TiO2 is generally considered an inert and safe pharmaceutical and cosmetic excipient.
Some uncoated (rutile, anatase and a commercial mixture of the two phases) and some coated samples (organic coated, SiO2 coated and a mixed coating), used in topical formulations, did not penetrate into the viable skin layers. However, uncoated TiO2 was found attached to the uppermost layer of the skin (stratum corneum, SC).
In a recent research it was found that TiO2 caused a decrease of SC lipid transition enthalpies, when applied on the most superficial layer of the skin, with uncoated ones inducing a higher effect. On the SC, uncoated nanosized TiO2 affects lipids and proteins causing an increase in SC disorder, thus altering skin permeation of drugs, topically applied.
The project concerns the study of the physico-chemical characteristics of the drugs in respect of which the titanium dioxide produce a high fluxes, exerting its penetration enhancer effect. The study aims to assess what characteristics (lipophilicity, molecular weight, degree of ionization) have greater influence on the properties of TiO2.