Ascorbic Acid for the safe use of a sunscreen agent: accumulation of nano zinc oxide and titanium dioxide on the skin.
Physical 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.



The 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.



Results 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.
Department of Pharmacy, National University of Singapore, Block S4, level 2, Science Drive 4, 117543, Singapore. ; Department of Medicine, Urmia University of Medical Sciences, Urmia, 5756115111, Iran.
Anahita
A
Fathi-Azarbayjani
Department of Pharmacy, National University of Singapore, Block S4, level 2, Science Drive 4, 117543, Singapore.
Poh Leng
PL
Tan
Department of Anesthesiology, Singapore General Hospital, 169608, Singapore.
Yew Ying
YY
Chan
Department of Pharmacy, National University of Singapore, Block S4, level 2, Science Drive 4, 117543, Singapore.
Sui Yung
SY
Chan
Ascorbic acid; Penetration enhancer; Skin permeation; Titanium dioxide; Zinc oxide