Influence of physical-mechanical properties on SPF in sunscreen formulations on ex vivo and in vivo skin.

The sun protection factor (SPF) is related to the selected UV filters. The objective of this study was to evaluate and compare the rheological behavior and texture profile of two sunscreen formulations and to correlate these data with the obtained SPF values. Two formulations (F1 and F2) were developed with the same type and amount of UV filters - whereby one of them also contained ethoxylated lanolin as additional film former (F2). Their rheological behavior, texture profile and in vitro and in vivo SPF were analyzed. The film-forming properties were evaluated by skin profilometry and diffuse reflectance spectroscopy. The structures of the formulations were examined by two-photon tomography combined with fluorescence lifetime imaging, and the penetration profile into the stratum corneum was investigated by tape stripping. The formulation with lanolin presented lower and constant values for physical-mechanical parameters, with a higher and better reproducible SPF. Both formulations did not penetrate the viable epidermis. In conclusion, formulations with better surface deposition on the skin surface can influence the film formation and, consequently, improve the SPF. These findings are important to improve the efficacy of sunscreen formulations and reduce the addition of UV filters.

Application of Factorial Design and Rheology to the Development of Photoprotective Formulations.

A sunscreen should form a stable and homogeneous film over the skin surface, which can improve its photoprotective activity and avoid adverse effects. For this purpose, the definition of the appropriate vehicle is of fundamental importance since emulsifying agents are known to directly influence the stability, sensorial properties and surface tension of sunscreens, modulating their film-forming performance. In this context, the objective of the present study was to systematically develop formulations with UVB/UVA protection and evaluate the effect of wax concentration on the rheological behaviour. A 2-level full factorial design was applied for the development of four formulations. Two categorical factors were evaluated, glyceryl stearate plus PEG-75 stearate (Wax 1) and methyl glucose sesquistearate (Wax 2). Rheological behaviour was determined in triplicate and rheograms were analysed using the Ostwald model. Rheological parameters were correlated by the Spearman rank correlation test and effects were evaluated by Pareto chart and surface response methodology (SRM). It was possible to identify the pseudoplastic and thixotropic behaviour of all formulations exhibiting a thinning effect on higher shear stress. Factorial analysis showed that both waxes significantly influenced consistency and thixotropic behaviour. The effect of Wax 2 concentration in thixotropy was positive and of higher magnitude and a synergistic effect was also observed. Spearman correlation coefficient of consistency index and apparent viscosity was significantly strong and positive. Finally, factorial analysis allowed the determination of the effects of waxes on the rheological parameters of the formulations. A quantitative relationship between wax concentration and significant responses was established, permitting the prediction of desirable rheological properties for improved sunscreen efficacy.

Application of biophysical and skin imaging techniques to evaluate the film-forming effect of cosmetic formulations.

OBJECTIVE: Products with film-forming effect, or 'second skin', which guarantees an immediate protective effect after application, is a highlight, especially when composed of natural ingredients. Thus, the objective of this study was to evaluate the immediate film-forming effect on skin of a gel and emulsion formulations added with Kappaphycus alvarezii and Caesalpinia spinosa extracts through biophysical and skin imaging techniques, especially with the Reflectance Confocal Microscopy (RCM). METHODS: The measurements were done in the forearm region before (baseline) and 1 h after of application of the developed formulation and its control. The parameters related to the stratum corneum water content, transepidermal water loss (TEWL), cutaneous microrelief and morphological and structural characteristics of the epidermis were analysed through the following biophysical and skin imaging techniques: Corneometer® CM 825, Tewameter® TM 300, Visioscan® VC98 and Vivascope® 1500, respectively. A sensorial analysis was also performed to study how the formulations were perceived on the skin. RESULTS: The obtained results showed that the active ingredient under study allows the film formation on the skin surface, leading to a reduction of TEWL and skin desquamation. The obtained images from RCM showed a reduction of furrows on the skin surface and a film formation after a single application of the formulations. However, these effects were more pronounced in the emulsion formulation, which suggests a synergistic effect of the active ingredient under study with the emollients of formulation composition. This result was also observed in the sensorial analysis, as both formulations added with the active substance were well evaluated. CONCLUSION: The presence of Kappaphycus alvarezii and Caesalpinia spinosa extracts in the studied cosmetic formulations, enabled a film formation on a skin surface, bringing benefits as a reduction of transepidermal water loss and skin desquamation, as well as a furrows reduction and an improvement of stratum corneum after 1 h of application. Finally, the skin imaging techniques can be suggested as an excellent tool to evaluate a film-forming effect of cosmetic formulations.

OBJECTIF: Les produits ayant un effet filmogène, ou « deuxième peau ¼ qui garantit un effet protecteur immédiat après l'application, sont un plus, notamment lorsqu'ils sont composés d'ingrédients naturels. L'objectif de cette étude visait ainsi à évaluer l'effet filmogène immédiat sur la peau de formulations avec gel et émulsion enrichies d'extraits de Kappaphycus alvarezii et de Caesalpinia spinosa grâce à des techniques d'imagerie cutanée et biophysique, en particulier par microscopie confocale par réflectance (MCR). MÉTHODES: Les mesures ont été effectuées dans la région de l'avant-bras avant (référence) et 1 h après l'application de la formulation développée et de son contrôle. Les paramètres liés à la teneur en eau de la couche cornée, perte d'eau transépidermique (Transepidermal Water Loss, TEWL), au microrelief cutané et aux caractéristiques structurelles et morphologiques de l'épiderme ont été analysés à l'aide des techniques d'imagerie cutanée et biophysique suivantes : Corneometer® CM 825, Tewameter® TM 300, Visioscan® VC98 et Vivascope® 1500, respectivement. Une analyse sensorielle a également été réalisée pour étudier comment les formulations étaient perçues sur la peau. RÉSULTATS: Les résultats obtenus ont montré que le principe actif étudié permet la formation d'un film à la surface de la peau, entraînant une réduction de la TEWL et de la desquamation de la peau. Les images obtenues par MCR ont montré une réduction des sillons à la surface de la peau et la formation d'un film après une seule application des formulations. Ces effets étaient toutefois davantage prononcés avec la formulation de type émulsion, ce qui suggère un effet synergique du principe actif étudié avec les émollients contenus dans la formulation. Ce résultat a également été observé dans l'analyse sensorielle, car les deux formulations enrichies en substance active ont été bien évaluées. CONCLUSION: La présence d'extraits de Kappaphycus alvarezii et de Caesalpinia spinosa dans les préparations cosmétiques étudiées a permis la formation d'un film à la surface de la peau, procurant des bénéfices sous forme d'une réduction de la perte d'eau transépidermique et de la desquamation de la peau, de même qu'une réduction des sillons et une amélioration de la couche cornée 1 h après l'application. Enfin, les techniques d'imagerie cutanée peuvent être proposées comme excellent outil d'évaluation de l'effet filmogène des préparations cosmétiques.

Photoageing-related skin changes in different age groups: a clinical evaluation by biophysical and imaging techniques.

OBJECTIVES: In view of the lack of studies about the morphological and structural changes caused by solar radiation in young people, the aim of the present study was to evaluate the photoageing-related changes in the skin of different age groups by biophysical and imaging techniques. METHODS: Forty-four healthy female subjects were divided into two age groups: Group 1 (G1): 18-35 years old and Group 2 (G2): 40-60 years old. The skin of malar region of the face was evaluated in terms of mechanical properties, disorder in the pigmentation pattern, morphological and structural changes using the Cutometer® , Colorimeter® , Visioface® and Dermascan C® devices and reflectance confocal microscopy (Vivascope® ). RESULTS: The results showed that the main changes in the skin of G1 were related to the pigmentation pattern, the papilla format and depletion of thin collagen fibres. These alterations were also observed in the skin of G2, but with more pronounced effects. CONCLUSION: The knowledge about the skin changes caused by photoageing obtained in this study is very important for the development of dermocosmetic products for more effective treatments particularly focused on this type of skin. Finally, objective characterization of photoageing showed the importance of photoprotective habits since the first years of life in order to retard the appearance of skin changes caused by solar radiation.

OBJECTIFS: Compte tenu du manque d'études sur les modifications structurelles et morphologiques causées par le rayonnement solaire chez les jeunes gens, le but de la présente étude était d'évaluer les changements liés au photovieillissement de la peau de différents groupes d'âges grâce des techniques de biophysique et d'imagerie. MÉTHODES: Quarante-quatre sujets féminins en bonne santé ont été divisés en deux groupes d'âges : Groupe 1 (G1) : 18-35 ans et Groupe 2 (G2) : 40-60 ans. La peau des régions malaires du visage a été évaluée en termes de propriétés mécaniques, troubles du schéma de pigmentation, et changements morphologiques et structurels à l'aide des dispositifs Cutometer®, Colorimeter®, Visioface® et Dermascan C® et de la microscopie confocale par réflectance (Vivascope®). RÉSULTATS: Les résultats ont montré que les principaux changements au niveau de la peau du G1 étaient liés au schéma de pigmentation, au format papillaire et à la déplétion de fines fibres de collagène. Ces altérations ont également été observées au niveau de la peau du G2, mais avec des effets plus prononcés. CONCLUSION: Les connaissances sur les modifications cutanées causées par le photovieillissement acquises grâce à cette étude sont très importantes pour le développement de produits dermo-cosmétiques pour des traitements plus efficaces axés plus particulièrement sur ce type de peau. Et enfin, la caractérisation objective du photovieillissement a montré l'importance des habitudes photoprotectrices depuis les premières années de vie afin de retarder l'apparition de modifications cutanées causées par le rayonnement solaire.

Characterization of oily mature skin by biophysical and skin imaging techniques.

BACKGROUND: The skin is a complex biological system and may suffer change according to the environmental factors, as higher temperatures can increase sebum excretion, presenting oiliness and acne. These alterations can persist during the aging and provoke more changes in aged skin. In this study we evaluated the mature oily skin characteristics using biophysical and skin imaging techniques. MATERIAL AND METHODS: Sixty healthy female subjects, aged between 39 and 55 years old were recruited and separated into 2 groups according to their skin type: normal/dry and oily skin. The skin was evaluated in terms of stratum corneum water content, transepidermal water loss (TEWL) sebum content, dermis thickness and echogenicity, skin microrelief, and pores content. RESULTS: The mature oily skin presented no significant differences when compared to the normal/dry skin on the stratum corneum water content and TEWL parameters. The sebum content was significantly higher on the oily skin group. The microrelief analysis showed an increase of skin roughness values in the oily skin and increase of scaliness in the normal/dry skin. The oily skin showed lower dermis echogenicity mainly in the frontal region and higher dermis thickness when compared to normal/dry skin. CONCLUSION: The mature oily skin showed different characteristics from normal/dry skin in terms of sebum content, microrelief parameters, and dermis thickness. This way, the characterization of mature oily skin in an objective way is very important to development of dermocosmetic products for more effective treatments focused specially on this type of skin.

Influence of UV filters on the texture profile and efficacy of a cosmetic formulation.

OBJECTIVE: Considering that many cosmetic products contain UV filters in their composition and that few studies have evaluated the role of UV filters in the physical properties and clinical efficacy of these products, the aim of this study was to assess the influence of UV filters on the properties and immediate effects of a cosmetic formulation. METHODS: Four cosmetic formulations, vehicle (V), vehicle containing UV filters (F), vehicle containing cassava polysaccharides and alfalfa (A) oligosaccharides and vehicle containing UV filters plus cassava polysaccharides and alfalfa oligosaccharides (multifunctional formulation, M) were developed. The texture profile of the formulations was analysed with a TA.XT plus Texturometer® . Twenty female volunteers aged 39-45 years were then selected for the assessment of immediate clinical efficacy of the formulations under study and of transepidermal water loss (TEWL), stratum corneum water content and microrelief of the skin obtained with their use. RESULTS: The presence of UV filters resulted in an improvement of the physical properties of the multifunctional cosmetic formulation (M) and of skin microrelief. However, the presence of UV filters also caused a significant decrease in hydration. CONCLUSION: The presence of sunscreens had a negative influence on immediate skin hydration and TEWL. On the other hand, it positively influenced parameters related to the physical properties of the multifunctional formulation and skin microrelief. Thus, we conclude that the influence of UV filters on the development of cosmetic formulations is an important factor to be considered because it can have either positive or negative effect on the efficacy of the product.

Physical-Mechanical characterization of cosmetic formulations and correlation between instrumental measurements and sensorial properties.

OBJECTIVE: The correct choice of raw materials in the development of cosmetic formulations is essential for obtaining stable and pleasant skin care products. Therefore, rheological, texture and sensory analyses are important to understand the behaviour and stability of the formulations. In this context, the aim of this study was to develop cosmetic formulations containing or not (vehicle) UV filters and chicory root extract, to evaluate their stability as well as to characterize their physical and texture properties and correlate them with the sensory attributes. METHODS: Four formulations containing organic UV filters and chicory extract, each alone or in combination, were developed and evaluated for 180 days with a cone and plate rheometer, a texture analyzer and consumer's sensorial analysis. Thus, the data obtained were correlated to observe the different influences. RESULTS: The developed formulations remained stable after 180 days regarding macroscopic aspects, organoleptic characteristics and pH values. The addition of the UV filters alone and in combination with the active substance resulted in significant increases in rheology properties, viscosity and consistency. The formulation with the active ingredient showed significant decreases in the texture parameters after 180 days, mainly due to its polysaccharide inulin. All formulations obtained high scores in sensorial parameters. A strong correlation was mainly found between spreadability and work of shear, and between the texture parameters. CONCLUSION: The raw materials strongly influenced the physical, texture and sensorial parameters. Finally, the UV filters showed a greater influence on the results of the formulations than the chicory root extract. In conclusion, the association of the mentioned methods allows the correct choice of ingredients and their combinations.

Mechanical characterization of curly hair: Influence of the use of nonconventional hair straightening treatments.

BACKGROUND/PURPOSE: Hair straighteners are very popular around the world, although they can cause great damage to the hair. Thus, the characterization of the mechanical properties of curly hair using advanced techniques is very important to clarify how hair straighteners act on hair fibers and to contribute to the development of effective products. On this basis, we chose two nonconventional hair straighteners (formaldehyde and glyoxylic acid) to investigate how hair straightening treatments affect the mechanical properties of curly hair. METHODS: The mechanical properties of curly hair were evaluated using a tensile test, differential scanning calorimetry (DSC) measurements, scanning electronic microscopy (SEM), a torsion modulus, dynamic vapor sorption (DVS), and Fourier transform infrared spectroscopy (FTIR) analysis. RESULTS: The techniques used effectively helped the understanding of the influence of nonconventional hair straighteners on hair properties. For the break stress and the break extension tests, formaldehyde showed a marked decrease in these parameters, with great hair damage. Glyoxylic acid had a slight effect compared to formaldehyde treatment. Both treatments showed an increase in shear modulus, a decrease in water sorption and damage to the hair surface. CONCLUSIONS: A combination of the techniques used in this study permitted a better understanding of nonconventional hair straightener treatments and also supported the choice of the better treatment, considering a good relationship between efficacy and safety. Thus, it is very important to determine the properties of hair for the development of cosmetics used to improve the beauty of curly hair.

Cichorium intybus root extract: A "vitamin D-like" active ingredient to improve skin barrier function.

During the aging process, the human skin suffers many alterations including dryness, skin barrier function damage. The skin barrier function is important to the prevention of skin alterations and maintenance of homeostasis. So, the objective of this study was to assess the clinical efficacy on skin barrier function of Cichorium intybus root extract in cosmetic formulations with or without UV filters. Fifty women, aged between 45 and 60 years, were divided into two groups. One group received vehicle formulations containing UV filters, and the other group received formulations without UV filters. Both groups received a formulation containing the extract and the vehicle. The formulations were applied twice daily to the upper arms after washing with sodium lauryl sulphate. Transepidermal water loss (TEWL) and skin microrelief were evaluated before and after a 14- and 28-day period of treatment. The control regions and regions where the vehicles were applied showed an increase in the TEWL. For the formulations containing the extract, decreased TEWL and improved microrelief were observed when compared to the vehicle and control areas after a 28-day period. In conclusion, Cichorium intybus root extract showed protective and restructuring effects on the skin and stands out as an innovative ingredient to improve skin barrier function.

Morphological, structural and biophysical properties of French and Brazilian photoaged skin.

BACKGROUND: Knowledge of skin biology and its alterations in different populations is very important for the development of appropriate skincare strategies. OBJECTIVES: To evaluate and compare morphological, structural and biophysical properties of photoaged skin in French and Brazilian populations, using biophysical and skin-imaging techniques. METHODS: Forty-one French and 41 Brazilian healthy, female volunteers aged between 40 and 65 years were enrolled. Each participant completed a questionnaire concerning habits related to cosmetic use, sun exposure and sun protection during different life periods. Skin on the face and volar forearm was evaluated using noninvasive techniques, to determine skin colour, transepidermal water loss (TEWL), stratum corneum water content, skin microrelief, skin viscoelasticity and dermis structure. Reflectance confocal microscopy was used to measure epidermal layer thickness and epidermal morphological and structural characteristics. RESULTS: Compared with Brazilian skin, French skin was more hydrated, had a lower TEWL and presented a distinct viscoelastic profile on the forearms and face. Brazilian facial skin was more wrinkled, and the dermis was less echogenic on the forearms and face. The French participants had thicker stratum corneum. Brazilian facial skin presented a higher prevalence of rete ridge effacement, low interkeratinocyte reflectance, huddled collagen and solar elastosis. CONCLUSIONS: Morphological, structural and biophysical differences were found when assessing the skin of the Brazilian and French participants, who were exposed to different environmental factors.

In vivo photoprotective effects of cosmetic formulations containing UV filters, vitamins, Ginkgo biloba and red algae extracts.

The aim of this study was to assess the photoprotective effects of cosmetic formulations containing UV filters, red algae, Porphyra umbilicalis, extracts and combinations of the extract with vitamins and Ginkgo biloba through the use of in vivo preclinical studies. For this study, 4 groups of 4 hairless mice each were treated with topical formulations applied on the dorsum for 5 days as follows: group 1 - control (no treatment); group 2 - application of the formulation F (sunscreen formulation containing only UV filters); group 3 - application of the formulation FA (sunscreen formulation with red algae extract); and group 4 - application of the formulation FVGA (sunscreen formulation with red algae extract, G. biloba and vitamins A, C and E). The effects of these formulations were evaluated by determining the transepidermal water loss (TEWL) and erythema index. Apoptosis was detected by immunohistochemical staining with anti-p53 and anti-caspase-3 antibodies. The results showed that the formulations protected the skin from erythema when exposed to UV radiation. The group that received the formulation FVGA presented a greater TEWL than did the other groups, suggesting that this formulation was involved in cell renewal. Immunohistochemical analysis showed that UV radiation caused an increase in the expression of p53 and active caspase-3, confirming that the damage caused by UV radiation exposure led to apoptosis. The application of all formulations studied resulted in a statistically significant reduction in the expression of p53 and caspase-3, with a more pronounced effect observed following treatment with FA. In conclusion, extracts from the red algae P. umbilicalis could be considered effective ingredients to be used in sunscreen formulations. The combination of vitamins A, E, C and G. biloba along with red algae extracts can improve significantly the performance of the sunscreens, preventing UV-induced DNA damage and inflammation. Thus, they should be considered an interesting combination for an effective photoprotective formulation with anti-aging properties.

Comparison of total water vapor column from GOME-2 on MetOp-A against ground-based GPS measurements at the Iberian Peninsula.

Water vapor column (WVC) obtained by GOME-2 instrument (GDP-4.6 version) onboard MetOp-A satellite platform is compared against reference WVC values derived from GPS (Global Positioning System) instruments from 2007 to 2012 at 21 places located at Iberian Peninsula. The accuracy and precision of GOME-2 to estimate the WVC is studied for different Iberian Peninsula zones using the mean (MBE) and the standard deviation (SD) of the GOME-2 and GPS differences. A direct comparison of all available data shows an overestimation of GOME-2 compared to GPS with a MBE of 0.7 mm (10%) and a precision quantified by a SD equals to 4.4mm (31%). South-Western zone presents the highest overestimation with a MBE of 1.9 mm (17%), while Continental zone shows the lowest SD absolute value (3.3mm) due mainly to the low WVC values reached at this zone. The influence of solar zenith angle (SZA), cloud fraction (CF), and the type of surface and its albedo on the differences between GOME-2 and GPS is analyzed in detail. MBE and SD increase when SZA increases, but MBE decreases (taking negative values) when CF increases and SD shows no significant dependence on CF. Under cloud-free conditions, the differences between WVC from GOME-2 and GPS are within the WVC error given by GOME-2. The changes of MBE and SD on Surface Albedo are not so evident, but MBE slightly decreases when the Surface Albedo increases. WVC from GOME-2 is, in general, more precise for land than for sea pixels.

Integrated approach in the assessment of skin compatibility of cosmetic formulations with green coffee oil.

OBJECTIVE: Green coffee oil (GCO) has been used in cosmetic formulations due to its emollient and anti-ageing properties. However, there are insufficient studies about its safety when applied in cosmetic formulations. METHODS: Cytotoxicity of GCO and of formulations containing 2.5-15% of GCO was evaluated by the MTT reduction assay, in human keratinocytes. Formulations containing 15% of GCO and the vehicle were applied under in use conditions in the volar forearm of human volunteers during 3 days. Transepidermal water loss, stratum corneum water content and erythema index were evaluated each 24 h using biophysical techniques. The same formulations were probed for skin tolerance through a patch test. RESULTS: Neither pure GCO nor its formulations showed cytotoxic effects in concentrations up to 100 µg mL(-1) . Transepidermal water loss values showed a slight reduction when the formulation containing GCO was applied. Stratum corneum water content and erythema index did not show significant differences, as the results observed in the first day of the study were maintained throughout 3 days. None of the volunteers display any reaction after using an occlusive patch. CONCLUSION: The results obtained in the study indicate that GCO seems to be safe for topical applications and showed good skin compatibility under the experimental conditions of the study.

Clinical scoring and instrumental analysis to evaluate skin types.

BACKGROUND: The biology of the skin is very complex, and there are a number of methods used to classify the different skin types. It is possible to measure or quantify the characteristics of the specific skin types, using a variety of techniques that can objectively evaluate the properties of the skin in a noninvasive manner. AIM: To clinically characterize different skin types by dermatological evaluation and biophysical and skin imaging techniques, and to evaluate the relationship between the different characteristics. METHODS: The study recruited 26 volunteers. Clinical scoring was performed by a dermatologist who classified the volunteers' skin as normal or dry (group 1) and combination or oily (group 2). Objective measurements included skin microrelief, pH, oiliness, water content of the stratum corneum and transepidermal water loss (TEWL). RESULTS: Positive correlations were found between the level of skin oiliness and skin texture obtained from both instrumental analysis and clinical scoring. The combination and oily skin types had higher clinical scores for shine intensity, oiliness and tendency to pigmentation, and also had higher objective scores for sebum secretion, TEWL and roughness. CONCLUSIONS: Biophysical and skin imaging techniques are effective tools to help characterize skin type and assist in clinical dermatology. We found that different skin types had different characteristics related to skin microrelief, oiliness and TEWL, and therefore require specific dermatological treatments.

Skin penetration of epigallocatechin-3-gallate and quercetin from green tea and Ginkgo biloba extracts vehiculated in cosmetic formulations.

Green tea (Camellia sinensis) and Ginkgo biloba extracts in cosmetic formulations have been suggested to protect the skin against UV-induced damage and skin ageing. Thus, it is very important to assess the human skin penetration of their major flavonoids to verify if they penetrate and remain in the skin to exert their proposed effects. The aim of this study was to evaluate the human skin penetration of epigallocatechin-3-gallate (EGCG) and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations. This study was conducted with fresh dermatomed human Caucasian skin from abdominal surgery mounted on static Franz diffusion cells. Skin samples were mounted between two diffusion half-cells and 10 mg/cm(2) of formulations supplemented with 6% of green tea or G. biloba extract were applied on the skin surface. The receptor fluid was removed after 6 and 24 h and analyzed by high-performance liquid chromatography for the quantification of the flavonoids. The stratum corneum was removed by tape stripping and immersed in methanol and the epidermis was mechanically separated from the dermis and triturated in methanol to extract EGCG and quercetin. The results showed that the flavonoids under study penetrated into the skin, without reaching the receptor fluid. The majority of EGCG was quantified in the stratum corneum (0.87 microg/cm(2)), which was statistically higher than the EGCG concentrations found in viable epidermis (0.54 microg/cm(2)) and in the dermis (0.38 microg/cm(2)). The majority of quercetin was quantified in the viable epidermis (0.23 microg/cm(2)), which was statistically higher than the EGCG concentration found in the stratum corneum layer (0.17 microg/cm(2)). Finally, it can be concluded that EGCG and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations presented good skin penetration and retention, which can favor their skin effects.

In vivo skin effects of a dimethylaminoethanol (DMAE) based formulation.

Dimethylaminoethanol (DMAE) has been used in anti-aging formulations but few scientifically based data address its efficacy. The aim of this study was to evaluate the effects of DMAE-based formulations on hairless mice and human skin. Formulations containing with or without DMAE were applied to the dorsum of hairless mice. Histopathological and histometric evaluations were carried out after seven days. Formulations were also applied to the ventral forearm and the lateral periocular area of human volunteers. Stratum corneum water content and skin mechanical properties were analyzed using Corneometer and Cutometer, before and after a single and repeated application. Histometric evaluations showed that formulations with or without DMAE increased the viable epidermis thickness, but only the DMAE-supplemented formulation led to increased dermal thickness. DMAE also induced increase in collagen fiber thickness, which was observed in the histopathological study. After the single and the 8-week period application on human skin, formulations with and without DMAE enhanced the stratum corneum water content in the forearm skin. Mechanical properties were not significantly modified. So, we can suggest that DMAE action is related to its effects on the dermis as observed in the histopathological and histometric studies and showed hydration effects on skin.

Shelf life and rheology of emulsions containing vitamin C and its derivatives

Ascorbic acid (AA), or vitamin C, is widely used in the pharmaceutical, cosmetic and food industries as an antioxidant and cosmetics containing AA have been gaining popularity in the last few years for the treatment of photoageing. To solve the problem of its low stability, some esters have been synthesised, such as magnesium ascorbyl phosphate (MAP), also available encapsulated in collagen-based microspheres (EMAP). The aim of this research was to study the physical and chemical stability of O/W emulsions containing AA, MAP or EMAP, by rheological and HPLC analysis, respectively. These emulsions were stored at 25, 37 and 45ºC for 28days and samples tested weekly during storage. It was concluded that all the formulations showed pseudoplastic behaviour. The presence of MAP provoked an initial rise in thixotropy. The formulation containing AA did not show any marked change in rheological behaviour. In the chemical analysis, the formulation with EMAP was more stable than those with MAP and AA. Hence, replacement of AA with EMAP in this cosmetic formulation may be a viable way to enhance the stability of the active principle.

Cosméticos contendo ácido ascórbico (AA) têm sido muito empregados nos últimos anos na prevenção e tratamento do fotoenvelhecimento cutâneo. Para solucionar o problema de sua baixa estabilidade, alguns derivados têm sido utilizados como substitutos dessa vitamina e dentre eles o Magnesium Ascorbyl Phosphate (MAP), disponível também em microesferas à base de colágeno (EMAP). O objetivo desta pesquisa foi estudar a reologia e a estabilidade química de emulsões contendo AA, MAP ou EMAP. Assim, formulações contendo AA, MAP ou EMAP foram armazenadas a 25, 37 e 45ºC durante 28 dias e avaliadas. Concluiu-se que todas as formulações apresentaram comportamento pseudoplástico. A presença de MAP provocou um aumento inicial da tixotropia e a formulação contendo AA não apresentou grande alteração no comportamento reológico. Nos estudos químicos a formulação contendo EMAP foi mais estável que o MAP e AA, com o maior prazo de validade. Desta forma, a substituição de AA pela EMAP em cosméticos pode ser uma alternativa viável do ponto de vista da estabilidade da formulação.

Evaluation of dermatological effects of cosmetic formulations containing Saccharomyces cerevisiae extract and vitamins.

Saccharomyces cerevisiae extract (SCE) is used in cosmetics since it can act in oxidative stress and improve skin conditions. This study investigated dermatological effects of cosmetic formulations containing SCE and/or vitamins A, C and E. The formulation studied was supplemented or not (F1: vehicle) with vitamins A, C and E esters (F2) or with SCE (F3) or with the combination of vitamins and SCE (F4). Formulations were patch tested on back skin of volunteers. For efficacy studies, formulations were applied on volunteers and transepidermal water loss (TEWL), skin moisture (SM), skin microrelief (SMR) and free radicals protection were analysed after 3h, 15 and 30 days of application. Volunteers were also asked about efficacy perception. It was observed that F4 provoked a slight erythema in one volunteer. All formulations enhanced forearm SM. Only F3 and F4 presented long term effects on SMR and showed higher texture values; F3 had the highest brightness values. Our results suggest that vitamins and SCE showed effects in SM and SMR. Only formulations containing SC had long term effects in the improvement of SMR. Thus, these kinds of evaluations are very important in cosmetics development to evaluate the best risk and benefit correlation.

GRK2-dependent desensitization downstream of G proteins.

G protein-coupled receptor kinases (GRKs) are serine/threonine kinases first discovered by its role in receptor desensitization. Phosphorylation of the C-terminal tail of GPCRs by GRKs triggers the docking of beta-arrestins and the functional uncoupling of G proteins and receptors. In addition, we and others have uncovered new direct ways by which GRKs could impinge into intracellular signalling pathways independently of receptor phosphorylation. In particular, we have characterized that elevated GRK2 levels can reduce CCR2-mediated activation of the ERK MAPK route in a manner that is independent of kinase activity and also of G proteins. This inhibition of ERK occurred in the absence of any reduction on MEK phosphorylation, what implicates that GRK2 is acting at the level of MEK or at the MEK-ERK interface to achieve a downregulation of ERK phosphorylation. In fact, we describe here that a direct association between GRK2 and MEK proteins can be detected in vitro. p38 MAPK pathway also appears to be regulated directly by GRK2 in a receptor-independent manner. p38 can be phosphorylated by GRK2 in threonine 123, a residue sitting at the entrance of a docking groove by which this MAPK associates to substrates and upstream activators. The T123phospho-mimetic mutant of p38 shows a reduced ability to bind to MKK6, concomitant with an impaired p38 activation, and a decreased phosphorylation of downstream substrates such as MEF2, MK2 and ATF2. Elevated levels of GRK2 downregulate p38-dependent cellular responses, such as differentiation of preadipocytic cells, while LPS-induced cytokine release is enhanced in macrophages from GRK2 (+/-) mice. In sum, we describe in this article different ways by which GRK2 directly regulates MAPK-mediated cellular events. This regulation of the MAPK modules by GRK2 could be relevant in pathological situations where the levels of this kinase are altered, such as during inflammatory diseases or cardiovascular pathologies.

Photostability and efficacy studies of topical formulations containing UV-filters combination and vitamins A, C and E.

It is already known that the photostability of a sunscreen is important for its performance on human skin. On the other hand, there are many formulations besides sunscreens containing combinations of UV-filters and daily use active substances with other claims like hydration and anti-aging effects. Vitamins A, C and E are frequently added in these kinds of products and it is not known if the UV-filters have some influence on the hydration and anti-aging effects of these vitamins on the skin as well as on their stability mainly when photounstable UV-filters like avobenzone and octyl methoxycinnamate are present in the formulation. Thus, the aim of this study was to evaluate the influence of two different UV-filters combinations, a photostable and a photounstable one, on the photostability as well as on the efficacy of a formulation containing vitamin A, C and E derivatives. The formulations that were investigated contained or not (vehicle: formulation 1) a combination of 0.6 % (w/w) vitamin A palmitate (1,700,000 UI/g), 2 % (w/w) vitamin E acetate and 2% (w/w) ascorbyl tetraisopalmitate (formulation 2) supplemented with a photounstable UV filter combination octyl methoxycinnamate (OMC), avobenzone (AVB) and 4-methylbenzilidene camphor (MBC) (formulation 3) or with a photostable UV filter combination OMC, benzophenone-3 (BP-3) and octocrylene (OC) (formulation 4). In the photostability studies, all formulations were spread onto a glass plate and exposed to UVA/UVB irradiation. The filter components and vitamins were quantified by HPLC analysis with detection at 325 and 235 nm and by spectrophotometry. To simulate the effects of these formulations daily use, all of them (formulations 1-4) were applied on the dorsum of hairless mice, which were submitted to a controlled light-dark cycle (and were not irradiated), once a day for 5 days. Transepidermal water loss (TEWL), water content of the stratum corneum and viscoelastic properties of the skin were analyzed by using different non-invasive Biophysics Techniques in order to evaluate hydration and anti-aging effects of these formulations as well as erythema to assess skin irritation. Histopathology, viable epidermal thickness as well as the number of epidermal cell layers were also evaluated. It was observed that both UV filters combinations (photounstable one containing OMC, AVB and MBC and photostable one containing OMC, BP-3 and OC) enhanced vitamin A photostability and F4 was more photostable than F3, in terms of vitamin A. In vivo efficacy studies showed that F2, F3 and F4 enhanced the viable epidermal thickness, the number of epidermal cell layers, TEWL and Uv/Ue parameter, when compared to the vehicle, which can suggest that they enhanced viable epidermis hydration and acted in cell renewal. However formulation 2 (containing only vitamins), which was the most photounstable formulation, provoked an irritation on hairless mouse skin, and consequently it cannot be considered as safe as the other formulations. It can be concluded that both UV filters combinations did not influence the hydration and anti-aging effects of the formulations containing the vitamins under study and reduced the skin irritation observed when the vitamins were present in the formulation. In addition, the photostable UV-filters combination had the highest recovery of vitamin A in the photostability studies. Finally, it could be suggested that the presence of UV-filters can be considered interesting for the reduction of skin irritation and the most suitable formulation was the one containing the combinations of vitamins A, C and E with photostable UV-filters.