Development and Validation of an Extractive Ion-Pair Spectrophotometric Method for the Determination of Ciprofloxacin Hydrochloride

Abstract

A new, rapid and sensitive assay is proposed for the spectrophotometric determination of Ciprofloxacin in pure form and in pharmaceutical formulation. The proposed method involves formation of purple coloured, Butanone extractable ion-pair complex of Ciprofloxacin with Eriochrome Black T (EBT) in acidic medium provided by phthalate buffer (pH 2). The extracted ion pair complex showed maximum absorbance at 514 nm and Beer’s law was obeyed in the concentration range of 5 – 25 μg/mL. The molar absorptivity and Sandells sensitivity were determined to be 65,491.02 L mol-1 cm-1 and 1.90 μg cm-2 respectively. The detection limit for the method was found to be 1.09 μg/mL while limit of quantitation was 2.27 μg/mL. Other validation parameters for the method were similarly established. The method was successfully applied for the determination of commercial brands of the drug. Statistical comparison of the results with the official titrimetric method showed good agreement and indicated no significant difference in accuracy and precision.