Determination of Metoclopramide Hydrochloride in Pharmaceuticals and Spiked Human Urine through Diazotization Reaction

Abstract

Three simple, rapid, sensitive and cost-effective titrimetric and spectrophotometric methods were described for the determination of metoclopramide (MCP) in its pharmaceutical dosage forms and spiked human urine. The titrimetric methods were based on the diazotization reaction involving the primary amine group of MCP and NaNO2 in acid medium with visual (method A) and potentiometric (method B) end point detection. The spectrophotometric method (method C) depends upon the diazotization of MCP in acid medium followed by coupling with diphenylamine to give a red colored chromogen with a wavelength of maximum absorption at 530 nm. The experimental conditions were optimized. Both the titrimetric methods were applicable over the concentration range of 1.0-20.0 mg and the calculations were based on a 1 : 1 (MCP: NaNO2) reaction stoichiometry. In the spectrophotometric method, Beer's law was obeyed over the concentration range or 0.3-7.5 ug/mL with a molar absorptivity of 4.73 x 10^4 L/mol cm and Sandell's sensitivity being 0.007 μg/cm^2. The limit of detection and the limit of quantification were calculated to be 0.22 and 0.67 μg/mL, respectively. The proposed methods were applied to the determination of MCP in tablets, injection and also in spiked human urine.