A simple, accurate, and sensitive UV-Vis spectrophotometric method was developed to determine metoclopramide (MCP) in its pure form and in pharmaceutical preparations. The analytical method is based on the azo-coupling reaction between metoclopramide and quercetin, followed by acidification with hydrochloric acid and sodium nitrate to yield the diazonium salt, and coupling in an alkaline medium at 0-5°C. The dark yellow, water-soluble product exhibited maximum absorption at 426 nm. The optimal experimental conditions were studied using univariate and multivariate methods, with the latter providing superior performance. A linear calibration curve was obtained over the concentration range of 5–70 μg mL-1, in strict accordance with Beer's law. The method demonstrated excellent precision (mean recovery 99.91%) and relative standard deviation (RSD = 0.70%), as well as high sensitivity, with a molar absorbance of 0.7397 × 10⁴ L mol-1 cm-1. The limits of detection (LOD) and quantification (LOQ) were established at 0.026 and 0.079 μg mL-1, respectively. The results were consistent with the official method and were not affected by common excipients. The proposed procedure has been successfully applied to the determination of MCP in various pharmaceutical preparations by UV-Vis spectrophotometry.
Ahmeda et al. (Sun,) studied this question.