Simultaneous Estimation of Sparfloxacin and Dexamethasone by Q-Absorbance Ratio Spectrophotometric Method in Eye/Ear Drops

The present manuscript describes simple, sensitive, rapid, accurate, precise and economical Q-absorbance ratio method for the simultaneous determination of Sparfloxacin and Dexamethasone. Absorbance ratio method uses the ratio of absorbances at two selected wavelengths, one which is an isoabsorptive point and other being the λ-max of one of the two components. Sparfloxacin and Dexamethasone show an isoabsorptive point at 271.2 nm in methanol. The second wavelength used is 241.6 nm, which is the λ-max of Dexamethasone  in methanol. The linearity was obtained in the concentration range of 3-18 μg/ml for Sparfloxacin and 1-6 μg/ml  for Dexamethasone. The concentrations of the drugs were determined by using ratio of absorbances at isoabsorptive point and at the λ-max of Dexamethasone. The method was successfully applied to pharmaceutical dosage form because no interference from the preservative was found. The suitability of this method for the quantitative determination of Sparfloxacin and Dexamethasone was proved by validation. The proposed method was found to be simple and sensitive for the routine quality control application of Sparfloxacin and Dexamethasone in Eye/Ear drops. The results of analysis have been validated statistically and by recovery studies.