Sensitive spectrophotometric determination of metoclopramide hydrochloride in dosage forms and spiked human urine using vanillin

A new spectrophotometric method which is simple, sensitive, selective and rapid is described for the determination of metoclopramide hydrochloride (MCP) in bulk drug and in dosage forms using vanillin as the chromogenic agent. The method is based on the condensation reaction between primary aromatic amine group present in MCP with aromatic aldehyde, vanillin to produce an intense yellow colored product. The resulting Schiff’s base shows an absorption maximum at 410 nm and the reaction product is stable for more than one day. The reaction was carried out in acetic acid and perchloric acid medium. Beer’s law was obeyed in the concentration range 1.5–15.0 μg ml−1 MCP with a molar absorptivity of 1.89 × 104 l mol−1 cm−1. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.51 and 1.55 μg ml−1, respectively. The method was statistically evaluated by calculating percent relative error (% RE) for accuracy and percent relative standard deviation (% RSD) for precision, and was applied successfully to the determination of MCP in tablets, in injection and also in spiked human urine. No interference was observed from common additives found in pharmaceutical preparations. The results obtained by the proposed method were validated statistically by comparing the results with those of the reference method by applying the Student’s t-test and F-test. The accuracy and reliability of the method were further ascertained by performing recovery tests via standard-addition technique.