Specific binding capacity of β-cyclodextrin with cis and trans enalapril: Physicochemical characterization and structural studies by molecular modeling

The main objective of this work was to study an inclusion complex between enalapril (ENA), and β-cyclodextrin (β-CD). From nuclear magnetic resonance (NMR) we determined that the complex showed a 1:1 stoichiometry, with an apparent formation constant (KC) of 439 and 290 M−1 for the cis and trans isomers, respectively. The molecular modeling and NMR techniques demonstrated that the aromatic moiety of ENA was inserted into the hydrophobic cavity of β-CD. When studying the chemical stability of ENA complexed to β-CD, a clear stabilizing effect was observed in both the aqueous solution and solid state.

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