Encapsulation of dicinnamalacetone in β-cyclodextrin: A physicochemical evaluation and molecular modeling approach on 1:2 inclusion complex

ABSTRACT

The aim of this research is to prepare and characterize the inclusion complex between Dicinnamalacetone (DCA) and β-CD. The inclusion complex of Dicinnamalacetone [DCA] and Beta-cyclodextrin [β-CD] was characterized both in solution and solid state by UV-visible spectroscopy, Fluorescence spectroscopy, Nano second time resolved fluorescence study, Fourier Transform Infra-red spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Powder X-ray diffractometry (XRD), Atomic Force Microscopy (AFM) and molecular modeling test. The 1:2 soichiometry of inclusion complex and binding constant values were determined by Benesi-Hildebrand plot and confirmed by Job's continuous variation method. FT-IR study indicated that the aromatic rings of the Dicinnamalacetone molecule were included in the β-CD cavities. The nano second time resolved fluorescence study revealed that DCA exhibits single exponential decay in aqueous medium and bi-exponential decay in β-CD medium indicating the formation of inclusion complex. From the DSC study it is observed that the thermal stability of the inclusion complex was significantly enhanced when compared with the pure compound due to strong interaction between DCA and β-CD. Furthermore, implementation of molecular modeling test confirmed that the complexation could reduce the energy of the system. The experimental studies revealed that the most predominant structure of 1:2 inclusion complex is the one in which the two aromatic ends of DCA were inserted into the cavities of two β-CD molecules.

KEYWORDS:

• Dicinnamalacetone
• β-cyclodextrin
• inclusion complex
• atomic force microscope
• UV-fluorescence spectrum
• molecular docking