title: Semisolid formulation containing a nanoencapsulated sunscreen: effectiveness, in vitro photostability and immune response.
abstract: The objective of this work was to verify if hydrophilic gels containing benzophenone-3 loaded nanocapsules (HG-NCBZ3) could improve the sunscreen in vitro effectiveness against UVA radiation and its photostability compared to a conventional hydrogel containing the free sunscreen (HG-BZ3). In parallel, the immune response of the nanostructured system was evaluated by mouse ear swelling test and the local lymph node assay. The nanocapsules were prepared by interfacial deposition of poly(epsilon-caprolactone) and characterized in terms of particle size, polydispersity index, zeta potential, drug content and encapsulation efficiency. HG-NCBZ3 UV scans showed higher absorption intensity values than HG-NCplacebo, prepared using unloaded nanocapsules. Films of the gels were irradiated with UVA light and the BZ3 recovery was evaluated by HPLC. BZ3 recovery decreased from 100% to 29% for HG-BZ3 and to 56% for HG-NCBZ3 after 13 h. After wavelength scans within 13 h, the relative areas under the curves (AUC) decreased from 1.00 to 0.62 for HG-BZ3 and remained constant for HG-NCBZ3. Sensitization assay showed that stimulation indexes lower than 3 for all the hydrogel samples. Formulations did not induce increases higher than 10% in ear swelling, indicating that the hydrogels did not cause cutaneous sensitization in mice. The nanoencapsulation improved both the photostability and the effectiveness of BZ3 compared to the non-encapsulated sunscreen and the topical application of free and nanoencapsulated BZ3 did not produce significant allergy response in mice.
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga 2752, Porto Alegre, 90610-000, RS, Brazil.
authors.forename: Karina
authors.initials: K
authors.lastname: Paese
authors.forename: Alessandro
authors.initials: A
authors.lastname: Jäger
authors.forename: Fernanda S
authors.initials: FS
authors.lastname: Poletto
authors.forename: Eduardo Fonseca
authors.initials: EF
authors.lastname: Pinto
authors.forename: Bartira
authors.initials: B
authors.lastname: Rossi-Bergmann
authors.forename: Adriana R
authors.initials: AR
authors.lastname: Pohlmann
authors.forename: Sílvia S
authors.initials: SS
authors.lastname: Guterres
mesh_terms: D000818:Animals; D004337:Drug Carriers / Q000009:adverse effects / Q000737:chemistry* / Q000528:radiation effects; D003875:Drug Eruptions / Q000175:diagnosis / Q000276:immunology*; D008027:Light; D008422:Materials Testing; D051379:Mice; D049329:Nanostructures / Q000009:adverse effects / Q000737:chemistry* / Q000528:radiation effects; D011208:Powders; D013473:Sunscreening Agents / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D004337:Drug Carriers; D011208:Powders; D013473:Sunscreening Agents