In vitro human skin penetration of diethanolamine

Natural alternatives from your garden for hair care: Revisiting the benefits of tropical herbs

Hair shampoos containing botanical ingredients without synthetic additives, such as parabens, petrochemicals, sulfates and silicones are more skin- and environmentally friendly. In recent years, there is a growing demand for shampoo products with botanical extracts. Shampoos with botanical extracts are well-known for their perceived health benefits. They are also generally milder, non-toxic, natural, and less likely to disrupt the hair and scalp's natural pH and oil balance. Many also believe that shampoos with botanical origins have higher standards of quality. Numerous botanical extracts had been used as natural active ingredients in cosmetic formulations to meet consumer demands. In this review, we have revisited six tropical plants commonly added as natural active ingredients in shampoo formulations: Acacia concinna, Camellia oleifera, Azadirachta indica, Emblica officinalis, Sapindus mukorossi, and Garcinia mangostana. These plants have been traditionally used for hair care, and scientific research has shown that they exhibit relevant physicochemical properties and biological activities that are beneficial for hair care and scalp maintenance.

Unlocking the Hidden Potential of Cosmetics Waste for Building Sustainable Green Pavements in the Future: A Case Study of Discarded Lipsticks

This investigation is dedicated to unlocking the hidden potential of discarded cosmetics towards building green sustainable road pavements in the future. It is particularly aiming at exploring waste lipstick (WLS) as a high-quality functional additive for advanced asphalt mix technologies. To fuel this novel innovation, the effect of various WLS doses (e.g., 5, 10, and 15 wt.%) on the performance of base AP-5 asphalt cement was studied in detail. A wide array of cutting-edge analytical lab techniques was employed to inspect in-depth the physicochemical, microstructural, thermo-morphological, and rheological properties of resultant admixtures including: elemental analysis, Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thin-layer chromatography-flame ionization detection (TLC-FID), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), needle penetration, ring and ball softening point, Brookfield viscometer, ductility, and dynamic shear rheometer (DSR) tests. Unlike the unstable response of asphaltenes, the additive/artificial aging treatments increased the fraction of resins the most, and decreased that of aromatics; however, asphaltenes did not impair the saturates portion, according to Iatroscan research. FT-IR scan divulged that the WLS-asphalt interaction was physical rather than chemical. XRD diagnosis not only revealed an obvious correlation between the asphaltenes content and the fresh-binder crystallinity but also revealed the presence of fillers in the WLS, which may generate outstanding technical qualities to bituminous mixes. According to AFM/SEM analyses, the stepwise incorporation of WLS grew the magnitude of the "bee-shaped" microstructures and extended the roughness rate of unaged/aged binders. The prolonged consumption of the high thermal-stable additive caused a remarkable drop in the onset degradation and glass transition temperature of mixtures, thus enhancing their workability and low-temperature performance, according to TGA/DTGA/DSC data. The DSR and empirical rheological experiments demonstrated that the WLS could effectively lower the manufacturing and compaction temperatures of asphalt mixes and impart them with valuable anti-aging/fatigue-cracking assets. In a nutshell, the use of waste lipstick as an asphalt modifier is viable and cost-effective and could attenuate the pollution arisen from the beauty sector, while improving the performance of hot/warm asphalt mixes (HAM/WAM) and extending the service life of roadways.

Sampling interstitial fluid from human skin using a microneedle patch

Tissue interstitial fluid (ISF) surrounds cells and is an underutilized source of biomarkers that complements conventional sources such as blood and urine. However, ISF has received limited attention due largely to lack of simple collection methods. Here, we developed a minimally invasive, microneedle-based method to sample ISF from human skin that was well tolerated by participants. Using a microneedle patch to create an array of micropores in skin coupled with mild suction, we sampled ISF from 21 human participants and identified clinically relevant and sometimes distinct biomarkers in ISF when compared to companion plasma samples based on mass spectrometry analysis. Many biomarkers used in research and current clinical practice were common to ISF and plasma. Because ISF does not clot, these biomarkers could be continuously monitored in ISF similar to current continuous glucose monitors but without requiring an indwelling subcutaneous sensor. Biomarkers distinct to ISF included molecules associated with systemic and dermatological physiology, as well as exogenous compounds from environmental exposures. We also determined that pharmacokinetics of caffeine in healthy adults and pharmacodynamics of glucose in children and young adults with diabetes were similar in ISF and plasma. Overall, these studies provide a minimally invasive method to sample dermal ISF using microneedles and demonstrate human ISF as a source of biomarkers that may enable research and translation for future clinical applications.

Ethanolamines permeate slowly across human skin ex vivo, but cause severe skin irritation at low concentrations

Skin exposures are common during cleaning activities, and may contribute to the overall body burden. Cleaning products may contain irritants such as monoethanolamine (MEA) and diethanol amine (DEA). The significance of the skin exposure route is unknown, as no estimates for MEA skin permeation are available. We used in vitro flow-through diffusion cells with excised fresh human skin to measure skin permeation, and assessed skin damage with histological methods. MEA(aq) by itself (2%) or as a constituent in cleaning products (0.25% working solution) did not permeate after 1 h or 24 h of exposure. MEA(aq) (10%) did not permeate skin after 1 h but after 24 h with a delay (T_lag; 7 h) and a moderate permeation rate (J; 26.6 μg/cm²/h). MEA permeation rate was 20-fold greater (544 μg/cm²/h) and ¼ of the time lag (1.5 h) when applied as undiluted cleaning product (13% MEA) compared to 10% MEA(aq). DEA in cleaning products did not permeate skin after 24 h. MEA and DEA produced skin irritations at low concentrations (1% MEA) and severe skin irritations when tested as a constituent in cleaning products. Absorption increased from 0 to 3% after 24 h to 14-29% after 88 h of MEA exposure, and is likely explained by the increased damage of the skin barrier. Limitations of this study are the low number of skin donors (N = 5) available. Our results demonstrate that topically applied MEA permeates across human skin relatively slowly and not below 5% while relatively extensively as a constituent of a commercial cleaning product.

Safety Assessment of Diethanolamine and Its Salts as Used in Cosmetics

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of diethanolamine and its salts as used in cosmetics. Diethanolamine functions as a pH adjuster; the 16 salts included in this rereview reportedly function as surfactants, emulsifying agents, viscosity increasing agents, hair or skin conditioning agents, foam boosters, or antistatic agents. The Panel reviewed available animal and clinical data, as well as information from previous CIR reports. Since data were not available for each individual ingredient, and since the salts dissociate freely in water, the Panel extrapolated from previous reports to support safety. The Panel concluded that diethanolamine and its salts are safe for use when formulated to be nonirritating. These ingredients should not be used in cosmetic products in which N-nitroso compounds can be formed.

Safety Assessment of Triethanolamine and Triethanolamine-Containing Ingredients as Used in Cosmetics

The Cosmetic Ingredient Review Expert Panel assessed the safety of triethanolamine (TEA) and 31 related TEA-containing ingredients as used in cosmetics. The TEA is reported to function as a surfactant or pH adjuster; the related TEA-containing ingredients included in this safety assessment are reported to function as surfactants and hair- or skin-conditioning agents. The exception is TEA-sorbate, which is reported to function as a preservative. The Panel reviewed the available animal and clinical data. Although data were not available for all the ingredients, the panel relied on the information available for TEA in conjunction with previous safety assessments of components of TEA-containing ingredients. These data could be extrapolated to support the safety of all included ingredients. The panel concluded that TEA and related TEA-containing ingredients named in this report are safe as used when formulated to be nonirritating. These ingredients should not be used in cosmetic products in which N-nitroso compounds can be formed.

Dose response effects of dermally applied diethanolamine on neurogenesis in fetal mouse hippocampus and potential exposure of humans

Diethanolamine (DEA) is a common ingredient of personal care products. Dermal administration of DEA diminishes hepatic stores of the essential nutrient choline and alters brain development. We previously reported that 80 mg/kg/day of DEA during pregnancy in mice reduced neurogenesis and increased apoptosis in the fetal hippocampus. This study was designed to establish the dose-response relationships for this effect of DEA. Timed-pregnant C57BL/6 mouse dams were dosed dermally from gestation day 7-17 with DEA at 0 (controls), 5, 40, 60, and 80 mg/kg body/day. Fetuses (embryonic day 17 [E17]) from dams treated dermally with 80 mg/kg body/day DEA had decreased neural progenitor cell mitosis at the ventricular surface of the ventricular zone (hippocampus, 54.1 +/- 5.5%; cortex, 58.9 +/- 6.8%; compared to controls; p < 0.01). Also, this dose of DEA to dams increased rates of apoptosis in E17 fetal hippocampus (to 177.2 +/- 21.5% of control; measured using activated caspase-3; p < 0.01). This dose of DEA resulted in accumulation of DEA and its metabolites in liver and in plasma. At doses of DEA less than 80 mg/kg body/day to dams, there were no differences between treated and control groups. In a small group of human subjects, dermal treatment for 1 month with a commercially available skin lotion containing 1.8 mg DEA per gram resulted in detectable plasma concentrations of DEA and dimethyldiethanolamine, but these were far below those concentrations associated with perturbed brain development in the mouse.

Absorption of Lawsone Through Human Skin

Lawsone (2-hydroxy-1,4-naphthoquinone) is the principal color ingredient in henna, a color additive approved with limitations for coloring hair by the Food and Drug Administration (FDA) under 21 CFR 73.2190. In 2002, the scientific committee on cosmetics and non-food products (SCCNFP), now known as the scientific committee for consumer products (SCCP), evaluated the safety of lawsone as a coloring agent in hair dye products of the European Union (EU). The SCCNFP concluded that lawsone was mutagenic and not suitable for use as a hair coloring agent. As a result, studies were conducted to measure the extent of lawsone absorption through human skin. Lawsone skin absorption was determined from two hair coloring products and two shampoo products, all containing henna. [(14)C]-Lawsone (sp. act. 22.9 mCi/mmol) was added to each commercial product and the products were applied to dermatomed, nonviable human skin mounted in flow-through diffusion cells perfused with a physiological buffer (HEPES-buffered Hanks' balanced salt solution, pH 7.4). Products remained on the skin for 5 minutes (shampoos) and 1 hour (hair color paste). For the henna hair paste products, 0.3 and 1.3% of the applied dose was absorbed into the receptor fluid in 24 hours while 2.2 and 4.0% remained in the skin. For both henna shampoo products, 0.3% of the applied dose was absorbed into the receptor fluid at 24 hours while 3.6 and 6.8% remained in the skin. For all products, most of the lawsone applied was washed from the surface of the skin (83-102%) at the end of the exposure period. Extended absorption studies were conducted for 72 hours to determine if skin levels of lawsone in the 24 hour studies might eventually be percutaneously absorbed. These studies determined that the majority of the lawsone remained in the skin with only a small but significant increase (for three out of four products) in receptor fluid values. Therefore, it appears that receptor fluid values would give a good estimate of lawsone absorption for an exposure estimate and that skin levels of lawsone need not be included.

Percutaneous absorption of aromatic amines - a contribution for human health risk assessment

Several aromatic amines (AA) are human carcinogens. AA are widely-used, e.g., in the rubber industry. The uptake of AA at the workplace occurs by inhalation and percutaneous absorption. At present there are no risk assessment studies for percutaneous AA absorption using occupationally relevant concentrations. We conducted diffusion cell experiments for aniline (ANI), o-toluidine (OT), 4,4'-methylenedianiline (MDA) and N-phenyl-2-naphthylamine (PBNA). Excised human skin was exposed to different AA concentrations in vehicles containing water and solvents. Recovery for ANI in receptor fluid was about 20-38% and for MDA 15% over 24h. PBNA could not be detected in the receptor fluid. Further data for OT and beta-naphthylamine (BNA) were considered from our recent study. A semi-quantitative percutaneous absorption ranking for AA was derived: BNA>OT>ANI>MDA>PBNA. For aqueous ANI solutions up to saturation a linear relationship of exposed dose and penetrated amount was observed. However, a linear extrapolation of the flux of neat compounds, as often recommended for risk assessment policies, underestimates considerably the percutaneous uptake. The in vitro data support our recent findings in rubber industry workers that the percutaneous absorption may significantly contribute to overall exposure of AA.

Application of the threshold of toxicological concern (TTC) to the safety evaluation of cosmetic ingredients

The threshold of toxicological concern (TTC) has been used for the safety assessment of packaging migrants and flavouring agents that occur in food. The approach compares the estimated oral intake with a TTC value derived from chronic oral toxicity data for structurally-related compounds. Application of the TTC approach to cosmetic ingredients and impurities requires consideration of whether route-dependent differences in first-pass metabolism could affect the applicability of TTC values derived from oral data to the topical route. The physicochemical characteristics of the chemical and the pattern of cosmetic use would affect the long-term average internal dose that is compared with the relevant TTC value. Analysis has shown that the oral TTC values are valid for topical exposures and that the relationship between the external topical dose and the internal dose can be taken into account by conservative default adjustment factors. The TTC approach relates to systemic effects, and use of the proposed procedure would not provide an assessment of any local effects at the site of application. Overall the TTC approach provides a useful additional tool for the safety evaluation of cosmetic ingredients and impurities of known chemical structure in the absence of chemical-specific toxicology data.

Assessment of skin absorption and irritation potential of arachidonic acid and glyceryl arachidonate using in vitro diffusion cell techniques

Arachidonic acid (AA), a precursor of pro-inflammatory mediators, and its glycerin ester, glyceryl arachidonate (GA), are reportedly used in cosmetic products. In vitro skin penetration of AA and GA and GA's ester hydrolysis was determined in flow-through diffusion cells. AA penetration with human and rat skin was 19.5% and 52.3% of the applied dose respectively, a substantial amount of which remained in the skin at 24h. Similar penetration results were obtained with GA in human skin. However, GA penetration through cultured skin (EpiDerm) was 51% of the applied dose, almost all of which appeared in the receptor fluid. At least 27.8% of GA penetrating skin was hydrolyzed to AA. In vitro methods were used to assess skin irritation in diffusion cells. Skin irritation of AA, sodium lauryl sulfate (SLS), and Tween 80 was determined by changes in transepidermal water loss (TEWL), skin viability (3-(4,5-dimethylthiaxol-2-yl)-2,5-diphenyltetrazolium bromide, MTT, formation), and cytokine release (IL-1alpha). SLS irritation was much less pronounced in an emulsion versus an aqueous vehicle. No significant irritation was observed in vitro from AA in an emulsion. This work predicts that AA would penetrate human skin in vivo and that it could be formed in skin from topically applied GA.

Postnatal development of rat pups after maternal exposure to diethanolamine

BACKGROUND

Diethanolamine (DEA), a widely used surfactant, was administered to pregnant mice at the oral LD10 resulting in failure of pups to grow and thrive through postnatal day (PND) 3 [National Toxicology Program, 1987; York et al., Teratology 37:503-504, 1988]. The toxicity profile for DEA differs among rodent species. This study investigated DEA-induced postnatal toxicity in a second species.

METHODS

Timed-mated Sprague-Dawley rats were dosed (0, 50, 125, 200, 250, or 300 mg DEA/kg/day, p.o.) on gestational days (GD) 6-19. Dams and pups were monitored for body weight, feed/water intake, clinical signs, litter size, and sex ratio. At necropsy (PND 21), maternal liver and kidney weights and number of uterine implantation sites were recorded.

RESULTS

The high-dose group was terminated early due to excessive toxicity. The estimated maternal LD10 was 218 mg/kg/day. Maternal effects included decreased body weight and relative feed intake (>or=200 mg/kg/day), transiently reduced relative water intake (125 and 250 mg/kg/day), and increased absolute kidney weight (>or=125 mg/kg/day). Postimplantation loss (PND 0) and pup mortality (PND 0-4) were increased (>or=200 and >or=125 mg/kg/day, respectively). Pup body weight was reduced (>or=200 mg/kg/day) as late as PND 21.

CONCLUSIONS

This study demonstrates reduced postnatal growth and survival in a second species after gestational exposure to DEA, persistence of toxic effects through the end of lactation, possibly due to long elimination half-life, and maternal and developmental toxicity no-observed-adverse-effect level (NOAELs) (50 mg/kg/day) and lowest-observed-adverse-effect level (LOAELs) (125 mg/kg/day) for oral DEA exposure during embryo/fetal development in the rat.

Decreasing malathion application time for lice treatment reduces transdermal absorption

OBJECTIVE

Head lice are the most common parasitic infestation in the United States requiring topical treatment with pediculicides. Ovide, the 0.5% malathion formulation used in treatment of head lice requires placement on dry hair for 8-12 h. Malathion, however, is effective at killing lice and nits in 10 min. Our concern of over exposing children to malathion has led us to examine whether significantly more malathion will penetrate transdermally when applied for the recommended 8 h than for a shorter but apparently equally effective period.

METHODS

In vitro absorption studies were performed across haired rat skin and human abdominal skin to determine whether reducing malathion application time decreased skin absorption.

RESULTS

A 0.5 h exposure caused 0.36+/-0.14% of the donor malathion to penetrate through human skin after 24 h and 2.1+/-0.6% remained in the skin after washing with shampoo. After 8 h of topical applications penetration was approximately three-fold greater (1.02+/-0.41) and 3.4+/-0.5% remained in the skin (p<0.05 versus 0.5 h). The relationship between absorption and exposure time also occurred for haired rat skin (p<0.05). This differential continued for 72 h even after removal of the source.

CONCLUSIONS

Significantly less malathion penetrated from Ovide after 0.5 h versus the suggested 8 h application, without decreasing the product's efficacy. Further clinical studies in children are warranted to confirm the efficacy of this shortened application time.