BINDING OF BILE-ACIDS BY POLYMERIZED CYCLODEXTRIN RESINS

Copolymers of beta-cyclodextrin and epichlorohydrin were prepared by a crosslinking reaction of beta-cyclodextrin with different amounts of epichlorohydrin. These copolymers were tested for their ability to bin d several bile salts (including the sodium salts of cholic acid, glyco cholic acid, taurocholic acid, and chenodeoxycholic acid), individuall y and competitively, from phosphate buffer solutions at room temperatu re. The polymer resins with a lower degree of crosslinking had a highe r binding capacity for cholic acid. In all cases the binding of chenod eoxycholate by the polycyclodextrin resins was much more effective tha n that of cholate and its conjugates, which indicates the marked impor tance of the host cavity size relative to that of the guest molecules. In addition, there were indications that hydrophobicity plays a role in the binding of the bile salts by these resins.