Enantioseparation of tropa alkaloids by means of anionic cyclodextrin-modified capillary electrophoresis

Abstract

Anionic cyclodextrins (CDs), i.e., sulfated CD, sulfobutylether b-CD (SBE-b-CD) and heptakis(2,3-di-O-acetyl-6-sulfato)-b-CD (HDAS-b-CD), were used to separate the isomers of atropine, homatropine, ipratropium, scopolamine and butylscopolamine. Variations in the pH value and the concentration of the various CDs revealed the sulfated b-CD to be superior to the other derivatives. In a basic medium at low concentrations of sulfated CD the enantiomers of atropine, homatropine and ipratropium were well resolved in a short migration time, which is appropriate for the routine analysis of the enantiomeric excess. Scopolamine and butylscopolamine compounds could not be separated with either CD.

Tropane alkaloid analysis by chromatographic and electrophoretic techniques: An update

“…The wide variety of cyclodextrin derivatives for enantioseparations has attired particular interest and was reviewed comprehensively [166,167]. Various cyclodextrins were initially evaluated for the enantiomer separation of tropane alkaloids in 1999 [168]. The racemic mixtures of atropine, homatropine, and ipratropium were resolved with short migration times in a basic medium at low concentrations of sulfated cyclodextrins.…”

Recent developments in chiral capillary electrophoresis and applications of this technique to pharmaceutical and biomedical analysis

“…The cavity of b-CD is large enough to accommodate a whole benzene ring [53]. Presence of an aryl group or a heterocycle in the analyte structure was found to be beneficial for enantioseparation [54,56].…”

“…The recent application and introduction of new charged derivatives of CDs in analytical practice during the past two years is reflected in several papers, as follows. Anionic b-CDs, i.e., SBE-b-CD and HDAS-b-CD, were used to separate enantiomers of pharmaceuticals [87], tropaalkaloids [91], analgethic drug candidates [93], ormexifene analogues [89], and amino acid derivatives [41,95]. SBEb-CD was found to be better than neutral and other anionic b-CDs.…”

“…CM-b-CD enabled enantiomeric separations of basic drugs [85,92,100]. Comparison between the performed enantioseparations using SBE-b-CD, sulfated-b-CD and CM-b-CD as chiral selectors [40,85,91,92] clearly illustrates the impact and role of the anionic substitutional groups on the enantioselectivity of the CD.…”

Comparison of chiral electrophoretic separation methods for phenethylamines and application on impurity analysis

“…The micelles have a negative charge on the surface because the hydrophilic sulfate head group of the surfactant remains in the aqueous buffer solution, whereas the hydrocarbon tails position in the oil core [12][13][14][15][16]. Application of CDs in CE is a useful technique for resolution of enantiomers and for determination of the enantiomeric excess [17,18]. However, for separation of enantiomers, chiral modifiers such as the cyclodextrins and their derivatives were added to the running buffer [9,10,[19][20][21][22][23][24].…”