(602f) Investigating the Impact of Texture Modifiers on the Flow Properties of Cosmetic and Personal Care Formulations

Across numerous industries, it is necessary to introduce additives and modifiers to formulations in order to improve their processability and final product quality. Within the cosmetics and personal care sectors, these additions can be made for a variety of reasons. In addition to improving process performance, additives can be introduced to improve consumer experience, such as product texture, spreadability on skin, appearance and scent, increase the stability of expensive fragrance components and influence substantivity on the skin or hair.

Despite several advantages of introducing additives or making adjustments to the formulation, it is important to understand how these changes affect the bulk flow properties throughout preceding unit operations. In this study, the powder flow properties of spherical silica texture modifiers are investigated. The purpose of this silica modifier is to improve the spreadability, ‘skin feel’ and appearance on skin of a powder or cream product, and can even provide SPF boosting. These performance parameters can be influenced by changes in surface properties and oil absorption ability of the silica bead. The relationship between these Critical Quality Attributes (CQAs) and the flow properties of the dry component is evaluated to understand whether compromise is required to simultaneously optimise process efficiency, yield and product quality.

Powder flow properties were evaluated using an FT4 Powder Rheometer® (Freeman Technology Ltd), a universal powder flow tester that provides automated measurements of dynamic, bulk and shear properties. These parameters were used to quantify the influence of surface area and oil absorption on the flow properties of the texture modifiers. Clear correlations were observed with several measured parameters quantifying performance across a range of different stress and flow regimes. In addition, the reproducibility of test methods across different instruments and locations was demonstrated.

This study highlights the wide range of process considerations that need to be made when adjustments are made to a formulation. Improvements in product quality and consumer experience through the introduction of additives and modifiers must be balanced with process efficiency. This is particularly important when the majority of process stages handle the formulation in a different physical state to the end product. Properties that are beneficial to liquid flow and performance may not be relevant to powder behaviour and vice versa.