Safety Testing of Cosmetic Products: Overview of Established Methods and New Approach Methodologies (NAMs)

Dermal bioavailability of perfluoroalkyl substances using in vitro 3D human skin equivalent models

Perfluoroalkyl substances (PFAS) have been identified in various products that come in contact with human skin, ranging from school uniforms to personal care products. Despite this, knowledge on human dermal uptake of PFAS is lacking. Thus, the human dermal absorption of 17 PFAS was assessed, for the first time, using in vitro 3D-human skin equivalent models exposed to 500 ng/cm2 PFAS dissolved in methanol over 24-36 h. The distribution of target PFAS is presented, based on three fractions: absorbed, un-absorbed, and retained within skin tissue (absorbable dose). Perfluoropentanoic acid (PFPeA) and perfluorobutane sulfonate (PFBS) had the highest absorbed fraction, 58.9 % and 48.7 % respectively, with the absorbed fraction decreasing with increasing carbon chain length of the studied perfluorocarboxylic acids (PFCAs) (r = 0.97, p = 0.001) and perfluorosulfonic acids (PFSAs) (r = 0.97, p = 0.004). Interestingly, while longer chain PFAS (Cn ≥ 9) were not directly absorbed, a large fraction of the exposure dose was detected within the skin tissue at the end of the exposure. This was most apparent for perfluoroundecanoic acid (PFUnDA) and perfluorononane sulfonate (PFNS) for which 66.5 % and 68.3 % of the exposure dose was found within the skin tissue, while neither compound was detected in the absorbed fraction. For compounds with a carbon chain length > 11, the fraction found within the skin tissue, decreases with increasing chain length. Physicochemical properties played a role in dermal permeation of PFAS, with a clear inverse correlation between logKOW and absorbed fraction for both PFCAs (r = -0.97; p ≤ 0.001) and PFSAs (r = -0.99; p ≤ 0.001). Steady-state flux (JSS) and permeation coefficients (Papp) were determined for target compounds with significant permeation after 36 h exposure (C5-C8 PFCAs and C4-C7 PFSAs). In general, both the flux and permeation coefficient decreased with increasing chain length.

Circular economyeast: Saccharomyces cerevisiae as a sustainable source of glucans and its safety for skincare application

Glucans, a polysaccharide naturally present in the yeast cell wall that can be obtained from side streams generated during the fermentation process, have gained increasing attention for their potential as a skin ingredient. Therefore, this study focused on the extraction method to isolate and purify water-insoluble glucans from two different Saccharomyces cerevisiae strains: an engineered strain obtained from spent yeast in an industrial fermentation process and a wild strain produced through lab-scale fermentation. Two water-insoluble extracts with a high glucose content (> 90 %) were achieved and further subjected to a chemical modification using carboxymethylation to improve their water solubility. All the glucans' extracts, water-insoluble and carboxymethylated, were structurally and chemically characterized, showing almost no differences between both yeast-type strains. To ensure their safety for skin application, a broad safety assessment was undertaken, and no cytotoxic effect, immunomodulatory capacity (IL-6 and IL-8 regulation), genotoxicity, skin sensitization, and impact on the skin microbiota were observed. These findings highlight the potential of glucans derived from spent yeast as a sustainable and safe ingredient for cosmetic and skincare formulations, contributing to the sustainability and circular economy.

The present state of the cosmetics supply chain in Thailand and the prospective role of Independent Quality Assurance Verifiers (IQAVs) within the supply chain

Within the well-established European cosmetic supply chain, Independent Quality Assurance Verifiers (IQAVs) such as NATRUE and COSMOS have been nurtured, facilitating the growth of robust markets and industries. In contrast, the cosmetics supply chain in Thailand remains enigmatic and insufficiently delineated. This opacity constrains the potential for quality assurance entities to establish and perform their functions. Therefore, the disorganized supply chain and the lack of IQAVs have given rise to unethical practices, truncated product life cycles, and diminished quality within the cosmetics supply chain. To address these concerns, the current study employs a bifurcated approach: 1) examining the extant state of Thailand's cosmetics supply chain, and 2) suggesting strategic positioning for IQAVs to enhance the Thai supply chain. A series of comprehensive interviews were conducted with numerous eminent experts representing various supply chain roles. By scrutinizing stakeholders in the Thai cosmetics supply chain, the research probes the reasoning behind the shortened product life cycles and identifies essential success factors for the improvement and expansion of the industry. The study utilized the IDEF0 framework to assess the supply chain's present condition and then adopted the PESTEL analysis to discern potential strategic roles for IQAVs. In conclusion, the study suggested that Thai authorities either establish their certification standards and processes or cooperate with extant foreign IQAVs to adapt their standards to the local environment. This research contributes to an understanding of the prevailing circumstances and introduces a strategic function for IQAVs in supporting Thailand's aspiration to become ASEAN's beauty hub.

Investigation into the effect of skin tone modulators and exogenous stress on skin pigmentation utilizing a novel bioengineered skin equivalent

Human skin equivalents (HSEs) are a popular technology due to limitations in animal testing, particularly as they recapitulate aspects of structure and function of human skin. Many HSEs contain two basic cell types to model dermal and epidermal compartments, however this limits their application, particularly when investigating the effect of exogenous stressors on skin health. We describe the development of a novel platform technology that accurately replicates skin pigmentation in vitro. Through incorporation of melanocytes, specialized pigment producing cells, into the basal layer of the epidermis we are able to re-create skin pigmentation in vitro. We observe apical distribution of melanin within keratinocytes and formation of supranuclear caps (SPNCs), only when the epidermal compartment is co-cultured with a dermal compartment, leading to the conclusion that fibroblast support is essential for correct pigment organization. We also evaluate the commonly observed phenomenon that pigmentation darkens with time in vitro, which we further explore through mechanical exfoliation to remove a build-up of melanin deposits in the stratum corneum. Finally, we demonstrate the application of a pigmented HSE to investigate drug modulation of skin tone and protection from UV-induced damage, highlighting the importance of such a model in the wider context of skin biology.

A State-of-the-Art Review on the Alternatives to Animal Testing for the Safety Assessment of Cosmetics

Almost a decade after the stipulated deadline in the 7th amendment to the EU Cosmetics Directive, which bans the marketing of animal-tested cosmetics in the EU from 2013, animal experimentation for cosmetic-related purposes remains a topic of animated debate. Cosmetic industry continues to be scrutinised for the practice, despite its leading role in funding and adopting innovation in this field. This paper aims to provide a state-of-the-art review of the field on alternative testing methods, also known as New Approach Methodologies (NAMs), with the focus on assessing the safety of cosmetic ingredients and products. It starts with innovation drivers and global regulatory responses, followed by an extensive, endpoint-specific overview of accepted/prospective NAMs. The overview covers main developments in acute toxicity, skin corrosion/irritation, serious eye damage/irritation, skin sensitisation, repeated dose toxicity, reproductive toxicity/endocrine disruption, mutagenicity/genotoxicity, carcinogenicity, photo-induced toxicity, and toxicokinetics. Specific attention was paid to the emerging in silico methodology. This paper also provides a brief overview of the studies on public perception of animal testing in cosmetics. It concludes with a view that educating consumers and inviting them to take part in advocacy could be an effective tool to achieve policy changes, regulatory acceptance, and investment in innovation.

Alternative in vitro models used in the main safety tests of cosmetic products and new challenges

BACKGROUND

Guided by ethical considerations and regulatory requirements such as the 7th Amendment to the European Cosmetics Directive N° 1223/2009, the cosmetic industry has developed and evaluated alternative test strategies such as in vitro assays, in silico approaches for toxicological endpoints and efficacy of cosmetic products and cosmetics ingredients. In consequence, the European Centre for the Validation of Alternative Methods (ECVAM) has proposed a list of validated cell-based in vitro models for predicting the safety and toxicity of cosmetic ingredients. These models have been demonstrated as valuable and effective tools to overcome the limitations of animal in vivo studies. For example, 3D human skin equivalent models are used to evaluate skin irritation potential; and excised human skin is used as the gold standard for the evaluation of dermal absorption.

OBJECTIVE

This review presents, in relation to the regulatory requirements, the main alternative in vitro models used in the safety tests of cosmetic products, focusing on skin sensitization, skin corrosion, skin irritation and skin absorption, with advantages and limitations of each model. Recent innovative 3D cell technologies such as Organ-on-a-Chip (OoC) models that can bring significant improvements for toxicology and efficacy testing are also presented.

CONCLUSION

The development of OoC technology is promising for assessing the toxicity of substances contained in cosmetics, particularly for repeated dose toxicity, for which no alternative in vitro methods are currently available. Nevertheless, aside from the challenges, the technology needs to be validated and accepted by regulatory organizations as an effective method. Collaboration between researchers, regulatory organizations and industry would be required to achieve this validation.

Modernizing Medical Research to Benefit People and Animals

In the context of widespread public and political concern around the use of animals in research, we sought to examine the scientific, ethical and economic arguments around the replacement of animals with New Approach Methodologies (NAMs) and to situate this within a regulatory context. We also analyzed the extent to which animal replacement aligns with British public and policymakers’ priorities and explored global progress towards this outcome. The global context is especially relevant given the international nature of regulatory guidance on the safety testing of new medicines. We used a range of evidence to analyze this area, including scientific papers; expert economic analysis; public opinion polls and the Hansard of the UK Parliament. We found evidence indicating that replacing animals with NAMs would benefit animal welfare, public health and the economy. The majority of the British public is in favor of efforts to replace animals and focusing on this area would help to support the British Government’s current policy priorities. We believe that this evidence underlines the need for strong action from policymakers to accelerate the transition from animal experiments to NAMs. The specific measure we suggest is to introduce a new ministerial position to coordinate and accelerate the replacement of animals with NAMs

Global Perspective of Plant-Based Cosmetic Industry and Possible Contribution of Sri Lanka to the Development of Herbal Cosmetics

The global consumption of plant-based cosmetics has shown spectacular growth in recent years because of rising consumer awareness regarding the long-term health benefits of natural ingredients. As the global demand for herbal cosmetics increases, there are ample opportunities for Sri Lanka as a tropical Asian country to expand its productions and global exports along with its unique biodiversity and inherited traditional knowledge. Therefore, the present review attempts to give an overview of the widely used medicinal plants in the global herbal cosmetic industry and strengths, challenges, and possible solutions for the development of the herbal cosmetic industry of Sri Lanka. Information was collected using electronic search (using Pub Med, Science Direct, Web of Science, Google Scholar, TEEAL, and Scopus) for articles published in peer-reviewed journals, industrial reports, market surveys, and library search for local books on ethnobotany. Important plant-derived ingredients used in the global herbal cosmetic industry are essential oils, colorants, oils, fats, and waxes. The traditional usage of 108 medicinal plant species (belonging to 58 families) in cosmetic treatments was identified from the local books of Sri Lanka. Of these, 49 plant species were reported as new ingredients for the herbal cosmetic industry. However, the lack of ethnobotanical and ethnopharmacological surveys to identify the cosmetic potential plants, insufficient or absence of continuous supply of raw materials for production in line with the existing demand, the lack of quality control of raw materials and finished cosmetic products, improper systematic cultivation systems for medicinal plants, poor postharvest practices, and the lack of innovations are major challenges encountered in Sri Lanka for the development of the herbal cosmetic industry. In conclusion, addressing these vital knowledge gaps is a timely requirement of the country for the sustainable development of the herbal cosmetic industry in Sri Lanka. Furthermore, assembling of the multidisciplinary cooperation of botanists, chemists, toxicologists, researchers, and biologists is crucial to analyze the interesting functional properties, efficacy, and effectiveness of documented medicinal plants with cosmetic potential.

True Grit: A Story of Perseverance Making Two out of Three the First Non-Animal Testing Strategy (Adopted as OECD Guideline No. 497)

In the last two decades, great strides have been made in developing alternative methods to animal testing for regulatory and safety testing. In 2021, a breakthrough in regulatory testing was achieved in that the first test strategies employing non-animal test methods for skin sensitization have been accepted as OECD guideline 497, which falls under the mutual acceptance of data (MAD) by OECD member states. Achieving this goal was a story of hard work and perseverance of the many people involved. This review gives an overview of some of the many aspects and timelines this entailed—just from the perspective of one stakeholder. In the end, the true grit of all involved allowed us to achieve not only a way forward in using test strategies for skin sensitization, but also a new approach to address other complex toxicological effects without the use of animals in the future.

Special Issue “Current and Evolving Practices in the Quality Control of Cosmetics”

Quality Control (QC) testing of Cosmetic personal care and fragrance products is a key part of the products’ launch to the market [...]