Spectral and molecular modeling investigations of supramolecular complexes of mefenamic acid and aceclofenac with α- and β-cyclodextrin

Abstract Inclusion complexes of mefenamic acid (MFA) and aceclofenac (ALF) with α- and β-cyclodextrins (CDs) in aqueous medium were investigated by absorption, fluorescence, time-resolved fluorescence methods. The solid inclusion complexes between drugs and CDs were characterized by SEM, TEM, FT-IR, 1 H NMR, DSC and powder XRD techniques. Spectral studies indicated that both CDs form 1:1 inclusion complex with MFA and ALF. The experimental results revealed that the inclusion process is a spontaneous process. Time-resolved fluorescence studies suggested that ALF exhibited biexponential decay in aqueous and triexponential decay in CD whereas significant enhancement of lifetime of decay components of MFA was observed. Morphologies of drug-CD complexes observed by TEM demonstrate that self-aggregates of MFA/α-CD, ALF/α-CD and ALF/β-CD were nano-sized particles while vesicles were observed for MFA/β-CD. A spatial arrangement of inclusion complex is proposed based on 1 H NMR and PM3 results. Investigations of thermodynamic and electronic properties confirmed the stability of the inclusion complex.