Flame Emission and Molecular Absorption Spectrophotometric Determination of Promethazine Hydrochloride via Potassium Dichromate as Oxidant Reagent
Two simple, rapid and sensitive Flame Atomic Emission and Molecular Absorption Spectrophotometric method for determination of trace amount of promethazine hydrochloride in pure and its pharmaceutical preparations were described. The methods were based on the oxidation of promethazine hydrochloride by potassium dichromate in acid solution to form an intense yellow soluble product and in first method the intensity emission measured of potassium at emission line of potassium 766 nm using flame emission spectrophotometer, the second methods used Molecular Absorption UV-Vis for oxidant reagent potassium dichromate at λmax. 440 nm. Beer's law is obeyed over the concentration range of 1-18 µg/mL for two methods, and relative standard deviation RSD% were (1.01, 1.29), and (1.37, 1.45), for tablets and injections in first and second methods respectively. The two proposed methods have been successfully applied for the determination of promethazine hydrochloride in bulk drug and pharmaceutical formulations. The common excipients and additives did not interfere in these methods.
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