New Sensitive Kinetic Spectrophotometric Methods for Determination of Omeprazole in Dosage Forms

• Published in: International Journal of Analytical Chemistry 2009-01, Vol.2009 (1), p.52-62
• Main Author: Mahmoud, Ashraf M.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Methods; Pharmaceuticals; Quality control
• ISSN: 1687-8760; 1687-8779
• DOI: 10.1155/2009/307045

New rapid, sensitive, and accurate kinetic spectrophotometric methods were developed, for the first time, to determine omeprazole (OMZ) in its dosage forms. The methods were based on the formation of charge-transfer complexes with both iodine and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The variables that affected the reactions were carefully studied and optimized. The formed complexes and the site of interaction were examined by UV/VIS, IR, and 1H-NMR techniques, and computational molecular modeling. Under optimum conditions, the stoichiometry of the reactions between OMZ and the acceptors was found to be 1 : 1. The order of the reactions and the specific rate constants were determined. The thermodynamics of the complexes were computed and the mechanism of the reactions was postulated. The initial rate and fixed time methods were utilized for the determination of OMZ concentrations. The linear ranges for the proposed methods were 0.10–3.00 and 0.50–25.00 μg mL-1 with the lowest LOD of 0.03 and 0.14 μg mL-1 for iodine and DDQ, respectively. Analytical performance of the methods was statistically validated; RSD was