Abstract

DEVELOPMENT AND VALIDATION OF SPECTROPHOTOMETRIC METHODS FOR THE DETERMINATION OF ESOMEPRAZOLE MAGNESIUM IN PHARMACEUTICAL FORMULATIONS

Makka Hashim Ahmed*, Mohamed El Mukhtar, M. Iqbal Choudhary, Shakil Ahmed and A.E.M. Saeed

ABSTRACT

Simple sensitive and validated spectrophotometric methods have been developed for the assay of esomeprazole magnesium trihydrate (ESO) in pure and pharmaceutical formulations. The first method was based on the reaction between (ESO) and alizarin red S (Aliz) to form a deep brown product, which absorb at max 521 nm (method a); the second method was based on the formation of a pink ion-pair complex between ESO and eriochrome black T (EBT) at pH 3, which absorbs at max 511 nm (method b). Beer's law is obeyed in the range 10 – 80 μgmL-1 for method a, and 5 – 35 μgmL-1 for method b. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.69, 5.37 and 0.44, 1.33 μgmL-1 for methods a and b, respectively. Recoveries were in the range of 99.53 to 100.05 and 99.57 to 100.52 for methods a and b, respectively. All parameters affecting the reaction in both methods have been examined. The two methods have been successfully applied for determination of the drug ESO in pure and pharmaceutical formulations. The results were in a good agreement with those obtained with the official USP method.

Keywords: Esomeprazole, alizarin Rd S, EBT, ion pair complex, colorimetry, method validation.