By Helene Hine, CRODA
Driven by our Purpose, to use ‘Smart Science to Improve Lives’ CRODA is tackling some of the biggest challenges the world is facing today and have made a commitment to be ‘Climate, Land and People Positive’ by 2030. One of our Hero Targets within our ‘People Positive’ commitment is to protect at least 60 million people annually from potentially developing skin cancer from harmful UV rays, through the use of our solar protection ingredients. CRODA’s latest UV filter launch, SOLAVEIL MICNO, is helping us to meet this hero target.
The patented technology behind SOLAVEIL MICNO is its micron-sized platelet shaped particles. This unique morphology is formed from primary crystals. Figure 1 shows Scanning Electron Microscopy (SEM) images that reveal this unique platelet structure. At high magnification, the SEM shows its platelet structure in a stacked formation. This stacked packing and separation of structural layers is why SOLAVEIL MICNO has unrivalled transparency on skin.
Figure 1: SEM images of SOLAVEIL MICNO particles
Measurement of mean particle size of uncoated SOLAVEIL MICNO by X-ray Disc Centrifuge (XRDC) by mass, gives a mean particle size of 516nm. Based on both the REACh definition of “nano”  and the Cosmetics Europe interpretation of “nano” , SOLAVEIL MICNO would therefore be considered to be “non-nano”. Furthermore, studies have revealed that the SOLAVEIL MICNO platelet structure is not broken-down during use, even when extremely high shear, such as bead milling, is applied to the product.
How does SOLAVEIL MICNO work?
Mineral inorganic sunscreens attenuate UV by two mechanisms: absorption and scattering. Conventional ZnO sunscreens scatter and reflect visible light back to the surface of the sunscreen film which can lead to a white appearance on skin. SOLAVEIL MICNO is comprised of platelets which form an ordered stacked structure (as shown in Figure 1), This structural composition results in less scattering and reflection back to the surface of the skin, and ultimately this results in unrivalled transparency on skin. This mechanism is summarised in Figure 2 below.
Figure 2: Mode of action of conventional ZnO sunscreens versus a SOLAVEIL MICNO ZnO sunscreen
Appearance on different skin phototypes
To visualise the appearance on skin, skin whitening was visually evaluated using a basic W/O emulsion containing 20% active ZnO. Subjects with skin phototypes from I to V were selected, with 2 subjects with skin phototype V being included in the study. 0.05ml of sample was applied to the subjects in a 5cm square. After application, the subjects were instructed to rub in the sample 40 times, the skin was left to dry for 5 minutes before images were taken.
Figure 3 shows the results for SOLAVEIL MZP3 (uncoated ZnO powder from the SOLAVEIL MICNO range) compared to the market leading uncoated ZnO powder which is a spherical and has a small particle size. In all cases SOLAVEIL MICNO has a lower level of whitening on skin.
Figure 3: Skin images of Solaveil MZP3 from the SOLAVEIL MICNO range, compared to the market leading ZnO (conventional small particle ZnO)
Safe and sustainable minerals
ZnO occurs naturally as the mineral Zincite, but in cosmetics, all ZnO used is of synthetic origin. SOLAVEIL MICNO is classified as a nature identical mineral and categorised by ISO 16128 as “derived mineral”. In the SOLAVEIL MICNO range there are three products that are COSMOS approved and the entire range is “vegan suitable” and Halal approved.
ZnO is well-known as a safe material that has been used in cosmetics for decades. In more recent times extensive safety reviews have been conducted by the US Food & Drug Administration (FDA) and the EU Scientific Committee for Consumer Safety (SCCS) and these reviews have concluded that whatever its size (nanomaterial or not) ZnO largely does not penetrate the skin. The FDA classify them as GRASE (Generally Recognised as Safe & Effective) Category 1. ZnO is approved by regulatory bodies globally at levels up to 25% active, which is the highest active level permitted of any UV active, along with Titanium Dioxide (TiO2). ZnO also has a very low potential for skin irritation, and in fact has a long history of use in topical treatments for skin conditions, making SOLAVEIL MICNO a great choice for formulators working on products for any skin type including babies, children, and sensitive skin.
SPF and UVA efficacy
SOLAVEIL MICNO is broad spectrum and comparable in UVA performance with conventional ZnO grades. It has a UVA PF per 1% solids of around 0.41. Used alone it passes the EU requirements for UVA and meets the US requirements for broad spectrum claims. It also meets the new proposed US requirement for broad spectrum, achieving a UVAI/UV ratio of around 0.875 would achieve a rating of High.
The SPF efficacy of SOLAVEIL MICNO has been studied in a wide range of formulations tested in vivo with independent test houses. Results show that SOLAVEIL MICNO has efficacy equal to, or better than, conventional ZnO. SOLAVEIL MICNO will typically achieve at least 0.52 SPF units for 1% solids, higher performance is obtained with SOLAVEIL MICNO dispersions. SPF efficacy is however highly formulation dependant and some studies SPF efficacy of 1 SPF unit or higher for 1% active. Further work is ongoing in CRODA’s global formulation laboratories to understand these findings and also find greater efficiencies for SOLAVEIL MICNO.
CRODA’s latest UV filter launch SOLAVEIL MICNO is based on a micron-sized particle that behaves more like a small particle, with unrivalled transparency on skin.
Based on ZnO, SOLAVEIL MICNO is inherently mild and non-irritant, and there are no concerns around skin penetration, so perfect for babies, children and sensitive skin. SOLAVEIL MICNO products are also ideal for natural and “clean” beauty brands, as “nature identical minerals” they are available as either coated or uncoated particles, with COSMOS variants available. For the first time ever, it is possible to formulate highly transparent mineral sunscreen systems to meet the needs of consumers looking for natural and “clean” sunscreens.
 Vegan suitable means it can be considered to be generally suitable for vegan; however, as there is no single agreed definition nor a standard, global certification, if you are interested in making a vegan claim, please request our Vegan Suitability statement for specifics on this product and compare to the certification(s) you are seeking to meet.
Marketing Manager, Personal Care
Helene has worked in the Personal Care Industry for 21 years. After completing an MChem in Medicinal Chemistry at University College London in 2000 she took her first role in formulation chemistry at the Body Shop and COSi Ltd where she worked within the product development team.
In 2002 she obtained the Diploma in Cosmetic Science and joined Uniqema, part of the ICI group. Throughout her time at Uniqema she gained experience in the formulation and testing of personal care products working in both applications research and technical service.
In 2006 when Croda acquired Uniqema she began working for Croda’s Sun Care & Biotechnology division based in Widnes in the UK, managing the Product Applications team.
Helene’s current role is Marketing Manager for Solar Protection. Her responsibilities include developing the business strategy by anticipating and understanding long term consumer market trends and customer needs and managing new product innovations from concept to launch.
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