DIFFERENTIAL INTERACTIONS OF CYCLODEXTRINS WITH HYDROPHOBIC DERIVATIVES OF SEPHAROSE CL-4B

The partition coefficients K(aV)between the solution phase and octyl- and phenyl-sepharose CL-4B were determined for three cyclodextrins (CDs), alpha-CD, beta-CD and gamma-CD in various aqueous solutions, as a measure of their interactions with the two hydrophobic ligands. K-aV of the CDs increased in the order of gamma-CD < beta-CD < alpha-CD for octyl-sepharose CL-4B and alpha-CD < gamma-CD < beta-CD for phenyl-sepharose CL-4B. ln all cases, K-aV increased by increasing NaCl concentration in the aqueous solution phase and also by lowering temperature, but in the presence of NaBr and NaSCN, both chaotropic salts, K-aV decreased markedly. The spontaneity of the transfer of the CDs from the aqueous solution phases to the gel phases was due to the enthalpy decrease. It was shown that discrete separation of the three CDs can be achieved by the hydrophobic chromatography on a short column (1x25cm) of octyl-sepharose CL-4B by adjusting the NaCl concentration and temperature.