Ascorbic Acid for the Safe Use of a Sunscreen Agent: Accumulation of Nano Zinc Oxide and Titanium Dioxide on the Skin

Abstract

ObjectivePhysical UV absorbers such as titanium dioxide or zinc oxide have been found to be highly protective against ultraviolet radiation. Sun protection factor depends on the accumulation of the minerals on the skin. UV-absorbing agents must accumulate within the upper skin layers in order to provide a dense light-absorbing layer and guarantee water resistance. The aim of this work was to increase the skin deposition and efficacy of sunscreens without increasing their skin permeation. The application possibility of EDX to determine the quantitative elemental composition of zinc and titanium on the skin surface was studied.MethodThe changes induced in the skin deposition of physical UV absorbers in conjunction with ascorbic acid were studied. In vitro skin permeation and X-ray elemental analysis were carried out to determine the mineral skin deposition effect of ascorbic acid.Key findingsResults indicate that ascorbic acid may significantly increase the skin deposition (p < 0.05) of these minerals on the skin without increasing their skin permeation (p > 0.05). Flow through diffusion cell and X-ray elemental analyses appear to be complementary and show that ascorbic acid is able to increase accumulation of sunscreen on the skin.

Analysis of Human and Porcine Skin in vivo/ex vivo for Penetration of Selected Oils by Confocal Raman Microscopy

“…oleic acid and glyceryl trioleate) disrupt the stratum corneum lipids, thus enhancing the penetration [21,22,23,24]. Leite-Silva et al [22] reported that the formulation containing paraffin oil acts as a penetration enhancer for zinc oxide nanoparticles which, along with titanium dioxide nanoparticles, normally do not penetrate through the barrier of the stratum corneum [25,26,27,28]. …”

Titanium Dioxide in Sunscreen

“…In the past, both titanium dioxide and zinc oxide sunscreens were less preferred due to their chalky, white appearance on application. However, micronization of particles and more recently "nanoparticle" formulations have made TiO 2 sunscreens more popular in recent years [11]. Early studies comparing micronized versions of TiO 2 versus micronized versions of zinc oxide sunscreens concluded that micronized zinc oxide sunscreens were superior as they conferred better protection against longer wave UVA and had greater cosmetic outcomes [12].…”

Development and evaluation of sunscreen creams containing morin-encapsulated nanoparticles for enhanced UV radiation protection and antioxidant activity

“…TiO 2 was able to penetrate into the vacant hair follicles. 11,[17][18][19][20] Physical UV absorbers like titanium dioxide and zinc oxide have been considered as highly protective agents against UVR. ZnO and TiO 2 combinations are particularly valuable because of their ability to filter both UVA and UVB radiations, providing broader UVR protection than that observed with individual component.…”