Spectrophotometric determination of promethazine hydrochloride via oxidative coupling reaction with sulfanilic acid

الملخص EN

A simple, rapid and sensitive spectrophotometric method for determination of trace amounts of promethazine hydrochloride in aqueous solution is described.

The method is based on the oxidation of promethazine hydrochloride by sodium hypochloride and coupling with sulfanilic acid in the presence of sodium hydroxide to form an intense red soluble product with maximum absorption at 513 nm.

Beer’s law is obeyed over the concentration range of 4-28 μg / ml with molar absorptivity of 8.28 × 103 l.mol-1.cm-1.

The optimum conditions for all colour development are described and the proposed method has been successfully applied for the determination of promethazine hydrochloride in bulk drug and pharmaceutical formulations.

The common excipients and additives did not interfere in this method.