Spectrophotometric and spectrofluorimetric determinations of veterinary drug enrofloxacin in pharmaceutical formulation

Abstract

Four simple, sensitive spectrophotometric and spectroflourimetric methods (A-D) for the determination of veterinary drug enrofloxacin (ENFX) in pharmaceutical formulation have been developed. Method (A) is based on formation of ternary complex of ENFX with Pd(II) in presence of methyl cellulose as surfactant and acetate-HCl buffer pH 4.0. Method (B) is based on the oxidation of ENFX 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 604 nm. Method (C) is based on the oxidation of the ENFX by a known excess of potassium permanganate in acid medium and subsequent determination of unreacted oxidant by reacting it with safronine O (SFO). Method (D) is based on the chelation of ENFX with Zr(IV), to produce fluorescent chelate. At the optimum reaction conditions, the drug/metal chelate showed excitation maxima at 280 nm and emission maxima at 440 nm. The optimum experimental parameters for the reaction have been studied. The validity of the described procedures was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed methods were successfully applied for the determination of the selected drug in pharmaceutical preparations with good recoveries. The procedures were accurate, simple and suitable for quality control application.