Reflectance-Based Elastic Polymer Test: A Novel Fast-Screening Method for Predicting Skin Adhesion Performance of Liquid Foundation
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Presented by: Juang Cita
Background
Long lasting effect has become a basic requirement for foundation products in which consumers would like to look flawless throughout the day. To achieve that property, the products must have proper spreadability and wettability on the skin, creating high skin-foundation bond quality that brings good adhesivity. Therefore it is crucial to develop reliable adhesion tests to provide faster and objectively quantified results especially during the formulation stage. In this study a new method to evaluate the skin attachment character of liquid foundation was proposed based on contact angle and skin-colorimeter reflectance values. The colorimeter allows objective measurement by calculating the color intensity portraying the amount of foundation adhere to the skin without bias.
Methods
The skin adhesion performance of four commercial foundations were compared. The contact angle measurement was conducted using water droplets to study the wetting and spreading character of the foundations on multiple substrates (artificial skin, PMMA plate and forearm). Quantitative evaluation of the skin/foundation layer affinity was conducted through an elastic polymer test by measuring the color intensity represented by Tape Removal Ratio (TPR) using skin-colorimeter. In addition, the area of remaining film was evaluated using image analysis.
A related in-vivo study was carried out in 5 expert panelists to evaluate the skin adhesion performance of the products using image analysis and self-assessment scoring system. Those results were used as the reference in determining the acceptance criteria of TPR which represent a good skin adhesion product.
Results
Contact angle measurement provides information regarding the physicochemical interactions between liquid foundation and the substrate from which the wettability and spreading character of the four foundation samples can be distinguished. The result obtained from reflectance-based elastic polymer test could be a reliable approach to predict skin/foundation affinity. In accordance with the in-vivo results, the foundation which has the mean %TPR <50% was considered to have good skin adhesion.
Discussion and Conclusion
Compared with consumer in use tests, this in vitro method could provide faster tests and objectively quantified results. Thus, the method proposed offers an effective, reliable approach to determine the skin adhesion of foundation, which could be used during product development to optimize desired properties.
Long lasting effect has become a basic requirement for foundation products in which consumers would like to look flawless throughout the day. To achieve that property, the products must have proper spreadability and wettability on the skin, creating high skin-foundation bond quality that brings good adhesivity. Therefore it is crucial to develop reliable adhesion tests to provide faster and objectively quantified results especially during the formulation stage. In this study a new method to evaluate the skin attachment character of liquid foundation was proposed based on contact angle and skin-colorimeter reflectance values. The colorimeter allows objective measurement by calculating the color intensity portraying the amount of foundation adhere to the skin without bias.
Methods
The skin adhesion performance of four commercial foundations were compared. The contact angle measurement was conducted using water droplets to study the wetting and spreading character of the foundations on multiple substrates (artificial skin, PMMA plate and forearm). Quantitative evaluation of the skin/foundation layer affinity was conducted through an elastic polymer test by measuring the color intensity represented by Tape Removal Ratio (TPR) using skin-colorimeter. In addition, the area of remaining film was evaluated using image analysis.
A related in-vivo study was carried out in 5 expert panelists to evaluate the skin adhesion performance of the products using image analysis and self-assessment scoring system. Those results were used as the reference in determining the acceptance criteria of TPR which represent a good skin adhesion product.
Results
Contact angle measurement provides information regarding the physicochemical interactions between liquid foundation and the substrate from which the wettability and spreading character of the four foundation samples can be distinguished. The result obtained from reflectance-based elastic polymer test could be a reliable approach to predict skin/foundation affinity. In accordance with the in-vivo results, the foundation which has the mean %TPR <50% was considered to have good skin adhesion.
Discussion and Conclusion
Compared with consumer in use tests, this in vitro method could provide faster tests and objectively quantified results. Thus, the method proposed offers an effective, reliable approach to determine the skin adhesion of foundation, which could be used during product development to optimize desired properties.