395 SKIN PERMEATION OF HAZARDOUS COMPOUNDS and C, respectively. This difference in the composition of polymers provided significant differences in antipollution effectiveness against organic compounds, being cosmetics B and C, those with higher antipollution effect. Moreover, the percentage of silicones used in the formula, mainly as dimethicone, was also different for the evaluated cosmetics, with concentration values of 3.0%, 6.8%, and 2.0% (w/w) in antipollution cosmetics A, B, and C, respectively. Polydimethylsiloxane has been previously used as synthetic skin simulant in dermal absorption experiments (25), being demonstrated that increasing the width of the polydimethylsiloxane layer decreases flux and increases lag time of organic compounds through the skin. Thus, dimethicone could be responsible of the increase of the antipollution effect at long exposition times. The addition of high-molecular-weight polysaccharides, such as xanthan gum, an anti- pollution active principle with demonstrated effects against the adsorption of organic compounds [4], also increases antipollution effectiveness, even at very low concentration. Xanthan gum concentration of cosmetic C was 0.014% (w/w), while for cosmetics A and B was 0.0005% and 0.0025% (w/w), respectively. Moreover, the presence of mineral particles in antipollution cosmetics, such as talc or silicates, adsorbs organic compounds in its surface (34,35) and, thus, it may improve the antipollution efficiency of cosmetic products. Percentage of fillers such as talc, silica, and silicates in antipollution cosmetic C was higher than that of A and B, which could also explain the increased efficiency of this product compared to A. In summary, the high antipollution effect of cosmetic B and C probably should be assigned to synergic effects of polymeric and surfactants, silicones, xanthan gum, and mineral particles, being the combination of all the aforementioned aspects the responsi- ble of an efficient antipollution effect of cosmetic products B and C. Previous in vivo studies, in which a method was developed to demonstrate the effect of antipollution cosmetic products against pollution generated by cigarette smoke included lipid peroxidation in human volunteers (36). The skin of the back of human volunteers is treated with the product under test, exposed to smoke, and then peroxidation of human sebum is assessed. Results confirmed that lipid peroxidation induced in human skin by cigarette smoke could be inhibited by topical antioxidants. Other in vivo and in vitro studies (37) demonstrated that the application of a face cream formulation containing a film-form- ing exopolysaccharide prior to exposure to carbon particles significantly decreased particle adherence to skin in human subjects. Moreover, Unilever has recently found that the three main types of film formers, polysaccharide-, acrylate-, and resin-based, enhanced efficacy of cosmetics in preventing lipoperoxidation-based damage to the skin (38). CONCLUSIONS A versatile and adaptable analytical methodology has been developed to evaluate the der- mal permeation of tobacco-smoke hazardous compounds from contaminated air. Perme- ation experiments were carried out inside a specifically developed exposition chamber to obtain a representative concentration of tobacco-smoke pollutants. A machine was devel- oped to simultaneously smoke three cigarettes, where inhaled smoke was reintroduced in the chamber. The designed manifold allowed to operate at finite and infinite conditions, with the single combustion of three cigarettes for a short-time exposition (around 40 min) and the combustion of three cigarettes every 30 min for long-time exposition (8 h), respectively.

396 JOURNAL OF COSMETIC SCIENCE Permeation of tobacco-smoke pollutants was monitored by control experiment using Franz cells and Strat-M® membranes, being nicotine the major pollutant present in both, Strat-M® membrane and receptor solution, with concentrations of 2.5 µg cm−2 and 11.6 µg L−1 after a 30-min exposition, respectively. In the case of infinite exposi- tion, nicotine concentration significantly increased to 50 µg cm−2 in Strat-M® mem- branes and 1,500 µg L−1 in the receptor solution, after 8 h exposure. The effect of three antipollution cosmetics was demonstrated using the developed conditions, decreasing the permeation of BTEX, styrene, p-Cymene, limonene, and nicotine for exposures of 1 and 2 h. In the case of longer exposure (till 8 h), antipollution effects of the evaluated cosmetics were insignificant, due to a saturation of cosmetic layer over the skin simu- lant. Thus, antipollution cosmetics should be re-applied from time to time to provide a lasting effect. ACKNOWLEDGMENTS We acknowledge the financial support obtained from RNB for the project ­ “Desarrollo de nuevos cosméticos antipolución, urbancream “under the Centro para el Desarrollo Tecno­ lógico Industrial (CDTI) funding project program (CPI-19-027) and that obtained from the Ministerio de Ciencia, Innovación y ­ Universidades, Spain (PID2019-110788GB-I00). CONFLICT OF INTEREST The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. REFERENCES (1) International Agency for Research on Cancer, World Health Organization, United Nations, Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans: Tobacco smoke and ­ involuntary smoking, International Agency for Research on Cancer, Lyon (2004). ISBN 92 832 1283 5. (2) S. K. Das, Harmful health effects of cigarette smoking, Mol. Cell. Biochem., 253, 159–165 (2003). (3) E. Randerath, D. Mittal, and K. Randerath, Tissue distribution of covalent DNA damage in mice treated dermally with cigarette “tar”: Preference for lung and heart DNA, Carcinogenesis, 9, 75–80 (1988). (4) W. A. Pryor, M. Tamura, and D. F. Church, ESR spin trapping study of the radicals produced in NOx/ olefin reactions: A mechanism for the production of the apparently long-lived radicals in AS phase cig- arette smoke, J. Am. Chem. Soc., 106, 5073–5079 (1984). (5) D. Bernhard, C. Moser, A. Backovic, and G. Wick, Cigarette smoke- an aging accelerator?, Exp. Geron- tol., 42(3), 160–165 (2007). (6) D. P. Kadunce, R. Gress, R. Kanner, J. L. Lyone, and J. Zone, Cigarette smoking: risk factor for prema- ture facial wrinkling, Ann. Intern. Med., 114(10), 840–844 (1991). (7) R. A. Norman and M. Rappaport, Smoking, Obesity/Nutrition, Sun, and the Skin. in Preventive Derma- tology, R. A. Norman. Ed. (Springer, London), pp. 17–20(2010). DOI: 10.1007/978-1-84996-021-2_2 (8) D. N. Doshi, K. K. Hanneman, and K. D. Cooper, Smoking and skin aging in identical twins, Arch. Dermatol., 143(12), 1543–1546 (2007). (9) J. S. Koh, H. Kang, S. W. Choi, and H. O. Kim, Cigarette smoking associated with premature facial wrinkling: image analysis of facial skin replicas, Int. J. Dermatol., 41(1), 21–27 (2002).