Host-guest inclusion complex of propafenone hydrochloride with α- and β-cyclodextrins: Spectral and molecular modeling studies

Host-guest inclusion complexes of cyclodextrins (CDs) with a potential cardiovascular drug propafenone hydrochloride (PFO), were prepared and characterized using absorption, fluorescence, time-resolved fluorescence, SEM, FT-IR, DSC, H-1 NMR, XRD and PM3 methods. The spectral studies suggested the phenyl ring along with carbonyl group is present inside of CD cavity. Solvent studies revealed that the normal Stokes shifted band originates from the locally excited state and the large Stokes shifted band occurs due to the emission from ICT. Nanosecond time-resolved studies indicated that PFO exhibits biexponential decay in water and triexponential decay in CD, indicating the formation of 1:1 inclusion complex. The results from solid state studies showed important modifications in the physicochemical properties of free PFO. The Delta H, Delta G and Delta S of the complexation process were determined and it was found that the complexation processes were spontaneous. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex. (C) 2013 Elsevier B.V. All rights reserved.