Enantioseparation in supercritical fluid chromatography using cellulose tris(3-chlor-5-methylphenylcarbamate) as chiral selector

Author: Lasha Giunashvili
Keywords: Supercritical Fluid Chromatography, Chirality
Annotation:

Separation of enantiomers represents one of the hot topics of contemporary chemistry from both theoretical and practical points of view. The importance of this problem from the pracrical point of view is caused by the fact that enantiomers of chiral biologically active molecules such as pharmaceuticals, food additives, agrochemicals, etc., are commonly characterized with different target activity, toxicity, metabolism, transformation in environment, etc. For instance, enantiomers of chiral pesticides may have not only different effect on target object but may also undergo transformation with different speed and form different final degradation products due to enantioselective action of enzymes and microbs [1]. More than half of currently used drugs are chiral and waste majoriy of them are still used in a racemic form. This is not justified since the enantiomers of chiral drugs commonly possess different pharmacodynamic and pharmacokinetic properties [2]. Chirality represent very challenging issue on the way of development of new chiral drugs, agrochemicals, food additives and other biologically active molecules. Therefore, chirality, enantiomer separation and other related topics represent the objects of many international conferences (for instance, annual series of Chirality conference), dedicated journals (for instance journal Chirality from Wiley, New York, USA), books [3] and governmental regulations, such as US Food and Drug Administration (FDA), European Medical Agency (EMA), etc. Based on above mentioned, the most effective and safe use of chiral biologically active compounds requires separation of their enantiomers and reliable evaluation of their enantiomeric purity. Separation of enantiomers remined as very challenging issue in chemistry for decades and the first chiral column for high-performance liquid chromatographic separation of enantiomers became commercially available since 1981. In the last 35 years several hundreds of chiral columns were described in the literature and several tens of them were commercialized. Among currently available chiral columns those based on polysaccharide-type chiral selectors are recognized to be the most powerfull ones [4]. Although polysaccharide based chiral selectors are involved in about 80% of all published analytical and over 90% of all preparative scale separations, the separation mechanisms of enantiomers by these chiral stationary phases (CSPs) are largely unknown.