Spectrophotometric Determination of Metoclopramide Hydrochloride in Pharmaceutical Preparations UsingDiazotization Reaction

A simple, rapid and sensitive spectrophotometric method has been developed for the quantitative determination of metoclopramide hydrochloride in both pure form and in its pharmaceutical formulations. The method is based on diazotization of primary amine group of metoclopramide hydrochloride with sodium nitrite and nitric acid followed by coupling with 8-hydroxyquinoline in alkaline medium to form a pinkish – red coloured species, which showed a maximum absorption at 528 nm against reagent blank. Beer's law was obeyed over the concentration range of 5-300 µg / 25 ml. with a molar absorptivity 3.1×10 4 l.mol -1 .cm -1 . 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 were obtained in the range of 98.9-100.0%. The method does not resort to temperature control or to solvent extraction. The effect of organic solvent on the spectrophotometric properties of the azo dye, the composition and stability constant have been worked out. The method has been successfully applied to the determination of metoclopramide in its pharmaceutical preparations ( tablet, syrup and drop ) .