Enantioseparation chromatography

J. Dingenen, Polysaccharide phases in enantioseparations in A practical approach to chiral separations by liquid chromatography, G. Subramanian, VCH, Weinheim (1994) Chapter 6. 

Discrimination between the enantiomers of a racemic mixture is a complex task in analytical sciences. Because enantiomers differ only in their structural orientation, and not in their physico-chemical properties, separation can only be achieved within an environment which is unichiral. Unichiral means that a counterpart of the race-mate to be separated consists of a pure enantiomeric form, or shows at least enrichment in one isomeric form. Discrimination or separation can be performed by a wide variety of adsorption techniques, e.g. chromatography in different modes and electrophoresis. As explained above, the enantioseparation of a racemate requires a non-racemic counterpart, and this can be presented in three different ways ... 

Nieoud R. M., Euehs G., Adam P, Bailly M., Kusters E., Antia E, Reuille R., Sehmid E. (1993) Preparative Seale Enantioseparation of a Chiral Epoxide Comparison of Liquid Chromatography and Simulated Moving Bed Adsorption Teehnology, Chirality 5 267-271. 

Kusters E., Gerber G., Antia E. D. (1995) Enantioseparation of a Chiral Epoxide by SMB Chromatography using Chiraleel-OD, Chromatographia 40 387-393. 

The versatility of chiral stationary phases and its effecitve application in both analytical and large-scale enantioseparation has been discussed in the earlier book A Practical Approach to Chiral Separation by Liquid Chromatography" (Ed. G. Sub-ramanian, VCH 1994). This book aims to bring to the forefront the current development and sucessful application chiral separation techniques, thereby providing an insight to researchers, analytical and industrial chemists, allowing a choice of methodology from the entire spectrum of available techniques. 

In this study, Ali and Aboul-Enein [80] used cellulose tr is (3,5-d ich Ioropheny 1 carbamate) chiral stationary phase for the enantioseparation of miconazole and other clinically used drugs by high performance liquid chromatography. The mobile... 

Keywords enantioseparation, racemic mixtures, single enantiomer of drug, chromatography, chromatographic resolution. 

White, C. A. In Preparative and Process-Scale Liquid Chromatography, Subramanian, G. (ed.) (Ellis Horwood, 1991) Chapter 13. An Introduction to large-scale enantioseparation. 

This review provides an overview of the literature published to date on macrocyclic antibiotics exploited for enantioselective separations in high-performance liquid chromatography (HPLC). It was not intended as a comprehensive issue on the applications of such antibiotics in sub- and supercritical fluid chromatography (SFC), thin layer chromatography (TLC), capillary electrophoresis (CE), and capillary electrochromatography (CEC). A number of structural properties of the most important macrocyclic antibiotics applied in HPLC enantioseparations are listed in Table 2.1. 

Tesafova, E., Bosdkovd, Z., and Zuskova, L, Enantioseparation of selected iV-tert-butyloxycarbonyl amino acids in high-performance liquid chromatography and capillary electrophoresis with a teicoplanin chiral selector. J. Chromatogr. A, 879, 147, 2000. 

Enantioselective separation by supercritical fluid chromatography (SFC) has been a field of great progress since the first demonstration of a chiral separation by SFC in the 1980s. The unique properties of supercritical fluids make packed column SFC the most favorable choice for fast enantiomeric separation among all of the separation techniques. In this chapter, the effect of chiral stationary phases, modifiers, and additives on enantioseparation are discussed in terms of speed and resolution in SFC. Fundamental considerations and thermodynamic aspects are also presented. 

The ability of proteins to form enantioselective interactions with a large variety of drugs is used in chiral affinity chromatography. Protein CSPs that are most frequently used for the enantioseparation of pharmaceuticals include bovine serum albumin (BSA), human serum albumin... 

As discussed earlier, the concepts of chiral chromatography can be divided into two groups, the indirect and the direct mode. The indirect technique is based on the formation of covalently bonded diastereomers using an optically pure chiral derivatizing agent (CDA) and reacting it with the pair of enantiomers of the chiral analyte. The method of direct enantioseparation relies on the formation of reversible quasi diastereomeric transient molecule associates between the chiral selector, e.g., i /t)-SO, and the enantiomers of the chiral selectands, [R,S)-SAs [(Ry SA + (S)-SA] (Scheme 1). 

Dingenen J, Polysaccharide phases in enantioseparations, in A Practical Approach to Chiral Separations by Liquid Chromatography (Subramanian G, Ed.), VCH Verlag, Weinheim, Germany, p. 115 (1994). 

R.-M. Nicoud, G. Fuchs, P. Adam, M. Bailly, E. Kusters, F. D. Antia, R. Reuille and E. Schmid, Preparative scale enantioseparation of a chiral epoxide comparison of hquid chromatography and simulated moving bed adsorption technology , Chirality 5 267-271 (1993). 

E. Kusters, G. Gerber and F. D. Antia, Enantioseparation of a chiral epoxide by simulated moving bed chromatography using chiralcel-OD , Chromatographia 40 387- 393 (1995). 

C. Wolf and W. H. Pirkle, Enantioseparations by subcritical fluid chromatography at cryogenic temperatures , J. Chromatogr. 785 173-178 (1997). 

Schulte, M. and Strube, J, (2001) Preparative enantioseparation by simulated moving bed chromatography. J. Chromatogr. A 906, 399-416. 

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