Production of hybrid lipid-based particles loaded with inorganic nanoparticles and active compounds for prolonged topical release

The production of particulate hybrid carriers containing a glyceryl monostearate (Lumulse® GMS-K), a waxy triglyceride (Cutina® HR), silanized TiO2 and caffeine were investigated with the aim of producing sunscreens with UV-radiation protection properties. Particles were obtained using the supercritical PGSS® (Particles from Gas Saturated Solutions) technique. This method takes advantages of the lower melting temperatures of the lipids obtained from the dissolution of CO2 in the bulk mixture. Experiments were performed at 13 MPa and 345 K, according to previous melting point measurements. Blends containing Lumulse® GMS-K and Cutina® HR lipids (50 wt%) were loaded with silanized TiO2 and caffeine in percentile proportions of 6 and 4 wt%, respectively. The particles produced were characterized using several analytical techniques as follows: system crystallinity was checked by X-ray diffraction and differential scanning calorimetry, thermal stability by thermogravimetric analysis, and morphology by scanning and transmission electron microscopy. Further, the UV-shielding ability of TiO2 after its dispersion in the lipidic matrix was assessed by solid UV–vis spectroscopy. Preliminary results indicated that caffeine-loaded solid lipid particles presented a two-step dissolution profile, with an initial burst of 60 wt% of the loaded active agent. Lipid blends loaded with TiO2 and caffeine encompassed the UV-filter behavior of TiO2 and the photoaging prevention properties of caffeine.