title: Influence of the photostabilizer in the photoprotective effects of a formulation containing UV-filters and vitamin A.
abstract: Vitamin A palmitate has been used in cosmetics; however, studies report that this substance shows photoreactivity that can lead to loss of safety and efficacy. On the other hand, photostabilizers have been used to increase sunscreen photostability and consequently their safety and effectiveness. Thus, this study aimed to evaluate the influence of photostabilizers on the photoprotective effects of a cosmetic formulation containing UV-filters and vitamin A palmitate. The formulation containing UV-filters was supplemented with vitamin A palmitate and the photostabilizers diethylhexyl 2,6-naphthalate (DEHN), bumetrizole and benzotriazolyl dodecyl p-cresol (BTDC). Hairless mice were treated daily by topical applications and irradiated (UVA/B). Erythema index, transepidermal water loss, histological/histometric analysis and number of sunburn cells (SBC) were evaluated. The results showed that all formulations protected from UV-induced enhancement of erythema and SBC but there was no difference among them. The formulation with no stabilizers reduced viable epidermis thickness due to atrophy induced by UV radiation. Thus, it can be concluded that the presence of photostabilizers influenced the effects of formulations containing UV-filters and vitamin A palmitate, which could be seen by histological and histometric analysis. Furthermore, the formulations containing the stabilizers DEHN and BTDC showed better protective effects on hairless mice skin.
authors.affiliation: Faculdade de Ciências Farmacêuticas de Ribeirão Preto-Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Carolina Gomes
authors.initials: CG
authors.lastname: Benevenuto
authors.forename: Miguel A Sala
authors.initials: MA
authors.lastname: Di Matteo
authors.forename: Patrícia M B G
authors.initials: PM
authors.lastname: Maia Campos
authors.forename: Lorena Rigo
authors.initials: LR
authors.lastname: Gaspar
mesh_terms: D000287:Administration, Topical; D000818:Animals; D002626:Chemistry, Pharmaceutical; D003358:Cosmetics / Q000008:administration & dosage; D004224:Diterpenes; D005079:Excipients / Q000008:administration & dosage; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D000084562:Retinyl Esters; D012867:Skin / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects; D013473:Sunscreening Agents / Q000008:administration & dosage*; D014466:Ultraviolet Rays / Q000009:adverse effects; D014801:Vitamin A / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D003358:Cosmetics; D004224:Diterpenes; D005079:Excipients; D000084562:Retinyl Esters; D013473:Sunscreening Agents; D014801:Vitamin A; C014794:retinol palmitate