STUDIES ON COMPLEXATION BETWEEN BETA-CYCLODEXTRIN AND BILE-SALTS

The thermodynamic parameters for the inclusion complexation of beta-cyclodextrin and thirteen bile salts have been measured with flow microcalorimetry. The results show that most of the bile salts studied here form 1:1 complexes with the exception of deoxycholate and its conjugates which form 1:1 plus 1:2 complexes. The complexation affinities follow the order: deoxycholates > ursodeoxycholates almost-equal-to chenodeoxycholates > cholates almost-equal-to dehydrocholate. The inclusion modes were established with H-NMR for beta-cyclodextrin and three bile salts. The thermodynamic data are consistent with the complex structures.