Spectrophotometric Determination of some Phenothiazines Using N-Chlorosuccinimide

Abstract

A simple and sensitive spectrophotometric method has been developed for the determination of some phenothiazine derivatives as pure and in dosage form. The method is based on oxidation of phenothiazines by N-chlorosuccinimide in hydrochloric acid medium to give red coloured species having maximum absorptions in the range 516.5-534.5nm. Beer‘s law is obeyed over the concentration ranges 2-28, 2-32 and 4-40µg.ml-1 with apparent molar absorptivity of 6.16×10³, 5.89×10³ and 5.34×10³ l.mol-1.cm-1 for phenothiazine, promethazine hydrochloride and chlorpromazine hydrochloride respectively. Additives and excipients normally found in dosage forms do not interfere.