Determination of stability constants of the inclusion complexes of beta-blockers in heptakis (2,3-dimethyl-6-sulfato)-beta-cyclodextrin.

The beta-blockers possess at least one chiral center and the S(-)-enantiomer shows higher affinity for binding to the beta-adrenergic receptors than antipode. The stability constants of acebutolol, celiprolol, propranolol and terbutaline in the inclusion complexes with single-isomer heptakis (2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-beta-CD) were determined by capillary electrophoresis. The approximation and linear double reciprocal methods were adapted with comparable results. Among the beta-blockers studied, propranolol had the lowest stability constant but the highest enantioselectivity, indicating that the magnitudes of the stability constants carried little information about enantioseparation. The magnitudes of enantioselectivities between the enantiomer pair were in the order of propranolol > celiprolol > terbutaline > acebutolol.