Spectrophotometric Determination of Promethazine Hydrochloride in Pharmaceutical Formulation by Oxidative Coupling.

A simple, rapid and sensitive spectrophotometric method for determination of trace amounts of Promethazine hydrochloric in aqueous solution is described. The method is based on using the oxidative coupling reaction of promethazine hydrochloride with 4-amino 2-hydroxy benzoate reagent in acid medium in the presence of N-bromo Succinimide to produce an intense green colour, water soluble, product which exhibit maximum absorbance at 605.5 nm. Beer's law is obeyed over concentration range of (2-32μg/m1), with a molar absorptivity 7540.68 l/mol.cm, Sandel index of 0.04255 μg / .The average recovery is 100.7703 %, relative standard deviation of 0.3101 to 0.8474 % and D.L of 0.40825 μg/ml.