New formulation technology to boost sun protection

OBJECTIVE

As every skin type worldwide is concerned by photoprotection, with consumers preferring cosmetic elegant and efficient sunscreen products, we aim at developing the most performant and desirable sun care products.

METHODS

We selected an interesting polymer, abbreviated AAHCP and designed scanning electron cryomicroscopy (cryoSEM), small angle and wide angle X-ray scattering and confocal laser scanning microscopy studies to understand its behaviour in solution and in simplex sun care formulations. This allowed us to develop innovative sunscreen formulation technology that was demonstrated by in vitro and in vivo photoprotection methods. Comprehensive photoprotection evaluations were made on the fully developed sun protection product.

RESULTS

We observed the polymer oil structuring properties as well as its ability to form small and stable droplets in simplex emulsions. In vitro and in vivo sun protection factor (SPF) measurements demonstrated the sun protection boosting efficacy of AAHCP polymer in several emulsions or as a stand-alone emulsifier. This formulation technology also allowed to filtering system concentration optimization. Use-test performed on a fully developed AAHCP-based sunscreen validated its optimal performances as well as its ideal cosmetic features, with non-sticky, non-greasy perception and invisible skin result.

CONCLUSION

For the first time, thanks to a new specific polymer creating a new type of emulsion, we succeed in reconciliate in a single sun care product maximal SPF efficacy, resistance to numerous stresses and optimal sensoriality.

A review of shampoo surfactant technology: consumer benefits, raw materials and recent developments

Surfactants form the core of all shampoo formulations, and contribute to a wide range of different benefits, including cleansing, foaming, rheology control, skin mildness and the deposition of benefit agents to the hair and scalp. The purpose of this review was to assist the design of effective, modern, shampoo surfactant technologies. The mechanisms through which surfactants help deliver their effects are presented, along with the appraisal techniques through which surfactant options can be tested and screened for product development. The steps that should be taken to select the most appropriate blend of surfactants are described, and useful information on the most widely used surfactants is provided. The review concludes with an examination of recent developments in 'greener' surfactants, 'sulphate-free' technologies and structured liquid phases for novel sensory properties and for suspending benefit agents.

Physical-Mechanical characterization of cosmetic formulations and correlation between instrumental measurements and sensorial properties

OBJECTIVE

The correct choice of raw materials in the development of cosmetic formulations is essential for obtaining stable and pleasant skin care products. Therefore, rheological, texture and sensory analyses are important to understand the behaviour and stability of the formulations. In this context, the aim of this study was to develop cosmetic formulations containing or not (vehicle) UV filters and chicory root extract, to evaluate their stability as well as to characterize their physical and texture properties and correlate them with the sensory attributes.

METHODS

Four formulations containing organic UV filters and chicory extract, each alone or in combination, were developed and evaluated for 180 days with a cone and plate rheometer, a texture analyzer and consumer's sensorial analysis. Thus, the data obtained were correlated to observe the different influences.

RESULTS

The developed formulations remained stable after 180 days regarding macroscopic aspects, organoleptic characteristics and pH values. The addition of the UV filters alone and in combination with the active substance resulted in significant increases in rheology properties, viscosity and consistency. The formulation with the active ingredient showed significant decreases in the texture parameters after 180 days, mainly due to its polysaccharide inulin. All formulations obtained high scores in sensorial parameters. A strong correlation was mainly found between spreadability and work of shear, and between the texture parameters.

CONCLUSION

The raw materials strongly influenced the physical, texture and sensorial parameters. Finally, the UV filters showed a greater influence on the results of the formulations than the chicory root extract. In conclusion, the association of the mentioned methods allows the correct choice of ingredients and their combinations.

Modified Corneosurfametry as a new accelerated high-throughput ex vivo methodology for predicting cleanser effects towards human skin

BACKGROUND

Corneosurfametry (CSM) was originally developed as a tool to predict irritation potential of cleansers. In this method, surface skin stripped using cyanoacrylate is contacted with surfactants/products, rinsed and stained with toluidine blue and basic fuschin dyes. The intensity of staining increases with increases in irritation potential of surfactant. Our objective was to modify the CSM technique to achieve better control of the tape stripping process. Another objective was to correlate the modified CSM (MCSM) with a traditional in-vivo forearm controlled application test (FCAT) for mildness and to explore its utility to assess the state of corneum after a clinical test.

METHODS

Surface skin cells were tape stripped from forearms of volunteers with D-Squame Adhesive Discs. Discs were treated with a 10% solution of the product in a 96-plate well for 10 min, rinsed, dried and treated with basic fuschin-toluidine blue dye solution, rinsed and dried again. Forearm Controlled Application Test (FCAT) was based on a published protocol. Tape strips obtained after product treatment were also analyzed by the MCSM procedure without additional product treatment.

RESULTS

Mildness/barrier damage assessed from in-vivo FCAT showed a similar ranking to the MCSM results. MCSM, TEWL and Erythema analysis of between-treatment differences showed a good correlation indicating that barrier damage seen in in-vivo studies can be predicted from ex-vivo MCSM studies. MCSM analysis of tape strips after the FCAT study showed that the damage decreased with increase in tape strip number. A moisturizing body wash (MBW) with mild surfactants showed the least damage in all layers. In contrast, harsh dish washing liquid showed significantly higher damage down to several layers. Another MBW with petrolatum in a harsher base showed damage almost similar to that of the harsh dish washing liquid in the surface layers. Thus, the MCSM was able to show underlying damage which would have been normally masked by the deposited petrolatum.

CONCLUSION

The MCSM assay was shown to be a valuable tool for accelerated high throughput evaluation of mildness of surfactants and fully formulated products. MCSM can also be used to assess the state of the corneum after a product treatment.