Publications by authors named "Klaus-Peter Wilhelm"

23 Publications

  • Page 1 of 1

New methods for assessing secondary performance attributes of sunscreens suitable for professional outdoor work.

J Occup Med Toxicol 2021 Jul 5;16(1):25. Epub 2021 Jul 5.

Institute for Health Research and Education, Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück, Am Finkenhügel 7a, 49076, Osnabrück, Germany.

Background: Outdoor workers (OW) are highly exposed to solar ultraviolet radiation (UVR) and thus at increased risk for developing skin cancer. An essential part of an overall strategy to reduce workplace UVR-exposure to OW's skin is the usage of sunscreens. However, compliance with regular sunscreen usage seems to be low, as products are usually designed for recreational sun exposure and thus do not meet the requirements of physically active OW. To date, no standardized test procedures assess the suitability of sunscreens for professional use. The aim of this pilot study was to develop standardized methods of testing secondary performance attributes (PA) to represent real-life working conditions of outdoor work.

Methods: Ten sunscreen products, carefully selected after a detailed market survey of all relevant producers available on the German market, were evaluated regarding their suitability for professional outdoor work on 24 healthy volunteers in a newly designed test procedure. In addition to three standardized efficacy characteristics, i.e., sun protection factor, water-resistance, and UVA protection, we evaluated each PA involving parameters typically associated with outdoor workplaces.

Results: We developed standardized methods for objectifying the suitability of sunscreen products for professional outdoor work. The test procedures used are well feasible and appropriate for testing the PA because they represent practical working conditions in detail - although the degree of discriminability of single test methods varied. The claimed sun protection factor (SPF) of the products was confirmed; bio-stability of the SPF after physical activity was achieved in most cases. While most products hardly irritate the eyes and are quickly absorbed, the evaluation of the subjective skin feeling and non-slip grip is inconsistent.

Conclusions: In this pilot study, for the first time secondary PA are defined and examined. Although further objectification of the PA assessment as well as the establishment of minimum standards should be sought, the new methods could already complement the so far mandatory labels and in this way provide a significant impetus for the current scientific and political focus on the improvement of occupational health in highly UVR-exposed OW.
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http://dx.doi.org/10.1186/s12995-021-00314-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8256554PMC
July 2021

Anti-pollution effects of two antioxidants and a chelator-Ex vivo electron spin resonance and in vivo cigarette smoke model assessments in human skin.

Skin Res Technol 2021 Jun 10. Epub 2021 Jun 10.

proDERM Institute for Applied Dermatological Research, Hamburg, Germany.

Background: Skin damage arising from pollutants in gaseous and particulate matter forms is mainly mediated by oxidative stress. The pollutants directly or indirectly generate free radicals on and in the skin, leading, for example, to MMP up-regulation and damage of collagen fibers. Antioxidants and chelators are used in anti-pollution cosmetics to reduce the harmful effects of free radical generation.

Materials And Methods: We investigated the efficacy of two antioxidants and one chelator in an anti-pollution cigarette smoke model. Free radical generation was measured directly after UV and cigarette smoke exposure ex vivo on pig skin (slaughterhouse waste), by use of Electron Spin Resonance (ESR). Effects of cigarette smoke were compared to those of Urban Dust (NIST-standard). ESR was also used to measure the copper chelation activity of the test products. Following cigarette smoke application in vivo, two markers of lipid peroxidation malondialdehyde (MDA), and squalene monohydroperoxide (SQOOH), were measured from swab solutions taken from the smoke-exposed skin sites.

Results: EDTA generated no effect and the non-chelator antioxidant Tocopherol only small antioxidant effects after exposed to cigarette smoke ex vivo as well as in vivo. Only the hydrophilic phenylethanoid H1 showed significant effects. A clear reduction of free radicals ex vivo and further a significant reduction of in vivo lipid peroxide formation was measured.

Conclusion: The cigarette smoke model is an ideal method for in vivo assessment of anti-pollution efficacy of topical products with close relation to the real situation of subjects exposed to urban pollution. Further research is required to better understand the role of chelators in anti-pollution cosmetics.
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http://dx.doi.org/10.1111/srt.13068DOI Listing
June 2021

A Randomized Exploratory Study to Investigate the Inflammatory Response During an Ultraviolet-Radiation-Induced Cold Sore Episode.

Dermatol Ther (Heidelb) 2021 Jun 28;11(3):983-994. Epub 2021 Apr 28.

proDERM Institute for Applied Dermatological Research, Schenefeld, Hamburg, Germany.

Introduction: Antivirals and occlusive lip patches are key treatments for cold sores. Additional therapeutic options, and validated methods to evaluate these, are needed.

Methods: This exploratory, double-blind, single-center study aimed to evaluate a novel lip patch containing the antiviral aciclovir (ACV) using noninvasive methods for measuring cold sore-associated inflammation. Healthy subjects with ultraviolet radiation (UVR)-induced cold sores were randomized to 10 days' treatment with a lip patch containing ACV (N = 12) or without ACV (N = 13). Outcome measures included blood flux (field laser perfusion imaging, FLPI), skin temperature (thermography), and skin redness (high-resolution color photography, HRCP).

Results: Mean blood flux (in perfusion units) and skin temperature (in °C/pixel) were higher for cold sores versus intrasubject control regions. For ACV versus placebo patches, skin temperature was higher for ACV with total day 1-5 mean values of 2.6 versus 0.5 (p = 0.036) and day 1-10 mean values of 3.2 versus 0.8 (p = 0.049). Conversely, mean total episode blood flux values over days 1-5 were lower for ACV versus placebo patch (flux 2227 versus 2939, p = 0.340) and remained lower over days 1-10 (flux ACV 810 versus placebo 961, p = 0.404). HRCP failed to discriminate cold sores from control regions or between treatments. Subject-reported pain/soreness, itching, and burning were generally lower with ACV patch.

Conclusions: FLPI reliably measures cold sore-related inflammation and thermography heat radiating from the skin. HRCP was of little value.

Trial Registration: NCT01653509.
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http://dx.doi.org/10.1007/s13555-021-00531-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8163941PMC
June 2021

Efficacy and tolerability of a detergent and care component for rosacea patients: A split-face, vehicle-controlled, randomized trial.

J Cosmet Dermatol 2021 Apr 7. Epub 2021 Apr 7.

Department of Dermatology and Allergy, University Hospital of Munich, LMU, Munich, Germany.

Background: The treatment of facial erythema and subjective symptoms of rosacea patients remains challenging in clinical practice. Cosmeceuticals, care components containing active ingredients such as phytochemicals, play a growing role in treatment plans. However, well-designed studies on their efficacy and limitations are widely missing.

Objective: A foam and a cream for rosacea patients were assessed based on objective and subjective methodology. The tolerability of skin and eyes was evaluated.

Methods: A randomized, double-blinded, split-face, and vehicle-controlled trial was conducted. At baseline and after four weeks of product use, dermatological and ophthalmological investigations were performed, employing image analysis of facial erythema, clinical assessments, and questionnaires.

Results: The patient cohort comprised 33 females with persistent facial erythema due to rosacea. No significant differences were found between the vehicle and the verum. According to the analysis of facial erythema, a "less pronounced" or "much less pronounced" appearance was seen in two thirds of patients comparing V1 to V0. Especially, the dryness of the skin improved by the use of the vehicle and the verum. Adverse subjective skin sensations decreased by 61.3% for the verum side and by 58.6% for the vehicle side. Subjective and objective analysis of ocular manifestation differed, with subjective manifestations reported more frequently, thus highlighting underdiagnosis of ocular rosacea.

Conclusions: As no clear differences between the verum and the vehicle were found, an optimal skin care regime itself seems to have a superior effect in the relief of facial erythema and foremost of subjective symptoms, rather than certain active ingredients.
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http://dx.doi.org/10.1111/jocd.14130DOI Listing
April 2021

Measurement of dermal water content by confocal RAMAN spectroscopy to investigate intrinsic aging and photoaging of human skin in vivo.

Skin Res Technol 2021 May 24;27(3):404-413. Epub 2020 Oct 24.

proDERM Institute of Applied Dermatological Research GmbH, Hamburg, Germany.

Background: In vivo confocal Raman spectroscopy (CRS) revealed a clear correlation of age and dermal water content, indicating increasing water content of the dermis with increasing age. This enhancement of water has been interpreted as an age-dependent depletion, of proteins, mainly of collagen. Chronical sun exposure is known to destroy the collagen network of the skin, which leads to the signs of photoaging as the formation of wrinkles. Noninvasive in vivo measuring techniques for photoaging are limited. Therefore, sensitive techniques to quantify even mild degrees of photoaging in a clinical setting are of high interest. We used CRS to measure the water content in human dermis in vivo, assuming that additionally to the increase of water content in intrinsic aging, photoaging would lead to further collagen depletion and an additional increase in water content of the dermis.

Materials And Methods: A panel of 24 female subjects of different age-groups and scores of photoaging was recruited. A ranking of high resolution dorsal forearm photographs was used to classify the degree of photoaging with high precision. After that, CRS water content and collagen measurements were performed in the photoexposed dorsal as well as the photoprotected volar dermis of the subjects.

Results: A positive correlation of water content in the dermis with age could be confirmed (r = .550). Further, a positive correlation between water content of dorsal dermis and photoaging ranks was observed (Pearson's r = .417).

Conclusion: Assessment of water content in the dermis with confocal Raman spectroscopy was found to be a promising method to measure the degree of photoaging in human subjects in vivo.
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http://dx.doi.org/10.1111/srt.12948DOI Listing
May 2021

A Dermonutrient Containing Special Collagen Peptides Improves Skin Structure and Function: A Randomized, Placebo-Controlled, Triple-Blind Trial Using Confocal Laser Scanning Microscopy on the Cosmetic Effects and Tolerance of a Drinkable Collagen Supplement.

J Med Food 2020 Feb;23(2):147-152

proDERM Institute for Applied Dermatological Research, Schenefeld-Hamburg, Germany.

The purpose of this randomized, placebo-controlled, triple-blind trial on 60 healthy female volunteers was to assess the cosmetic effects on skin quality of a food supplement containing special collagen peptides together with acerola extract, vitamin C, vitamin E, biotin, and zinc after an intake of 12 weeks (Elasten, QUIRIS Healthcare, Germany). To reduce assessment bias maximally and increase the accuracy and objectivity of the outcomes, the trial design was triple blinded in a manner that neither the subjects nor the person administering the products nor the person who assessed the primary outcomes knew which subjects had received the test product and which had received the placebo. The expert grader assessing the confocal laser scanning microscopy images was additionally blinded regarding the time when the image was taken (on days 1 or 85). The objective, blinded, and validated image analyses using confocal laser scanning microscopy showed a significant improvement of the collagen structure of facial skin (primary endpoint) after intake of the test product, while no improvements were found after intake of the placebo. The proven positive nutritional effect on the collagen structure was fully consistent with positive subjective evaluations of relevant skin parameters such as elasticity, crinkliness/wrinkliness, and evenness in different body areas such as face, hands, décolleté, neck, backside, legs, and belly, all serving as secondary endpoints. The test product was found to be safe and very well tolerated. A cosmetically relevant improvement of the facial skin was demonstrated after administration of the collagen supplement.
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http://dx.doi.org/10.1089/jmf.2019.0197DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7041324PMC
February 2020

Characterization and validation of an in vivo confocal Raman spectroscopy led tri-method approach in the evaluation of the lip barrier.

Skin Res Technol 2020 May 9;26(3):390-397. Epub 2019 Dec 9.

proDERM Institute of Applied Dermatological Research GmbH, Hamburg, Germany.

Background/aim: It was the aim to establish and validate in vivo confocal Raman spectroscopy for characterization of the lip barrier in conjunction with transepidermal water loss (TEWL) and skin capacitance assessments. For the first time in vivo, barrier-relevant components of the lip (derived, natural moisturizing factors (NMFs) and ceramides are described.

Methods: In 32 healthy volunteers, a dental tongue fixation device was inserted to prevent both voluntary and involuntary lip moisturization during measurements. Seventeen individual parameters relating to water, ceramide, and NMF content were assessed via Raman spectroscopy. Additionally, corneometry and TEWL were measured. To give a guidance for the required volunteer group size of future lip barrier studies for all test parameters, coefficients of variation (CV) were calculated and plots showing the required sample size for a given percentage treatment effect.

Results: Raman spectroscopy assessed parameters on the lower lip comprehensively characterized the state of the lip barrier. Parameter variability was sufficiently low to corroborate changes in most parameters using relatively small study populations.

Conclusions: Lip skin is comparatively well hydrated. Biophysical measurement of the lip barrier function is a challenge, as unconscious licking of the lower lip has to be prevented. In vivo confocal Raman spectroscopy provides insightful parameters for the characterization of the lip barrier and sufficiently low inter-individual variability to assess relatively small parameter changes employing relatively few study subjects. Differences at the molecular level and at a high spatial resolution are detectable, and these insights might provide a breakthrough in the evaluation of lip barrier function and developing solutions for lip care.
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http://dx.doi.org/10.1111/srt.12814DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317720PMC
May 2020

Confocal Raman Spectroscopy as a tool to measure the prevention of skin penetration by a specifically designed topical medical device.

Skin Res Technol 2019 Jul 16;25(4):578-586. Epub 2019 Feb 16.

Kaymogyn GmbH, Wiesbaden, Germany.

Background/aim: The scope of this study was to utilize confocal Raman spectroscopy in the evaluation of the degree of non-penetration into the viable skin layers of a paraffin and petrolatum-based product for use in the intimate areas of the skin. The formulation was purposely designed with properties to prevent undesirable skin penetration.

Methods: Product-The test product was a proprietary topical medical device comprising paraffinum liquidum, petrolatum, paraffin, and tocopheryl acetate. Volunteers-A total of 20 healthy volunteers were recruited onto the study-17 females and three males. Product Testing-Raman spectra were obtained at Baseline and 90 minutes after product application. Product Penetration-Skin penetration was calculated from Raman spectra taken at skin depths of -5, 0, 5, 10, 15, and 20 μm.

Results: Raman spectra of the investigated product could be clearly differentiated from the skin spectrum. The minimum measurable concentration of the test product was determined at a detection level of 0.5%. In this study, the test product did not penetrate down to skin depths of 10 to 20 μm.

Conclusions: Within the precision range of the test method, the investigated product did not penetrate into the compact part of the stratum corneum. The study revealed Raman spectroscopy to be suitable to detect not only penetration but also non-penetration of substances into human skin.
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http://dx.doi.org/10.1111/srt.12689DOI Listing
July 2019

The combined use of a nonabrasive, activator-containing toothpaste and a light emitting diode device improves the onset time of tooth whitening.

Eur J Dent 2018 Jul-Sep;12(3):329-333

proDERM Institute for Applied Dermatological Research GmbH, Schenefeld, Hamburg, Germany.

Objective: The objective of this randomized clinical study was to assess the onset time of the whitening effect of a combined use of a nonabrasive, activator-containing toothpaste and a light emitting diode (LED) device, compared to that of the toothpaste alone.

Materials And Methods: A nonabrasive, activator-containing toothpaste was used twice daily alone or combined with an LED device for 15 days. The onset of the tooth whitening effect was evaluated through tooth color (a* b*, CIELAB) and tooth whiteness (WIO) by image analysis of standardized images. Local tolerance was assessed at days 1, 8, and 15.

Results: On day 8, a significant ( = 0.003) tooth whitening effect compared to day 1 was observed with the toothpaste and the LED device, sustaining until the end of the study. Whitening using the toothpaste alone was significant compared to day 1 after 15 days, only. One subject reported mild redness, itching, and burning on day 1 on the gum of the lower jaw that was possibly related to with the toothpaste. The subject withdrew from the study. No adverse event was reported in the group using the LED device.

Conclusion: Both tooth whitening methods had a significant whitening effect after 15 days of use. However, the onset of whitening was significantly faster when using the nonabrasive, activator-containing toothpaste combined with an LED device. The toothpaste and LED device were both safe.
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http://dx.doi.org/10.4103/ejd.ejd_167_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089063PMC
August 2018

Measurement of Skin Surface pH.

Curr Probl Dermatol 2018 21;54:19-25. Epub 2018 Aug 21.

The acidic nature of the skin surface was recognised more than a century ago and has been measured since 1928. Several non-invasive methods for measuring skin surface pH have been developed ever since and have contributed to our understanding of healthy and diseased skin. This chapter summarises the endogenous physiological, exogenous and environmental factors that influence skin surface pH and its measurement as well as the different measurement methods for skin surface pH, with specific emphasis on the classic planar glass electrode method. Also, practical guidance for measurement of skin surface pH using the planar glass electrode method is provided. Adherence to practical skin surface pH measurement (method) guidelines with due consideration and practicable control of all factors that may affect skin surface pH will ensure credible pH measurement results in our continuous pursuit of understanding especially diseased skin.
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http://dx.doi.org/10.1159/000489514DOI Listing
December 2018

A new topical panthenol-containing emollient: skin-moisturizing effect following single and prolonged usage in healthy adults, and tolerability in healthy infants.

J Dermatolog Treat 2017 May 22;28(3):251-257. Epub 2016 Aug 22.

a Bayer Consumer Care AG , Basel , Switzerland.

Purpose: Two studies were conducted with a new topical panthenol-containing emollient (NTP-CE) to investigate the skin-moisturizing effect in healthy adults and tolerability in healthy infants.

Methods: In Study 1 (N = 44), a single skin application of NTP-CE was performed followed by a 4-week twice-daily application. Skin hydration and stratum corneum (SC) water content change (using Raman spectroscopy) were measured. In the 4-week Study 2 (N = 65, aged 3-25 months), NTP-CE tolerability was assessed using a 5-point scoring system; skin hydration was determined in a subset (N = 21).

Results: In Study 1, mean AUC for skin capacitance change from baseline was 302.03 i.u. with NTP-CE and -15.90 i.u. in control areas (p < .001). With NTP-CE (at 4 h), the water content within the upper SC part was reduced (-45.10 vs. -13.39 g/cm, p = .013) and the water gradient increased (0.51 vs. 0.11 g/cm, p = .036), indicating relocation of water into deeper layers. In Study 2, there was no statistically significant change from baseline in mean cutaneous tolerability scores. At days 7, 14, and 28, skin hydration had increased by 42%, 54%, and 49%, respectively (all p < .001).

Conclusions: Single and prolonged NTP-CE usage is associated with sustained and deep skin moisturization. NTP-CE is well tolerated by healthy infants.
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http://dx.doi.org/10.1080/09546634.2016.1218417DOI Listing
May 2017

A new topical panthenol-containing emollient: Results from two randomized controlled studies assessing its skin moisturization and barrier restoration potential, and the effect on skin microflora.

J Dermatolog Treat 2017 Mar 2;28(2):173-180. Epub 2016 Aug 2.

a Bayer Consumer Care AG , Basel , Switzerland.

Purpose: Two randomized, intra-individual comparison studies were performed in healthy subjects to evaluate the skin moisturization and barrier restoration potential of a new topical panthenol-containing emollient (NTP-CE) (Study 1), and its effect on skin microflora (Study 2).

Methods: In Study 1 (N = 23), two skin areas, one challenged with 0.5% sodium dodecyl sulfate (SDS) solution and one unchallenged, were treated with NTP-CE for 3 weeks. Transepidermal water loss (TEWL), skin hydration, and intercellular lipid lamellae (ICLL) organization were measured at regular intervals during the study. In Study 2 (N = 20), quantitative bacterial cultures were obtained over 6 h from a skin area undergoing wash stress with 10% SDS with subsequent single application of NTP-CE.

Results: In Study 1, mean AUC for TEWL reduction from baseline was more pronounced with NTP-CE compared with control (-168.36 vs. -123.38 g/m/h, p = 0.023). NTP-CE use was also associated with statistically significant improvements in stratum corneum hydration and an increase in mean ICLL length from baseline (day 22: 120.61 vs. 35.85 nm/1000 nm, p < 0.001). In Study 2, NTP-CE use had no negative impact on bacterial viability.

Conclusions: NTP-CE use has favorable and lasting effects on barrier function and repair as well as skin hydration without negatively influencing bacterial viability.
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http://dx.doi.org/10.1080/09546634.2016.1214235DOI Listing
March 2017

Clinical efficacy of a new tooth and tongue gel applied with a tongue cleaner in reducing oral halitosis.

Quintessence Int 2012 Sep;43(8):709-18

proDERM Institute for Applied Dermatological Research, Schenefeld, Germany.

Objective: The short-term and overnight effect of three treatment regimens on oral halitosis were investigated: toothbrushing with a reference toothpaste, toothbrushing with reference toothpaste and tongue cleaning, and toothbrushing and tongue cleaning with a tooth-and-tongue gel.

Method And Materials: Fifty-four subjects meeting the inclusion criteria for bad breath were enrolled in the study. All subjects received each of the three treatment regimens in a balanced design. Efficacy was assessed by organoleptic ratings and volatile sulfur compound (VSC) measurements 5 and 60 minutes after first application and overnight after 7 days of repeated use.

Results: The combination of toothbrushing and tongue cleaning with tooth-and-tongue gel provided the best results in terms of organoleptic ratings and VSC measurements at all time points compared to the other treatment regimens.

Conclusion: The use of tooth and tongue gel for both toothbrushing and tongue cleaning showed a positive short-term and overnight effects after 7 days of use. This treatment regimen is a promising approach to control halitosis.
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September 2012

A new methodology for evaluating the damage to the skin barrier caused by repeated application and removal of adhesive dressings.

Skin Res Technol 2013 Feb 13;19(1):e366-74. Epub 2012 Jun 13.

Devicemark Ltd, Wirral, UK, CH49 1SE.

Background: Chronic wounds require frequent dressing changes. Adhesive dressings used for this indication can be damaging to the stratum corneum, particularly in the elderly where the skin tends to be thinner. Understanding the level of damage caused by dressing removal can aid dressing selection.

Methods: This study used a novel methodology that applied a stain to the skin and measured the intensity of that stain after repeated application and removal of a series of different adhesive types. Additionally, a traditional method of measuring skin barrier damage (transepidermal water loss) was also undertaken and compared with the staining methodology.

Results: The staining methodology and measurement of transepidermal water loss differentiated the adhesive dressings, showing that silicone adhesives caused least trauma to the skin.

Conclusion: The staining methodology was shown to be as effective as transepidermal water loss in detecting damage to the stratum corneum and was shown to detect disruption of the barrier earlier than the traditional technique.
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http://dx.doi.org/10.1111/j.1600-0846.2012.00653.xDOI Listing
February 2013

Anti-aging data and support claims--consensus statement.

J Dtsch Dermatol Ges 2011 Nov;9 Suppl 3:S1-32

Department of Dermatology and Allergology, University Hospital Jena, Erfurter Strasse 35, Jena, Germany.

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http://dx.doi.org/10.1111/j.1610-0379.2011.07746.xDOI Listing
November 2011

Interlaboratory studies with a proposed patch test design to evaluate the irritation potential of surfactants.

Contact Dermatitis 2010 Mar;62(3):157-64

Cognis GmbH, Duesseldorf, Germany.

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 microl 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.
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http://dx.doi.org/10.1111/j.1600-0536.2009.01656.xDOI Listing
March 2010

Non-invasive evaluation techniques to quantify the efficacy of cosmetic anti-cellulite products.

Skin Res Technol 2008 Aug;14(3):336-46

proDERM Institute for Applied Dermatological Research GmbH, Schenefeld, Germany.

Background: The majority of women suffer from the unattractive sight of dimpling skin on the thighs and buttocks, globally known as cellulite. Cellulite can be regarded as the most investigated non-disease, because, from the cosmetic viewpoint, most women desire a reduction in cellulite severity. Despite investigations made, cellulite is still not well understood at the cellular level, which leads to controversy regarding the investigative methods for cellulite reduction as well as the development of products to treat cellulite skin.

Objective: The aim of our work was to improve the set up of macrophotography for making images of dimpled skin and to automatize image analysis of 20 MHz ultrasound imaging - these two methods being just two of a variety of available methods for investigating cellulite skin.

Methods: Macrophotography was standardized on the aspects of volunteer's positioning, skin illumination, background used, and camera position. It was performed before, during and after a 3-month-treatment of a cosmetic product. Scoring assessments of the generated images were made by the volunteers themselves as well as by six trained experts. Ultrasound imaging was performed at the baseline visit in order to correlate the newly developed analysis with the visually rated cellulite score. A second study is also presented showing a variety of parameters that can be used for cosmetic testing of cellulite products: skin firmness, blood circulation and circumferential thigh measurements.

Results: Standardization of macrophotography minimized differences in image features between assessment times, therefore, enabling follow-up rating assessments of the images. A custom-made rating program simplified the scoring procedure by presenting images as blind and randomized, and by implementing computer-based analysis using an online rating scale. Volunteers and experts scored significant improvement of skin appearance over the course of a 3-month cosmetic treatment. Image analysis of ultrasound imaging was automatized, and a modification of the commonly known roughness parameter Ra was implemented to characterize cellulite severity. Comparison with the visually rated cellulite score showed an existing correlation between the score and the modified parameter Ra(m). Further parameters investigated in an exemplary study, as mentioned above, demonstrated a significant improvement of skin appearance after treatment with a cosmetic product.

Conclusions: Macrophotography and ultrasound imaging can be regarded as important tools for determining and quantifying the aspects of cellulite. With a gold standard missing for investigating cellulite severity, these two methods may not determine cellulite at the cellular level, but they do characterize the skin appearance so typical for cellulite. Combined with a variety of other methods, macrophotography and ultrasound imaging can very well define cellulite-reducing efficacy from the cosmetic point of view.
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http://dx.doi.org/10.1111/j.1600-0846.2008.00300.xDOI Listing
August 2008

Influence of climatic conditions on antiperspirant efficacy determined at different test areas.

Skin Res Technol 2008 May;14(2):213-9

proDERM Institute for Applied Dermatological Research GmbH, Schenefeld, Germany.

Background: The efficacy of antiperspirants is a current topic among the developers of cosmetic products. According to the Food and Drug Administration (FDA) for the US market, efficacy testing performed in the axilla of human volunteers is mandatory. Another method is yet available, which enables comparison of more than one antiperspirant formula in a single study by performing the test on the backs of volunteers. However, how reproducible are these methods, comparing between the back and axilla? Do they differ as a result of seasonal variation? Is a correlation between the results of the two methods possible?

Methods: To answer these questions, the antiperspirant efficacy of aluminium chlorohydrate (ACH) aqueous solutions was investigated in the axilla and on the backs of volunteers, in four separate clinical studies covering cold and warm seasons. Four days of product application were followed by thermal sweat induction on the fifth day, using a sauna. The amount of sweat recovered by weighing cotton pads before and after sweat induction was used to calculate sweat reduction. Testing in the axilla and on the back was performed on the same volunteers simultaneously to achieve the best comparable data. For this reason, the FDA guideline was slightly modified to thermal stimulation in a sauna instead of in a hot room.

Results: Increasing concentrations of ACH in aqueous solutions on the backs of volunteers showed a saturation for 8% ACH with a sweat reduction of approximately 50%. The antiperspirant efficacy of solutions containing 4%, 8% or 12% ACH was repeatedly found at the same levels, when tested on the backs during summer, autumn and winter time. Axilla tests, with an 8% ACH aqueous solution, showed strongly varying results for summer and winter time, represented by sweat reduction values of -2% to 25%. As an assumption, these high variations might result from reduced gel formation in cold seasons due to low humidity in the axillae during the application phase. On the back, this effect was avoided by applying occlusive foils after product application. To gain further insight, a study, during which summer conditions were artificially simulated by thermal stimulation during the application phase, again showed decreased antiperspirant efficacy in the axilla for winter conditions with sweat reduction values of 2%, compared with 25% under simulated summer conditions.

Conclusion: These strongly varying values of sweat reduction in the axilla under summer and winter conditions make comparisons between antiperspirant products difficult and a statement about correlation between the two test sites back and axilla impossible. A standardization of the application phase, comparable to the simulated summer conditions described here, could be a solution to reduce the high variation of results in the axilla. Consequently, testing on the back is not only a more cost-effective method to investigate the antiperspirant efficacy of more than one formulation, but a reproducible method more independent of climatic influences during test implementation than the axilla test method. It could, therefore, be regarded as the method of choice for discriminating antiperspirant efficacy between several products during development of new antiperspirant formulations.
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http://dx.doi.org/10.1111/j.1600-0846.2007.00282.xDOI Listing
May 2008

Skin-lightening effects of a new face care product in patients with melasma.

J Cosmet Dermatol 2008 Mar;7(1):68-75

Beiersdorf AG, Hamburg, Germany.

Background: Melasma is a common pigmentation disorder having considerable effect on patients' emotional and psychological well-being.

Objective: Assessment of efficacy and tolerability of a new face care product for the targeted spot treatment of darker pigmented areas in subjects with melasma and evaluation of effects on patients' quality of life.

Methods: Twenty subjects with melasma were enrolled in this study. Data of 19 participants were available for analysis. Melasma severity was evaluated at baseline, after 4 weeks, and after 8 weeks by using the Melasma Area and Severity Index (MASI). Furthermore, chromametry and digital image analysis of videomicroscopic photographs were performed, and quality of life was measured using the Melasma Quality of Life Scale.

Results: The application of the product resulted in a significant lightening of melasma in comparison with baseline and to untreated control areas. The MASI score dropped by more than 40% after 8 weeks. Measurement of skin color by chromametry revealed lightening of pigmented areas and a significant decrease in contrast between melasma and normal-pigmented surrounding skin. These results were confirmed by digital image analysis. Tolerability of the product was rated to be excellent, and patients experienced a significant gain in quality of life.

Conclusion: The data demonstrate that the new face care product is effective and highly skin tolerable and clearly improves quality of life of patients with melasma.
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http://dx.doi.org/10.1111/j.1473-2165.2008.00364.xDOI Listing
March 2008

Do atopics tolerate alcohol-based hand rubs? A prospective, controlled, randomized double-blind clinical trial.

Acta Derm Venereol 2006 ;86(2):140-3

Bode Chemie GmbH & Co, Scientific Affairs, Melanchthonstr. 27, DE-22525 Hamburg, Germany.

Alcohol-based hand rubs are used frequently in healthcare settings, but their tolerance among atopic subjects is unknown. The dermal tolerance to five alcohol-based hand rubs was assessed among atopic and non-atopic subjects in a repetitive occlusive patch test. In total, 54 subjects were analysed. One half of the subjects were atopic (modified Erlanger atopy score > or = 8), the other half were non-atopic. Treatments were controlled with water and 2% sodium dodecyl sulphate (SDS). Treatment sites were assessed by visual inspection (tolerability score 0-4). Skin redness was determined with a chromameter. The overall mean tolerability to all five hand rubs was lower than or identical to the negative control (0.02+/-0.07) and significantly different from the SDS control (0.19+/-0.39). Skin redness was in the same range as for the negative control (0.15+/-0.8) which was significantly lower than the SDS control (1.35+/-1.6). A comparison of the atopic and non-atopic subjects revealed no significant difference. In conclusion, we found that tolerance to the five alcohol-based hand rubs was good among atopic and non-atopic subjects.
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http://dx.doi.org/10.2340/00015555-0045DOI Listing
September 2006

An examination of non-invasive imaging techniques in the analysis and review of cellulite.

J Cosmet Sci 2005 Nov-Dec;56(6):379-93

proDERM Institute for Applied Dermatological Research, Hamburg, Germany.

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April 2006

Emollients in a propanol-based hand rub can significantly decrease irritant contact dermatitis.

Contact Dermatitis 2005 Dec;53(6):344-9

Bode Chemie GmbH & Co., Scientific Affairs, Melanchthonstr. 27, 22525 Hamburg, Germany.

The objective of this study is to determine the effect of emollients in a propanol-based hand rub on skin dryness and erythema. In this prospective, randomized, controlled, double-blind trial, 35 subjects participated; of them approximately half were atopic (modified Erlanger atopy score > or =8). 2 propanol-based formulations were tested in a repeated open application test, 1 contained a mixture of emollients (0.81%, w/w). 2 aliquots of 0.7 ml of each formulation were applied twice per day over 2 weeks to the cubital fossa of each subject after random assignment of the preparations. Treatment areas were assessed before each application and 3 days postfinal application by visual inspection for erythema and dryness according to a standard scale. The sum score over all assessment time-points served as primary parameter. The mean sum score for erythema and dryness was significantly lower for the hand rub with emollients (0.8 +/- 2.4) in comparison with that for the hand rub without emollients (1.5 +/- 3.5; P = 0.022; Wilcoxon signed rank test). A comparison of the atopic and non-atopic subjects revealed no significant difference for any of the products (P > 0.05; Mann-Whitney U-test). It is concluded that the addition of emollients to a propanol-based hand rub can significantly decrease irritant contact dermatitis under frequent-use conditions.
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http://dx.doi.org/10.1111/j.0105-1873.2005.00727.xDOI Listing
December 2005
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