and pipemidic acid (PIP) through charge transfer (CT) complex formation with 7,7,8,8tetracyanoquinodimethane (TCNQ). TCNQ was found to react with these drugs to produce stable complexes and the fluorescence intensity of the complexes was enhanced in 15–90 times higher than that of the studied drugs itself. The formation of such complexes was also confirmed by both infrared and UV–vis measurements. The different experimental parameters that affect the fluorescence intensity were carefully studied, At the optimum reaction conditions, the rectilinear calibration graphs were obtained in the concentration range 0.02–2.2 (mu)g ml^-1 for the investigated drugs and the limits of detection ranged from 0.006 to 0.016 (mu)g ml^-1. The proposed procedures could be applied successfully for the determination of the investigated drugs in their pharmaceutical dosage forms with a good precision and accuracy compared to official and reported methods as revealed by t- and F-tests. Also they were applied to determine spiked urine and plasma samples.