Nanostructured materials for hydrophobic drug delivery

Porous silicon (Psi) and nanocellulose (NC) hydrogels are nanostructured materials with several properties that make them promising for drug delivery applications. In this work, β-carotene (BC) and clofazimine (CFZ) are used as model molecules to investigate the physical and chemical processes governing the interactions of hydrophobic molecules with both inorganic (Psi) and organic (NC) nanostructured carriers. Despite the large number of advantages, Psi does not perform well as carrier for BC, since it stimulates the molecule degradation even if its surface is carefully passivated. Furthermore, during the release experiments, BC tends to nucleate on Psi surface forming aggregates whose dissolution is much slower than the BC molecules release, thus they negatively impact on the control over the drug release. On the other hand NC hydrogels do not pose heavy issues to the release of lipophilic drugs, provided that a suitable surfactant (either Tween-20 or Tween-80) mediates the molecule solvation and its subsequent release into aqueous media. Moreover, NC gels protect BC from degradation much better than its storage in freezer or in organic solvent, making these carriers interesting for DD.