The aim of this study was to evaluate the in vitro skin
phototoxicity of cosmetic formulations containing photounstable and photostable UV-filters and
vitamin A palmitate, assessed by two in vitro techniques: 3T3
Neutral Red Uptake
Phototoxicity Test and Human 3-D Skin Model In Vitro
Phototoxicity Test. For this, four different formulations containing
vitamin A palmitate and different UV-filters combinations, two of them considered photostable and two of them considered photounstable, were prepared. Solutions of each UV-filter and
vitamin under study and solutions of four different combinations under study were also prepared. The
phototoxicity was assessed in vitro by the 3T3 NRU
phototoxicity test (3T3-NRU-PT) and subsequently in a
phototoxicity test on reconstructed human skin model (H3D-PT).
Avobenzone presented a pronounced
phototoxicity and
vitamin A presented a tendency to a weak phototoxic potential. A synergistic effect of
vitamin A palmitate on the
phototoxicity of combinations containing
avobenzone was observed. H3D-PT results did not confirm the positive 3T3-NRU-PT results. However, despite the four formulations studied did not present any acute
phototoxicity potential, the combination 2 containing
octyl methoxycinnamate (OMC),
avobenzone (AVB) and 4-methylbenzilidene
camphor (MBC) presented an indication of
phototoxicity that should be better investigated in terms of the frequency of photoallergic or chronic
phototoxicity in humans, once these tests are scientifically validated only to detect phototoxic potential with the aim of preventing phototoxic reactions in the general population, and positive results cannot predict the exact incidence of phototoxic reactions in humans.