Test guidelines for the assessment of skin tolerance of potentially irritant cosmetic ingredients in man. European Cosmetic, Toiletry and Perfumery Association

Formulation and evaluation of antioxidant and antibacterial activity of a peel-off facial masks moisturizer containing curcumin and Rosa Damascena extract

BACKGROUND

Acne is a common skin issue that typically occurs during adolescence. It causes long-lasting redness and swelling in the skin. An alternative approach to treating acne could involve using a cosmetic facial mask containing herbal ingredients such as Curcumin and Rosa Damascena extract for its antibacterial properties.

AIMS

This study aims to create and try out a peel-off mask gel made from Curcumin and R. Damascena extract. This gel is intended to have the ability to kill bacteria such as Staphylococcus aureus, Escherichia coli, and Propionibacterium acnes and remove dead cells from the skin surface.

METHODS

The peel-off mask was made using polyvinyl alcohol (PVA) in 8% and 10% as solidifier. The evaluation of peel-off masks comprises the examination of physiochemical and mechanical aspects. Furthermore, their longevity, effectiveness, and antibacterial properties are also considered.

RESULTS

The white color, pleasant smell, and soft texture were the defining features of the peel-off gel mask. The changes in PVA affect the pH level, thickness, and how quickly the peel-off mask dries. The stability test found that the peel-off mask had no significant physical changes when exposed to freezing and thawing. However, there were some differences in color and separation when using the real-time method. A prepared peel-off mask containing 10% PVA and curcumin works best against P. acne. The amount of PVA in the formula affected the physical and chemical qualities, but it did not impact on the antibacterial abilities of the peel-off mask gel. The best formula that gives the best results uses 10% PVA + curcumin.

CONCLUSIONS

Using the Curcumin and R. Damascena extract in the creation of the peel-off mask gel ensures its efficacy and safety for skin application.

Evaluation of Physicochemical and Microbial Properties of Extracts from Wine Lees Waste of Matelica’s Verdicchio and Their Applications in Novel Cosmetic Products

Wine lees are sediments deposited on the walls and bottom of barrels resulting from wine fermentation and mainly consist of yeasts. Saccharomyces cerevisiae extracts, rich in beneficial components for the skin, have already been used in cosmesis, while wine lees have not been well exploited by the cosmetics industry yet. The aim of this work was the full characterization of the wine lees from Verdicchio’s wine, with the aim to exploit it as a beneficial ingredient in new cosmetic products. After mapping the microbial composition of the sample waste, the parameters for the sonication extraction process were optimized and the physicochemical properties of the extract were analyzed. The efficiency of the aqueous extraction—and in particular the yeast cell lysis necessary for the release of proteins from the cell—was assessed by evaluating cell shape and size, and protein release, under scanning electron microscopy (SEM), dynamic light scattering (DLS) and Bradford’s protein assays. Thus, the total phenol content and antioxidant capacity of the supernatant recovered from native and sonicated lees were determined by Folin–Ciocalteu’s and spectrophotometric assays, respectively. To quantify the heavy metals and highlight the presence of microelements beneficial for the skin, inductively coupled plasma-mass spectrometry (ICP-MS) was applied. In vitro metabolic activity and cytotoxicity were tested on both HaCat keratinocytes and human gingival fibroblasts, showing that wine lees are safe for skin’s cells. The results show that sonicated lees appear to be more interesting than native ones as a consequence of the release of the active ingredients from the cells. Due to the high antioxidant capacity, content of beneficial elements for skin and an appropriate microbiologic profile, wine lees were included in five new solid cosmetic products and tested for challenge test, compatibility with human skin, sensory analysis, trans epidermal water loss (TEWL) and sebometry.

Cosmetic Formulation Based on an Açai Extract

(1) Background: Açai berry extract is known for its high content in polyphenols and thus is a promising ingredient for cosmetic antiaging formulations; (2) Methods: In this study, the açai extract was firstly evaluated for its total phenol content (Folin Ciocalteau essay) and antioxidant activity (radical scavenging activity—DPPH; radical cation scavenging capacity—ABTS; ferric reducing antioxidant capacity—FRAP). Next, the açai extract was included in an O/W formulation and again was evaluated for its polyphenol content and antioxidant capacity. The formulation was tested for general characteristics, physicochemical properties and microbial stability. The proliferative effect on human immortalized fibroblasts was evaluated by the MTT essay, while TAC assay served to confirm that fibroblasts are protected from UV irradiation. The irritant potential was verified on 20 volunteers. The study concluded with the assessment of the sensorial characteristics of the cosmetic formulation; (3) Results: The pure açai extract exhibited high polyphenol content and antioxidant activity, and these characteristics were preserved in the O/W formulation as well. The O/W cosmetic formulation proved to be stable under accelerated and normal conditions, and the preservatives were successful in challenging the resistance against microbial contamination. The mean irritant potential was zero in all volunteers, and the cosmetic formulation showed a good sensorial profile; (4) Conclusions: Açai extract is an interesting ingredient for cosmetic antiaging formulations.

Local treatment of chloasma in pregnant women

Goal. To assess the efficacy and safety of Azelic (15% gel of azelaic acid for topical administration) for the treatment of chloasma in pregnant women. Materials and methods. The study involved 28 pregnant women aged 18-36 (mean age: 24.7) with a normal course of pregnancy. The patients consulted a doctor in the spring, summer or fall complaining of focal skin hyperpigmentation on the face, chin and chest area. Ten patients (35.7%) developed hyperpigmentation prior to their pregnancy and 18 women (64.3%) - during the pregnancy. As of the consultation date, the pregnancy terms in all of the patients were 18-20 weeks. Chloasma was diagnosed by using dermatoscopy and skin examination with the Wood’s lamp. The patients were informed about the content and procedure of the study and gave their consent to take part in the study. Thin layers of Azelic (15% gel of azelaic acid for topical administration) were applied to the hyperpigmented skin of the patients and gently rubbed twice a day (in the morning and evening) as topical treatment for four months. The treatment results were assessed taking into consideration the patient’s subjective assessment, study group structure depending on the clinical efficacy, percentage of adverse events, and survey results based on the Dermatology Life Quality Index questionnaire. To reveal any potential general toxicological effects of the treatment, hepatic samples, total blood count and coagulogram results were analyzed as a part of obstetrical and gynecologic care for pregnant women. Key findings. Positive dynamics of the following characteristics was revealed: subjective assessment of treatment results by the patients, clinical efficacy of treatment and life quality index. Therapeutic results were observed as early as after one month but not later than three months after the treatment began. The therapeutic efficacy was recorded in 92.9-96.4% of all cases after four months of treatment: pigment spots disappeared or became paler, and their dimensions and their contrast as compared to the healthy skin reduced, the skin texture and life quality improved (the Dermatology Life Quality Index reduced from 15.5 ± 1.8 to 6.7 ± 0.5 points against the background of the treatment efficacy: from severe to moderate impact of the disease on the patient’s life, respectively). Five women (17.9%) developed erythema and burning sensations in the drug application site within the first two weeks immediately after the gel application (one of the patients had the same symptoms for six weeks of the treatment); the symptoms were weak and transient and did not require any additional treatment. Hepatic samples, total blood count and coagulogram results were within physiological standards during the treatment. Conclusion. Topical application of Azelic (15% gel of azelaic acid for topical administration) twice a day for four months is an efficient and safe method to treat chloasma in pregnant women.

Preparation and evaluation of topical microemulsion system containing metronidazole for remission in rosacea

The aim of this study was to prepare a topical water-in-oil type microemulsion containing metronidazole and to compare its effectiveness with a commercial gel product in the treatment of rosacea. A pseudo-ternary phase diagram (K(m)=2:1) was constructed using lecithin/butanol/isopropyl myristate/water. The microemulsion was chosen from the microemulsion region in the phase diagram. The formulation was a water-in-oil type microemulsion (droplet size: 11.6 nm, viscosity: 457.3 mPa·s, conductivity: 1.5 µs/cm, turbidity: 6.89 NTU) and the addition of the metronidazole did not alter the properties of the system. The release experiment showed that the release rate of metronidazole from the commercial gel product was higher than that of the microemulsion. Stability experiments showed that the metronidazole microemulsion remained stable for at least 6 months; none of the characteristic properties of the microemulsion had changed, the system retained its clarity and there was no sign that crystallization of metronidazole has occurred. Microemulsion was compared to a gel product in a randomized, double-blind, baseline-controlled, split-face clinical trial for the treatment of patients. After the 6-week treatment period there was a statistically significant difference in reduction of the main symptoms of rosacea. Of the patients treated with the microemulsion, 17% experienced complete relief from inflammatory lesions, and 50% from erythema. The microemulsion resulted in complete relief in 38% of the patients with telangiectasia while the commercial product did not provide any relief of telangiectasia symptoms. In conclusion, the microemulsion containing metronidazole was found to be more effective in reducing the symptoms of rosacea compared to the commercial gel product.

The human repeated insult patch test in the 21st century: a commentary

The human repeated insult patch test (HRIPT) is over half a century old, but is still used in several countries as a confirmatory test in the safety evaluation of skin sensitizers. This is despite the criticism it receives from an ethical perspective and regarding the scientific validity of such testing. In this commentary, the HRIPT is reviewed, with emphasis on ethical aspects and where the test can, and cannot, contribute in a scientifically meaningful manner to safety evaluation. It is concluded that where there is a specific rationale for testing, for example, to substantiate a no-effect level for a sensitizing chemical or to ensure that matrix effects are not making an unexpected contribution to sensitizing potency, then rigorous independent review may confirm that an HRIPT is ethical and scientifically justifiable. The possibility that sensitization may be induced in volunteers dictates that HRIPTs should be conducted rarely and in cases where the benefits overwhelmingly outweigh the risk. However, for the very large majority of HRIPTs conducted concerning the risk of skin sensitization, there is neither scientific justification nor any other merit.

In vivo investigation, in mice and in man, into the irritation potential of novel amphiphilogels being studied as transdermal drug carriers

Amphiphilogels, gels that consist solely of non-ionic surfactants, are being developed as dermal/transdermal drug delivery vehicles in our laboratories. The irritation potential of two amphiphilogels was investigated on shaved mouse skin, in vivo, and compared to those of Aqueous Cream BP (a moisturiser) and 5% sodium lauryl sulphate (SLS) solution (a known irritant). The skin irritation potential of one of these gels was then investigated in human, using Aqueous Cream BP as a negative control. Skin irritation (following daily application of gels and of controls for 5 days) was assessed by laser Doppler velocimetry, a visual erythema scoring method, and histological evaluations of excised mice skin. We found that the amphiphilogels caused no significant increase in blood flow and in epidermal irritation. In contrast, the SLS solution caused significant perturbation to mouse skin. From this study we conclude that these amphiphilogels may be used as dermal/transdermal drug delivery vehicles.

Facial variations in sensory responses

Subjective effects such as stinging, itching and burning commonly occur in the absence of any visible irritation and give rise to discomfort, which may be enough to deter an individual from using even the most effective of skin care products. The purpose of this study was to evaluate the sensitivity of different anatomical regions of the face to determine which region displayed the most intense stinging response to the application of lactic acid. The effect of occlusion on the level of response was also investigated. 45 volunteers were treated with 10% lactic acid on the nasolabial fold, forehead, chin and cheek, occluded and unoccluded for 8 min. Sensory reactions were recorded at 2.5, 5 and 8 min. The response levels on the occluded sites were always significantly lower than on the unoccluded sites, despite the dose per unit area being comparable. Females showed a trend towards being more sensitive to the subjective effects elicited by lactic acid than males, but these results were not conclusive. Interestingly, there was not a complete correlation between individuals who reacted on the nasolabial fold and the other sites, particularly the forehead. A positive stinging response on the nasolabial fold may not necessarily predict subjective responses to a product when used on other areas of the face.

Skin cleansers for occupational use: testing the skin compatibility of different formulations

OBJECTIVES

Skin-compatible hand cleansing is crucial for the prevention of occupational dermatitis. In this article we give an overview of skin-cleansing products and their ingredients and investigate whether solvents or abrasives could be avoided in cleansers for severely soiled skin.

METHODS

Comparison of skin compatibility, cleansing power and effectiveness of different formulations of skin cleansers was performed via Duhring chamber tests [visual score, trans-epidermal water loss (TEWL)] and standard hand-wash tests.

RESULTS

The results show that, dependent on the grade of contamination, a range of skin cleansers that allow adequate skin cleansing, is necessary. Solvents could be avoided, by the use of powerful cleansing systems based on tenside/oil mixtures. Only for special contaminations may solvents be useful. Powerful cleansing activity could be performed without abrasives.

CONCLUSIONS

The worker must be able to choose the skin cleanser that is adequate for the contamination that is present. Therefore, information and education of the workers are crucial for skin-compatible skin cleansing.

Non-animal testing strategies for assessment of the skin corrosion and skin irritation potential of ingredients and finished products

The dermatotoxicologist today is faced with a dilemma. Protection of workers and consumers from skin toxicities (irritation and allergy) associated with exposure to products, and the ingredients they contain, requires toxicological skin testing prior to manufacture, transport, or marketing. Testing for skin corrosion or irritation has traditionally been conducted in animals, particularly in rabbits via the long established Draize test method. However, this procedure, among others, has been subject to criticism, both for its limited predictive capacity for human toxicity, as well as for its use of animals. In fact, legislation is pending in the European Union which would ban the sale of cosmetic products, the ingredients of which have been tested in animals. These considerations, and advancements in both in vitro skin biology and clinical testing, have helped drive an intensive effort among skin scientists to develop alternative test methods based either on in vitro test systems (e.g. using rat, pig or human skin ex vivo, or reconstructed human skin models) or ethical clinical approaches (human volunteer studies). Tools are now in place today to enable a thorough skin corrosion and irritation assessment of new ingredients and products without the need to test in animals. Herein, we describe general testing strategies and new test methods for the assessment of skin corrosion and irritation. The methods described, and utilized within industry today, provide a framework for the practicing toxicologist to support new product development initiatives through the use of reliable skin safety testing and risk assessment tools and strategies.

Ethnic variation in the skin irritation response

There is a widespread, but largely unsubstantiated, view that certain skin types may be more susceptible to the effect of skin irritants than others. One expression of this would be that certain ethnic groups may also be more likely to experience skin irritation. As a consequence, when evaluating the skin compatibility of substances/preparations, these differences may need to be taken into account. However, other evidence indicates that, within any particular group, inter-individual variation is likely to be much larger than the differences between means for distinct groups. In this study, we have investigated 2 carefully matched panels of Caucasian and Japanese women volunteers to determine their topical irritant reaction, both acute and cumulative, to a range of materials. The results indicated that the acute irritant response tended to be greater in the Japanese panel and this reached statistical significance with the stronger irritants. Cumulative irritation was investigated only with the weaker irritants and, although again the trend was to a higher response in Japanese compared to Caucasian panelists, this rarely reached significance. Nevertheless, where risk assessment for skin irritation was critical, then at the population level, these differences might be relevant, both for safety in use of substances and products and for skin acceptability.

Validity and ethics of the human 4-h patch test as an alternative method to assess acute skin irritation potential

For more than 50 years, the Draize rabbit skin irritation test has reigned supreme as the regulatory method of choice for the identification of skin irritant chemicals. To date no in vitro alternative test has been validated as an adequate replacement. However, one potential option, to test the endpoint of concern (skin irritation) in the species of concern (man) has been overlooked. The advent of predictive in vitro tools for the identification of substances corrosive to the skin has opened up the practical possibility of carrying out safe and ethical studies on small panels of humans. The human 4-h patch test has been developed to meet the needs of identifying chemical skin irritation potential, providing data which is inherently superior to that given by a surrogate model, such as the rabbit. This paper reviews in detail the present state of the human 4-h patch test, highlighting its advantages and noting its utility as the 'gold standard' on which to build future in vitro models.

Use of human skin equivalent Apligraf for in vitro assessment of cumulative skin irritation potential of topical products

The main goal of the present study was to investigate the response of the human skin equivalent Apligraf in vitro to the application of irritant substances and its predictivity as a screening tool for cumulative skin irritant potential in humans. Vaseline, calcipotriol, trans-retinoic acid, and sodium lauryl sulfate were applied to Apligraf in vitro for 24 h. Cell viability (lactate dehydrogenase leakage), release and mRNA expression of the proinflammatory cytokines IL-1alpha and IL-8, and morphological changes were assessed. The same products were applied to 30 healthy volunteers in a double-blind, randomized, vehicle-controlled within-subject study. The skin reactions after repeated 24-h applications over 3 weeks under Finn chamber patches were monitored by visual scoring and biophysical methods (trans-epidermal water loss, chromametry, and blood flow). Sodium lauryl sulfate was cytotoxic to Apligraf, and increased the release and expression of cytokines at low (0.2%, 0. 4%), but not at high (0.8%, 1%) concentrations. It induced severe irritancy in vivo. Trans-retinoic acid increased the expression and release of cytokines with no detectable cytotoxicity and showed moderate irritancy in humans. Although calcipotriol did neither affect cell viability nor the production of cytokines, it induced morphological signs of irritation and was mildly irritant for healthy volunteers. Vaseline was innocuous in vivo and induced no changes in Apligraf. In conclusion, the cumulative skin irritation potential of the tested products could be predicted with Apligraf in a sensitive and specific manner, by monitoring cytotoxicity, proinflammatory cytokines, and morphological changes.

Unexpected skin barrier influence from nonionic emulsifiers

Skin disorders are often treated with creams containing various active substances. The creams also contain emulsifiers, which are surface-active ingredients used to stabilize the emulsion. Emulsifiers are potential irritants and in the present study the influence of stearic acid, glyceryl stearate, PEG-2, -9, -40, and -100 stearate, steareth-2, -10 and -21 on normal as well as on irritated skin have been evaluated with non-invasive measurements. Test emulsions were created by incorporating 5% emulsifiers in a water/mineral oil mixture (50:50). The emulsions and their vehicle were then applied to normal skin for 48 h and to sodium lauryl sulfate (SLS) damaged skin for 17 h in aluminum chambers. Twenty-four hours after removal of the chambers the test sites were evaluated for degree of irritation. In normal skin, the emulsifiers induced significant differences in TEWL but not in skin blood flow. Five of the emulsifiers increased TEWL. In SLS-damaged skin an aggravation of the irritation was expected. However, no differences regarding skin blood flow was noted from the emulsifiers. Furthermore, three emulsifiers unexpectedly decreased TEWL. These results highlight the possibility of absorption of these emulsifiers into the lipid bilayer, which increase TEWL in normal skin and decrease TEWL in damaged skin.