Extractive spectrophotometric methods for determination of ciprofloxacin in pharmaceutical formulations using sulfonephthalein acid dyes

Abstract

Three simple, rapid, sensitive and accurate extractive-spectrophotometric method for the determination of ciprofloxacin in pharmaceutical preparation has been developed. These methods are based on the formation of yellow ion-pair complexes between the examined drug and three sulfonephthalein acid dyes, namely; bromophenol blue (BPB), bromocresol green (BCG), and bromothymol blue (BTB) in acidic medium. The formed complexes were extracted with chloroform and measured at 420, the colored chromogen was stable for twenty four hours. The effect of optimum condilions via pH, dye concentration, time and solvent are studied. Beer’s law is obeyed in the concentration ranges 0.50-25.0 µg/mL with molar absorptivity of 1.46x10⁴, 1.83x10⁴ and 2.07x10⁴ L. moi⁻1, cm⁻1 and limit of detcction (LOD) of 0.105, 0.101, 0.084 for BPB, BCG and BTB methods, respectively. No interference was observed from common excipients present in pharmaceutical formulations. The proposcd method has been applied suceessfully to determine ciprofloxacin in pharmaceutical preparation (tablets, infusion and eye drops).