The separation of the enantiomers of Dimethinden using cyclodextrins as a chiral selectors

Author: Tamar Gegelashvili
Co-authors: Ana Gogolashvili, Natia Tsertsvadze, Nini Megeneishvili, Davit Khutsishvili
Keywords: Capillary electroforesis, chiral selectors, enantiomers, Dimethinden, cyclodextrins
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Summary Capillary electrophoresis (CE), which is beginning to play a major role in the separation of chiral compounds, being considered often superior to high-performance liquid chromatography (HPLC), accepted as the most universally applied method in pharmaceutical analyses. The advantages of using CE in chiral separations are related to its high resolving power, relatively short analysis time, rapid method development, low consumption of solvent, sample and chiral selector and especially with the high selectivity of choosing and changing the chiral selector. Another big advantage is that in CE, direct chiral separation is typically carried out by simply dissolving an enantiomerically pure additive in the buffer solution. CE is working by creating complexes within the capillary and moving them with the help of potential difference, different orientation in the space and specific molecular interaction makes complexes to separate. These differences are the reason why enantiomers can be separated. This research is discussing separation of dimethindene enantiomers in CE by using α- β- γ- TM- and DM- Cyclodextrins as chiral selectors because enantioseparation can be achieved only using chiral selectors. Cyclodextrins (CDs)are the important and frequently used class of chiral selectors in CE, as they are nontoxic and multimodal selectors since multiple chiral interactions are possible by very different stereo selective mechanisms. Using CDs are very comfortable due to their solubility in aqueous solutions. In the process of enantioseparation, CDs discriminate between the enantiomers by an enantioselective complexation of the analyte and the chiral selector, giving rise to differences in the electrophoretic mobilities of the enantiomers. The differences between them are the result of different effective charge densities, which is caused by different spatial orientations or specific intermolecular interactions. In the present thesis the affinity pattern of dimrthindene enantiomers towards native α-, β- and γ-CDs, DM-β-CD and TM-β-CD was studied.