Equilibria between vitamin B6-compounds and cyclodextrins.

Convenient chromatographic methods to measure equilibrium constants between cyclodextrins and aromatic compounds were developed. The use of 'Hummel-Dreyer' elution profile allows us to determine values above 15-20 M-1. The weaker associations (below 15-20 M-1) can be measured with cyclo-dextrin-derivatized Biogel P-2 column. The latter method is very suitable to determine the equilibrium constants between cyclodextrins and vitamin B6-compounds which can't be measured with the conventional photometric procedure.