A. Gadre et Ka. Connors, BINDING OF SUBSTITUTED ACETIC-ACIDS TO ALPHA-CYCLODEXTRIN IN AQUEOUS-SOLUTION, Journal of pharmaceutical sciences, 86(11), 1997, pp. 1210-1214
Complex binding constants of 23 aliphatic acids with alpha-cyclodextri
n in aqueous solution were measured by potentiometry, solubility, or c
ompetitive spectrophotometry at 25 degrees C. All systems formed 1:1 a
cid:cyclodextrin complexes, and some of them also formed 1:2 complexes
. The conjugate acids formed stronger complexes than did the conjugate
bases (except for glycine). Empirical correlations of complex stabili
ties are shown with partition coefficients surface areas, molar refrac
tion, and other descriptors Complex stability appears to result from t
he hydrophobic effect, the dispersion interaction, and interaction oi
the carboxylic acid group with the cyclodextrin.