Cloud point extraction method for the sensitive determination of metoclopramide hydrochloride in pharmaceutical dosage forms

Abstract

In this work, a simple and very sensitive cloud point extraction (CPE) process was developed for the determination of trace amount of metoclopramide hydrochloride (MTH) in pharmaceutical dosage forms. The method is based on the extraction of the azo-dye results from the coupling reaction of diazotized MTH with p-coumaric acid (p-CA) using nonionic surfactant (Triton X- 114). The extracted azo-dye in the surfactant rich phase was dissolved in ethanol and detected spectrophotometrically at λ_max 480 nm. The reaction was studied using both batch and CPE methods (with and without extraction) and a simple comparison between the two methods was performed. The conditions that may be affected by the extraction process and the sensitivity of methods were carefully studied. Using optimal conditions, the linearity of calibration curves was in the range of 0.4-13 and 0.05-4 µg/mL and limits of detection of 0.044 and 0.028 µg/mL of MTH for batch and CPE methods respectively. Average recoveries for samples were detected to be between 97- 101% for both methods, with the relative standard deviation (RSD %) best than 2.7 % and 4.5 % for both methods, respectively. The suggested methods were applied successfully for assay of MTH in commercial pharmaceutical tablets.