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The effect of the inclusion into cyclodextrins (CD) cavity on the low-frequency vibrational dynamics of the anti-inflammatory drug ibuprofen (IBP) is here investigated by using Raman and inelastic neutron scattering (INS) experiments. The differences observed in the frequency regime 0-100 cm(-1) between the vibrational modes of uncomplexed racemic and enantiomeric IBP are discussed on the basis of comparison with the quantum chemical computation results, taking into account the distinct symmetry properties of the molecules involved in the formation of the host-guest complex. Subsequently, the inspection of the same frequency range in the spectra of pure host methyl-β-CD and its IBP-inclusion complexes allows one to identify significant modifications in the vibrational dynamics of the guest molecule after their confinement into CD cavity. The experimental Raman and neutron spectra and the derived Raman coupling function C(R)(ω) show that the complexation process gives rise to a complete amorphization of the drug, as well as to a partial hindering, in the vibrational dynamics of complexes, of the modes between 50 and 150 cm(-1) attributed to CD molecule. The comparison between the Raman and neutron spectra of free and complexed IBP in the energy range of the Boson peak (BP) gives evidence that the dynamics related to this specific vibrational feature is sensitive to complexation phenomena.

An integrated experimental approach, based on inelastic light-scattering techniques, has been here employed for a multilength scale characterization of networking properties of cyclodextrin nanosponges, a new class of cross-linked polymeric materials built up from natural oligosaccharides cyclodextrins. By using Raman and Brillouin scattering experiments, we performed a detailed inspection of the vibrational dynamics of these polymers over a wide frequency window ranging from gigahertz to terahertz, with the aim of providing physical descriptors correlated to the cross-linking degree and elastic properties of the material. The results seem to suggest that the stiffness of cross-linked polymers can be successfully tuned by acting on the type and the relative amount of the cross-linker during the synthesis of a polymer matrix, predicting and controlling their swelling and entrapment properties. The proposed experimental approach is a useful tool for investigating the structural and physicochemical properties of polymeric network systems.

The vibrational dynamics of a new class of cross-linked polymers obtained from both native and modified cyclodextrin, referred to as cyclodextrin nanosponges, is here investigated. The main purpose is to spot the structure of these materials at molecular level unlikely to be characterized by diffraction methods due to the low or null degree of crystallinity. The analysis of the spectral features of the vibrational bands observed between 1650 and 1800 cm−1 in both Raman and infrared spectra, and assigned to the carbonyl stretching modes of the polymeric network, is performed by using band deconvolution procedures. At the same time, a detailed inspection of the low-wavenumber vibrational dynamics of these polymers is carried out, focusing on the modifications occurring on the so-called boson peak. The simultaneous analysis of different wavenumber ranges in Raman and infrared spectra of cyclodextrin nanosponges allows us to develop a reliable strategy for exploring both the cross-linking degree and the elastic properties of these innovative materials. The overall results give a complete characterization of the structural and dynamical properties of the system, in turn strictly connected to the entrapment/transport ability of these polymeric matrices. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]