Spectrophotometric Determination of Benzocaine via Oxidation and Bleaching Colour of Rifampicin Dye

Abstract

Abstract Benzocaine(BENZ) has been estimated by indirect spectrophotometric method. The suggested method based on oxidation of BENZ via N-bromosuccinamide (NBSA) in presence of hydrochloric acid, then the unreacted or the excess NBSA was immerse in bleaching the colour of rifampicin dye(REFPD),the absorbance of unreacted REFPD has been estimated at wavelength 476 nm (the highest absorption of REFPD) .The measured absorbance is directly proportional to the amount of BENZ in the solution. All parameters affected the oxidation of BENZ and bleaching the colour of REFPD and the optimum values have been fixed. Beer’s law(linearity) of the method is in the range of 2 to 15 μ.g.ml−1, the molar absorptivity value equal to 4.295 x 10 3 l.mol−1.cm−1 and the Sandall’s index for sensitivity is calculated and equal to 0.0384 μg.cm−2. The suggested method has an application part included estimation of BENZ in its pharmaceutical formulation (sterile ear drops).