Inclusion complexation of isoprenaline and methyl dopa with α- and β-cyclodextrin nanocavities: Spectral and theoretical study

• Spectral results showed that ISOP and MDOP formed monomer emission in water where as dual emission (excimer) in CDs.
• Aliphatic chain of the drugs is present in the inner part of the CDs nanocavities.
• Complex formation was confirmed by FTIR, DSC, 1H NMR, XRD and PM3 methods.
• Nanomaterial structures of the inclusion complexes were observed by SEM and TEM.
• Statistical thermodynamics calculations confirmed the better stability of the inclusion complex.

Inclusion complex formation of isoprenaline (ISOP) and methyldopa (MDOP) with α-CD and β-CD were investigated. Solid inclusion complex nanomaterials were characterized by SEM, TEM, FTIR, DSC, 1H NMR and XRD methods. Spectral results showed that single emission (monomer) noticed in aqueous solution where as dual emission (excimer) in CD. Both drugs formed 1:2 (CD–drug2) inclusion complexes with CDs. Time-resolved fluorescence studies show that single exponential decay observed in water whereas biexponential decay observed in CD. Nano-sized particles were found in ISOP/CD while vesicles were obtained in MDOP/CD complexes. DSC results revealed that the thermal stability of drugs was improved when it was included in the CD nanocavity. Based on PM3 calculations, the inclusion structure of ISOP/CD and MDOP/CD complexes were proposed. Thermodynamic parameters and binding affinity of complexation of CD were determined by PM3 method.

Formation of vesicles from MDOP/β-CD complex.Figure optionsDownload as PowerPoint slide