Direct and Derivative Spectrophotometric Determination of Gemifloxacin Mesylate in Pure Form and Pharmaceutical Preparations

Two simple, quick and sensitive methods were described for the spectrophotometric determination of Gemifloxacin mesylate (GFX) either in pure form or in the Pharmaceutical form. The methods were based on the reaction of GFX as ‘n’ electron donor with Chloranilic acid(CLA) and Parachloranil(CL) as π acceptors to give highly coloured complex species. The coloured products were quantitated spectrophotometrically at 530nm and 540nm at zero order, 590and 610nm for the first derivative and 630and 650nm for second order derivative. Optimization of the different experimental conditions were described. Beer’s law was obeyed in the concentrations range of 10to60μg/ml, 5to25μg/ml at zero order,5to 25μg/ml, 5to40μg/ml at first order and 2to20μg/ml and 2to 14μg/ml at second order. The limit of detection and quantification were calculated and relative standard deviation (RSD) for different concentrations of GFX using various acceptors were less than 0.128 %.The association constant of 1:1 complexes and Standard free energy changes were studied. The proposed methods were successfully applied to the determination of GFX in pharmaceutical dosage form without interference from common additives encountered.