Spectrophotometric determination of metoclopramide hydrochloride in pharmaceutical preparations by the diazotization-coupling method with phloroglucinol

Abstract

A simple, rapid and sensitive spectrophotometric method for the determination of trace amounts of metoclopramide in pharmaceutical preparations has been worked out. The method is based on the conversion of the intended compound to the corresponding diazonium salt, and subsequent coupling with phloroglucinol in alkaline medium to form an intense yellow water-soluble coloured azo dye with maximum absorption at 424 nm and molar absorptivity of 4.3 × 104 l.mol-1.cm-1. Beer’s law is obeyed over the range 5-400 g of metoclopramide per 25 ml as final volume, i.e. 0.2-16 ppm. The relative error and the relative standard deviation were -0.6 to +1.2% and 0.2 to 1.3% respectively depending on the concentration level. The proposed method has been applied successfully to pharmaceutical preparations.