Subchronic (26- and 52-week) toxicity and irritation studies of a novel microbicidal gel formulation containing sodium lauryl sulfate in animal models

Development of an oral mucosal irritation test using a three-dimensional human buccal oral mucosal model

The oral mucosa can become irritated by oral care products and lip cosmetics. Therefore, it is important to determine the irritation potential of their ingredients and products during safety evaluations. We developed a method for oral mucosal irritation test using EpiOral, which is a three-dimensional cultured model. Exposure of sodium lauryl sulphate (SLS) to EpiOral showed a dose-dependent decrease in cell viability. Under 120 min exposure conditions, SLS irritation was detected when 60% cell viability was set as a criterion. Evaluation of the irritancy of SLS and four other raw materials used in oral products at three laboratories under the above conditions confirmed good transferability of the test. Focused on the similarity of the oral and eye mucous, 32 chemicals categorised by the UN-GHS eye-irritation classification were evaluated to ensure the reliability of our criteria at these laboratories. The concordance rate between the UN-GHS classification and our test results was 100% for irritants and 60% for non-irritants. The good intra-laboratory reproducibility of our test was confirmed from the evaluation results of negative and positive controls, and the good inter-laboratory reproducibility was confirmed from the results of 32 chemicals. These findings showed that oral mucosal irritation can be evaluated using EpiOral.

Human and Environmental Toxicity of Sodium Lauryl Sulfate (SLS): Evidence for Safe Use in Household Cleaning Products

Environmental chemical exposure is a major concern for consumers of packaged goods. The complexity of chemical nomenclature and wide availability of scientific research provide detailed information but lends itself to misinterpretation by the lay person. For the surfactant sodium lauryl sulfate (SLS), this has resulted in a misunderstanding of the environmental health impact of the chemical and statements in the media that are not scientifically supported. This review demonstrates how scientific works can be misinterpreted and used in a manner that was not intended by the authors, while simultaneously providing insight into the true environmental health impact of SLS. SLS is an anionic surfactant commonly used in consumer household cleaning products. For decades, this chemical has been developing a negative reputation with consumers because of inaccurate interpretations of the scientific literature and confusion between SLS and chemicals with similar names. Here, we review the human and environmental toxicity profiles of SLS and demonstrate that it is safe for use in consumer household cleaning products.

The future of microbicides

There is an urgent need to develop vaginal microbicides to empower women to better control their own sexual life and to protect themselves against HIV and other sexually transmitted infections (STIs). Prevention of STIs with its 330 million cases a year would have a great global health impact. Because of their anatomy, women are up to 8 times more susceptible than men to STIs including HIV. Women who can't negotiate condom use with their male partners have no means of protecting themselves from these infections. In the last few years, especially after the recent failures of several microbicides in Phase III trials, there was increasing pressure from those favoring the use of a more targeted approach to introduce marketed antiretroviral drugs (ARVs) into microbicides. This Pre-Exposure Prophylaxis (PrEP) concept which targets only HIV using specific ARVs contrasts with the primary approach of broad spectrum microbicides which aimed at offering universal protection against several sexually transmitted pathogens. However, before using ARVs as PrEP for HIV prevention, there are still many important issues to consider. In this article, we compare both strategies, while reviewing the last 15 years of microbicide research and its future.