Study of compliance with international standards for some pharmaceutical forms of omeprazole

Author: Tamari Matsiashvili
Keywords: chiral chromatography, separation of omeprazole enantiomers, validation, evaluation of enantiomeric purity, determination of the content of the API
Annotation:

Chiral sulfoxides are mostly used as pesticides, drug compounds, etc. The enantioselective biological activity of chiral sulfoxides is well known and became the reason for developing some of them as enantiomerically pure chiral drugs. Because of this, the separation of enantiomers is a hot topic, and chromatographic methods have been used for this purpose for many years. Omeprazole is one of the chiral sulfoxides and it belongs to a class of drugs known as proton pump inhibitors (PPIs). The first step of our research was the screening of thirteen polysaccharide-based chiral columns for the separation of omeprazole enantiomers under the following mobile phases: methanol and methanol:water:formic acid 90:10:0.1 (v/v/v). We also determined the enantiomer elution order. The optimal separation of enantiomers was observed on the cellulose tris(4-chloro-3-methylphenylcarbamate)-based chiral column (Lux Cellulose-4) with methanol as a mobile phase. The objective of the validation of an analytical procedure is to demonstrate that it is suitable for its intended purpose. Commercially available pharmaceutical formulations of omeprazole contain either a racemic active pharmaceutical ingredient (API) or its S-enantiomer (esomeprazole). Therefore, two validated methods were developed: one for the determination of the content of the API in racemic omeprazole and esomeprazole formulations, and the other one for the evaluation of enantiomeric purity of API in commercially available esomeprazole formulations. At the end of the study, twelve medicinal products were analyzed by the mentioned methods. Their compliance with international standards was evaluated. In particular, according to the quantitative content and enantiomeric purity of the API.