Complexation of bile acids with 2-hydroxypropyl-β-cyclodextrin: A¹³C-NMR study

Abstract

The interaction of chenodeoxycholic acid (3 alpha,7 alpha-dihydroxy-5 beta-cholan-24-oic acid) 1; cholic acid (3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholan-24-oic acid) 2, deoxycholic acid (3 alpha,12 alpha-dihydroxy-5 beta-cholan-24-oic acid) 3 and ursodeoxycholic acid (3 alpha,7 beta-dihydroxy-5 beta-cholan-24-oic acid) 4 with 2-hydroxypropyl-beta-cyclodextrin HP beta CD (partially functionalized) is studied by measuring the changes in C-13-NMR chemical shifts induced by complexation in methanol-d(4). The alkyl chain of the bile acids enters the cyclodextrin cavity. The interaction of 1 and 4 with HP beta CD is stronger, in this solvent, with respect that of 2 and 3.