title: Effect of the product type, of the amount of applied sunscreen product and the level of protection in the UVB range on the level of protection achieved in the UVA range.
abstract: Using a topical product is part of the overall strategy for skin cancer prevention. The level of protection attainable when using commercial products is indicated by the Sun Protection Factor (SPF) value, in use everywhere. This value reflects the level of protection primarily in the UVB range. However, UVA radiation also has deleterious effects on the skin, and it is essential to prevent it, which is why products must offer a wide spectrum of protection. Tests conducted in vivo, before any marketing, are done by applying the studied product at a rate of 2.0 mg cm(-2), while users, in practice, only use 1.0-1.5 mg cm(-2). We now know that this reduction in the amount of applied product greatly affects the SPF. To complete the state of knowledge in this area, we sought to evaluate the effect of a decrease in the amount of applied sunscreen product by studying sunscreen creams and oils on the level of protection attainable in the UVA range. We have shown that the PF-UVA is divided by a factor of 2.2, on average, when the amount of applied product is reduced by half, with differences depending on the product type under consideration (cream or oil) and depending on the SPF of the preparation.
authors.affiliation: Université de Nantes, Nantes Atlantique Universités, LPiC, MMS, EA2160, Faculty of Pharmacy, 9 rue Bias, F-44000 Nantes, France.
authors.forename: C
authors.initials: C
authors.lastname: Couteau
authors.affiliation: Institut de Mécanique et d'Ingénierie (Institute of Mechanics and Engineering) I2 M, CNRS (Centre national de la recherche scientifique [National Center for Scientific Research]), UMR (Unité Mixte de Recherche [Mixed Research Unit]) 5295, Université de Bordeaux (University of Bordeaux), 146 rue Léo Saignat (case 15), Laboratoire de pharmacie galénique et biopharmacie (Pharmaceutics and Biopharma Laboratory), Bâtiment pharmacie 1ère tranche, 3ème étage, F-33076 Bordeaux Cedex, France; Université Paris Sud, 5 rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France.
authors.forename: H
authors.initials: H
authors.lastname: Diarra
authors.affiliation: Université de Nantes, Nantes Atlantique Universités, LPiC, MMS, EA2160, Faculty of Pharmacy, 9 rue Bias, F-44000 Nantes, France. Electronic address: laurence.coiffard@univ-nantes.fr.
authors.forename: L
authors.initials: L
authors.lastname: Coiffard
mesh_terms: D004305:Dose-Response Relationship, Drug; D004655:Emulsions; D009821:Oils; D059405:Sun Protection Factor; D013473:Sunscreening Agents / Q000008:administration & dosage; D014466:Ultraviolet Rays
chemical_list: D004655:Emulsions; D009821:Oils; D013473:Sunscreening Agents
keywords: Amount of product; Creams; Oil; Protection factor UVA (PF-UVA); Sunscreens