The effect of optimum conditions via pH, dye concentration, time and solvent are studied. Beer’s law is obeyed in the concentration ranges μg/mL with molar absorptivity of 104 , 104 and 104 L. mol-1 . cm-1 and limit of detection (LOD) of , , for BPB, BCG and BTB methods, respectively. No interference was observed from common excipients present in pharmaceutical formulations. The proposed method has been applied successfully to determine ciprofloxacin in pharmaceutical preparation (tablets, infusion and eye drops). | Vietnam Journal of Chemistry, International Edition, 55(6): 767-774, 2017 DOI: Extractive spectrophotometric methods for determination of ciprofloxacin in pharmaceutical formulations using sulfonephthalein acid dyes Nguyen Trung Dung1*, Le Hoc Bau1, Le Quang Thao1, Nguyen Quang Dat1 Faculty of Physics and chemical Engineering, Le Quy Don Technical University, Ha Noi, Viet Nam Received 17 August 2017; Accepted for publication 29 December 2017 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 conditions via pH, dye concentration, time and solvent are studied. Beer’s law is obeyed in the concentration ranges μg/mL with molar absorptivity of 104, 104 and 104 L. mol-1. cm-1 and limit of detection (LOD) of , , for BPB, BCG and BTB methods, respectively. No interference was observed from common excipients present in pharmaceutical formulations. The proposed method has been applied successfully to determine ciprofloxacin in pharmaceutical preparation (tablets, infusion and eye drops). Keywords. Ciprofloxacin, extraction-spectrophotometry, ion pair complex; sulfonephthalein dyes. 1. INTRODUCTION Ciprofloxacin (CPF), 1-cyclopropyl-6-fluoro-4-oxo7-(piperazin-1-yl)-quinoline-3-carboxylic acid (), is a second generation fluoroquinolone antibacterial agent with a broad spectrum of activity against a variety of gram positive and gram negative bacteria. It is widely used in the treatment of .
