38 ANTI-POLLUTION Possible challenges of using mineral
sunscreens are the formation of white cast, especially on deeper skin tones and uncoated TiO2
can generate free radicals, causing
oxidative damage, while uncoated ZnO can alter the product’s pH and release OH- ions. Further suspensions of these mineral oxide particles must be stabilized at pH 6.5-7.5 to ensure formulation stability during shelf life.8 Due to the lower refractive index of ZnO , it has a lower tendency to However, these challenges
compared to TiO2 form white cast.9
can be resolved by use of innovative coatings such as silica, alkyl silane or polymers along with optimized particle size imparting improved transparency to the formulation. Coating these pigments prevents particle agglomeration, ensures dispersion, and enhances the stability and UV protection efficacy of sunscreen products.10 Newer sunscreens such as BEMT, DHHB
and EHT have higher protection both for UVA and UVB and therefore provide efficient coverage at lower doses compared to conventional agents. However, they are oil- soluble solids and need adequate amounts of solvents for formulation. This can impact the emulsion properties
and after-feel of the product. Sunjin Beauty Science has created breakthrough technologies to encapsulate these oil-based ingredients in silica and poly methyl methacrylate systems making them easily dispersible in water phase.11 Encapsulating UV filters in various matrices
has shown promise in improving their stability. In cosmetics, carriers like nanoclays and mesoporous silica are used to deliver molecules like UV filters, antioxidants, and vitamins. Research has focused on encapsulating
organic UV filters in both inorganic and organic nanoparticles, highlighting their potential benefits. Encapsulation prevents skin sensitization by blocking interactions between UV filters and skin, reduces photodegradation, and inhibits filter aggregation and incompatibility with other formulation components. Notably, encapsulating organic UV filters
in zeolites with different topologies and chemical compositions has shown remarkable efficacy in stabilizing and enhancing UV filter performance. Hybrid materials (ZEOfilters) were created by encapsulating sunscreens in zeolites with various framework topologies and Si/Al ratios, demonstrating improved stability and performance.12 Solid lipid nanoparticles (SLNs) have
emerged as a carrier system, offering a controlled release profile and synergistic effects with UV filters. This results in longer- lasting sun protection without compromising on SPF values. SLNs also provide a physical barrier that reflects and scatters UV radiation, enhancing their protective effects. Polymeric nanoencapsulation is another
promising technology. Biocompatible polymers like PLA, PLGA, and PMMA have shown improved photostability and UV protection when encapsulating UV filters. This approach
PERSONAL CARE October 2024
■ Nano-Zinc Oxide ■ Nano-Titanium Dioxide
■ Butylparaben (Preservative; Thailand only)
offers versatility and flexibility, making it an exciting development in sunscreen technology. By tailoring the polymer properties,
researchers can create customized nanoparticles that optimize UV filter performance. As research continues, we can expect to see more effective and stable sunscreens that provide reliable protection against harmful UV rays.13 While formulators can use various sensory
enhancers to improve the skin feel and film formers for higher SPF coverage, the major challenge lies in the regulatory landscape. Sunscreens are covered under non- prescription, over-the counter class by the US Food and Drug Administration (FDA) to ensure consumers have safe and efficacious products. However, no new UV filter has been approved since 1999. Furthermore, a recent guideline by the
USFDA in 2019, has classified the total of 16 ingredients approved as sunscreen actives
as per Generally Recognised as Safe and Effective (GRASE) status. Only two ingredients - titanium and zinc oxides - are considered GRASE while not GRASE status is allotted for sunscreens containing cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone, and avobenzone because of inadequate data to support a safety finding. Products containing aminobenzoic acid and
trolamine salicylate are marked as non GRASE because of data showing safety concerns.14 Such regulations pose a larger challenge for formulators in designing globally acclaimed reef safe products.
Certifications related to marine safety It is the need of the hour for all of us to take action to preserve and restore our ecosystems for future generations. Seven regions all over
www.personalcaremagazine.com
■ Avobenzone (Butyl methoxy dibenzoyl methane / BMDM)
■ Octocrylene (OCR) ■ Octinoxate (Ethylhexylmethoxycinnamate/ Octylmethoxycinnamate OMC/EHMC)
■ Oxybenzone (BP3/Benzophenone-3) ■ Enzacamene (4-methylbenzylidene camphor; Thailand only)
TABLE 1: CLASSIFICATION OF ‘REEF SAFE’ AND DISPUTED MATERIALS Agents under dispute for coral reef toxicity
Organic UV filters
■ Ecamsule (Terephthalylidene dicamphor sul- fonic acid/Mexoryl SX)
■ Ethylhexyl Triazone (EHT)(6) ■ Bemotrizinol (Bis-Ethylhexyloxyphenol Meth- oxyphenyl Triazine/BEMT)(6)
■ Homosalate (HMS/Homomethyl salicylate)
■ Ensulizole (Phenylbenzimidazole Sulfonic Acid/ PBSA)
■ Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB)(7)
■ Octisalate (Ethylhexyl salicylate/ Octyl salicylate/ EHS)
■ Cinoxate ■ Padimate O (Ethylhexyl dimethyl PABA) ■ Dioxybenzone (Benzophenone-8) ■ Meradimate (Menthyl anthranilate) ■ Sulisobenzone (Benzophenone-4/ BP4) ■ Aminobenzoic acid (PABA) ■ Trolamine salicylate (TEA salicylate) ■ Benzophenones
■ Bisoctrizole (Methylene bisbenzotriazolyl tetramethylbutyl- phenol/ MBBT)
■ Tris-biphenyl triazine ■ Drometrizole trisiloxane (Meroxyl xl) ■ Diethylhexyl butamido triazone (DBT) ■ Bisdisulizole disodium ■ Isoamyl pmethoxycinnamate ■ 3-benzylidene camphor ■ Benzylidene camphor sulfonic acid ■ Polyacrylamidomethyl benzylidene camphor ■ Camphor benzalkonium methosulfate ■ Polysilicone-15
Inorganic UV filters
■ Zinc Oxide ■ Titanium Dioxide
Other materials
'Reef safe' UV filters
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