Influence of substituent position and cavity size of the regioisomers of monocarboxymethyl-alpha-, beta-, and gamma-cyclodextrins on the apparent stability constants of their complexes with both enantiomers of Troger's base
Abstract
Enantiomers of Troger's base were separated by capillary electrophoresis using 2(I)-O-, 3(I)-O-, and 6(I)-O-carboxymethyl-alpha-, beta-, and gamma-cyclodextrin and native alpha-, beta-, and gamma-cyclodextrin as chiral additives at 0-12 mmol/L for beta-cyclodextrin and its derivatives and 0-50 mmol/L for alpha- and gamma-cyclodextrins and their derivatives in a background electrolyte composed of sodium phosphate buffer at 20 mmol/L concentration and pH 2.5. Apparent stability constants of all cyclodextrin-Troger's base complexes were calculated based on capillary electrophoresis data.
The obtained results showed that the position of the carboxymethyl group as well as the cavity size of the individual cyclodextrin significantly influences the apparent stability constants of cyclodextrin-Troger's base complexes.