Spectrophotometric method for the determination of benzocaine by cerium ammonium sulphate with promethazine hydrochloride in pure and pharmaceuticals preparation

Abstract

Easy, the accurate, sensitive spectrophotometric method used to determine Benzocaine in a pure and pharmaceutical preparation. The proposed method depends on using Promethazine hydrochloride as a reagent. Where it depends on oxidative coupling reaction of benzocaine by cerium ammonium sulphate with promethazine hydrochloride in the presence of hydrochloric acid to form green dye product, lmax 615 nm. Beers law is obeyed in the concentration of (5 –300 µg.ml^-1). The molar absorptivity is (1.77 * 10 3) L.mol ^-1.cm^-1, a sandal sensitivity of (0.0098) µq.cm^-2 and RSD (± 0.56 %). The method gave a successful determination for benzocaine in a pharmaceutical preparation.