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Importance of substrate roughness for in-vitro sun protection assessment / Louis Ferrero in IFSCC MAGAZINE, Vol. 9, N° 2 (04-05-06/2006)
[article]
Titre : Importance of substrate roughness for in-vitro sun protection assessment Type de document : texte imprimé Auteurs : Louis Ferrero, Auteur ; Marc Pissavini, Auteur ; Adeline Dehais, Auteur ; Stephanie Marguerie, Auteur ; Leonhard Zastrow, Auteur Année de publication : 2006 Article en page(s) : p. 97-108 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Sunscreen testing' 'In vitro SPF' 'UVA protection' 'Surface roughness' microtopography' 'Irregularfilm geometry' 'UV filters' Index. décimale : 668.5 Parfums et cosmétiques Résumé : The purpose of this study is to demonstrate the influence of plate roughness on well-known absolute or relative UV
spectroscopic indices such as the in vitro SPF, in vitro UVA PF (PPD), UVA/UVB ratio, critical wavelength and SPF/UVA
PF (PPD) ratio. First a roughness index was measured by non-contact surface topography analysis on different
PMMA plates which are available today on the European market. A large difference between maximum and minimum
plate roughness values could be measured ranging from 1.88 μm to 6.76 μm. Then the PMMA plates were grouped
into five different roughness classes. To measure the different spectroscopic indices, the same sunscreen preparation
was applied at the same amount rate (1 mg cm-2) to each of the selected plates. Large differences were noted for
the absolute in vitro indices SPF and UVA PF (PPD), with the SPF varying in one instance from 13.5 to 40.7. On the other
hand, the relative absorbance indices UVA/UVB ratio and critical wavelength showed a small but significant variation
in relation to roughness. The SPF/UVA PF (PPD) ratio index based on direct in vitro values was found to be very
sensitive to roughness variation. However, adjusting the UV absorbance curve to reach equality between the in vitro
SPF and in vivo SPF is a recognized and efficient mathematical process to limit the variation.
All these results can be interpreted using the irregular sunscreen film theory. Mathematical developments can be
achieved by modeling the height distribution with a gamma function.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10847
in IFSCC MAGAZINE > Vol. 9, N° 2 (04-05-06/2006) . - p. 97-108[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 008185 - Périodique Bibliothèque principale Documentaires Disponible A national web-based survey of sunscreen products as a tool for industry self-regulation, consumer awareness campaigns and marketing / Beverley Summers in IFSCC MAGAZINE, Vol. 8, N° 3 (07-08-09/2005)
[article]
Titre : A national web-based survey of sunscreen products as a tool for industry self-regulation, consumer awareness campaigns and marketing Type de document : texte imprimé Auteurs : Beverley Summers, Auteur ; Rob S. Summers, Auteur ; Esme Muller, Auteur Année de publication : 2005 Article en page(s) : p. 201-204 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Produits antisolaires Tags : 'Produits de protection solaire' 'Protection anti UV' 'Test SPF' Index. décimale : 668.5 Parfums et cosmétiques Résumé : The objective of the work was to test a web-based tool in the collection and presentation of data for our regular sunscreen surveys and to develop, test and conduct a web-based survey of sunscreen products, with instant data reporting. After the Photobiology Laboratory at MEDUNSA was approached by SurveyIT to pilot a new web-based data collection and reporting tool, companies were contacted via e-mail and invited to visit a secure web-based site to complete the provided questionnaire. Data collection and processing were greatly simplified by the new approach. The survey gleaned responses from 18 companies on 31 brands with a total of 110 primary sunscreen products. The data revealed a reduction in the number of companies marketing sunscreens in South Africa compared with the previous year, despite an increase in the volume of sunscreen sales. Ninety-eight percent of the products were claimed to be in vivo SPF tested. Fifty-seven percent of the products had undergone in vitro SPF testing for determination of their UVA protection. Fifty-one percent of the products were claimed to be water-resistant. Octyl methoxycinnamate was the most popular UV filter (88% of products), followed by benzophenone-3 (60%). Butyl methoxydibenzoylmethane was in 52% of the products and surprisingly only 29% of the products contained titanium dioxide. The major conclusions are that the data collection tool was a success and that sunscreens are becoming more widely used and more thoroughly tested in South Africa. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10546
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Code-barres Cote Support Localisation Section Disponibilité 003888 - Périodique Bibliothèque principale Documentaires Disponible Membrane structured solid nanoparticles – A novel nanotechnology for delivery of cosmetic active ingredients / Gerd H. Dahms in IFSCC MAGAZINE, Vol. 8, N° 3 (07-08-09/2005)
[article]
Titre : Membrane structured solid nanoparticles – A novel nanotechnology for delivery of cosmetic active ingredients Type de document : texte imprimé Auteurs : Gerd H. Dahms, Auteur Année de publication : 2005 Article en page(s) : p. 193-198 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biomolécules actives
Cosmétiques
Nanoparticules
Nanotechnologie
Vitamine ETags : 'Nanoparticules solides' 'Membrane structurée par des nanoparticules' 'Pénétration du tocophérol' Nanocarrière 'Fabrication continue' 'Amplification de SPF' Index. décimale : 668.5 Parfums et cosmétiques Résumé : Lipid nanoparticles have a structure similar to that of nanoemulsions. Their size ranges typically from 50 to 1000 nm. They differ from nanoemulsions in that the lipid core is a solid. The matrix consists of solid lipids or mixtures of lipids. Over the past years it has been demonstrated that solid lipid nanoparticles appear to be a promising drug carrier system for the future. Their occlusion properties reduce transepidermal water loss and can enhance penetration of active ingredients through the stratum corneum. As with all new technologies, some problems with the solid lipid nanoparticle technology need to be solved. One major problem is the homogeneous incorporation of amphiphilic active ingredients into the crystal matrix of the nanoparticles. Actives with an amphiphilic character like tocopherol or retinol cannot be kept homogeneously distributed in the wax structure during the emulsification process. Due to their hydrophilic head group they accumulate at the exterior layer of the nanoparticles together with the surfactant system used. Consequently, homogeneous release over time is not guaranteed and a burst release has to be expected. A second disadvantage is the manufacturing process. Solid lipid nanoparticles can be produced only under high pressure conditions. Also the concentration of the solid particles in the dispersion, which is added to an emulsion, is quite low. To overcome these problems membrane structured solid nanoparticles (MSSN) have been developed. These MSSN systems consist of liquid crystalline membrane systems with extremely low surfactant concentrations. The lateral movement of actives is controlled by amphiphilic solid actives such as ceramides and solid emollients. This guarantees maintenance of the advantageous properties of solid lipid nanoparticles such as retarded release of actives and their protection against chemical decomposition, but it also allows the homogeneous incorporation of amphiphilic actives. Membrane structured solid nanoparticles are produced using a continuous three-phase emulsification technique. This allows protection of heat-sensitive actives against decomposition. The concentration of nanoparticles in the MSSN dispersion can be kept higher than 60% (w/w). Even at these concentrations the nanodispersions keep their flow properties. As a result, they can be easily incorporated into the final formulation. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10494
in IFSCC MAGAZINE > Vol. 8, N° 3 (07-08-09/2005) . - p. 193-198[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 003888 - Périodique Bibliothèque principale Documentaires Disponible