Human Repeated Insult Patch Test Research Articles

Skin irritation of capsicum patches by in vitro study and human repeated insult patch test.

Skin irritation of capsicum patches by in vitro study and human repeated insult patch test.

Low-cost quantum mechanical descriptors for data efficient skin sensitization QSAR models

Quantitative Structure Activity Relationship modelling methodologies need to incorporate relevant mechanistic information to have high predictive performance and validity. Electrophilic reactivity is a common mechanistic feature of skin sensitization endpoints which could be concisely characterized with electronic descriptors which is key to enabling the modelling of small datasets in this domain. However, quantum mechanical methodologies have previously featured high computational costs which would exclude the use of large datasets. Consequently, we investigate the use of electronic descriptors calculated using the Hartree Fock with 3 corrections (Hf-3c) method, a low-cost ab initio methodology that has higher chemical accuracy than previous semiempirical methodologies for modelling in vitro skin sensitization assay outcomes. We also model the Ames assay as a surrogate for determining skin sensitization outcomes. The quantum chemical descriptors calculated using the Hf-3c method with conductor-like polarizable continuum model (CPCM) implicit solvation found improved QSAR model performance for the in vitro Ames (n = 6049, 0.770 AUC), KeratinoSens (n = 164, 0.763 AUC), and Direct Peptide Reactivity Assay (n = 122, 0.750 AUC) datasets, with their combination producing high predictive performance for unseen in vivo Local Lymph Node Assay (n = 86, 0.789 AUC) and Human Repeated Insult Patch Test (n = 86, 0.791 AUC) assay toxicant outcomes.

Evaluation of an Anhydrous Permeation-Enhancing Vehicle for Percutaneous Absorption of Hormones.

The efficiency and safety of hormone delivery through the skin partly depend on the appropriate choice of vehicle and the type of formulation. The present study reports the skin cytotoxicity, irritancy, and safety of a newly developed anhydrous permeation-enhancing base (APEB) and the percutaneous absorption of progesterone, testosterone, estriol, and estradiol in APEB formulations. Using the human skin EpiDerm model, cell death was not observed after 4h of exposure to APEB and was 48% after 24h, indicating its mild to non-irritating property. APEB did not change the expression level of skin cell proliferation markers including PCNA, MCL-1, iNOS, and NFκB proteins, and apoptosis was minimal after 8-h exposure. The in vivo skin irritation and sensitization evaluation of APEB using a Human Repeat Insult Patch Test showed no adverse reaction of any kind during the course of the study. These results indicate the safety of APEB on skin tissues. The hormone percutaneous absorption was performed using human cadaver abdomen skin tissues and the Franz diffusion system, and hormone concentrations were determined by ELISA. Absorption was observed as early as 2h of application and accumulated after 24h to 2851 ± 66ng/cm2, 2338 ± 594ng/cm2, 55 ± 25ng/cm2, and 341 ± 122ng/cm2 for progesterone, testosterone, estriol, and estradiol, respectively. A steady flux rate of absorption of the hormones was observed within 24h of application. These results suggest that APEB can be used as a vehicle to deliver these hormones through the skin and into the bloodstream for hormone replacement therapy.

Decision making in next generation risk assessment for skin allergy: Using historical clinical experience to benchmark risk

Our aim is to develop and apply next generation approaches to skin allergy risk assessment that do not require new animal test data and better quantify uncertainties. Quantitative risk assessment for skin sensitisation uses safety assessment factors to extrapolate from the point of departure to an acceptable human exposure level. It is currently unclear whether these safety assessment factors are appropriate when using non-animal test data to derive a point-of departure.Our skin allergy risk assessment model Defined Approach uses Bayesian statistics to infer a human-relevant metric of sensitiser potency with explicit quantification of uncertainty, using any combination of human repeat insult patch test, local lymph node assay, direct peptide reactivity assay, KeratinoSens™, h-CLAT or U-SENS™ data. Here we describe the incorporation of benchmark exposures pertaining to use of consumer products with clinical data supporting a high/low risk categorisation for skin sensitisation. Margins-of-exposure (potency estimate to consumer exposure level ratio) are regressed against the benchmark risk classifications, enabling derivation of a risk metric defined as the probability that an exposure is low risk. This approach circumvents the use of safety assessment factors and provides a simple and transparent mechanism whereby clinical experience can directly feed-back into risk assessment decisions.

Next generation risk assessment for skin allergy: Decision making using new approach methodologies

Our aim is to develop and apply next generation approaches to skin allergy risk assessment (SARA) that do not require new animal test data and better quantify uncertainties. Significant progress has been made in the development of New Approach Methodologies (NAMs), non-animal test methods, for assessment of skin sensitisation and there is now focus on their application to derive potency information for use in Next Generation Risk Assessment (NGRA). The SARA model utilises a Bayesian statistical approach to infer a human-relevant metric of sensitiser potency and a measure of risk associated with a given consumer exposure based upon any combination of human repeat insult patch test, local lymph node, direct peptide reactivity assay, KeratinoSens™, h-CLAT or U-SENS™ data. Here we have applied the SARA model within our weight of evidence NGRA framework for skin allergy to three case study materials in four consumer products. Highlighting how to structure the risk assessment, apply NAMs to derive a point of departure and conclude on consumer safety risk. NGRA based upon NAMs were, for these exposures, at least as protective as the historical risk assessment approaches. Through such case studies we are building our confidence in using NAMs for skin allergy risk assessment.

Evaluation of skin irritation and skin sensitization potential of Venusia max lotion (paraben-free, alcohol-free, mineral oil-free, animal origin free) using human repeat insult patch test

<p class="abstract"><strong>Background:</strong> Topical exposure to chemicals from cosmetics can lead to adverse skin effects or skin irritation. This study aimed to investigate the skin irritation and sensitizing potential of a moisturizer Venusia max lotion (paraben-free, alcohol-free, mineral oil-free, animal origin free (PAMA) free).</p><p class="abstract"><strong>Methods:</strong> In this single-center, non-randomized, observational study, skin irritation, and skin sensitization potential of a test product was assessed using the human repeat insult patch test (HRIPT) technique. Approximately 0.04 g of the test product and filter papers dipped in 0.9% isotonic saline solution (~0.04 ml of solution) were filled in different wells of patch chambers and applied occlusively, on the back of each participant. Scoring of the skin reactions in the induction phase and challenge phase was done using Draize and international contact dermatitis research group (ICDRG) scales respectively. Scores were compared to the baseline and the negative control (isotonic saline).<strong></strong></p><p class="abstract"><strong>Results:</strong> In total 234 participants (50 with sensitive skin), 224 and 221 participants completed the induction phase and challenge phase respectively. Scores for the induction phase for Venusia max lotion (PAMA free) and isotonic saline were 0.46 and 0.06 respectively. The mean cumulative score of erythema and oedema for Venusia max lotion (PAMA free) was below 2. For the challenge phase, none of the participants showed any positive reactions at any time point for test product and isotonic saline.</p><p class="abstract"><strong>Conclusions:</strong> Test product Venusia max lotion (PAMA free) found to be non-irritant and hypoallergenic. Thus, it can be used without fear of skin irritation or sensitization.</p>

Control Effect of Palmitoyl Teterapeptide-7 Gel to Inflammatory Responses Elicited by PM10

Purpose: As a cosmetic approach to prevent pollution-induced skin damage, the topical application of skincare products, infused with functional ingredients, can offer an optimal solution to skin problems. The study aims to assess the anti-inflammatory effect of PT-7 gel. Methods: This study prepared antipollution cosmetics using palmitoyl tetrapeptide-7 (PT-7; 3% PT-7 gel, 5% PT-7 gel) and performed safety testing. For the safety assessment, the human repeat insult patch test (HRIPT) was performed to detect erythema occurrence on the patch area, following the ICDRG criteria. The panels comprised of 30 adults, aged 20–50 years. Furthermore, this study also analyzed particulate matter (PM) 10-induced inflammation on the skin of a hairless mouse by immunohistochemistry and Western blot. Results: The cosmetic safety testing results showed no skin reactions to antipollution gels containing PT- 7. Immunohistochemistry and the Western blot analysis demonstrated reduced levels of IL-1β and IL-6 expression levels in the 3% PT-7 and 5% PT-7 application groups after PM10 treatment. In particular, after PM10 treatment, the IL-1β and IL-6 expression levels were statistically significantly decreased in the group treated with 5% PT-7. Conclusions: Collectedly, this study provided evidence of the PT-7 gel’s safety and found that PT-7 gel reduced the IL-1β and IL-6 expression levels caused by PM10 exposure. In view of these results, it supports that PT-7 is a promising antipollution cosmetic ingredient with great commercial potential.

Investigations of Olive Oil Industry By-Products Extracts with Potential Skin Benefits in Topical Formulations.

The by-products of olive oil industry are a major ecological issue due to their phenolic content, highly toxic organic load, and low pH. However, they can be recovered and reused, since their components have antioxidant, anti-inflammatory, and photoprotector properties. In this work, oil-in-water creams containing three different olive oil industry by-products extracts were produced without the use of organic solvents. First, the extracts were thoroughly characterized in vitro for cytotoxicity, inhibition of skin enzymes, and antioxidant and photoprotection capacities. Safety studies were then performed, including ocular and skin irritation tests, ecotoxicity evaluation, and in vivo Human Repeat Insult Patch Test. The results obtained in this initial characterization supported the incorporation of the extracts in the cream formulations. After preparation, the creams were characterized for their organoleptic, physicochemical, droplet size and rheological properties, and microbial contamination. The results showed that all formulations were semi-solid creams, with stable pH, compatible with the skin, without microbial contamination, and with the expected droplet size range. The rheological analysis showed shear-thinning behavior with yield stress, with the viscosity decreasing with increasing shear rate. The oscillatory results suggest that the creams have a strong network structure, being easily rubbed into the skin. Finally, compatibility, acceptability and antioxidant efficacy were evaluated in vivo, in human volunteers. No adverse reactions were observed after application of the formulations on skin and the cream with the highest concentrations of phenolic compounds showed the highest antioxidant efficiency. In conclusion, the results suggest that olive oil industry by-products extracts have valuable properties that favor their re-use in the cosmetic industry. The example presented here showed their successful incorporation into creams and their impact in these formulations’ appearance, pH, and rheological performance, as well as their in vivo compatibility with skin and antioxidant efficiency.

Safety and Photoprotective Efficacy of a Sunscreen System Based on Grape Pomace (Vitis vinifera L.) Phenolics from Winemaking.

In winemaking, a large amount of grape pomace is produced that is rich in polyphenolics and highly beneficial for human health, as phenols are useful for skin ultraviolet (UV) protection. In this investigation, we evaluated the safety and clinical efficacy of a sunscreen system containing a grape pomace extract from Vitis vinifera L. as a bioactive ingredient. The recovery of phenolics in the waste was performed by percolation. Nine emulsions were developed using a factorial design and two were evaluated clinically: Formulation E, containing only UV filters (butylmethoxydibenzoyl methane, ethylhexyl methoxycinnamate and ethylhexyl dimethyl PABA), and F, with the extract at 10.0% w/w + UV filters. The antioxidant activity was determined by the DPPH assay and the in vitro efficacy was established by sun protection factor (SPF) measurements (Labsphere UV-2000S). Clinical tests were performed to determine safety (human repeated insult patch test) and to confirm efficacy (photoprotective effectiveness in participants). The results showed a synergistic effect between the sunscreen system and the extract on UVB protection and antioxidant activity. Both samples were considered safe. Formulation F was 20.59% more efficient in protecting skin against UVB radiation, taking approximately 21% more time to induce erythema compared to the extract-free sample.

Fragrance Skin Sensitization Evaluation and Human Testing: 30-Year Experience.

BackgroundThe human repeated insult patch test (HRIPT) has a history of use in the fragrance industry as a component of safety evaluation, exclusively to confirm the absence of skin sensitization at a defined dose.ObjectiveThe aim of the study was to document the accumulated experience from more than 30 years of conducting HRIPTs.MethodsA retrospective collation of HRIPT studies carried out to a consistent protocol was undertaken, with each study comprising a minimum of 100 volunteers.ConclusionsThe HRIPT outcomes from 154 studies on 134 substances using 16,512 volunteers were obtained. Most studies confirmed that at the selected induction/challenge dose, sensitization was not induced. In 0.12% of subjects (n = 20), there was induction of allergy. However, in the last 11 years, only 3 (0.03%) of 9854 subjects became sensitized, perhaps because of improved definition of a safe HRIPT dose from the local lymph node assay and other skin sensitization methodologies, as well as more rigorous application of the standard protocol after publication in 2008. This experience with HRIPTs demonstrates that de novo sensitization induction is rare and becoming rarer, but it plays an important role as an indicator that toxicological predictions from nonhuman test methods (in vivo and in vitro methods) can be imperfect.

Mesoporous magnesium carbonate for use in powder cosmetics.

ObjectiveIn the present study, we describe the features and functional properties of a new powder cosmetic ingredient, an amorphous mesoporous magnesium carbonate (MMC, also named Upsalite®) with regard to physical characteristics as well as functional attributes.MethodsPhysical and functional characterization of MMC, as compared to other common powder cosmetic ingredients (silica, mica, kaolin, talc and starch), was assessed using nitrogen gas adsorption, powder X‐ray diffraction, particle size distribution by laser diffraction, scanning electron microscopy (SEM), and oil and moisture uptake tests. The powder ingredients were also applied on human skin and analysed for short‐ and long‐term mattifying effect, and a new method was developed to measure flashback effect. MMC was tested for skin irritation using an in vitro cell model as well as in vivo, through the Human Repeated Insult Patch Test on 50 human volunteers.ResultsMesoporous magnesium carbonate has a high surface area and pore volume. It has an excellent absorption capacity and can take up both oil and water simultaneously. It provides instant and long‐lasting mattifying effect when applied on human skin without drying or irritating skin and exhibits no measured flashback effect.ConclusionMesoporous magnesium carbonate has good sensory and visual characteristics as well as excellent absorbing and mattifying properties, suggesting that it has great potential to replace other powder ingredients currently used as fillers and absorbers in powder cosmetics.

Pred-Skin: A Web Portal for Accurate Prediction of Human Skin Sensitizers.

Safety assessment is an essential component of the regulatory acceptance of industrial chemicals. Previously, we have developed a model to predict the skin sensitization potential of chemicals for two assays, the human patch test and murine local lymph node assay, and implemented this model in a web portal. Here, we report on the substantially revised and expanded freely available web tool, Pred-Skin version 3.0. This up-to-date version of Pred-Skin incorporates multiple quantitative structure-activity relationship (QSAR) models developed with in vitro, in chemico, and mice and human in vivo data, integrated into a consensus naïve Bayes model that predicts human effects. Individual QSAR models were generated using skin sensitization data derived from human repeat insult patch tests, human maximization tests, and mouse local lymph node assays. In addition, data for three validated alternative methods, the direct peptide reactivity assay, KeratinoSens, and the human cell line activation test, were employed as well. Models were developed using open-source tools and rigorously validated according to the best practices of QSAR modeling. Predictions obtained from these models were then used to build a naïve Bayes model for predicting human skin sensitization with the following external prediction accuracy: correct classification rate (89%), sensitivity (94%), positive predicted value (91%), specificity (84%), and negative predicted value (89%). As an additional assessment of model performance, we identified 11 cosmetic ingredients known to cause skin sensitization but were not included in our training set, and nine of them were accurately predicted as sensitizers by our models. Pred-Skin can be used as a reliable alternative to animal tests for predicting human skin sensitization.

New topical tranexamic acid derivative for the improvement of hyperpigmentation and inflammation in the sun-damaged skin.

Skin-lightening products are used worldwide to treat persistent pigmentation disorders that impact our quality of life and self-confidence. However, consumers of cosmetic and over-the-counter skin lighteners struggle to find products that perform to their expectations. New, safe, and effective bioactives are needed to fill this gap. To investigate the safety and skin-lightening performance of a new topical tranexamic acid derivative, that is, cetyl tranexamate mesylate. The test material was a facial serum containing 2.0% (w/w) of the new bioactive. Safety was evaluated by a modified Human Repeat Insult Patch Test with 54 subjects of either sex. Performance was objectively assessed based on the improvement of melanin and erythema indexes through time, and also subjectively by photographs and self-perception questionnaires. Thirty-five female subjects applied the serum twice a day for 8weeks. No questionable adverse reactions were observed. Melanin and erythema indexes improved significantly and continuously from the baseline to the end of the study (-16.9% and -34.3%, respectively). Photographs further support instrumental data. On average, after 2weeks, the subjects already noticed an improvement in skin tone (79.3%), a reduction in dark spots (78.6%), and an improvement in facial redness (77.1%). A topical serum containing cetyl tranexamate mesylate was well-tolerated and successfully improved the overall facial skin tone, as well as the appearance of dark spots and redness.

Evaluation of Potential Skin Sensitization of Humans Receiving Bright and Firm Hybrid Emulsion I

OBJECTIVES: The aim of this study was to evaluate potential skin sensitization of human receiving Bright and Firm Hybrid Emulsion I. MATERIAL AND METHODS: 130 subjects were recruited and the human repeated insult patch test (HRIPT) was used to assess the skin sensitization potential of the Bright and Firm Hybrid Emulsion I. The test article container was 0.2 g and the size per patch test was 2x2 cm2. The placebo patch tests were applied on normal skin at the right scapula area and Bright and Firm Hybrid Emulsion I patch tests were applied on the left scapula area. In the induction phase, subjects applied patch tests on Monday, Wednesday, and Friday for three consecutive weeks. All of the patch tests were removed 24 hours (h) after being applied and the HRIPT score was evaluated. After the induction phase, a single challenge patch was applied to a naive site of normal skin. The challenge phase is scored 24, 48, and 72 h after application and the experiment was monitored at the 72 h HRIPT score reading. RESULT: All 130 subjects completed the study. The age of subjects ranged between 19 to 33 years old (mean age 21.45 ± 1.45 years). The HRIPT scoring scale was measured for to the induction and challenge phase, edema, papules, vesicles, and bullae of the subjects who applied Bright and Firm Hybrid Emulsion I. The results were not significantly different when compared to the placebo patch test group. CONCLUSION: This study shown that Bright and Firm Hybrid Emulsion I is a low skin sensitization potential among subjects.

Fragaria vesca L. Extract: A Promising Cosmetic Ingredient with Antioxidant Properties.

Fragaria vesca L. (F. vesca), popularly known as wild strawberry, is a plant from the Rosaceae family, found in temperate and subtropical areas of the northern hemisphere. F. vesca leaves have been shown to have antiseptic, emollient, and dermatological protection properties, due to the presence of bioactive compounds, such as flavonoids, phenolic acids, ellagitannins, and proanthocyanidins. In this study, a F. vesca extract was obtained by an optimized extraction process, and was characterized by HPLC, ROS scavenging activity, cytotoxicity assays in HaCaT cells, and tyrosinase inhibitory activity determination. The most active extract was then incorporated in a hydrogel with hydroxyethylcellulose at 2% (w/w), which was characterized at the physicochemical, stability, cytotoxicity, and ROS scavenging activity levels to evaluate its quality, safety, and efficacy. In vivo studies, human repeat insult patch testing, and an assay to determine their antioxidant efficacy, were also performed. The results showed that the Fragaria vesca extracts had antioxidant activity and that the F. vesca extract-based hydrogel exhibited cutaneous compatibility, acceptability and antioxidant efficacy, being stable, and suitable for topical application.

Setting surface wipe limits for skin sensitizers.

Guidance for managing potential dermal exposures has historically been qualitative in nature, for example, in the form of a DSEN notation. We propose a method that can provide quantitative guidance on how to establish and use surface wipe limits for skin sensitizers. The murine local lymph node assay (LLNA) is a validated test that not only identifies potential skin sensitizers but also provides an effective concentration (EC3) value. This provides quantitative dose-response information on induction of skin sensitization that permits estimates of sensitization thresholds and potency. Building upon the previously established correlation between LLNA EC3 values and human repeat insult patch testing no-effect levels, we present a quantitative method for setting surface wipe guidelines using the LLNA EC3. These limits can be used to assign compounds to occupational exposure bands and provide handling guidance for skin sensitizers of varying potency, supporting both exposure assessment and control strategies. A table is included that suggests a band of reasonable surface wipe limits (mg/100 cm2) for potentially all chemical sensitizers. When used in conjunction with a comprehensive industrial hygiene program that includes hazard communication, engineering controls, and personal protective equipment, skin exposure and consequent skin sensitization risks in the workplace can be minimized.

Stepwise approach of development of dermo-cosmetic products in healthy and atopic dermatitis paediatric population: safety evaluation, clinical development and postmarket surveillance.

Background/objectivesPaediatric skin, considered sensitive, and infant skin, more susceptible to percutaneous toxicity, require specially formulated cosmetic products. As recently shown, early use of emollients in infants “at risk” of developing atopic dermatitis has shown controversial results in reducing the incidence of atopic dermatitis. Development of dermo‐cosmetic products for this specific population should especially ensure tolerance and safety. In absence of good clinical practice guideline, we propose here a stepwise approach for the development of paediatric cosmetic skincare products.MethodsOur stepwise methodology for cosmetics aimed at paediatrics, starts with in vitro assessment of product's ingredients safety, followed by preclinical and clinical evaluations of the final product, including sequentially: (1) Repeated Open Application Test (ROAT), (2) Human Repeated Insult Patch Test (HRIPT), (3) In‐use dermatological and ophthalmological tolerance studies (sequentially in 3a: healthy adults, 3b: healthy paediatric subjects and finally 3c: paediatric patients). We also describe the integrated cosmetovigilance–toxicological surveillance during the clinical development phase and postmarketing.ResultsAs illustrated with one dermo‐cosmetic product intended to be used as a preventative/maintenance treatment for atopic dermatitis in paediatric population, we show that using this stepwise methodology to test a product reduces potential risks of irritation and contact dermatitis in this sensitive population.ConclusionStandardized ethical stepwise development approach is needed to ensure the commercialization of safe and well‐tolerated dermo‐cosmetics for paediatrics. The approach described here could potentially serve as guidance for evaluation of new paediatric cosmetic products.

Safety Assessment of Natural Color Foundation for Atopy

Purpose: As a therapeutic makeup product, foundation is used to reduce the anxiety and unease associated with appearance in people with atopic skin problems. The aim of the present study was to prepare and evaluate the safety of natural color foundation for atopy. Methods: Color foundations containing organic kaolin and zinc oxide were prepared. Safety of color foundation was evaluated by MTT cell viability assay (CCD-986sk human skin fibroblast cell line), and human repeat insult patch test for atopic dermatits. Results: Results of the MTT cell viability assay showed that the growth activity of human skin fibroblast cells was over 88% in all concentrations of the natural color foundations (sample C and D). Patch test revealed that the natural color foundations were safe. While two cases showed weak positive reactions (+) to sample A and B (general foundation on the market). Conclusion: Natural color foundation with kaolin and zinc oxide was verified safe for atopic dermatitis and it appears to be beneficial for use as a foundation for atopy.

171 Retrospective analysis of a subset of human repeat insult patch tests conducted by the Research Institute for Fragrance Materials over the past 30 years

171 Retrospective analysis of a subset of human repeat insult patch tests conducted by the Research Institute for Fragrance Materials over the past 30 years

Evaluation of Potential Skin Sensitization of Humans Receiving Proteoglycan Facial Mask

OBJECTIVES: The aim of this study was to evaluate potential skin sensitization of the proteoglycan (PG) facial mask. MATERIAL AND METHODS: 140 volunteers were recruited. The human repeated insult patch test (HRIPT) was used to assess skin sensitization and the potential of the proteoglycan (PG) facial mask. The test article material was 0.3 ml and the size was 1x1 cm2 per patch test. The placebo patch tests were applied on normal skin at left scapula area and applied PG facial mask patch tests on the right scapula area. In the induction phase, healthy volunteers applied patch tests on Monday, Wednesday, and Friday for three consecutive weeks. All of the patch tests were removed 24 hours (h) after having been applied and HRIPT scoring was evaluated. After the induction phase, a single challenge patch was applied to a naive site of normal skin. The challenge phase is scored 24, 48, and 72 h after having been applied and the experiment monitor presented at the 72 h reading of the HRIPT score. RESULTS: All 140 volunteers completed the study. Age of subjects ranged from 19 to 26 years old (mean age 21.59 ± 1.90 years). The HRIPT scoring scale of induction phase and challenge phase, edema, papules, vesicles, and bullae of healthy volunteers applied with the PG facial mask were not significantly different when compared to the placebo patch test group. CONCLUSION: This study has demonstrated that PG facial mask has low skin sensitization potential among healthy volunteers. Keywords: proteoglycan, potential skin sensitization, human repeated insult patch test DOI: 10.31524/bkkmedj.2019.02.002