Kinetic spectrophotometric method for determination of ciprofloxacin and lomefloxacin in their pharmaceutical dosage forms

Abstract

A simple and sensitive kinetic spectrophotometric method has been developed and validated for the determina- tion of ciprofloxacin (CIP) and lomefloxacin (LOM) in their pharmaceutical dosage forms. The method was based on the oxidation of CIP and LOM with alkaline potassium permanganate to give a green colored reaction product. The reaction was monitored spectrophotometrically by measuring the absorbance of the reaction product at 610 nm. The factors affecting the reaction was studied and optimized. The stoichiometries of the reaction were de- termined and the reaction pathway was postulated. The activation energy of the reaction was calculated and found to be 4.48 and 4.17 KJ mole^–1 for CIP and LOM, respectively. The initial rate and fixed time (at 5 min) me- thods were utilized for constructing the calibration graphs. The analytical performance of both methods was fully validated, and the results were satisfactory. The proposed methods were successfully applied to the determina- tion of both CIP and LOM in their commercial pharmaceutical dosage forms. The label claim percentages were 99.4 – 100.2 ± 1.15 – 1.81%. Statistical comparison of the results with those obtained by a reference method showed excellent agreement between the accuracy and precision of the two methods. The proposed method has a great value in its application to the analysis of CIP and LOM in quality control laboratories.