VITAMIN A AND LIPOIC ACID STABILITY 415 (2) A. Segall, M. Sosa, A. Alami, C. Enero, F. Hormaechea, M. T. Pizzorno, C. Bregni, and R. Serrao, Stabil- ity study of lipoic acid in the presence of vitamins A and E in O/W emulsions for cosmetic application, J. Cosmet. Sci., 55, 449–461 (2004). (3) M. E. Carlotti, V. Rossatto, M. Gallarate, M. Trotta, and F. Debernardi, Vitamin A palmitate photosta- bility and stability over time, J. Cosmet. Sci., 55, 233–252 (2004). (4) M. E. Carlotti, V. Rossatto, and M. Gallarate, Vitamin A and vitamin A palmitate stability over time and under UVA and UVB radiation, Int. J. Cosmet. Sci., 240, 85–94 (2002). (5) V. Jenning, M. Schäfer-Korting, and S. Gohla, Vitamin A-loaded solid lipid nanoparticles for topical use: Drug release properties, J. Controlled Release, 66, 115–126 (2000). (6) A. Akhavan and J. Levitt, Assessing retinol stability in a hydroquinone 4%, retinol 0.3% cream in the presence of antoxidants and sunscreen under simulated-use conditions: A pilot study, Clin. Ther., 30, 543–547 (2008). (7) L. R. Gaspar and P. M. B. G. Maia Campos, Photostability and effi cacy studies of topical formulations containing UV-fi lters combination and Vitamins A, C and E, Int. J. Pharm., 343, 181–189 (2007). (8) Q. Xia, J. J. Yin, S. H. Cherng, W. G. Wamer, M. Boudreau, P. C. Howard, and P. P. Fu, UVA photo- irradiation of retinyl palmitate: Formation of singlet oxygen and superoxide, and their role in induction of lipid peroxidation, Toxicol. Lett., 163, 30–43 (2006). (9) T. Guaratini, M. D. Gianeti, and P. M. B. G. Maia Campos, Stability of cosmetic formulations contain- ing esters of vitamin E and A: Chemical and physical aspects, Int. J. Pharm., 327, 12–16 (2006). (10) S. H. Cherng, Q. Xia, L. R. Blakenship, J. P. Freeman, W. G. Wamer, P. C. Howard, and P. P. Fu, Pho- todecomposition of retinyl palmitate in ethanol by UV light, formation of photodecomposition prod- ucts, reactive oxygen species, and lipid peroxides, Chem. Res. Toxicol., 18, 129–138 (2005). (11) R. Gatti, M. G. Gioia, and V. Cavrini, Analysis and stability study of retonoids in pharmaceuticals by LC with fl uorescence detection, J. Pharm. Biomed. Anal., 23, 147–159 (2000). (12) A. K. Singh and J. Das, Liposome encapsulated vitamin A compounds exhibit greater stability and di- minished toxicity, Biophys. Chem., 73, 155–162 (1998). (13) L. Halbaut, C. Barbé, M. Aróztegui, and C. de la Torre, Oxidative stability of semi-solid excipient mix- tures with corn oil and its implication in the degradation of vitamin A, Int. J. Pharm., 147, 31–40 (1997). (14) M. A. Moyano and A. I. Segall, Stability of vitamin C derivatives in topical formulations containing lipoic acid, vitamins A and E, Int. J. Cosmet. Sci., 30, 453–458 (2008). (15) M. A. Moyano, A. M. Broussalis, and A. I. Segall, Thermal analysis of lipoic acid and evaluation of the compatibility with excipients, J. Therm. Anal. Calorimetry, 99(2), 631–637 (2010). (16) M. A. Moyano and A. I. Segall, Estudios de estabilidad de nuevas formulaciones y en diversos envases conteniendo vitaminas A, E y ácido lipoico, Ciencia Cosmética, 2, 19–23 (2009). (17) M. E. Calotti, E. Ugazio, S. Sapino, E. Peira, and M. Gallarate, Photodegradation of retinol and anti- aging effectiveness of two comercial emulsions, J. Cosmet. Sci., 57, 261–277 (2006). (18) Cosméticos, Guía de Estabilidad de Productos Cosméticos, Editora Agencia Nacional de Vigilancia Sanitaria (ANVISA, 2005), Vol 1, pp. 17. (19) The United States Pharmacopeia, 32th ed. (U.S. Pharmacopeial Convention, Rockville, MD, 2009).