부산대학교 도서관

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1468-2494.2008.00443.x Byline: M. Vettor (*), P. Perugini (*), S. Scalia ([dagger]), B. Conti (*), I. Genta (*), T. Modena (*), F. Pavanetto (*) Keywords: nanoencapsulation; octylmethoxycinnamate; photostability; poly(d,l-lactide); sun protection factor; sunscreen Abstract: Synopsis The use of sunscreens is the 'gold standard' for protecting the skin from ultraviolet light. Octyl methoxycinnamate (OMC) is one of the most widely used UVB filter but it can act as a sensitizer or photoallergen. When exposed to sunlight, OMC can change from the primary trans-form to cis-form and the isomerization, not reversible, conducts to a reduction of the UVB filtering efficiency because the trans-form has a higher extinction coefficient. Photostability is the most important characteristic of effective sunscreens and it can be influenced by formulation ingredients and by applying technological strategies. In this work, photostability experiments, performed on emulsion-gels containing different percentages of OMC free or loaded in poly(d,l-lactide) nanoparticles, were carried out. The presence of a polymeric envelop may act to protect the active ingredient. In this study, the influence of poly(d,l-lactide) matrices on the photochemical stability of the sunscreen agent was investigated. As highlighted in this study, free OMC in different formulations has different photoisomerization degree. Moreover, a dissimilar behaviour was observed by studying different sunscreen concentrations in the same cosmetic formulation. Photostability results show a significant reduction in photoisomerization degree for formulations containing sunscreen loaded in nanoparticles, highlighting that the encapsulation is a suitable strategy to improve OMC photostability. Moreover, sun protection factor (SPF) results show that the UVB filter protective power is also maintained after encapsulation. Abstract (French) Resume L'emploie de filtres solaires est le 'gold standard' pour la protection solaire. L'Octyl methoxycinnamate (OMC) est un filtre UVB tres utilise mais il peut agir comme sensibilisant ou fotoallergene. Quand il est exposea la lumiere du soleil il peut changer de la forme primaire transa la forme cis et l'isomerization, pas reversible, mene a la reduction de la capacite filtrant UVB parce que la forme trans a un coefficient d'extinction molaire plus haut. La fotostabilite est une des caracteristiques plus importantes d'un produit solaire et elle peut etre influencee des ingredients des formulations ou bien en appliquant des strategies technologiques. Dans ce travail les experiences de fotostabilite ont ete menees sur des emulsion-gels contenants differents pourcentages d'OMC libre ou encapsule dans nanoparticules de poly(d,l-lactide). Les nanoparticules polimeriques ils peuvent defendre l'ingredient actif. Dans ce etude a eteevaluee l'influence de la matrice sur la stabilite photochimique du filtre solaire. Comme a ete souligne par ce etude l'OMC libre dans differentes formulations a differerentes degres de fotoisomerization. En outre un comportement diverge a ete observe pendant l'etude des differents pourcentages de filtre solaire dans la meme formulation cosmetique. Les resultats de fotostabilite montrent une riduction significative du degre de fotoisomerization pour les formulations contenant le filtre solaire encapsule dans nanoparticules. Ca souligne que l'incapsulation c'est une strategie efficace pour augmenter la fotostabilite de l'OMC. En outre les resultats du facteur de protection solaire (SPF) montrent que la capacite protectrice solaire du filtre UVB est maintenu meme apres de l'encapsulation. Author Affiliation: (*)Department of Pharmaceutical Chemistry, School of Pharmacy, University of Pavia, 27100 Pavia ([dagger])Department of Pharmaceutical Sciences, School of Pharmacy, University of Ferrara, 44100 Ferrara, Italy Article History: Received 22 November 2007, Accepted 27 February 2008 Article note: Dr Manuela Vettor, Department of Pharmaceutical Chemisty, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy. Tel.: +39 038 2987363 ; fax +39 038 2422975; e-mail: manuela.vettor@unipv.it