Octakis-6-sulfato-gamma-cyclodextrin as additive for capillary electrokinetic chromatography of dibenzoazepines: carbamazepine, oxcarbamazepine and their metabolites.
Single isomer octakis-(2,3-dihydroxy-)6-sulfato-gamma-cyclodextrin used as pseudostationary phase of the background electrolyte interacts with dibenzo[b,f]azepines (consisting of a condensed 3-ring system) and forms negatively charged complexes. Hydroxygroups in position 2 and 3 at carbamazepine increase the extent of interaction, whereas substitution by oxygen at position 10 and/or 11 reduces it. The complex constants for the analytes are ranging from few tens L/mol (10-hydroxycarbamazepine, 10,11-dihydroxycarbamazepine, 10,11-epoxycarbamazepine, oxcarbazepine) to several hundreds L/mol (carbamazepine, 2-hydroxycarbamazepine, 3-hydroxycarbamazepine), and are much larger than those of the analytes with octakis-(2,3-dimethyl-)-6-sulfato-gamma-cyclodextrin. Full enantiomeric separation of the chiral metabolites of carbamazepine and oxcarbazepine is obtained at octakis-(2,3-dihydroxy-)-6-sulfato-gamma-cyclodextrin concentrations of about 10 mM (3 mM borate buffer, pH 8.5). Compared to heptakis-6-sulfato-beta-cyclodextrin, selectivity differs and stereoselectivity is more pronounced.
Institute for Analytical Chemistry, University of Vienna, Vienna, Austria.
Ettore
E
Marziali
Maria Augusta
MA
Raggi
Natalja
N
Komarova
Ernst
E
Kenndler
D001381:Azepines / Q000032:analysis / Q000302:isolation & purification*; D002220:Carbamazepine / Q000032:analysis / Q000302:isolation & purification; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003505:Cyclodextrins / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods; D007202:Indicators and Reagents / Q000737:chemistry; D047408:gamma-Cyclodextrins
D001381:Azepines; D003505:Cyclodextrins; D007202:Indicators and Reagents; D047408:gamma-Cyclodextrins; C476609:octakis-(2,3-dihydroxy-)-6-sulfato-gamma-cyclodextrin; D002220:Carbamazepine