A pilot study on the percutaneous absorption of microfine titanium dioxide from sunscreens

Abstract

Many Australians are being advised to apply microfine titanium dioxide sunscreen daily from the cradle to the grave. However, there is a surprising lack of data on the percutaneous absorption of microfine titanium dioxide. A prospective pilot study was conducted to analyse the percutaneous absorption of microfine titanium dioxide from sunscreens. Selected patients scheduled to have skin surgery, applied titanium dioxide sunscreen to the skin daily for 2-6 weeks prior to their operation. After excision, the stratum corneum of the sample was stripped and the titanium concentration of the remaining epidermis and dermis was measured by inductively coupled plasma-mass spectrometry. The results from this pilot study showed that levels of titanium in the epidermis and dermis of subjects who applied microfine titanium dioxide to their skin were higher than the levels of titanium found in controls. Studies with larger cohorts are necessary to establish if this absorption is statistically significant.

Rhetorical gamesmanship in the nano debates over sunscreens and nanoparticles

“…They admit that it may be a function of a ''secondary phenomenon due to contaminants deposited with the titanium dioxide'' (352). Tan et al (1996) is discussed above.…”

“…PLEASE NOTE (emphasis was Tinkle's)-we used FITC-labeled polystyrene spheres and not metal oxide particles. We did not use, nor make any conclusions about, uptake and massage, other than to cite the Tan et al (1996) article that applied TiO 2 topically to the skin. This was used as background and context only'' (2007).…”

“…This was used as background and context only'' (2007). Tan et al (1996) studied human skin excised from 13 patients. Tan reported in results: ''There was no correlation between the duration of sunscreen application and the concentration of titanium in the samples, and no relationship between the site of sunscreen application and concentration of titanium in the samples'' (186).…”

“…Third, the authors indicate absorption of TiO 2 has yet to be adequately demonstrated (7). Generally, the exposure issue is tabled in the text by referencing Dupre et al (1985), Moran et al (1991) and Tan et al (1996). Dupre et al (1985) studied a single patient with a penile pigmentation allegedly caused by an ointment called Parkipan containing titanium dioxide.…”

Toxicity Associated with the Photo Catalytic and Photo Stable Forms of Titanium Dioxide Nanoparticles Used in Sunscreen lotion

“…3,[195][196][197][198][199][200] Skin exposure to nano particle-containing sunscreens leads to incorporation of TiO 2 and ZnO in the stratum corneum, which may alter certain properties due to particle-particle, particle-skin, and skin-particle-light physicochemical interactions. 195 Overall, the weight of scientific evidence suggests that insoluble nanoparticles used in sunscreens pose no or negligible risk to human health 196,197,[201][202][203][204][205][206][207][208][209][210] however there are some discrepancies in the results probably related to differences in techniques and methods, laboratory conditions, and the absence of standardized evaluation protocols.The reason for these results is unclear based on the observation that most other nano particle types (polymers, metals and carbon nano tubes) permeate the skin. The answer may be that it is possible that the particle agglomeration, 211,212 when combined with the particles' intrinsic hydrophobicity, allows particles to become trapped in the lipid lamella and remain until desquamation or sebaceous secretion removes them from follicles.…”