Spectrophotometric micro determination of pro-methazine hydrochloride in pharmaceutical dosage forms via oxidative coupling reaction with P-aminobenzoic acid and N-Bromosuccinimide

Abstract EN

A simple, accurate and sensitive spectrophotometric method for the determination of promethazine.IIC1 has been developed.

The method is based on the oxidative coupling reaction of promethazine.

1 ICi with P-aminobenzoic acid and in the presence of N-bromosuceinimide to form an intense bluish-green water soluble dye that is stable and has a maximum absorption at 600nm.A graph of absorbance versus concentration shows that Beer’s law is obeyed over the concentration range of 50-750 j.ig of promethazine.I ICI in a final volume of 25ml.(i-e 2-30ppm) with a molar absorptivity of 1.0*10'* L modern'1, a recovery% of 98.10-101.00 and a relative standard deviation of better than 1.2% depending on the concentration .The optimum conditions for full colour development are described and the proposed method was applied satisfactorily to the pharmaceutical dosage forms