Shaher Duchi, PhD, Tagra Biotechnologies, Netanya, Israel. COSSMA 9/2024, pp. 10–13.

The 'hybrid' lifestyle is no longer just a trend but a new way for consumers to view just about anything, including their skincare routines. As part of this lifestyle shift, the 'buy less, buy better' motto has been widely adopted by the beauty market in its process of creating products that meet this hybrid focus. As part of this trend, the beauty industry is making more of an effort to be inclusive in its offerings by creating products and, namely, makeup tailored to dark skin tone consumers.

Simplified routines have become a priority, with many consumers seeking ways to reduce the number of products they use daily as they become increasingly conscious of excessive consumption [1]. This new standard opens up the opportunity for innovation in crafting goods that provide multiple solutions through one product. While traditional skin care and makeup products focus on cosmetics that reduce blemishes, treat acne or clear dark spots, they do not do it all under one product umbrella.

Today's hybrid cosmetics, which have grown in popularity amongst consumers, have been further promoted due to the coronavirus pandemic's hybrid consumption culture. Users are looking for products that offer a range of benefits and save time and money. Blur, BB, and CC creams were the first versions of hybrid cosmetics and now the multifunctional, hybrid, or 2-in-1 product lines represent a new opportunity for innovation in cosmetics [2].

Moreover, hybrid cosmetics open a new avenue of customisation for skin-specific concerns. New developments can include makeup focusing on oily skin or foundation specially tailored for dark skin tones.

As part of this trend, the beauty industry is making more of an effort to be inclusive in its offerings by creating products and, namely, makeup tailored to dark skin tone consumers. But not just pure make-up products are being created. Mixed beauty products also act as colour cosmetics and are rich in skincare ingredients.

Makeup is a major area of interest when it comes to these innovations, as it is widely used for the purposes of masking blemishes and hiding imperfections. Beauty stores can offer an array of brands to choose from, but one of the biggest challenges in the colour cosmetic industry is providing everyone with equal access to their perfect shade. Many makeup brands include a limited number of shades that focus on people with lighter skin tones, thus facing difficulties in matching the colour to people with darker skin tones.

As such, colour cosmetics have become one of the most highly regarded products. Market review and analysis show the struggle of many people who feel they are not included in current makeup products, showing a lack of diversity in the cosmetics industry [3]. Finding makeup that matches one's skin colour can be challenging, and especially if you are a darker-skinned person, finding makeup that matches your unique colour complexion is even more of a challenge.

Understanding how makeup plays into appearance and how to change current industry norms to support everyone is very important. It is also critical to make sure that all individuals who want a product to match their skin tone have equal access. Therefore, creating products so that buyers will have no difficulty choosing their true colour shade has become a new trend in the cosmetic industry.

Colouring agents are classified as dyes or pigments according to their structure, source, colour, solubility, and application method. Pigment-grade titanium dioxide is the most common compound used in colour cosmetics to both aid in hiding blemishes and brighten the skin by providing full coverage [4]. Nevertheless, typically, pigments are solid inorganic particulate forms such as titanium dioxide (TiO2), zinc oxide (ZnO) and iron oxide (Fe2O3). These particles are insoluble in the formulation, meaning uniform dispersion and distribution of pigments are critical for achieving high quality, functional and aesthetically pleasing finished products. Likewise, these realities make their incorporation into existing cosmetic products a technically challenging process [5,6].

The pigments can be used in different ratios and formulators can achieve a wide range of shades. To create a quality product for darker skin tones, the products require reformulation, and that is where processes can get complicated, as it can result in a brighter shade which is not dark enough to meet the exact natural dark shade.

Formulators and brands cannot just change the pigment ratio to create a product matching darker skin tones; the formulation needs to be corrected and modified. For example, as shades became darker and deeper, titanium dioxide has had to be removed to prevent an ashy look [7]. By removing the titanium dioxide, the makeup coverage ability is negatively impacted and the product quality decreases.

Tagra has developed a multifunctional ingredient that provides formulators with the capability and flexibility to design innovative hybrid products, while overcoming the challenges of matching the colour of darker-skinned users. The ingredient is based on the microencapsulation technology platform that Tagra has developed over the years. The microcapsules ("DeeperCaps") are a combination of iron oxide pigments and various components that deliver the multifunctionality of the ingredient. The pigment is fully shielded by a sophisticated double-layer, cellulose-based microcapsule structure, with the polymeric shell also containing zinc oxide and shea butter.

The microcapsules are multifunctional and provide a true colour match and boost the SPF and moisturisation qualities of a given formula. The microcapsules' Release on Demand ("RND") feature also means that once applied to a person's skin, the polymeric shell collapses, creating an adhesive film while releasing the pigments and other components, providing optimal coverage, a natural appearance, and other moisturising and UV protection benefits.

Microencapsulation and Preparation

Microcapsules loaded with yellow, red, or black iron oxides (CI 77492, CI 77491, CI 77499) were prepared by the solvent extraction method [10,11].

The microcapsules were prepared by dissolving cellulose acetate polymer in the organic solvent to form a homogeneous polymer solution. Iron oxide and the additives were added into the polymeric solution and mixed to form a homogeneous polymer suspension. The organic phase was mixed with a water phase containing PVA as an emulsifier.

Following agitation, the resulting emulsion was transferred into the extraction water phase. At this stage, due to the extraction of the organic solvent to the external water phase, the droplets solidified, resulting in rigid microcapsules.

Once sedimentation of the solid microcapsules was completed, they were collected by filtration followed by a washing step with purified water to remove any residual impurities. The microcapsules were dried by lyophilisation, and a free-flowing powder was obtained.

The developed microcapsules loaded with iron oxide pigments were able to mask the initial colour of the pigment, as shown in Figure 1.

Figure 1: Visual appearance of encapsulated pigment powder (top row) vs. free iron oxides (lower row).

Colour Release Demonstration

As stated, the microcapsules were designed to release their content (in this case, pigments) by mechanical pressure, such as rubbing.

To confirm this release, the unique mechanism of the microcapsules was demonstrated following incorporation into a cosmetic cream base. The microcapsule powders (a blend of Yellow, Red, and Black) were gradually added during the last stage of formulation preparation, using a simple paddle/anchor type mixer at 70 RPM at temperatures up to 40°C.

The colour release was performed as follows: an accurate amount of the cosmetic formulation was applied upon white paper and rubbed in a circular movement (a mechanical force). The colour release demonstration was done visually using a Light Box (BGD 274, China).

The rubbing process of the cream releases the colour in an even way with excellent coverage following application upon white paper (Figure 2).

Figure 2: Visual representation of the colour release from a blend of encapsulated pigment powder incorporated into a cream base.

Colour Strength Evaluation

The colour coverage property of the released pigments was evaluated following incorporation into a cosmetic cream (as described previously). A formulation containing free iron oxide pigments and other additives (at the same % levels as in the microcapsules) served as a control.

The free pigments were incorporated into the oil phase in the typical way using intense homogenisation. This was then added to water using a surfactant to form the final emulsion.

Colour strengths (WSUM) were tested after being released from the microcapsules, and quantified upon white paper by an X-rite device (VS450, USA). Colourant strength is defined as a pigment's ability to change the colour of a colourless material.

The measured value for the microcapsule formula was 1.5 times higher compared with the formulation containing free pigments. This indicated the colour strength of the microcapsules was superior to the free pigments at the same concentration level (Figure 3).

Figure 3: Visual representation (left) and colour strengths (right) of the colour obtained from a blend of encapsulated pigment powder incorporated into a cream base vs free pigments.

Clinical Assessment of the Moisturising Effects

Skin hydration stands as a fundamental aspect of skin health, contributing to its overall appearance, elasticity, and function. Adequate skin hydration promotes a smooth and supple complexion, while insufficient hydration can lead to dryness, flakiness, and various skin disorders. Water is essential for the normal functioning of the skin and especially its outer layer, the stratum corneum (SC). Loss of water from the skin must be carefully regulated, a function dependent on the complex nature of the SC. The retention of water in the SC is dependent on the presence of natural hygroscopic agents within the corneocytes (natural moisturising factor) and the orderly arrangement of SC intercellular lipids to form a barrier to Trans Epidermal Water Loss (TEWL). Moisturisers are one of the most widely used preparations in cosmetics and have been extensively used to soften the skin. Moisturisers work effectively in combating dry skin, which may cause pain, tightness, itch, stinging, and/or tingling [12].

To evaluate the hydration effects of the microcapsules incorporated in a model base formulation, a clinical evaluation was carried out on 22 volunteers, aged from 24 to 52 years (mean 38.9 ± 8.9). The volunteers were required to be male or female, between 18 and 60 years of age, presenting dry skin (30 - 45 A.U.) or very dry skin (< 30 A.U.). The study followed the Declaration of Helsinki. The volunteers were ordered according to the date of recruitment and applied the test product for 4 weeks. All the recruited volunteers completed the study. Before the start of the treatment (D0) and after 4 weeks of treatment (D28), subjects attended the facilities to receive the samples, sign the corresponding informed consents and for the corresponding measurements. Upon arrival, volunteers were allowed to acclimatise to environmental conditions (23 ± 1°C, 45 ± 10% humidity) for 15 minutes. Then, hydration levels were evaluated on the cheek using a Corneometer CM 825. Data recorded from every individual at each of the time points were normalised versus baseline values (D0) and statistically analysed.

The results show that a 4-week treatment with a model base containing DeeperCaps™ significantly increased skin hydration by 19.9 ± 7.1%, compared to baseline values before the start of the treatment (Figure 4). Regarding cutaneous compatibility and acceptability, participants showed no Serious Undesirable Effects (SUE) and declared neither discomfort nor Undesirable Effects (UE) throughout the period of treatment.

Figure 4: The effects of a model base formulation containing the microcapsules on skin hydration after 4 weeks of treatment. Graphical representation of the skin hydration levels on the cheek before the start of the treatment (D0) and after 4 weeks of treatment (D28), with BB Cream in 22 volunteers. Values obtained at different time points were normalised to the corresponding baseline levels of the whole panel at D0. Mean and Standard Error of the Mean (SEM) are shown. A paired sample t-test was applied for statistical significance between timepoints.

Conclusion

Consumers engage with multiple aspects of a formula when making purchasing decisions. Results of clinical trials, visual elements, ingredients, activity, and the product's carbon footprint, etc., may influence those decisions. How a product looks on social media when unboxed and applied will hugely influence purchasing decisions, too, and consumer engagement is key to traction in the cosmetic market.

In this article, the authors introduced encapsulated pigments to achieve a colour-change effect for not just makeup but also skin care, allowing formulators to simply add colour to products and combine colour with skin care. No special production lines are needed, and the microcapsules are added gradually during the last stage of formulation preparation with a simple paddle mixer. Furthermore, there is no need to treat or handle the pigments, e.g., grinding or preparing a stable dispersion, and as the current study shows, the microcapsules remain stable during storage.

Additionally, the microcapsules are environmentally friendly and sustainable since they do not contain chlorinated solvents, reactive materials, free radicals, or high energy-consuming reactions. They can be easily incorporated into many kinds of formulations such as serums, water gels, powders, and cream-based make-up, suncare, and skincare products.

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