International Journal of Cosmetic Science最新文献

This study aims to find the quick ways to predict sensorial attributes of sunscreens using instrumental measurements. We specifically focus on the attributes most relevant to consumer 'liking' and the easiest measurements to implement in industrial labs for product development. Of the latter, we consider three types of measurements: emulative 'textural' tests typically performed with a texture analyser as well as rheological and tribological measurements. Textural tests are generally preferred but may be paralleled by rheological measurements provided they are implementable on simple viscometers used in industry (albeit with additional data processing). We found that both textural and simple rheological/viscometrical tests work well for predicting sensorial attributes about flow before (thickness) and during (spreadability) application of the products. Tribology provides useful additional information for the latter but is primarily useful for after-feel or residue attributes (absorption and skin stickiness). These findings show that simple lab tests relying on these techniques can predict human sensory attributes, thus efficiently guide product developers while reducing the need for costly and time-consuming panel studies.

Sun protection products play a critical role in defending consumers' skin against the harmful effects of ultraviolet radiation during sun overexposure. Regular use of these products is essential, but it is equally important to ensure that the sun protection factor (SPF) communicated to consumers is accurate and allows consistent comparison between products. This is particularly vital since the vast majority of consumers base their purchasing decisions on the SPF value displayed on the label.

The current international standard for SPF testing, ISO 24444:2019, relies on testing conducted with human volunteers. Until 2024, this was the sole accepted method for SPF evaluation. However, this approach is invasive, complex, time-consuming, costly, and – as a biological test – has a high variability. Over many years, the cosmetics industry has been working to develop suitable alternative methods that give comparable results to ISO 24444:2019.

Validating such new methods is done through ring tests that benchmark the results of the new test methods against the gold standard. This requires the availability of robust in vivo reference SPF data on a large number of sun protection products – a significant experimental undertaking that cannot be repeated for each proposed method.

Recognizing this need, a consortium of sunscreen testing users and developers launched the ALT-SPF initiative in 2018 to identify, characterize, and evaluate alternative sunscreen testing methods against the ISO 24444:2019 gold standard. It included SPF testing methods that were expected to be less invasive, more precise, and more cost-effective. As part of this effort, ALT-SPF conducted an extensive study using 32 sunscreen samples. These were tested with the current ISO 24444:2019 standard and five alternative methods, including in vitro, in silico, and non-invasive in vivo testing approaches.

Each alternative method was benchmarked against the gold standard, with results analysed through statistically robust models. This rigorous approach not only evaluated the alternative methods but also laid the foundation for ISO's landmark publication in December 2024 of two alternative SPF testing methods – marking the first time non-in vivo approaches have been formally recognized as viable options to ISO 24444.

The editors, Professor Majella Lane and Professor Marc Pissavini, are honoured to welcome Mr. John Chave, Director General of Cosmetics Europe, as the guest editor of this special edition of the International Journal of Cosmetic Science. His participation underscores the importance of collaborative efforts and expertise in advancing SPF testing methodologies.

This edition features seven groundbreaking publications authored by leading experts. These papers detail the protocols, findings, and conclusions of the ALT-SPF initiative. Their contributions have been instrumental in advancing the science of SPF testing and shaping a future where in

This paper presents the results of the Alt-SPF consortium ring test, obtained by the in-silico methodology, and discusses these results in the context of existing standards. To evaluate the effectiveness of the in-silico methodology in correlating with these standards, a comparison was made between the in-silico sun protection factor (SPF) and the UVA protection factor (UVA-PF) and the values derived by standard in vivo SPF (ISO24444) and in vitro UVA-PF (ISO24443). The model utilises the same algorithm as in vitro measurements of SPF and UVA-PF, with the measured UV transmission substituted by calculated transmission simulated through an applied sunscreen film. The in-silico approach necessitates quantitative UV absorbance data of all UV-filters, their photodegradation and photointeraction properties, oil/water phase synergies and a model describing the irregular distribution of the film thickness on the skin. The performance factors are calculated using an initial analytical evaluation of the 32 test formulations of the ring test, to ascertain the presence and concentration of individual UV absorbers. The filter concentrations obtained are then processed via computational analysis to calculate the SPF and UV-PF values. It has been demonstrated that, in accordance with defined statistical parameters to characterize the ability of a method to correlate with the in vivo SPF standard, the in-silico methodology is a highly reproducible and accurate tool for SPF prediction. The alignment with the lowest measured in vivo SPF values serves to ensure the safety of the end consumer and is not a weakness of the method. Additionally, it has been demonstrated that the methodology facilitates precise prediction of UVA protection in comparison to the in vitro standard ISO 24443. These calculations can be employed to engineer novel sunscreens, thereby diminishing the necessity for ethically questionable and extensive laboratory measurements. In case still in-vivo measurements are needed, the methodology can deliver the frequently required SPF/UVA-PF values and may also support functions such as those of responsible persons, including safety assessors, in their evaluations.

Objective: Over the last two decades, consumers have been calling for greater transparency for ingredient sourcing and manufacturing practices; therefore, more sustainable alternatives need to be evaluated to meet industry demands. While many organizations give standards for 'clean', 'organic' and 'natural' cosmetic products, sustainable formulations lack standardization and harmonization globally. This study aimed to formulate sustainable lipsticks and moisturizers using resources and standards currently available in the cosmetic industry and compare select sustainable alternatives to a conventional control product.

Methods: After thoroughly screening ingredients for each product type, five different lipsticks and five batches of moisturizers were formulated and tested for quality, performance and stability characteristics.

Results: Pay-off and friction were the most different among the lipsticks, with M4, the lipstick containing sustainable ingredients, having the highest average friction and pay-off at Week 1. As for the moisturizers, spreadability had the largest differences, mostly due to the different emulsifier systems, as expected.

Conclusion: Incorporating sustainable ingredients can be challenging, but having quality products while being more environmentally friendly is possible. These case studies are meant to serve as examples for formulation chemists.

Objective: Sensitive skin syndrome (SSS) affects individuals from all ethnic groups. However, studies across different populations remain limited, despite recognised differences between populations. Thus, we examined SSS in Thai and Polish subjects, assessing the tolerance and efficacy of a dermo-cosmetic product in both populations.

Methods: Thai participants were involved in a 28-day open-label study, while Polish subjects took part in a 56-day double-blind, randomised study comparing the product with a control cream. Clinical and functional signs were evaluated, alongside quality of life (QoL) using the Burden of Sensitive Skin (BoSS) questionnaire.

Results: The product was well tolerated in both groups over time, leading to significant improvements in all clinical and functional signs (p < 0.05 to p < 0.001) and enhancing QoL (p < 0.005 in Thailand; p < 0.001 in Poland). At baseline, Polish subjects exhibited greater redness and higher BoSS scores to questions relating to visual signs (p < 0.001). Conversely, Thai participants reported more pronounced tingling, pain and itching, along with higher BoSS scores relating to sensory symptoms (p < 0.001).

Conclusions: The study highlights differences existing in the perception of SSS symptoms between a Thai and Polish population and demonstrates that the dermo-cosmetic cream effectively alleviates SSS symptoms and improves QoL in both ethnic groups.