Spectrophotometric Estimation of Fluroquinolones as Ion-Pairs with Bromocresol Green in Bulk and Pharmaceutical Dosage Form

A simple, rapid and sensitive spectrophotometric method has been proposed for the estimation of fluroquinolones viz., norfloxacin (NRF), ciprofloxacin (CPF), ofloxacin (OFL) and moxifloxacin (MXL) in bulk and pharmaceutical formulations. The method is based on the reaction of selected drugs with bromocresol green (BCG) in neutral medium for NRF, CPF and OFL and in acetate buffer of pH 3.7 for MXL to give chloroform soluble ion association complexes. The effects of various parameters have been studied. The ion association complexes exhibited absorption maxima at 421.4 nm for NRF, 418.8 nm for CPF, 417.4 nm for OFL and 415.8 nm for MXF Beer-Lambert's law were obeyed in the concentration ranges of 2-24, 2-10, 2-12 and 2-20 mu g/mL for NRF, CPF, OFL and MXL, respectively with correlation coefficient not less than 0.9998. The results obtained by the proposed methods have been statistically compared by means of student t- test and by the variance ratio F-test.