Enhanced release of the poorly soluble drug itraconazole loaded in ordered mesoporous silica

It is known that the energy of the amorphous state of itraconazole loaded in ordered mesoporous materials is high relative to that of the crystalline state and is responsible for enhanced solubility and dissolution rate. We investigated the effects of particle size (0.7–5 μm), mesostructure (2D p6mm, cubic Ia-3d and cubic Fm-3m) and pore size (2.2–15.4 nm) of mesoporous silicas on the release performance of itraconazole. Results indicated that the release performance was not influenced by the particle sizes tested here, that the release performance increased with increasing pore diameter due to the lower probability of drug molecules colliding to recrystallize in large pores, and that the release performance was decreased in the cage-type pore structure (Fm-3m) compared to that in the cylindrical pore structures (p6mm and Ia-3d) because of the small entrance to the cagelike pores that retards the drug release.