Determination of norfloxacin in pharmaceutical formulation using simple spectrophotometric method

Abstract

Introduction: Norfloxacin (1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piprazinyl)-3-quinoline carboxylic acid) is used in a wide range of gastrointestinal, urinary and respiratory tract infections. Material and method: An UV-Visible spectrophotometer with matched quartz cells was used for measuring an absorption of the standard or sample solutions. Accurate volumes (2.0 mL) of the standard solutions of norfloxacin were mixed with 1.0 ml of 4.0 X 10^-1 mol l-¹ ferrous sulfate solution and then 0.1 ml of 2.5 X 10^-2 % (v/v) of hydrogen peroxide was added and mixed well. The absorbance of the complexation was monitored at 440 nm against the corresponding reagent blank. For sample determination, twenty tablets of norfloxacin were weighed and ground into a fine powder. A portion of the powder equivalent to 400 mg of active ingredient was transferred to 250 ml volumetric flask and dissolve by 5.0 x10^-3 mol l^-1 HNO₃ and filtered through Whatman No. 42 filter paper and diluted with 5.0 x10^-3 mol l^-1 nitric acid to volume in order to obtain the appropriate concentration for analysis. Results: The studied method based on the reaction between drug sample and ferrous sulfate tablets in acidic solution. The presence of hydrogen peroxide enhances the absorption signal. The reaction between the investigated drugs and ferrous sulfate in the presence of hydrogen peroxide was gave the soluble yellow complex. The optimum volume ratio of drug sample, ferrous sulfate solution and hydrogen peroxide were 2.0:1.0:0.1 (v/v). The maximum absorption was recorded at the wavelength of 440 nm. The proposed spectrophotometric method was developed and optimized using an univariate method. Under the developed condition, linear calibration graphs were obtained for the concentration range of 1.0 - 100 µg ml^-1. Over the above concentration range, linear regression equation of the absorbance of drug (y) versus drug concentration (x) was y = 0.0041X + 0.0026. Conclusion: The proposed method can be used for the quantification of norfloxacin. The advantages of this method showed good linearity, precision and reproducibility. This developed method can be used as an alternative including method for the routine quality control of norfloxacin tablet in pharmaceutical formulation. It should be using this proposed method for analysis of others fluoroquinolone.