Simultaneous Determination of Gatifloxacin and Prednisolone in their Bulk Powder, Synthetic Mixture and Their Combined Ophthalmic Preparation Using Micellar Liquid Chromatography.

A simple rapid and accurate micellar high performance liquid chromatographic method was improved and validated for the analysis of mixture containing gatifloxacin sesquihydrate (GTF) and prednisolone acetate (PRED) in their synthetic mixture and their combined preparation. The separation was achieved using a C18 column, micellar mobile phase consisted of 0.2 M sodium dodecyl sulfate, 12.5% n-propanol and 0.3% triethylamine in 0.02 M orthophosphoric acid at pH 7.0 at a flow rate of 1 ml/min with UV detection at 270 nm. The proposed method was found to be rectilinear over the concentration ranges of 5.0-45 μg ml-1 and 10-50 μg ml-1 with recovery percentage of 99.95 ± 0.82 and 100.07 ± 0.84 for GTF and PRED, respectively. The separation of both drugs was accomplished in a very short chromatographic run (<5 min), the method is reproducible (R.S.D. < 1.0%) and show satisfactory resolution between GTF and PRED (Rs) = 1.67. The developed method was validated according to International Conference on Harmonization (ICH) guidelines. The limit of detection of the proposed method was 0.33 and 0.21 μg ml-1, and the limit of quantitation was 0.99 and 0.64 μg ml-1 for GTF and PRED, respectively.