VSE knjižnice (vzajemna bibliografsko-kataložna baza podatkov COBIB.SI)
  • Physical state of a model drug in mesoscopic confinement
    Ukmar Godec, Tina ...
    The incorporation of drugs into mesoporous silicates as a means to achieve controlled release has been intensively investigated over the past few years. It was demonstrated that by doping drugs into ... mesoporous matrices, one can modify the release of drugs in a specific and controllable manner. While the current research is directed mainly towards tailoring drug release kinetics, there are only a few studies focusing on the structure and the physical state of meso-confined phases. It is believed that the physical state of confined drugs is either glassy or liquid-like; some authors even report the existence of a molecular dispersion inside the porous network. To explore the effect of spatial confinement on the physical state of the drug, we incorporated indomethacin (IMC) into a very well defined porous structure, such as SBA-15 and MCM-41. These model systems were prepared by impregnation with a sub-saturated solution of IMC followed by a two-step drying process. After determining the loading content, the physical state of confined IMC was probedby a combination of differential scanning calorimetry and solid-state NMR. We show that the physical state of drugs confined to nanometer dimensions cannot be unambiguously defined, since it behaves thermally as a crystal (i.e. it melts), while at the same time its NMR spectral properties are clearly those of a glass. Dynamical properties were assessed by measuring proton spin-lattice relaxation times which have shown that the dynamical behavior strongly depends on pore size and interactions with the silica walls.
    Vrsta gradiva - prispevek na konferenci
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 4719898