Spectrophotometric Assay of Metoclopramide Hydrochloride in Pharmaceutical Preparations via Arsenazo III-Cerium (III) Reaction

A simple, rapid, accurate and precise spectrophotometric method is proposed for determining metoclopramide hydrochloride (MCPH) in pure form and in pharmaceutical preparations .The method is based on oxidation - reduction reaction between metoclopramide - hydrochloride and cerium (IV) ion, then the subsequent reaction of cerium (III) and arsenazo III reagent in acidic medium to produce a blue-violet complex which is stable, water-soluble and has a maximum absorption at 654nm with a molar absorptivity of 9.36x104 l.mol-1.cm-1 and Sandell's sensitivity of 0.0038 g.cm-2. Beer's law is obeyed in concentration range from 1-30 g metoclopramide - hydrochloride in final volume of 25 ml, (0.04-1.2) ppm with a relative standard deviation (RSD) ( 1.80% - 3.98%) and the limit of detection (LOD) is 0.0095 g/ml and the limit of quantitation (LOQ) is 0.0317 g/ml . The method is suitable for the determination of metoclopramide - hydrochloride in the presence of other ingredients that are usually present in dosage forms and the recoveries are obtained in the range of 97.6-101.0 % . The proposed method has been applied successfully to the determination of the intended compound in its pharmaceutical preparations ( tablet and injection).