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-NRUPT)
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.