Development of solid dispersion lipid nanoparticles for improving skin delivery.

Applications of poorly water-soluble drugs in skin delivery pose several challenges to pharmaceutical formulation. This research originally developed solid lipid nanoparticles (SLNs) packaging a modified core of a solid dispersion (SD) in the lipid matrix to modulate the skin release patterns. Curcumin (CUR) was selected as the poorly water-soluble drug applied in the formulation. The designed system, so-called solid dispersion lipid nanoparticles (SD-SLNs), was fabricated by incorporating a solidifying SD or a non-solidifying SD into the core of the SLNs by ultrasonication. Release studies illustrated an important enhancement in the drug release of the proposed system compared to pure CUR and SLN formulations without the presence of SD as the modified core, which indicated the positive effect of the combined colloidal method of SD and SLNs. The physicochemical properties of the SD-SLN systems were also elucidated using powder X-ray diffraction, Fourier transform infrared spectroscopy, and particle size analysis. The drug was found to change to an amorphous state without any molecular interactions along with a marked particle size reduction. This work demonstrated the strong potential of applying a novel SD-SLN system for the skin delivery of a drug with poor water solubility.