Chiral Separation of Nonsteroidal Anti-Inflammatory Drugs
Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of minor pain and for the management of edema and tissue damage resulting from inflammatory joint disease. In drug development, analytical methods are required to evaluate the enantiomeric purity of starting materials, reagents, and catalysts, because the quality of these compounds limits the enantiomeric purity of the resulting products. Nonaspirin NSAIDs can be classified based on the chemical structure as follows: slicylates; popionic acids; ayl and heteroarylacetic acids; athranilates; oicams; penylpyrazolones; and ailides. From well-documented experiments, the possibility of analytes migrating in two mutually perpendicular directions, that is, in the direction of mobile phase flow and in the direction perpendicular to this, becomes an evident advantage of chiral separations by tin layer chromatography (TLC). Three main/basic mechanisms of resolution of enantiomers on impregnated TLC could be considered, which would largely be related to the approach of impregnation. These are ligand exchange, inclusion complex formation, that is, guest-host interaction, and ion exchange.