Extractive Spectrophotometric Estimation of Gatifloxacin, Levofloxacin HCl and Lomefloxacin HCl in Bulk and Dosage Forms

Two simple, sensitive and extractive spectrophotometric methods have been developed for the determination of gatifloxacin, levofloxacin HCl and lomefloxacin HCl in pure form and in pharmaceutical formulations. The methods are based on the formation of yellow and blue coloured ion-pair extractable complexes between the three drugs and two dyes, bromophenol red and fast green FCF with absorption maxima at 426-430 nm and 631 nm for both dyes, respectively. The stoichiometry of the complex in either cases was found to be 1:1. Beer's law was obeyed in the range of 10-55 μg/ml for gatifloxacin and 10-70 μg/ml for levofloxacin HCl and lomefloxacin HCl in case of bromophenol red method and in the range of 0.2-1.8 μg/ml for the three drugs in case of fast green FCF method. Various analytical parameters have been evaluated and the results were validated according to ICH guidelines. The proposed methods have been applied successfully to the analysis of drugs in pure form and in its dosage forms and no interference was observed from common excipients present in pharmaceutical formulations.