Cosmetic formulations containing <Emphasis Type="Italic">Lithospermum erythrorhizon</Emphasis> root extract show moisturizing effects on human skin

Retention of water in the stratum corneum of skin epidermis plays an important role in regulation of skin function. Loss of water may decline skin appearance gradually and lead to irregular skin disorders. The root extract of Lithospermum erythrorhizon (LES) is known for its various pharmacological activities. However, the potential skin care effect of LES is not clear. The aim of this study was to evaluate the moisturizing efficacy and skin barrier repairing activity of LES. For this study, 30 healthy Asian females (age 20-30) with healthy skin had applied the test emulsions twice daily over a period of 28 days. The skin properties were measured by skin bioengineering techniques. Our preliminary results indicated that LES show moisturizing effect on skin hydration in a time- and dose-dependent pattern, and the maximum increase in skin humidity was 11.77 +/- 1.18% for emulsion LES5.00. Particularly, LES-containing emulsions significantly improve skin barrier function by decreasing the value of transepidermal water loss (TEWL) in a time- and dose-dependent pattern, and the maximum decrease in TEWL value was 7.68 +/- 0.79% for emulsion LES5.00. Taken together, our data demonstrate that LES is more effective in increasing skin humidity and decreasing the TEWL values, indicating the potential skin care effects of LES.     

EIectrical impedance and transepidermal water loss of healthy human skin under different conditions

Background/aims: The skin barrier function is a multidimensional quality, which can be defined by a combination of noninvasive measurements, including EIectrical impedance (EI) and transepidermal water loss (TEWL). Methods: TEWL and EI were determined on in five different areas of the body in 25 healthy volunteers. The effects of hydration (a 15 min water bath, a 1 h occlusion and application of an oil-in-water emulsion combined with occlusion) were measured on the volar forearm. Results: EI was highest in the axillary region, followed by the cheek, spinal region, presternal area and upper arm. TEWL was highest in the axillary region, followed by the cheek. Lowest levels were detected in the spinal region, the presternal region and the upper arm. The water bath increased EI but not TEWL. After 1 h occlusion TEWL was not increased and EI decreased, which corresponds to stratum corneum hydration. After a single application of an oil-in-water emulsion, we observed a reduction of EI and an increase of TEWL. The simultaneous use of occlusion and application of an emulsion led to the most significant reduction of EI. TEWL was increased during the following 30 min. Conclusions: EI and TEWL show a topological variability. Acute hydration increased EI but occlusion and/or moisturizing decreased EI. Acute hydration and occlusion alone did not significantly affect TEWL, but moisturizing in combination caused a longer lasting TEWL increase. To examine the stratum corneum function, the use of different noninvasive techniques seem to provide more complex information.     

Influence of surfactant mixtures on intercellular lipid fluidity and skin barrier function

Background/aims: Surfactant mixtures are used in cosmetic and pharmaceutical formulas in order to establish product efficacy while maintaining mildness and skin lipids. The electron paramagnetic resonance (EPR) technique of the spin labeling method with a nitroxide spin probe is a valuable method in the study of biological membranes. The objective of this study was to define the influence of surfactant mixtures on intercellular lipid fluidity and correlate EPR spectral data with in vivo safety data. Methods: EPR experiment: EPR spectra of 5-doxyl stearic acid (5-DSA) labeled stratum corneum treated with sodium lauryl sulfate (SLS), sodium lauroyl glutamate (SLG) and their mixtures were measured and order parameters were calculated. Clinical testing: Fifteen healthy volunteers free of skin disease and with no history of atopic dermatitis were treated with SLS solutions (0.25%, 0.50%, 0.75%, 1.00%), 1.00% SLG solution and 1.00% surfactant mixture solutions: 0.75% SLS+0.25% SLG, 0.50% SLS+0.50% SLG, 0.25% SLS+0.75% SLG. One hundred μl of solution was applied using a polypropylene chamber for 24 h. Transepidermal water loss (TEWL) was measured with an evaporimeter before and after the application of surfactant solutions and each site was also visually graded according to Lee (1). Results: The order parameter (S) calculated from 1.00 %wt SLS treated stratum corneum was 0.56 ± 0.03, indicating disordering of lipid structure. On the contrary, the high S value (0.82 ± 0.02) for 1.00 %wt SLG suggests a reduced effect on the structured lipid, almost equaling the value of water. Treatment with 0.25 %wt, 0.50 %wt and 0.75 %wt SLS solutions revealed intermediate levels between 1.00 %wt SLG and SLS. The order parameters at each SLS concentration (0.25, 0.50, 0.75 and 1.00 %wt SLS) with 1.00 %wt SLG showed higher values than those of SLS only solutions. There were statistically significant differences between with and without 1.00 %wt SLG (P < 0.05). These results suggest that the addition of 1.00 %wt SLG inhibits the fluidization of intercellular lipid induced by SLS. The visual scores and TEWL values of 1.00% SLG solution were lower than those of the other test solutions (except for the vehicle control: deionized water). The 1.00% surfactant mixture solutions showed lower visual scores and TEWL values of the 1.00% SLS solution. An increase of SLG concentration decreased the visual scores and TEWL values. Order parameter S obtained from EPR spectra correlated with the clinical study. The correlation coefficient (r²) of visual score and TEWL values was 0.73 and 0.83, respectively. Conclusion: SLS disorder (fluidity) intercellular lipids at low concentrations, such as 0.25 %wt, presumably due to the SLS molecules being intercalated into the intercellular lipids. However, EPR spectral data suggest that the addition of 1.00 %wt SLG to an SLS solution (<1.00 %wt) inhibits the fluidization of intercellular lipid induced by SLS. A reasonable correlation between order parameters and human clinical data (visual scores and TEWL values) was observed (r²=0.73 and 0.83, respectively). The use of the EPR spin labeling method for predicting the fluidity of stratum corneum should give further insight into the mechanism of epidermal barrier disruption by surfactants and possibly other chemicals.     

A double-blind, placebo-controlled study of a commercial Aloe vera gel in the treatment of slight to moderate psoriasis vulgaris

BACKGROUND: The Aloe vera plant has been used for an array of ailments, including skin diseases. Recent experimental research have substantiated the presence of biologically active compounds in the gel, but there are few controlled, clinical trials to assess the efficacy. OBJECTIVE: To test the effect of a commercial, preserved, but otherwise untreated Aloe vera gel in psoriasis. PATIENTS/METHODS: Forty-one patients with stable plaque psoriasis were included in a randomized, double-blind, placebo-controlled right/left comparison. The study comprised a 2-week wash-out period followed by a 4-week treatment period with two daily applications and follow-up visits after 1 and 2 months. RESULTS: Data on 40 patients were analysed. The score sum of erythema, infiltration and desquamation decreased in 72.5% of the Aloe vera-treated sites compared with 82.5% of the placebo-treated areas from week 0 to week 4, which was statistically significant in favour of the placebo treatment (P = 0.0197). Fifty-five per cent of the patients reported local side-effects, mainly drying up of the skin on test areas. CONCLUSIONS: The effect of this commercial Aloe vera gel on stable plaque psoriasis was modest and not better than placebo. However, the high response rate of placebo indicated a possible effect of this in its own right, which would make the Aloe vera gel treatment appear less effective.     

Silk sericin as a moisturizer: an in vivo study

Background Excessive transepidermal water loss (TEWL) is the one of the causes of dry skin, and skin moisturizers have been used to overcome it. Aim The purpose of this research was to study the moisturizing effect of sericin, a silk protein. Because silk sericin has resemblance with the natural moisturizing factor (NMF), it has been studied for its application in skin cosmetics. Methods Sericin gels were prepared using sericin solution and with pluronic and carbopol as stabilizers. The gels were applied on the skin of healthy human volunteers and its moisturizing efficiency was evaluated by measuring the skin hydroxyproline content, impedance, TEWL, and scanning electron microscopy (SEM) results. Results Decrease in skin impedance, increase in hydroxyproline level, and hydration of epidermal cells revealed the moisturizing effect of sericin, whereas decrease in the value of TEWL may be attributed to occlusive effect, which prevents water loss from the upper layer of the skin. Skin surface topography revealed the smoothness of the upper layer of the skin as a result of moisturization. Conclusion Increase in the intrinsic moisturization of skin by sericin may be attributed to restoration of the amino acids and its occlusive effect. Thus, it would become a promising and important moisturizing ingredient in moisturizing formulations.     

Defective barrier function accompanied by structural changes of psoriatic stratum corneum

Although barrier function of psoriatic skin is shown to be decreased by measuring transepidermal water loss (TEWL), few reports exist examining other physical skin properties and components including stratum corneum hydration, natural moisturizing factor (NMF), free fatty acids (FFA), β‐sheet and α‐helix ratio of structural protein(s), and sebum content. We compared the skin properties and components of normal, involved and uninvolved skin of psoriasis. Using a corneometer and attenuated total reflection‐infrared spectrometer, we measured TEWL, stratum corneum hydration, NMF, FFA, β/α ratio and sebum in psoriasis vulgaris patients and healthy controls. TEWL and β/α ratio of involved psoriatic skin were significantly increased compared with uninvolved skin and normal control skin. In contrast, stratum corneum hydration , NMF and FFA, but not sebum, are significantly decreased in the involved skin compared with uninvolved skin and normal skin. TEWL and stratum corneum hydration returned to the normal levels following clinical improvement of the lesion. Barrier function and hydration of psoriatic skin are defective and secondary structure in stratum corneum protein is altered in the involved psoriatic skin.     

Improvement of mild inflammatory changes of the facial skin induced by winter environment with daily applications of a moisturizing cream. A half-side test of biophysical skin parameters, cytokine expression pattern and the formation of cornified envelope

OBJECTIVE: Based on our previous findings that, reflecting mild inflammation, the exposed facial skin shows much poorer functional properties of the stratum corneum (SC) in the dry and cold winter than those evaluated in the same individuals in the warm and humid summer time, we conducted a half-side test on the face to determine how the facial skin changes induced by a winter environment are improved by daily applications of a moisturizing cream as assessed by non-invasive biophysical and cytological methods. METHODS: One side of the face of 16 young females was treated with a moisturizing cream twice daily for 6 weeks, with the other side serving as the non-treated control. Before treatment, 3 and 6 weeks after the start of the treatment, high-frequency conductance as a parameter of the skin surface hydration, transepidermal water loss (TEWL), a parameter of the water barrier function of the skin, and the skin surface lipid level were measured on the cheeks. Obtaining the SC from the skin surface by adhesive tape, interleukin (IL) 1alpha and IL-1 receptor antagonist (IL-1ra) in the SC and cornified envelope (CE) maturation were determined. RESULTS: At first, baseline measurements conducted before treatment showed rather high TEWL values suggestive of an impaired skin barrier. During the treatment with the moisturizing cream, significantly higher conductance values and lower TEWL values were found on the moisturizer-treated side, accompanied by a decreasing IL-1ra/IL-1alpha ratio and immature CEs. CONCLUSION: These results suggested that the daily application of a moisturizing cream is effective in improving mild subclinical inflammation that is induced on the facial skin by the winter environment.     

The 24‐hr, 28‐day,and 7‐day post‐moisturizing efficacy of ceramides 1, 3, 6‐II containing moisturizing cream compared with hydrophilic cream on skin dryness and barrier disruption in senile xerosis treatment

Direct replacement of decreased ceramides in the stratum corneum can be efficacious for skin hydration, skin barrier function, and skin pH. Our study aimed to evaluate the 24‐hr, 28‐day, and 7‐day post‐moisturizing efficacy of ceramide‐containing moisturizer in senile xerosis treatment. A split site, double‐blinded, randomized, controlled study was conducted in 24 senile subjects (91.7% females, mean age 54.83 ± 5.45 years) with mild to moderate xerosis, who were randomized to receive ceramide‐containing moisturizer or hydrophilic cream, daily applied on each side of the shin. A single application of ceramide‐containing moisturizer increased skin hydration, while improving transepidermal water loss (TEWL) and skin pH for up to 24 hr, with statistically significant difference. After 28 days of twice‐daily application, more significant improvement on skin hydration, barrier function, and skin pH was observed in those with ceramide‐containing moisturizer at all‐time points. At day 28, there was a statistically significant decrease of hemoglobin index, wrinkle, and texture on the ceramide treated side. The 7‐day post‐moisturizing efficacy on the ceramide treated side was superior for skin hydration, TEWL, skin pH, and wrinkle. Thus, the ceramide‐containing moisturizer can be a novel promising treatment for senile xerosis.     

Stratum corneum cytokines and skin irritation response to sodium lauryl sulfate

Little is known about cytokines involved in chronic irritant contact dermatitis. Individual cytokine profiles might explain at least part of the differences in the individual response to irritation. Our objective was to investigate the relation between baseline stratum corneum (SC) cytokine levels and the skin response to a single and a repeated irritation test. This study also aimed to determine changes in SC cytokine levels after repeated irritation. Transepidermal water loss (TEWL) and erythema were measured in 20 volunteers after single 24-hr exposure to 1% sodium lauryl sulfate (SLS), and during and after repeated exposure to 0.1% SLS over a 3-week period. SC cytokine levels were measured from an unexposed skin site and from the repeatedly exposed site. Interleukin (IL)-1alpha decreased by 30% after repeated exposure, while IL-1RA increased 10-fold and IL-8 increased fourfold. Baseline IL-1RA and IL-8 values were predictors of TEWL and erythema after single exposure (r = 0.55-0.61). 6 subjects showed barrier recovery during repeated exposure. Baseline IL-1RA and IL-8 levels are likely to be indicators of higher skin irritability after single exposure to SLS. Barrier repair in some of the subjects might explain the lack of agreement between the TEWL response after single and repeated irritation.     

Effects of glycerol on human skin damaged by acute sodium lauryl sulphate treatment

Glycerol, widely used as humectant, is known to protect against irritants and to accelerate recovery of irritated skin. However, most studies were done with topical formulations (i.e. emulsions) containing glycerol in relatively high amounts, preventing drawing conclusions from direct effects. In this study, acute chemical irritations were performed on the forearm with application of a 10% sodium lauryl sulphate (SLS) aqueous solution under occlusion for 3 h. Then, glycerol aqueous solutions from 1 to 10% were applied under occlusion for 3 h. After elimination of moist excess consecutive to occlusive condition, in ambient air for 15 and 30 min, skin barrier function was investigated by dual measurement of skin hydration and transepidermal water loss (TEWL). Treatments with SLS solution under occlusion significantly increased TEWL and decreased skin hydration as assessed by capacitance measurements. The SLS irritant property was raised by the occlusion and the water barrier function as well as water content appeared impaired. Recovery with glycerol at low doses was remarkable through a mechanism that implies its hygroscopic properties and which is saturable. This precocious effect acts through skin rehydration by enhancing water-holding capacity of stratum corneum that would facilitate the late physiological repair of impaired skin barrier. Thus, glycerol appears to substitute for natural moisturizing factors that have been washed out by the detergent action of SLS, enhancing skin hydration but without restoring skin barrier function as depicted by TEWL values that remained high. Thus, irritant contact dermatitis treated with glycerol application compensate for skin dehydration, favouring physiological process to restore water barrier function of the impaired skin. Empirical use of glycerol added topical formulations onto detergent altered skin was substantiated in the present physicochemical approach.     

Electrical measurement of moisturizing effect on skin hydration and barrier function in psoriasis patients

Transepidermal water loss (TEWL) in psoriatic skin lesions seems to be related to the severity of the psoriasis, and the electrical capacitance and conductance of the skin are indicators of the hydration level of the stratum corneum. We compared the characteristics of these electrical measurements, in assessing the persistent effect of a moisturizing cream on skin hydration and barrier function in psoriasis patients. Seventeen Korean psoriasis patients were recruited. Their right leg was treated with the moisturizer twice daily for 6 weeks, while their left leg was used as the control site. For each patient, one psoriatic plaque on each leg was selected as the involved psoriatic lesion. Uninvolved psoriatic skin was regarded as the apparently healthy looking skin 4-5 cm away from the periphery of the psoriatic lesion. The TEWL, electrical capacitance and conductance were measured, in order to evaluate the barrier function and hydration level of the stratum corneum. The clinical and biophysical data for each patient were recorded at the start of the study and after 2, 4 and 6 weeks. The degree of skin dryness at the applied area improved progressively. The electrical capacitance at the treated psoriatic lesion increased significantly after 2 weeks, and this improvement was maintained during the entire study period. However, no noticeable change was observed in the electrical conductance. The TEWL showed an inverse pattern to that of the skin capacitance, decreasing during the study period. The skin capacitance and TEWL exhibited good correlation with the visual assessment of skin dryness, but the skin conductance did not. Our data suggest that electrical capacitance and TEWL may be useful in the evaluation of the effect of a moisturizer on the hydration status and barrier function of psoriatic skin.     

Role of Topical Emollients and Moisturizers in the Treatment of Dry Skin Barrier Disorders

Emollients and moisturizing creams are used to break the dry skin cycle and to maintain the smoothness of the skin. The term 'moisturizer' is often used synonymously with emollient, but moisturizers often contain humectants in order to hydrate the stratum corneum. Dryness is frequently linked to an impaired barrier function observed, for example, in atopic skin, psoriasis, ichthyosis, and contact dermatitis. Dryness and skin barrier disorders are not a single entity, but are characterized by differences in chemistry and morphology in the epidermis. Large differences also exist between moisturizing creams. Moisturizers have multiple functions apart from moistening the skin. Similar to other actives, the efficacy is likely to depend on the dosage, where compliance is a great challenge faced in the management of skin diseases. Strong odor from ingredients and greasy compositions may be disagreeable to the patients. Furthermore, low pH and sensory reactions, from lactic acid and urea for example, may reduce patient acceptance. Once applied to the skin, the ingredients can stay on the surface, be absorbed into the skin, be metabolized, or disappear from the surface by evaporation, sloughing off, or by contact with other materials. In addition to substances considered as actives, e.g. fats and humectants, moisturizers contain substances conventionally considered as excipients (e.g. emulsifiers, antioxidants, preservatives). Recent findings indicate that actives and excipients may have more pronounced effects in the skin than previously considered. Some formulations may deteriorate the skin condition, whereas others improve the clinical appearance and skin barrier function. For example, emulsifiers may weaken the barrier. On the other hand, petrolatum has an immediate barrier-repairing effect in delipidized stratum corneum. Moreover, one ceramide-dominant lipid mixture improved atopic dermatitis and decreased transepidermal water loss (TEWL) in an open-label study in children. In double-blind studies moisturizers with urea have been shown to reduce TEWL in atopic and ichthyotic patients. Urea also makes normal and atopic skin less susceptible against irritation to sodium laurilsulfate. Treatments improving the barrier function may reduce the likelihood of further aggravation of the disease. In order to have optimum effect it is conceivable that moisturizers should be tailored with respect to the epidermal abnormality. New biochemical approaches and non-invasive instruments will increase our understanding of skin barrier disorders and facilitate optimum treatments. The chemistry and function of dry skin and moisturizers is a challenging subject for the practicing dermatologist, as well as for the chemist developing these agents in the pharmaceutical/cosmetic industry.     

In vitro antioxidant activity and in vivo efficacy of topical formulations containing vitamin C and its derivatives studied by non-invasive methods

Background/purpose: Vitamins C and its derivatives, mainly due to their antioxidant properties, are being used in cosmetic products to protect and to reduce the signs of ageing. However, there are no studies comparing the effects of vitamin C [ascorbic acid (AA)] and its derivatives, magnesium ascorbyl phosphate (MAP) and ascorbyl tetra‐isopalmitate (ATIP), when vehiculated in topical formulations, mainly using objective measurements, which are an important tool in clinical efficacy studies. Thus, the objective of this study was to determine the in vitro antioxidant activity of AA and its derivatives, MAP and ATIP, as well as their in vivo efficacy on human skin, when vehiculated in topical formulations. Methods: The study of antioxidant activity in vitro was performed with an aqueous and a lipid system. The in vivo methodology consisted of the application of these formulations on human volunteers' forearm skin and the analysis of the skin conditions after 4‐week period daily applications in terms of transepidermal water loss (TEWL), stratum corneum moisture content and viscoelasticity using a Tewameter^®, Corneometer^® and Cutometer^®, respectively. Results: In vitro experiments demonstrated that in an aqueous system, AA had the best antioxidant potential, and MAP was more effective than ATIP, whereas in the lipid system ATIP was more effective than MAP. In in vivo studies, all formulations enhanced stratum corneum moisture content after a 4‐week period daily applications when compared with baseline values; however, only the formulation containing AA caused alterations in TEWL values. The formulations containing MAP caused alterations in the viscoelastic‐to‐elastic ratio, which suggested its action in the deeper layers of the skin. Conclusion: AA and its derivates presented an in vitro antioxidant activity but AA had the best antioxidant effect. In in vivo efficacy studies, only the formulation containing AA caused alterations in TEWL values and the formulation containing MAP caused alterations in the viscoelastic‐to‐elastic ratio. This way, vitamin C derivatives did not present the same effects of AA on human skin; however, MAP showed other significant effect‐improving skin hydration, which is very important for the normal cutaneous metabolism and also to prevent skin alterations and early ageing.     

Moisturizing and antisebum effect of cosmetic application on facial skin

Background Water content of the stratum corneum and skin surface lipids are important factors in the appearance and function of skin. High water content and low sebum secretion are considered main features of fair skin. Aim This paper aims to study the change of skin physiological parameters after cosmetic application. Methods The skin water content, transepidermal water loss, and skin sebum secretion on different regions of the facial skin before and after the cosmetic application were measured using Corneometer, Tewameter, and Sebumeter, respectively. Results The cosmetics kept higher water content and lower transepidermal water loss, at the same time lower sebum secretion 4  and 8 h after the cosmetic application, compared with those before it. The situation was maintained in the following 3‐week continuous use of the cosmetics. Conclusion The cosmetic application on human facial skin could provide some moisturizing effect and at the same time some antisebum effect according to different regions on facial skin, which favored the maintenance of good skin physiological function after applying skin care products.     

Increased stratum corneum turnover induced by subclinical irritant dermatitis

The chronic effects of the irritant sodium lauryl sulphate (SLS) on stratum corneum (SC) barrier function, determined by transepidermal water loss (TEWL) measurements and on epidermal cell kinetics, estimated by stratum corneum turnover time (SCTT) determination (dansyl chloride staining method), were investigated in 18 healthy female volunteers. SLS (7.5%) was applied without occlusion for 20 min once daily, over a period of 3 weeks (5 days a week) on dansyl chloride-stained skin and on untreated skin. SCTT of untreated skin (19.3 +/- 0.8 days; mean +/- SEM) was not changed by daily treatment with water (control) (19.3 +/- 2.0) but was significantly reduced by SLS (10.9 +/- 0.6; P less than or equal to 0.0001; compared to controls). However, TEWL was increased in SLS-treated sites 1.5-fold after 4 days of treatment (5.3 +/- 0.6 vs. 3.5 +/- 0.3; P less than 0.001). At the end of the second week, TEWL was increased 2.6-fold and after 3 weeks TEWL was 3.3 times higher than in controls 13.0 +/- 1.6 vs. 3.9, P less than or equal to 0.0001). The intensity of SLS-induced irritation as measured by TEWL was significantly correlated with baseline TEWL (r = 0.50; P less than or equal to 0.02) and significantly negatively correlated with SCTT of SLS treated sites (r = -50; P less than or equal to 0.02) but not with SCTT of untreated skin (r = 0.19).     

Repair of acetone- and sodium lauryl sulphate-damaged human skin barrier function using topically applied emulsions containing barrier lipids

BACKGROUND: It is generally acknowledged that well-formulated moisturizing skin care products can restore disturbed barrier function that can be assessed by transepidermal water loss (TEWL) measurements. When ceramides and/or other barrier lipids are incorporated, it is, however, not always clearly demonstrated which ingredients of the formulation exert the beneficial effects. OBJECTIVES: In this study the effects of topically applied ceramide-containing mixtures on the barrier repair of sodium lauryl sulphate (SLS)- and acetone-induced skin damage have been studied in human volunteers. TEWL and stratum corneum hydration measurements were carried out. The emulsions applied contained either a mixture of two types of ceramides, CerIII and CerIIIB (emulsion 1) or a complete mixture of ceramides III, IIIB and VI together with phytosphingosine, cholesterol and the free fatty acid linoleic acid (emulsion 2). RESULTS: After SLS damage, it was observed that barrier recovery was significantly accelerated by topical application (14 days, 2 x/d) of emulsion 2 compared with the results obtained with emulsion 1. Corneometrical results were not relevant due to the occurrence of scaly fissured skin, failing to provide a good skin/probe contact. Although no effect on TEWL could be observed, the improvement of skin hydration after acetone treatment and a single application of the emulsions, was significantly more positive for emulsion 2 than for emulsion 1. CONCLUSIONS: The investigative methods used in this study show that ceramides combined with other skin lipids can improve barrier repair after damage.     

Hydrating effects of a corticoid oil formulation and its vehicle on human skin

Factors in the treatment of atopic dermatitis include restoring skin moisture and reducing inflammation. This study evaluated a corticoid oil formulation and its components with respect to their skin hydration potential. Ten healthy Caucasians were enrolled. Five test sites on the left and right forearm of each subject were tested: one site served as a normal skin control (without treatment), whereas four were wetted by spraying distilled water (approximately 0.1 ml) over a 3-cm2 skin surface area, and spraying was repeated every 5 min for a total of three applications. Five minutes after the final application, 0.2 ml of the corticoid oil formulation, moisturizing vehicle, and plain peanut oil were applied to each pre-designated site (3 cm2); one site was kept as a blank control (water saturation only). Thirty minutes later, test sites were gently wiped with paper tissues, and visual scoring, transepidermal water loss (TEWL), and capacitance were recorded and repeated at 2 and 3 h. The corticoid oil formulation, plain peanut oil, and moisturizing vehicle significantly increased skin hydration 30 min after each single application, with no statistically significant difference among the treatments at any point. The corticoid oil formulation and plain peanut oil slightly but not significantly elevated TEWL 30 min after application. The results support intuitive dermatologic judgment of advising patients to apply moisturizing medicaments after bathing.     

Protection effect of cosmetics on human skin under simulated rigorous environment.

BACKGROUND/PURPOSE: The efficacy of cosmetics on human skin measured under normal mild laboratory environment might be discounted by exterior environment factors such as wind, UV exposure, etc. Few studies have focused on the 'genuine' efficacy of cosmetics on human skin during exposure to external rigorous environment. The aim of this study was to develop a model for the evaluation of the efficacy of cosmetics on human skin under simulated rigorous environment. METHODS: We measured skin water content and transepidermal water loss (TEWL) before and after products application under simulated windy and sub-erythema UV exposure treatment in a constant temperature and humidity laboratory. RESULTS: The results showed that the products had higher water content and lower TEWL at 2, 4 and 8 h of products application, and ameliorated the skin moisturization situation after a 3-week continuous use of the products. In addition, the products might protect the skin to maintain the normal water content and TEWL under the simulated windy or sub-erythema UV exposure treatment in our laboratory when compared with untreated area. CONCLUSION: Our data indicate that this model may provide a more accurate evaluation for the genuine moisturizing effect of cosmetics under external natural climate.     

Facilitating facial retinization through barrier improvement

The utility of topical tretinoin as a treatment for improving the appearance of photodamaged skin is limited by irritation that occurs during the early phases of facial retinization. The observed side effects are consistent with stratum corneum barrier compromise. This paired double-blinded study was conducted to determine if preconditioning the skin with a barrier-enhancing cosmetic facial moisturizer before beginning tretinoin therapy and continuing moisturizer application during therapy would mitigate these side effects. Women with facial photodamage were recruited and randomly assigned to apply one cosmetic moisturizer to one side of the face and the other cosmetic moisturizer to the other side of the face twice daily for 10 weeks. One moisturizer contained a mixture of vitamins (niacinamide, panthenol, and tocopheryl acetate) to enhance stratum corneum barrier function, and the other moisturizer contained similar moisturizing ingredients but no vitamins. Daily full-face treatment with tretinoin cream 0.025% commenced 2 weeks into the study. Subjects' facial skin condition was monitored via investigator assessments, instrumental measurements, and subject self-assessments. The results show that improving stratum corneum barrier function before beginning topical tretinoin therapy and continuing use of a barrier-enhancing cosmetic moisturizer during therapy facilitates the early phase of facial retinization and augments the treatment response.