Cosmetics, Volume 3, Issue 1 (March 2016) – 12 articles

Chemical allergy is of considerable importance to the toxicologist, who, amongst other things, has the responsibility of identifying and characterizing the skin (and respiratory) sensitizing potential of chemicals, and estimating the risk they pose to human health. Allergic contact dermatitis (ACD) is to a large extent a preventable disease. Although quantitative risk assessment (QRA) for contact allergy can be performed, it is reasonable to ask why the burden of the skin disease ACD appears to remain stubbornly high, and in particular, that the general level of ACD to sensitizing ingredients found in cosmetics has not fallen noticeably over recent decades; some could argue that it has increased. In this review, this conundrum is addressed, considering whether and to what extent the prevalence of cosmetic allergy is truly unchanged, whether the predicted test methods and potency estimations are sufficiently precise and how proposed changes to the QRA process (i.e., cumulative exposure) may ameliorate the situation. Improved and more widespread use of risk assessment, better education of risk assessors, better post-marketing surveillance and monitoring of dermatology clinic feedback to improve QRA, all together could help to “make contact allergy history”. Full article

Rutin is a well-known antioxidant from the group of flavonoids. Its use in cosmetic dermal products is, however, limited due to its poor water solubility. In order to increase rutin saturation solubility and improve the diffusion to the skin, rutin nanocrystals were produced by the smartCrystal process, e.g., bead milling followed by high pressure homogenization. Rutin nanocrystals were further incorporated into hydroxypropyl cellulose (HPC) gel and its long-term stability was assessed. Determination of the antioxidant activity was made by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay for these formulations: rutin nanocrystals (mean size 300 nm), rutin raw drug powder (mean size 33 μm) and commercial product. Furthermore, the skin penetration profile of rutin was investigated by the tape-stripping method on porcine skin. This study demonstrated that rutin nanocrystal gel had the highest neutralizing activity (90%), followed by a commercial product and rutin raw drug powder. According to the skin study, rutin nanocrystals penetrated to the deeper layers of the stratum corneum, the horny layer of the skin. Full article

Photothermal radiometry is an infrared remote sensing technique that has been used for skin and skin appendages research, in the areas of skin hydration, hydration gradient, skin hydration depth profiling, skin thickness measurements, skin pigmentation measurements, effect of topically applied substances, transdermal drug delivery, moisture content of bio-materials, membrane permeation, and nail and hair measurements. Compared with other technologies, photothermal radiometry has the advantages of non-contact, non-destructive, quick to make a measurement (a few seconds), and being spectroscopic in nature. It is also colour blind, and can work on any arbitrary sample surfaces. It has a unique depth profiling capability on a sample surface (typically the top 20 µm), which makes it particularly suitable for skin measurements. In this paper, we present a review of the photothermal radiometry work carried out in our research group. We will first introduce the theoretical background, then illustrate its applications with experimental results. Full article

Cosmetic products contain potential contact allergens or precursors that require metabolic conversion or oxidation to generate contact allergens. The most relevant contact allergens are fragrances and preservatives. These substances can pose hazards to human health due to their ability to activate T cells that can cause allergic contact dermatitis, an inflammatory skin disease. In recent years, much progress has been made in the elucidation of the mechanistic basis for immune system activation by contact allergens. This is essential for the development of better diagnostic tools, targeted therapies and animal-free in vitro assays for contact allergen identification. This overview will highlight some aspects of the activation of innate and adaptive immune responses by contact allergens. Full article

Over the last decade, incredible progress has been made in the development of non-animal tests to assess contact hypersensitivity. Four methods have been successfully validated and Organisation for Economic Co-operation and Development (OECD) guidelines are available or soon will be. Currently validated methods are useful for hazard identification, classification and labeling. However, to achieve a complete replacement of animals in skin sensitization assessment, dose-response information and evaluation of relative skin sensitizing potency to support effective risk assessment are necessary. In this context, potency is based on the concentration of chemicals needed to induce a positive response. This will require a better understanding of the mechanisms determining potency, including pathway analysis and marker signature identification (selection of an appropriate immune-mediated response to serve as the basis), together with quantitative and qualitative correlations between marker signatures and potency of chemicals in relation with T cell responses. This review aims to discuss the state-of-the-art in the field of in vitro assessment of the no induction sensitization level of contact sensitizers. Full article

Understanding the interactions of nanoparticles (NPs) with skin is important from a consumer and occupational health and safety perspective, as well as for the design of effective NP-based transdermal therapeutics. Despite intense efforts to elucidate the conditions that permit NP penetration, there remains a lack of translatable results from animal models to human skin. The objectives of this study are to investigate the impact of common skin lotions on NP penetration and to quantify penetration differences of quantum dot (QD) NPs between freshly excised human and mouse skin. QDs were mixed in seven different vehicles, including five commercial skin lotions. These were topically applied to skin using two exposure methods; a petri dish protocol and a Franz diffusion cell protocol. QD presence in the skin was quantified using Confocal Laser Scanning Microscopy. Results show that the commercial vehicles can significantly impact QD penetration in both mouse and human skin. Lotions that contain alpha hydroxyl acids (AHA) facilitated NP penetration. Lower QD signal was observed in skin studied using a Franz cell. Freshly excised human skin was also studied immediately after the sub-cutaneous fat removal process, then after 24 h rest ex vivo. Resting human skin 24 h prior to QD exposure significantly reduced epidermal presence. This study exemplifies how application vehicles, skin processing and the exposure protocol can affect QD penetration results and the conclusions that maybe drawn between skin models. Full article

This article presents trends in the frequency of cosmetics as causal factors of allergic contact dermatitis during a 26-year period in 14,911 patients patch-tested between 1990 and 2014, and discusses the cosmetic allergens identified during the last six years (2010–2015) in 603 patients out of 3105 tested. The data were retrieved from, and evaluated with, a patient database developed in-house. The results show the increasing importance of cosmetic allergies, up to 25% of the patients tested during the last five-year period. As expected, fragrance materials, preservatives, and hair dyes were the most frequent culprits, but a great variety of other allergenic ingredients were involved as well. This underlines the need of additional and extensive patch testing with the patient’s products used and their ingredients. Full article

Most common prostaglandin analogs, bimatoprost, latanoprost and travoprost, are licensed for the reduction of elevated intraocular pressure in patients with open angle glaucoma and ocular hypertension, but their non approved use as eyelash enhancers is becoming popular, especially in patients with eyelashes hypotrichosis. A fast and sensitive high performance liquid chromatography tandem mass spectrometry method was developed for the measurement of bimatoprost, latanoprost and travoprost in cosmetic serums freely web-sold to increase eyelash length, thickness and darkness. The analytes and the internal standard (reserpine) were separated by reversed phase chromatography with 5 mM ammonium acetate with 0.02% formic acid (mobile phase A) and 5 mM ammonium acetate in acetonitrile/water (95/5; v/v) with 0.02% formic acid (mobile phase B) by gradient elution and detected with tandem mass spectrometry operated in multiple reaction monitoring mode. Linearity between 1 and 500 μg/g shows good correlation coefficients (r² = 0.99) for all substances. Analytical recovery of analytes under investigation were always higher than 90% and intra-assay and inter-assay precision and accuracy always better than 11%. This method was successfully applied to analyze cosmetic serums freely sold on the Internet websites. Full article

We investigated the Rapid Alert System (RAPEX) database from January 2008 until week 26 of 2014 to give information to consumers about microbiologically contaminated cosmetics and over-preserved cosmetic products. Chemical risk was the leading cause of the recalls (87.47%). Sixty-two cosmetic products (11.76%) were recalled because they were contaminated with pathogenic or potentially pathogenic microorganisms. Pseudomonas aeruginosa was the most frequently found microorganism. Other microorganisms found were: Mesophilic aerobic microorganisms, Staphylococcus aureus, Candida albicans, Enterococcus spp., Enterobacter cloacae, Enterococcus faecium, Enterobacter gergoviae, Rhizobium radiobacter, Burkholderia cepacia, Serratia marcescens, Achromabacter xylosoxidans, Klebsiella oxytoca, Bacillus firmus, Pantoea agglomerans, Pseudomonas putida, Klebsiella pneumoniae and Citrobacter freundii. Nine cosmetic products were recalled because they contained methylisothiazolinone (0.025%–0.36%), benzalkonium chloride (1%), triclosan (0.4%) in concentrations higher than the limits allowed by European Regulation 1223/2009. Fifteen products were recalled for the presence of methyldibromo glutaronitrile, a preservative banned for use in cosmetics. Thirty-two hair treatment products were recalled because they contained high concentrations of formaldehyde (0.3%–25%). Full article

The skin, being the largest organ of the body, functions as a barrier between our body and the environment. It is consistently exposed to various exogenous and endogenous stressors (e.g., air pollutants, ionizing and non-ionizing irradiation, toxins, mitochondrial metabolism, enzyme activity, inflammatory process, etc.) producing reactive oxygen species (ROS) and physical damage (e.g., wounds, sunburns) also resulting in reactive oxygen species production. Although skin is equipped with an array of defense mechanisms to counteract reactive oxygen species, augmented exposure and continued reactive oxygen species might result in excessive oxidative stress leading to many skin disorders including inflammatory diseases, pigmenting disorders and some types of cutaneous malignancy. The nuclear factor erythroid 2-related factor 2 (Nrf2) is an emerging regulator of cellular resistance and of defensive enzymes such as the phase II enzymes. Induction of the Keap1–Nrf2 pathway may have a beneficial effect in the treatment of a large number of skin disorders by stimulating an endogenous defense mechanism. However, prolonged and enhanced activation of this pathway is detrimental and, thus, limits the therapeutic potential of Keap1–Nrf2 modulators. Here, we review the consequences of oxidative stress to the skin, and the defense mechanisms that skin is equipped with. We describe the challenges of maintaining skin redox balance and its impact on skin status and function. Finally, we suggest a novel strategy for maintenance of skin redox homeostasis by modulating the Keap1–Nrf2 pathway using nanotechnology-based delivery systems. Full article