Development and Application of Difference Spectrophotometric Method for the Determination of Febuxostat in Tablets

A simple, rapid, sensitive and cost effective difference spectrophotometric method have been developed for the determination of Febuxostat in its tablet dosage form. The method is based on the induced spectral changes upon changing the pH of the medium that differ in their UV spectra. Difference spectrum, obtained by keeping Febuxostat in 0.1N NaOH in reference cell and same in 0.1N HCl in sample cell, showed two characteristic peaks at 260nm and 315nm with positive and negative absorbance respectively and viceversa. Difference of absorbance between these two maxima was calculated to find out the amplitude, which was plotted against concentration. The calibration curve is linear over the concentration range of 5-25 μg/ml (r2 = 0.999), with a detection limit of 0.58μg/ml. The method was successfully applied to the commercial pharmaceutical drug without interference from common ingredient accompanying the drug along with its dissolution profile and very cost effective as its prevents the use of hazardous and costly organic solvents. INTRODUCTION: Febuxostat, antigout agent is chemically 2[3cyano-4(2methlypropoxy) phenyl]4methlythiazole5 carboxylic acid (fig. 1). It is a non purine selective inhibitor of xanthine oxidase . It inhibits both oxidized and reduced forms of xanthine oxidase 2, 3 and has very less effects on other enzymes of purine and pyrimidine metabolism 3, . Based on the literature survey it shows that very few analytical methods have been reported for the estimation of Febuxostat which includes UV (Drug dissolution 5 and determination ), HPLC , GC 8 and LC/MS/MS (Impurity profiling) . The aim of the study is to develop a simple, sensitive, accurate, precise and cost effective method for determination of febuxostat in pharmaceutical formulations and bulk drugs using UV spectrophotometer without using costly and hazardous organic solvents. FIG. 1: STRUCTURE OF FEBUXOSTAT Difference spectrophotometric assay measure the difference absorbance between two equimolar solutions of the analyte in different chemical forms, which exhibit difference spectral characteristics. The simplest and most commonly employed technique for altering the spectral properties of analyte is the adjustment of the pH by means of aqueous solution of acids and alkali.