52 SUN CARE


MCC + CMC High molecular weight CMC


Xanthan Gum Guar Gum


Valida S+ 0 35 70 105 140


Figure 6: The storage modulus of Microcrystalline Cellulose + CMC, high molecular weight CMC, xanthan gum, guar gum and the fibrillated cellulose to demonstrate the stabilising capability of these natural rheology modifiers


texture profiles. As the fibrillated cellulose can uniformly disperse the thickener particles, a lower concentration of the said thickener can be used to achieve the desired viscosity. The synergy between the fibrillated cellulose


with xanthan gum and tara gum is shown in Figure 8, where adding the fibrillated cellulose in 0.1% increments to 0.5% of each rheology modifier, significantly boosts the viscosity.


Texture and skin-feel Due to the significant number of OH groups available and the large surface area of the fibrillated cellulose a refreshing and hydrating skin-feel is observed. Therefore, it can be suggested that the fibrillated cellulose can help improve the texture and skin-feel of a sunscreen formulation by creating a lightweight, moisturising formulation that does not leave the skin feeling tacky or greasy. Many consumers do not wear sunscreen


because they do not like how it feels on their skin.10


In the case of mineral sunscreens, they


tend to feel heavy due to the high level of titanium dioxide and zinc oxide creating a thick


10000 7500 5000 2500 0


0 0.1 0.2 0.3 Percentage Valida S+ based on solid content


Figure 8: The synergistic viscosity-boosting effect of the fibrillated cellulose and commonly-used natural rheology modifiers xanthan gum and tara gum


PERSONAL CARE October 2023 0.4


formulation and are hard to spread compared to chemical sunscreens, which are often more lightweight but can be quite greasy due to the high level of silicones and acrylate polymers being used. According to Mintel, the top benefits that


consumers are looking for when purchasing a new sun care product include moisturisation (as the most important) along with long-lasting protection and natural ingredients.11 The fibrillated cellulose can improve the spreading of thick mineral sunscreens as well as provide moisture retention due to its film-forming properties (Figure 9). Figure 9 shows the corneometric


measurements of skin hydration from a preliminary moisturisation study of the fibrillated cellulose. The skin of volunteers were treated with a base containing the fibrillated cellulose and the control. Before application of the two products on the skin, pre-treatment of the skin was performed where four areas on the left and right volar part of the forearm were cleaned, using a 0.5% solution of sodium lauryl sulfate (SLS).


0.5% Xanthan Gum ■ 0.5% Tara Gum ■


Figure 7: The shear-thinning rheology profile of the fibrillated cellulose, which allows suspension of dense particles to be formulated into sprayable products with a good spray pattern, reducing overall drip


The SLS solution was used to clean the skin of the volunteers with the view to eliminate individual factors. Thereafter, a one-off application of the individual products, with a volume of 0.1 ml for each site, was applied (Figure 10). Each area was measured at a time interval of 0, 1, 2, 4, 8, and 24 hours. The hydration was determined five times for each volunteer, in each area on the volar forearm. The results show that the product


containing the fibrillated cellulose was found to have significant improvement in reducing transepidermal water loss after 1, 2, 4, 8 and 24 hours of application compared to the control, conveying its potential hydrating properties. The formulations used in the moisturising study are found in Table 1. Finally, the tolerance towards electrolytes and its stability across a broad range of pH (3-10) means the fibrillated cellulose can be used in several different cosmetic chassis and provide multiple benefits to a formulation including stabilisation, moisturisation and SPF-boosting. Therefore, the fibrillated cellulose should not


be limited to be used in sunscreen formulations alone and instead, there is the opportunity to develop multifunctional personal care products that include SPF such as moisturisers, BB creams and serums. Mintel research indicates that beauty and


personal care products which also offer sun protection are more likely to be used on a more regular basis by both men and women, than conventional sunscreen products, indicating a trend towards multifunctional personal care products.12


Conclusion To conclude, the global sun protection market is growing rapidly due to the increased awareness of sun-related damage such as skin cancer and accelerated ageing of the skin cells. In particular, there is a considerable demand for high sun protection factor products with an SPF of 50 or more.


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Viscosity (mPas)


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