Spectrophotometric Determination of Gemifloxacin Mesylate, Moxifloxacin.HCl and Gatifloxacin Sesquihydrate in Pure and in Pharmaceutical Preparations

SIMPLE, rapid and sensitive spectrophotometric method was developed for the determination of gemifloxacin mesylate (GMF), moxifloxacin.HCl (MXF) and gatifloxacin sesquihydrate (GAF) in pure and pharmaceutical preparation. This method is based on ion pair formation reaction between GMF, MXF and GAF and rosebengal indicator in universal buffer of pH 5.The formed ion pair is measured at λmax = 575 nm. All optimum conditions are established. The calibration graphs are rectilinear at concentration ranges 9.71 – 53.40, 8.758 – 52.55 and 8.048– 48.29 μg ml-1 for GMF, MXF and GAF, respectively. The sandell sensitivity (S) = 0.0263 , 0.0244 and 0.0263 μg cm-2 , molar absorptivity = 1.861x 104 , 1.835x 104 and 1.561x 104 L mol-1 cm-1 , correlation coefficient 0.9998 and LOD = 01.90, 1.607 and 1.876 μg ml-1 and LOQ = 05.74, 0.2036 and 5.684 μg ml-1 are calculated for GMF, MXF and GAF, respectively. The values of SD are = 0.0218 - 0.0297, 0.02 - 0.0377 and 0.0216 - 0.0282 and RSD are = 0.0554 - 0.3075, 0.0380 - 0.4344 and 0.0537 - 0.3497 % for GMF, MXF and GAF. The method is applied for the assay of investigated three drugs in pharmaceutical dosage forms. The results are in good agreement with those obtained by the official methods