Journal
INTERNATIONAL JOURNAL OF PHARMACEUTICS
Volume 322, Issue 1-2, Pages 161-170Publisher
ELSEVIER
DOI: 10.1016/j.ijpharm.2006.05.037
Keywords
carnauba wax; nanofine titanium dioxide; cinnamates; fatty acid matrices; nanoparticles; nanostructured lipid carriers; UV absorption; in vitro sun protection factor; TEM
Categories
Ask authors/readers for more resources
Carnauba wax is partially composed of cinnamates. The rational combination of cinnamates and titanium dioxide has shown a synergistic effect to improve the sun protection factor (SPF) of cosmetic preparations. However, the mechanism of this interaction has not been fully understood. In this study, an ethanolic extract of the carnauba wax and an ethanolic solution of a typical cinnamate derivative, ethylcinnamate, were prepared and their UV absorption and SPF either alone or in the presence of titanium dioxide were compared. The titanium dioxide crystals and the cinnamates solutions were also distributed into a matrix composed of saturated fatty acids to emulate the structure of the crystallized camauba wax. SPF, differential scanning calorimetry (DSC) and X-ray studies of these matrices were performed. Additionally, camauba wax nanosuspensions containing titanium dioxide either in the lipid phase or in the aqueous phase were prepared to evaluate their SPFs and their physical structure. Strong UV absorption was observed in diluted suspensions of titanium dioxide after the addition of cinnamates. The saturated fatty acid matrices probably favored the adsorption of the cinnamates at the surface of titanium dioxide crystals, which was reflected by an increase in the SPF. No modification of the crystal structure of the fatty acid matrices was observed after the addition of cinnamates or titanium dioxide. The distribution of the titanium dioxide inside the lipid phase of the nanosuspensions was more effective to reach higher SPFs than that at the aqueous phase. The close contact between the camauba wax and the titanium dioxide crystals after the high-pressure homogenization process was confirmed by transmission electron microscopy (TEM). (c) 2006 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available