Assessment of penetration and permeation of caffeine by confocal Raman spectroscopy in vivo and ex vivo by tape stripping.

OBJECTIVE: Tape stripping is an often-used non-invasive destructive method to investigate the skin penetration of a substance. In recent years, however, the suitability of confocal Raman spectroscopy (CRS) as a non-invasive method of non-destructive examination of the skin has become increasingly apparent. In this study, we compared invasion and depletion penetration and permeation kinetics of a 2% caffeine solution with and without 1,2-pentanediol as a penetration enhancer measured with CRS and tape stripping. METHODS: Porcine skin was used for tape stripping and human skin for CRS. 2% caffeine solution was applied to the skin for different incubation times. Human skin was then examined by CRS while caffeine was extracted from porcine skin and quantified via reverse-phase HPLC. Fluxes were also measured and calculated by sum of the total amounts of caffeine penetrated into the skin. RESULTS: Without penetration enhancers, there is hardly any difference between the penetration profiles of the two measurement methods for invasion, but the curves for depletion are different. Furthermore, the calculated flux values for the invasion are almost identical, but for the depletion the tape stripping values are about twice as high as the CRS values. CONCLUSION: The relevance of conducting invasion and depletion studies became clear and was able to show the still existing problems in the comparability of CRS and tape stripping.

OBJECTIF: Le décapage au ruban adhésif est une méthode destructive non invasive fréquemment utilisée pour examiner la pénétration cutanée d'une substance. Cependant, ces dernières années, la pertinence de la spectroscopie raman confocale, une méthode non invasive pour examiner la peau de manière non destructive, a été de plus en plus mise en évidence. Dans cette étude, nous avons comparé les cinétiques d'invasion et de déplétion de la pénétration et de la perméation d'une solution de caféine à 2 % avec et sans 1,2-pentanediol en tant qu'amplificateur de pénétration, mesurées par spectroscopie raman confocale et par décapage au ruban adhésif. MÉTHODES: La peau de porc a été utilisée pour le décapage au ruban adhésif et la peau humaine pour la spectroscopie raman confocale. Une solution de caféine à 2 % a été appliquée sur la peau pendant différents temps d'incubation. La peau humaine a ensuite été examinée par spectroscopie raman confocale tandis que la caféine a été extraite de la peau porcine et quantifiée par HPLC en phase inverse. Les flux ont également été mesurés et calculés par la somme des quantités totales de caféine ayant pénétré dans la peau. RÉSULTATS: Sans amplificateurs de pénétration, il n'y a presque aucune différence entre les profils de pénétration des deux méthodes de mesure pour l'invasion, mais les profils pour la déplétion sont différents. De plus, les valeurs de flux calculées pour l'invasion sont presque identiques, mais pour la déplétion, les valeurs de ruban adhésif sont environ deux fois plus élevées que les valeurs CRS. CONCLUSION: La pertinence de conduire des études d'invasion et de déplétion est devenue claire et a pu montrer les problèmes toujours existants dans la comparabilité du CRS et du décapage au ruban adhésif.

Investigating the effect of the pH of foot care product formulations on pedal skin in diabetic and non-diabetic subjects.

OBJECTIVE: The use of skin care formulations with acidic pHs is seen as an effective method to maintain the acidic mantel of the skin; however, because the skin pH varies depending on the area of the body and as data are lacking for the skin pH of the feet, there was a need to examine whether this assumption holds true for skin care formulations designed for the foot. Thus, three foot creams formulated with a neutral, acidic or alkaline pH were compared with each other as well as to an untreated control group in order to analyse their impact on skin pH, hydration and general skin condition. METHODS: An exploratory clinical investigation with 60 enrolled subjects, half of whom had a diagnosis of diabetes (type 1 or type 2), was undertaken. The investigation followed a randomized, double-blind, balanced incomplete block design (BIBD) including intra-individual comparison (before and after treatment). Evaluations of skin pH and hydration were carried out using a pH meter and a Corneometer respectively. Objective evaluation of skin condition for efficacy assessment was performed by a trained grader. For tolerability evaluation, objective and subjective dermatological assessments were performed. RESULTS: At the end of the treatment period, the skin pH was largely unchanged at five out of six of the test areas, with the mean value for each treatment group using test products showing similar fluctuations as the untreated control group. Furthermore, the skin condition parameters studied all improved by a comparable magnitude for each of the treatment groups using the test products, whereas the untreated control group experienced a worsening of the skin condition parameters. CONCLUSIONS: The results of this investigation suggest that where the skin of the foot is concerned, the pH of skin care formulations has no (physiologically) relevant influence on the skin's pH in either diabetic or non-diabetic subjects. Furthermore, the expectation that acidic formulations would be more beneficial for the skin's condition was not found to hold true for the skin of the foot, as no significant difference was observed between the performance of the three test products investigated in this study.

OBJECTIF: L'utilisation de formulations de soins cutanés à pH acide est considérée comme une méthode efficace pour préserver le manteau acide de la peau. Cependant, comme le pH de la peau varie en fonction de la zone corporelle et comme les données manquent concernant le pH de la peau des pieds, il était nécessaire d'examiner si cette hypothèse est vraie pour les formulations de soins cutanés conçues pour le pied. Ainsi, 3 crèmes pour les pieds à pH neutre, acide ou alcalin ont été comparées entre elles, ainsi qu'à un groupe témoin non traité, afin d'analyser leur impact sur le pH de la peau, l'hydratation et l'état général de la peau. MÉTHODES: Une étude clinique exploratoire a été menée sur 60 sujets inclus, dont la moitié avait reçu un diagnostic de diabète (de type 1 ou de type 2). L'étude a suivi une conception randomisée, en double aveugle, en blocs incomplets équilibrés (balanced incomplete block design, BIBD), comprenant une comparaison intra-individuelle (avant et après le traitement). Les évaluations du pH de la peau et de l'hydratation ont été réalisées à l'aide d'un pH-mètre et d'un cornéomètre, respectivement. Une évaluation objective de l'état de la peau a été réalisée par un évaluateur formé en ce qui concerne l'évaluation de l'efficacité. Pour l'évaluation de la tolérance, des évaluations dermatologiques objectives et subjectives ont été réalisées. RÉSULTATS: À la fin de la période de traitement, le pH de la peau était en grande partie inchangé dans 5 des 6 zones de test, la valeur moyenne pour chaque groupe de traitement utilisant des produits testés montrant des fluctuations similaires à celles du groupe témoin non traité. En outre, les paramètres de l'état de la peau étudiés se sont tous améliorés dans une mesure comparable pour chacun des groupes de traitement utilisant les produits à l'étude, tandis que le groupe témoin non traité a présenté une aggravation des paramètres de l'état de la peau. CONCLUSIONS: Les résultats de cette étude indiquent qu'en ce qui concerne la peau du pied, le pH des formulations de soins de la peau n'a pas d'influence (physiologiquement) pertinente sur le pH de la peau chez les sujets diabétiques ou non diabétiques. En outre, l'attente selon laquelle des formulations acides seraient plus bénéfiques pour l'état de la peau n'a pas été confirmée pour la peau du pied, car aucune différence significative n'a été observée entre les performances des 3 produits testés étudiés dans cette étude.

Confocal Raman spectroscopy is suitable to assess hair cleansing-derived skin dryness on human scalp.

BACKGROUND: The purpose of this pilot study was to provide information about the washout-dependent depletion of important skin components in the horny layer of the scalp. They were taken as markers for scalp drying effects of cosmetic cleansing products and were measured directly in vivo. METHOD: In vivo confocal Raman spectroscopy was used to measure the depletion of the total natural moisturizing factor (total NMF) and some of its components (urea and lactic acid) as well as a fraction of stratum corneum lipids, after repeated washing with a standard shampoo on the human scalp. RESULTS: The measurements showed a reduction in the amount of NMF and lipids of the stratum corneum caused by repeated shampooing. CONCLUSION: Confocal Raman spectroscopy is an innovative technology that can be used successfully in vivo on the hairy scalp. The loss of the most important skin components caused by hair washing can be quantified directly with this technology. The method is valuable to support the development cosmetic cleansing products, as it is suitable to directly compare the effects of different product candidates on the human scalp in a most realistic way.

A novel clinical method to measure skin staining reveals activation of skin damage pathways by cigarette smoke.

BACKGROUND: Long-term use of cigarettes can result in localised staining and aging of smokers' skin. The use of tobacco heating products (THPs) and electronic cigarettes (ECs) has grown on a global scale; however, the long-term effect of these products' aerosols on consumers' skin is unknown. This pilot clinical study aimed to determine whether THP or EC aerosol exposure results in skin staining or activation of biomarkers associated with oxidative stress. MATERIALS AND METHODS: Eight areas were identified on the backs of 10 subjects. Two areas were used for air control, and two areas exposed to 32-puffs of cigarette smoke (CS), THP or EC aerosols, which were delivered to the skin using a 3-cm diameter exposure chamber and smoke engine. Skin colour was measured using a Chromameter. Squalene (SQ), SQ monohydroperoxide (SQOOH) and malondialdehyde (MDA) levels were measured in sebum samples by mass spectrometry and catalase colorimetry. RESULTS: CS exposure significantly increased skin staining, SQOOH and MDA levels and SQOOH/SQ ratio. THP and EC values were significantly lower than CS; EC values being comparable to air control. THP values were comparable to EC and air control at all endpoints, apart from skin staining. SQ and catalase levels did not change with exposure. CONCLUSIONS: CS stained skin and activated pathways known to be associated with skin damage. THPs and ECs produced significantly lower values, suggesting they could offer hygiene and cosmetic benefits for consumers who switch exclusively from smoking cigarettes. Further studies are required to assess longer-term effects of ECs and THPs on skin function.

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

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.

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

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.

Targeted dry skin treatment using a multifunctional topical moisturizer.

OBJECTIVE: The development of dry skin is a complex process, with a wide variety of factors each playing different roles in its evolution. Given this, it is important when designing a formulation to tackle dry skin that these varied aspects of skin behaviour are addressed. Presented here are the results of a 3-week moisturization study carried out on dry legs. A wide range of traditional and more recently developed biophysical measurement methods have been combined with visual assessment of skin condition to enable multiple aspects of skin function to be determined. The observed changes in the skin are discussed in terms of the ingredients used in the moisturizing formulation. METHODS: A range of novel and traditional skin assessment methods and techniques were used to assess the effects of an oil in water-based moisturizing product compared to an untreated site during a 3-week in vivo study on dry lower leg skin. RESULTS: Statistically significant improvements were observed in a range of skin parameters as a result of product usage. Skin hydration assessed using Corneometer®, Epsilon® and visual dry skin grading all increased after 3 weeks of use. Skin barrier function measured using transepidermal water loss also improved. Levels of cholesterol, free fatty acids and Ceramide NH increased, as well as the average length of the stratum corneum (SC) lipid lamella bilayers, and the ratio of lipid to protein increased (measured using Lipbarvis® and in vivo Confocal Raman Spectroscopy). Increases in the levels of Ceramide EOS and NP were also observed, along with an improvement in corneocyte maturity, although these were not statistically significant. CONCLUSIONS: Using a variety of traditional and novel skin assessment techniques, a wide range of factors associated with the evolution of dry skin have been assessed upon treatment with a new topical moisturizer. Product usage resulted in significant improvements to skin hydration and barrier function, the levels and morphology of SC barrier lipids, and overall epidermal differentiation. As a result there was a significant reduction in the characteristics associated with the development of dry skin after use of the test product.

OBJECTIF: le développement de la sécheresse cutanée est un processus complexe, une grande variété de facteurs jouant chacun des rôles différents dans son évolution. De ce fait, il est important d'aborder ces différents aspects du comportement de la peau lors de la conception d'une formulation pour lutter contre la sécheresse cutanée. Les résultats d'une étude de 3 semaines sur l'hydratation des jambes sèches sont présentés ci-dessous. Un large éventail de méthodes de mesure biophysiques traditionnelles et plus récemment développées ont été combinées à une évaluation visuelle de l'état de la peau pour permettre de déterminer de multiples aspects de la fonction cutanée. Les changements observés sur la peau sont abordés en termes des ingrédients utilisés dans la formulation hydratante. MÉTHODES: une série de méthodes et de techniques nouvelles et traditionnelles d'évaluation de la peau ont été utilisées pour évaluer les effets d'un produit hydratant à base d'émulsion huile dans eau par comparaison à un site non traité au cours d'une étude in vivo de 3 semaines sur la peau sèche de la partie inférieure des jambes. RÉSULTATS: des améliorations statistiquement significatives ont été observées au niveau d'une gamme de paramètres cutanés suite à l'utilisation du produit. L'hydratation cutanée évaluée à l'aide de Corneometer®, Epsilon® et de la cotation visuelle de la sécheresse cutanée s'est améliorée selon toutes ces méthodes après 3 semaines d'utilisation. La fonction de barrière cutanée mesurée d'après la perte d'eau transépidermique s'est également améliorée. Les taux de cholestérol, d'acides gras libres et de céramides NH ont augmenté, ainsi que la longueur moyenne des bicouches des lamelles lipidiques de la couche cornée (CC), et il en a été de même pour le rapport lipide/protéine (mesuré à l'aide du Lipbarvis® et de la spectroscopie confocale de Raman in vivo). Des augmentations des taux de céramides EOS et NP ont également été observées, ainsi qu'une amélioration de la maturité des cornéocytes, bien qu'elles n'aient pas été statistiquement significatives. CONCLUSION: à l'aide d'une gamme de techniques d'évaluation de la peau traditionnelles et nouvelles, un large éventail de facteurs associés à l'évolution de la sécheresse cutanée a été évalué lors du traitement avec un nouveau produit hydratant topique. L'utilisation du produit a entraîné une amélioration significative de l'hydratation et de la fonction de barrière de la peau, des taux et de la morphologie des lipides de la barrière SC , et de la différenciation épidermique globale. Cela a entraîné une amélioration significative des facteurs associés au développement de la sécheresse cutanée.

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

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.

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

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.

Randomized Clinical Dose-Response Study to Evaluate Plaque Removal by Three Experimental Sodium Bicarbonate Toothpastes Using a Single Brushing Model.

OBJECTIVES: This randomized, examiner-blind, crossover clinical study compared the plaque removal efficacy of three experimental toothpastes containing 20%, 35%, and 50% w/w sodium bicarbonate (NaHCO3) with commercial toothpastes containing 67% and 0% w/w NaHCO3 (positive and negative controls, respectively). METHODS: Fifty-six adults with a mean Turesky Modification of the Quigley-Hein Plaque Index (TPI) score of = 2.00 at screening and at the first treatment visit (pre-brushing) were randomized to a supervised single, timed (one minute) brushing with a 0%, 20%, 35%, 50%, or 67% w/w NaHCO3-containingtoothpaste. TPI was measured pre- and post-brushing. Participants completed five treatment visits, separated by a four- to six-day washout, and brushed once with each toothpaste. The primary efficacy analysis was change in whole mouth TPI score from pre- to post-brushing between the positive and negative control toothpastes (validation step). Secondary analyses were comparisons between each experimental toothpaste and the control toothpastes. Change in TPI score was analyzed using a mixed effect analysis of covariance. RESULTS: The difference in adjusted mean TPI change from pre- to post-brushing between the 67% and 0% w/w NaHCO3 toothpastes was -0.01 points (95% CI -0.06, 0.04), with no statistically significant difference between them (p = 0.6674). As such, study validity was not attained. Differences in adjusted mean change from pre- to post-brushing between each experimental toothpaste and the positive and negative controls ranged from 0.00 to -0.02 points. Twenty-two treatment-emergent, treatment-related adverse events, all oral, were reported by 17 participants (30.4%). These were spread uniformly across test toothpastes and controls. No serious adverse events were reported. CONCLUSIONS: There was no statistically significant difference in change in mean TPI score between toothpastes containing 67% w/w NaHCO3 and 0% w/w NaHCO3 following a single timed brushing. This unexpected observation may be attributed to lower than expected reduction in overall plaque and a possible Hawthorne effect. As study validation was not met, no further conclusions can be made. The study products were generally well tolerated.

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

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.

Performance Metrics of Sunscreen Formulations: In Vitro and In Vivo Techniques.

Effective skin protection of consumers by sunscreens can only be achieved when meaningful and reliable test methods are available to objectively measure the protection of sunscreen products. Quantitative, scientifically sound, and valid methods to detect UVB and UVA light protection as well as methods to assess sunscreen substantivity to water are required. Continuous improvement and, if necessary, extension of the test methods are important to provide optimum protection from harmful sun rays to the consumer. This work documents the historical background of the development of sunscreen test methods and provides the actual worldwide status of applied methods. Future developments and trends are discussed as far as they actually become apparent.

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

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.

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

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.

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.

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.

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

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.

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

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.

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

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 (P = 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.

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.

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/m2/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 nm2, 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.

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

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 AUC0 - 24 h 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/cm2, p = .013) and the water gradient increased (0.51 vs. 0.11 g/cm4, 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.