Study of the colloidal stability and optical properties of sunscreen creams

Abstract

Sunscreen formulations containing inorganic/organic filters or mixture of them were synthesized by oil/water dispersion. The viscosity measurements show that sunscreen formulations are time-dependent non-newtonian fluids. In the CIELab color diagram, the white and/or beige colors presented by formulations do not compromise the aesthetics of the cosmetic product. UV-VIS absorption spectra show that sunscreen creams have high UV shielding ability, mainly the formulations containing inorganic and organic filters mixtures, which provide in vitro SPF and critical wavelength values recommended for UV protection.

Antibacterial activity, quality and stability study of creams with new potential silver(I) complexes and in vivo case report

“…3), from 8 × 10 4 to 1 × 10 5 at 20 ± 1 °C and from 5 to 6.2 × 10 4 mPa s at 37 ± 1 °C; resp. similar behaviour is expected and has been observed in the case of sunscreen creams (27). The viscosity decrease is attributed to the break of intermolecular interactions in the interfacial region, which provides the loss of colloidal stability.…”

UV Protection and Antioxidant Activity of Nanodiamonds and Fullerenes for Sunscreen Formulations

“…Compared to commercial chemical sunscreens with numerous peaks and troughs (Figure S1), these graphs are monotonic with more effective UV reduction at the UVB than the UVA regions. The peaks and troughs in chemical-based sunscreens suggest that their mechanism of UV protection is based on UV absorption . In contrast, the mechanism of protection by nanoparticles is a combination of scattering and absorption, resulting in a more monotonic transmittance spectrum .…”

“…The peaks and troughs in chemical-based sunscreens suggest that their mechanism of UV protection is based on UV absorption. 43 In contrast, the mechanism of protection by nanoparticles is a combination of scattering and absorption, resulting in a more monotonic transmittance spectrum. 44 ND, C 60 , and TiO 2 nanoparticles have similar mechanisms of UV protection.…”

Zn(ferulate)-LSH Systems as Multifunctional Filters

“…The cosmetic formulations were prepared by the colloidal dispersion of Nafel salt, Zn-NO 3 -LSH matrix or LSH-ferulate materials (Zn-fel(4)-LSH and Zn-fel(4)-LSH/U10 samples) in the oil phase of the skin care formulation described by Saito et al [ 11 ]. The oil/water-type dispersions were subjected to magnetic stirring for 1 h to cream formation.…”

“…These compounds are optical filters [ 9 , 10 ], which attenuate UV light and can transmit other radiations that compose solar spectrum. The UV shielding capacity of inorganic or organic filters makes them active constituents of the photoprotective products, e.g., sunscreens [ 11 ].…”