Time filter

Source Type

Schenefeld, Germany

Rohr M.,Schrader | Klette E.,Symrise GmbH and Co. KG | Ruppert S.,Symrise GmbH and Co. KG | Bimzcok R.,Mann and Schroder GmbH | And 16 more authors.
Skin Pharmacology and Physiology | Year: 2010

In the past, several attempts have been made to develop in vitro methods for determining protection against UV radiation. To date however, there is no broadly accepted method. Various known and unknown parameters influence the transmission measurements of scattering films, such as the multifaceted compositions of sunscreens, the technical limitations of measurement devices as well as the difficulty to apply very thin films of sunscreen in a reproducible manner throughout different laboratories. In vitro data were measured in this multicenter study to compare possible methodologies and strategies for an in vitro approach to the sun protection factor (SPF). This publication will not present a final in vitro SPF test method, but it will point out which technical side effects may influence such a method. Influential factors such as the quality of spectrophotometer used, the amount of product applied, pretreatment of samples, time and temperature of equilibration, size of the measured surface, the application process or the calculation on the basis of standardized data are presented and discussed. Finally, a reduction of the standard deviations within single laboratories could be realized for in vitro SPF testing, but no improvement of the interlaboratory comparison was obtained. The development of a valid and reliable SPF in vitro test still remains a challenge, and further work is necessary to develop a satisfactory method. © 2010 S. Karger AG, Basel. Source

Mehling A.,Cognis GmbH | Chkarnat C.,Cosmital SA | Degwert J.,SIT Skin Investigation and Technology Hamburg GmbH | Ennen J.,Beiersdorf AG | And 8 more authors.
Contact Dermatitis | Year: 2010

Background: Development of cosmetic products and household detergents necessitates comparative study designs to assess the skin tolerance of products. In initial tests, the epicutaneous patch test for irritation is widely used. Objectives: This study was conducted to develop a protocol that would facilitate a comparison of results obtained when tests are conducted by different laboratories. Methods: 'In-house' and standardized patch test protocols were used to assess irritation potentials of surfactant-based products in intra- and interlaboratory studies using defined surfactant samples. Results: The various in-house protocols tested did not consistently produce equivalent results. In order to develop a study design that yields comparable results, various factors were identified and adjusted. The standardized study protocol includes occlusive application of 70 μl of the test substance to the back of 30 subjects, defined reading times and schemes, assessments based mainly on erythema, and inclusion of sodium laureth sulfate and sodium dodecyl sulfate as positive controls as well as water as a negative control. Conclusions: Use of the standardized protocol and training of assessors improved the reliability and consistency of results whereby the irritation potentials of the references and test samples were ranked similarly by the laboratories. © 2010 John Wiley & Sons A/S. Source

Daehnhardt-Pfeiffer S.,Microscopy Services Daehnhardt GmbH | Surber C.,Spirig Pharma AG | Surber C.,Dermatologische Universitatsklinik | Wilhelm K.-P.,ProDERM GmbH | And 4 more authors.
Skin Pharmacology and Physiology | Year: 2012

Introduction: Therapy of atopic dermatitis encloses use of medicated and nonmedicated preparations. Results of clinical and biophysical procedures indirectly describe the condition of the impaired skin barrier (SB). Direct evaluation of SB integrity is only possible by electron microscopical visualization, e.g. intercellular lipid lamellae (ICLL) organization of the stratum corneum. Method: SB integrity was measured by morphometric analysis of ICLL in healthy and atopic skin and after a 15-day treatment (plus 7-day follow-up) of atopic skin with a glycerin preparation. Results: Significant treatment effect was shown by the restoration of the ICLL. Conclusions: The study reveals that morphometric analysis of ICLL organization is suitable to differentiate between healthy and diseased skin and to semiquantitatively determine the effect of a nonmedicated glycerin formulation. Limitation: Small treatment cohort. Copyright © 2012 S. Karger AG, Basel. Source

Heise R.,RWTH Aachen | Skazik C.,RWTH Aachen | Marquardt Y.,RWTH Aachen | Czaja K.,RWTH Aachen | And 8 more authors.
Skin Pharmacology and Physiology | Year: 2012

Topical application of dexpanthenol is widely used in clinical practice for the improvement of wound healing. Previous in vitro experiments identified a stimulatory effect of pantothenate on migration, proliferation and gene regulation in cultured human dermal fibroblasts. To correlate these in vitro findings with the more complex in vivo situation of wound healing, a clinical trial was performed in which the dexpanthenol-induced gene expression profile in punch biopsies of previously injured and dexpanthenol-treated skin in comparison to placebo-treated skin was analyzed at the molecular level by Affymetrix® GeneChip analysis. Upregulation of IL-6, IL-1β, CYP1B1, CXCL1, CCL18 and KAP 4-2 gene expression and downregulation of psorasin mRNA and protein expression were identified in samples treated topically with dexpanthenol. This in vivo study might provide new insight into the molecular mechanisms responsible for the effect of dexpanthenol in wound healing and shows strong correlations to previous in vitro data using cultured dermal fibroblasts. Copyright © 2012 S. Karger AG, Basel. Source

Discover hidden collaborations