Abstract
The production of particulate hybrid carriers containing a glyceryl monostearate (Lumulse
® GMS-K), a waxy triglyceride (Cutina
® HR), silanized TiO
2 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 CO
2 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 TiO
2 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 TiO
2 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 TiO
2 and caffeine encompassed the UV-filter behavior of TiO
2 and the photoaging prevention properties of caffeine.