Principles for the safety evaluation of cosmetic powders

Consumer exposure to cosmetic (personal care) products is mostly by dermal contact, however additional considerations with regards to potential inhalation exposure from some cosmetics, such as sprays and powders, may be needed for a robust and reliable safety assessment. To get a deeper understanding of the exposure to airborne particles and droplets during product application, a team of international experts was founded under the umbrella of the European Association of the Cosmetic Industry "Cosmetics Europe" (CE) in Brussels. This expert team has worked out a pragmatic strategy how small and medium sized enterprises (SMEs), but also relevant authorities, could handle the safety evaluation of cosmetic powder products. Sufficient information on the aerodynamic diameter of sprayed droplets and here specifically of airborne particles is essential in addition to knowing the exposure after typical product application. The current article is focused on the determination of inhalation exposure to solids, and the derivation of safe exposure levels for cosmetic powder products found in the market. The principles described herein are very similar to spray products as published earlier and should be applied in a similar way (Steiling et al., 2014). Prediction models for the best estimate of inhalation exposure, developed with data from computer simulation programs, individual real-time measurements or finally by experience from the market were introduced and applied. Safety assessment approaches for exposure from powder spray products were developed and have been already considered in regulatory guidelines like the EC Cosmetics Regulation.

Potency values from the local lymph node assay: application to classification, labelling and risk assessment

Hundreds of chemicals are contact allergens but there remains a need to identify and characterise accurately skin sensitising hazards. The purpose of this review was fourfold. First, when using the local lymph node assay (LLNA), consider whether an exposure concentration (EC3 value) lower than 100% can be defined and used as a threshold criterion for classification and labelling. Second, is there any reason to revise the recommendation of a previous ECETOC Task Force regarding specific EC3 values used for sub-categorisation of substances based upon potency? Third, what recommendations can be made regarding classification and labelling of preparations under GHS? Finally, consider how to integrate LLNA data into risk assessment and provide a rationale for using concentration responses and corresponding no-effect concentrations. Although skin sensitising chemicals having high EC3 values may represent only relatively low risks to humans, it is not possible currently to define an EC3 value below 100% that would serve as an appropriate threshold for classification and labelling. The conclusion drawn from reviewing the use of distinct categories for characterising contact allergens was that the most appropriate, science-based classification of contact allergens according to potency is one in which four sub-categories are identified: 'extreme', 'strong', 'moderate' and 'weak'. Since draining lymph node cell proliferation is related causally and quantitatively to potency, LLNA EC3 values are recommended for determination of a no expected sensitisation induction level that represents the first step in quantitative risk assessment.

Probabilistic modelling of European consumer exposure to cosmetic products

In this study, we describe the statistical analysis of the usage profile of the European population to seven cosmetic products. The aim of the study was to construct a reliable model of exposure of the European population from use of the selected products: body lotion, shampoo, deodorant spray, deodorant non-spray, facial moisturiser, lipstick and toothpaste. The first step in this process was to gather reliable data on consumer usage patterns of the products. These data were sourced from a combination of market information databases and a controlled product use study by the trade association Colipa. The market information study contained a large number of subjects, in total 44,100 households and 18,057 habitual users (males and females) of the studied products, in five European countries. The data sets were then combined to generate a realistic distribution of frequency of use of each product, combined with distribution of the amount of product used at each occasion using the CREMe software. A Monte Carlo method was used to combine the data sets. This resulted in a new model of European exposure to cosmetic products being constructed.

European consumer exposure to cosmetic products, a framework for conducting population exposure assessments

Access to reliable exposure data is essential to evaluate the toxicological safety of ingredients in cosmetic products. This study was carried out by European cosmetic manufacturers acting within the trade association Colipa, with the aim to construct a probabilistic European population model of exposure. The study updates, in distribution form, the current exposure data on daily quantities of six cosmetic products. Data were collected using a combination of market information databases and a controlled product use study. In total 44,100 households and 18,057 individual consumers in five European countries provided data using their own products. All product use occasions were recorded, including those outside of home. The raw data were analysed using Monte Carlo simulation and a European Statistical Population Model of exposure was constructed. A significant finding was an inverse correlation between frequency of product use and quantity used per application for body lotion, facial moisturiser, toothpaste and shampoo. Thus it is not appropriate to calculate daily exposure to these products by multiplying the maximum frequency value by the maximum quantity per event value. The results largely confirm the exposure parameters currently used by the cosmetic industry. Design of this study could serve as a model for future assessments of population exposure to chemicals in products other than cosmetics.

Repeated topical treatment, in contrast to single oral doses, with Vitamin A-containing preparations does not affect plasma concentrations of retinol, retinyl esters or retinoic acids in female subjects of child-bearing age

BACKGROUND

Vitamin A is widely used in cosmetic preparations. Given that oral Vitamin A and its metabolites present a potential reproductive risk, the present study investigated the effect of topical Vitamin A on human endogenous plasma levels of Vitamin A and its metabolites.

METHODS

Two groups of 14 female volunteers of child-bearing age were kept on a Vitamin A-poor diet and treated topically for 21 days with creams containing 0.30% retinol or 0.55% retinyl palmitate on approximately 3000 cm2 of their body surface area, amounting to a total of approximately 30,000 IU Vitamin A/subject/day. After a 12-day wash-out period, the study groups received single oral doses of 10,000 IU or 30,000 IU retinyl palmitate (RP), corresponding to the maximal EU allowance during pregnancy or three-times higher, respectively. Blood samples were collected over 24h on study days -3 (pre-study), 1, 21 (first and last days of topical treatment) and 34 (oral administration) at 0, 1, 2, 4, 6, 8, 12, 14-16 h and 24 h after treatment for determination of plasma concentrations of retinol (REL), retinyl palmitate (RP), oleate (RO) and stearate (RS), 9-cis-, 13-cis-, all-trans- (AT), 13-cis-4-oxo- or AT-4-oxo-retinoic acids (RAs).

RESULTS

With the exception of transient mild (RP-group) to moderate (REL-group) local irritation on the treatment sites, no adverse local or systemic effects were noted. On days 1 or 21 of topical treatment, no changes were measured in individual or group mean plasma Cmax, AUC0-24 h or other pharmacokinetic parameters of REL, retinyl esters or RAs relative to pre-study data. In contrast, single oral doses of RP at 10,000 IU or 30,000 IU produced dose-related and sustained increases in Cmax and AUC0-24 h values of plasma RP, RO, RS, 13-cis- and 13-cis-4-oxo-RAs, as well as a transient increase in AT-RA. In conclusion, our results provide evidence that human topical exposure to retinol- or retinyl ester-containing cosmetic creams at 30,000 IU/day and maximal use concentrations do not affect plasma levels of retinol, retinyl esters or RAs, whereas single oral doses at 10,000 IU or 30,000 IU produce significant increases in plasma retinyl esters and RAs.

Classification of contact allergens according to potency: proposals

It is clear that contact allergens vary substantially with regard to the relative potency with which they are able to induce skin sensitisation. Considerations of potency will in the future become a significant factor in the classification of skin sensitising chemicals. It is therefore appropriate to establish what is known of potency and thresholds in the induction of skin sensitisation and the elicitation of allergic contact dermatitis, and to identify approaches that might be available for assessment of relative potency for the purposes of categorising chemical allergens. This paper was prepared by an ECETOC (European Centre for Ecotoxicology and Toxicology) Task Force that had the objective of recommending approaches for the measurement of potency and definition of thresholds for both the induction and elicitation of contact sensitisation. The deliberations recorded here build upon recommendations made previously by an ECETOC Task Force that considered the conduct of standard skin sensitisation test methods for the purposes of hazard identification and risk assessment (ECETOC, Monograph No. 29, Brussels, 2000). The emphasis in this present paper is also on standard and accepted methods for the assessment of skin sensitisation, and for which OECD guidelines are available: the local lymph node assay (LLNA), the guinea pig maximisation test and the occluded patch test of Buehler. For various reasons, discussed in detail herein, attention focused primarily upon consideration of categorisation of chemical allergens and the identification of thresholds with respect to the induction of skin sensitisation, rather than the elicitation of allergic contact dermatitis. It is concluded that although the LLNA is the method of choice for the determination of skin sensitisation potency for the purposes of categorisation, if data are already available from appropriate guinea pig tests then their judicious interpretation may provide information of value in determinations of potency and categorisation. Included here are detailed and specific recommendations for how best the results of the three test methods considered can be used for the categorisation of chemical allergens as a function of skin sensitisation potency.

Percutaneous penetration/dermal absorption of hair dyes in vitro

This paper presents an in vitro technique to analyse percutaneous penetration and dermal absorption of hair dyes, topically applied to excised pig skin. Representative examples are given by the radio-labelled hair dyes p-phenylenediamine and bis-(5-amino-1-hydroxyphenyl)-methane. Both compounds were assessed under simulated use conditions and were analysed in representative formulations including the specific conditions for oxidation hair dyes. To be able to differentiate between topically adsorbed and systemically available amounts, the bioavailability of the hair dyes is defined as the amount penetrated and/or remaining in the exposed skin after removing the stratum corneum. Less than 1% of the assessed topically applied dyes was found to be bioavailable in the presence of hydrogen peroxide, typically added to oxidation hair dyes prior to applications. Compared with published results and unpublished in-house in vivo data, the level of confidence was high. Owing to in-house experience over about 5 years in using excised pig skin for measurements of percutaneous penetration and dermal absorption of hair dyes, the technique was found to be successful and appropriate to reduce the number of test animals normally used for toxicological assessments. The essentials of this technique are actually recommended by the SCCNFP (The Scientific Committee on Cosmetic Products and Non Food Products intended for Consumers) for the safety evaluation of cosmetic ingredients, particularly for hair dyes. The corresponding OECD guideline as well as the guidance document has been drafted and is currently in discussion on the level of the national coordinators.

Skin sensitisation testing--new perspectives and recommendations

Various methodological aspects of skin sensitisation testing have been explored, particularly in the context of animal welfare considerations and reliability and sensitivity of test methods. Recommendations are made for the conduct of current and proposed OECD skin sensitisation tests with respect to appropriate test configurations for the purposes of hazard identification and labelling, and the requirement for positive controls. Specifically, the following aspects of guinea pig sensitisation test methods have been addressed: (1) the number of test and control animals required; (2) the option of using joint positive controls between independent laboratories; (3) the choice of positive control chemicals; (4) the optimal conduct and interpretation of rechallenge; and (5) the requirement for pretreatment with sodium lauryl sulfate. In addition, the use of the murine local lymph node assay (LLNA) has been considered. A number of conclusions have been drawn and recommendations made as follows: In many instances, particularly with the conduct of the guinea pig maximisation test, it is acceptable to halve the number of test and control animals used. An optional scheme for the conduct of joint positive control studies within a co-ordinated group of laboratories is appropriate. Only one positive control chemical (alpha-hexyl cinnamic aldehyde) is necessary for the routine assessment of assay sensitivity. The proper conduct and interpretation of rechallenge can provide valuable information and confirmation of results in guinea pig sensitisation tests. Sodium lauryl sulfate should no longer be used as a pretreatment in the guinea pig maximisation test. The LLNA is a viable and complete alternative to traditional guinea pig test methods for the purposes of skin sensitisation hazard identification. These recommendations provide the opportunity for both animal welfare benefits and improved hazard identification.

The red blood cell phototoxicity test (photohaemolysis and haemoglobin oxidation): EU/COLIPA validation programme on phototoxicity (phase II)

In the EU/COLIPA validation programme on "Photoirritation in vitro", two core tests and a number of mechanistically based tests were carried out to examine their suitability as regulatory tests for phototoxicity testing. In the meantime, one core test, the 3T3 neutral red uptake phototoxicity test (NRU PT) has been validated and has been accepted by ECVAM and the European Commission. The second core test, the red blood cell phototoxicity test (Photo-RBC test), has passed through a prevalidation process during this programme. This test protocol combines two endpoints, photohaemolysis and met-haemoglobin (met-Hb) formation. These endpoints are determined by measuring changes in the optical density of the haemoglobin spectrum at 525 nm and 630 nm, respectively. In addition, a prediction model was inserted into the Standard Operating Procedure (SOP) with two cut-off values: a photohaemolysis factor (PHF) > or = 3.0 for photohaemolysis, and a deltaOD(max) > or = 0.05 for met-Hb formation. Three laboratories agreed to implement the SOP and to perform the study by testing 30 selected test chemicals (25 phototoxicants and 5 non- phototoxic chemicals). The outcome of the study presents a good overall fit, including acceptable accuracy, sensitivity, and positive predictivity. The specificity and the negative predictivity are comparably low, due to the low number of non-phototoxic substances among the test chemicals. Further analysis of the data showed that the transfer of the SOP from between laboratories could have been more efficient. The results, especially of the lead laboratory, clearly indicate that an experienced laboratory can handle the SOP with high predictivity for phototoxicants and non-phototoxic substances. Finally, it was concluded that the combined Photo-RBC test can be considered as a second in vitro test, which can be used advantageously to obtain some mechanistic information, in particular on photodynamic effects on cellular proteins and biomembranes.

Skin sensitization testing in potency and risk assessment

The purpose of this article is to review, and make recommendations for, the use of relevant skin sensitization test methods, for the purposes of determination of relative potency and the threshold dose necessary for the induction of skin sensitization, and for risk assessment. In addressing the first area, the utility of three guinea pig tests (the guinea pig maximization test, the occluded patch test, and the open epicutaneous test) of the local lymph node assay (LLNA) and of human volunteer testing for the assessment of relative potency and identification of thresholds for sensitization were considered. The following conclusions were drawn. (1) Although attempts have been made to modify the guinea pig maximization test for the purposes of deriving dose-response relationships, this method is usually unsuitable for determination of relative sensitizing potency. (2) Guinea pig methods that do not require the use of adjuvant and which employ a relevant route of exposure (the occluded patch test and the open epicutaneous test) are more appropriate for the assessment of relative skin-sensitizing potency. (3) The LLNA is suitable for the determination of relative skin sensitizing potency, and the adaptation of this method for derivation of comparative criteria such as EC3 values (the estimated concentration of test chemical required to induce a stimulation index of 3 in the LLNA) provides an effective and quantitative basis for such measurements. (4) For all the methods identified above, potency is assessed relative to other chemical allergens of known skin sensitizing potential. The estimation of likely threshold concentrations is dependent upon the availability of suitable benchmark chemicals of known potency for human sensitization. (5) Human testing (and specifically, the Human Repeat Insult Patch Test) can provide information of value in confirming the absence of skin sensitizing activity of formulations and products under specific conditions of use and exposure. Based on the above, the following recommendations are made. (1) If results are already available from suitable guinea pig tests, then judicious interpretation of the data may provide information of value in assessing relative skin sensitizing potency. This option should be explored before other analyses are conducted. (2) The LLNA is the recommended method for new assessments of relative potency, and/or for the investigation of the influence of vehicle or formulation on skin sensitizing potency. (3) Whenever available, human skin sensitization data should be incorporated into an assessment of relative potency. With respect to risk assessment, the conclusion drawn is that all the available data on skin-sensitizing activity in animals and man should be integrated into the risk-assessment process. Appropriate interpretation of existing data from suitable guinea pig studies can provide valuable information with respect to potency, as the first step in the development of a risk assessment. However, for de novo investigations, the LLNA is the method favored for providing quantitative estimations of skin-sensitizing potency that are best suited to the risk assessment process. Finally, human testing is of value in the risk assessment process, but is performed only for the purposes of confirming product safety.

A critical review of the assessment of eye irritation potential using the Draize rabbit eye test

Traditionally, the eye irritation potential of substances and products has been assessed using the Draize eye test. While this procedure has been criticized in terms of its scientific validity and its ethical acceptability, it remains the only official, government-recognized procedure for predicting the irritant effect of substances in the eye. The relative absence of serious human accidents testifies to the success of the predictions. With the development of alternative non-animal procedures to replace the Draize test, the data generated in the Draize procedure are also being used as a 'gold standard' against which the performance of alternative procedures is measured. The major sources of variability are small group size and inability of existing scoring systems to reflect the complexities of the total in vivo response. In addition, the use of algorithms to simplify the in vivo data (for comparison with in vitro data) also misrepresents the in vivo data. Addressing the above issues would inevitably increase the use of animals. This would go against the general public demand for a reduction in the use of animals. Therefore the issue is to decide upon a simple parameter (for comparison with in vitro data) that encompasses the complexity of the irritation response and accurately reflects irritation without requiring the use of additional test animals. Such a parameter could be the recovery time. In addition, controlled human testing to benchmark the Draize data would be invaluable. The future use of Draize data in the validation of in vitro alternatives is undisputed, but the utility of these data will only be enhanced by a proper understanding of the shortcomings of the Draize test.

IRAG working group 2. CAM-based assays. Interagency Regulatory Alternatives Group

CAM-based assays, in which test material is applied to the chorion allantoic membrane (CAM) of embryonated chicken eggs, were assessed as alternatives to the Draize eye irritation test. Two general types of CAM-based assays are currently in use, the HET-CAM test and the CAMVA assay. Evaluations were made of five data sets produced with three different modifications of the HET-CAM test and two data sets obtained with the same CAMVA protocol. Data sets consisted of 9-133 test chemicals, usually from the sponsor's product line, and also from a validation trial. Each data set and assay protocol were analysed for quality of data, purpose and proposed use of the assay, range of responses covered, range of test materials amenable, current use in safety and risk assessment both in-house and for regulatory purposes. Since the MMAS Draize score was not available for all in vivo data sets, the sigma MMMIS, which correlates well with the MMAS, was used instead. In vitro/in vivo correlations calculated with Pearson's linear coefficient ranged from r = 0.6 to r = 0.9 for six of seven data sets. Corneal opacity and inflammation of the iris showed the best correlation to in vitro data. Prediction rates were significantly improved when partial linear regression was used, and the predictivity of three different HET-CAM protocols was almost the same. HET-CAM assays showed the best prediction with surfactants and surfactant-based formulations, whereas the CAMVA assay provided the best performance with alcohols.