• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.1-7
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• 2021

With increasing interest in the effectiveness and safety of sunscreen worldwide, research on the development of new inorganic sunscreen is also gaining momentum. In the present study, non-nano sized needle type zinc oxide, which can meet the regulation of nano-material as a recent problem, has been synthesized and surface-modified with cetyl alcohol to obtain needle type zinc oxide powder. Here, we also investigated their physical properties and evaluated their potential application as sunscreens. As a result of the experiment, the sunscreen with needle type zinc oxide powder, which was non-nano, showed similar UV-protection properties and transparency compare to that of 40nm size zinc oxide. It was further confirmed that the UV blocking effect was significantly increased when the needle type zinc oxide dispersion was applied to the sunscreen. Therefore, although the needle type zinc oxide is non-nano (200 nm) material, it has the potential to be applied to the product as an excellent transparency (improvement of whiteness), UV protection efficacy and smooth texture.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.231-238
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• 2013

In this study, the $TiO_2$ nano spheres were synthesized by Sol-gel method to give an excellent UV-blocking effect and increase waste adsorption. The pH value was adjusted to obtain a superb UV-blocking effect and adsorption capacity due to the high surface area which is the characteristics of porosity. Base treated $TiO_2$ showed outstanding characteristics. The adsorption of gycerine onto the $TiO_2$ sample using TGA resulted in a high surface area of 1.16 mg/mg. This also showed a high reflectance in the UV-A region. In order to find the optimum dispersion, inorganic powder particles were maintained their sizes as 180 nm for about 6 months. The size of particles were measured using ester oil and silicon oil. Overall, the results reveal that $TiO_2$ has an excellent capability sunscreen in the UV-A region and skin waste adsorption.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.4
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• pp.383-390
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• 2020

Blue light is a blue-based light existing at a wavelength between 380 and 450 nm, and it has been reported that it induces active oxygen and causes aging, and accordingly, interest in the blue light blocking effect is increasing. In this study, the effects of the polarity of oil, viscosity of the formulation, type of emulsifier, emulsified particles, and inorganic UV blocking agents on the blue light blocking effect in UV blocking products were investigated. As a result, it was confirmed that the blue light blocking rate increased as the polarity of the oil became similar to that of the organic UV blocker, and the higher the viscosity of the formulation, the higher the blue light blocking rate. The types of emulsifiers and emulsified particles had little effect on the blue light blocking effect, and the presence of inorganic UV blocking agents was found to be one of the factors that greatly influenced the blue light blocking rate. These results can effectively increase the efficiency of blocking blue light, and may be used in the development of blue light blocking products and formulation research in the future.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.289-293
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• 2005

Nowadays there are many sun protection cosmetics including organic or inorganic UV filter as an active ingredient. Chemically stable inorganic sunsEreen agents, usually metal oxides, we widely employed in high SPF products. Titanium dioxide is one of the most frequently used inorganic UV filters. It has been used as pigments for a long period of cosmetic history. With the development of micronization techniques, it becomes possible to incorporate titanium dioxide in sunscreen formulations without whitening effect and it becomes an important research topic. However, there are very few works related to quantitations of titanium dioxide in sunscreen products. In this research, we analyzed amounts of titanium dioxide in sunscreen cosmetics by adapting redof titration, reduction of Ti(IV) to Ti(III) and reoxidation to Ti(IV). After calcification of other organic ingredients of cosmetics, titanium dioxide is dissolved by hot sulfuric acid. The dissolved Ti(IV) is reduced to the Ti(III) by adding aluminum metals. The reduced Ti(III) is titrated against a standard oxidizing agent, Fe(III) (ammonium iron(III) sulfate), with potassium thiocyanate as an indicator In order to test accuracy and applicability of the proposed method, we analyzed the amounts of titanium dioxide in four types of sunscreen cosmetics, such as cream, make-up base, foundation and powder, after adding known amounts of titanium dioxide $(1{\sim}25w/w%)$. The percent recoveries of the titanium dioxide in four types of formulations were in the range between 96 and 105%. We also analyzed 7 commercial cosmetic products labeled titanium dioxide as an ingredient and compared the results with those of obtained from ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry), one of the most powerful atomic analysis techniques. The results showed that the titrated amounts were well coincided with the analyzed amounts of titanium dioxide by ICP-AES. Although instrumental analytical methods, ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) and ICP-AES, are the best for the analysis of titanium, it is hard to adopt because of their high prices for small cosmetic companies. It was found that the volumetric method presented here gat e quantitative and reliable results with routine lab-wares and chemicals.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.1
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• pp.47-55
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• 2010

UV-screening agents have some adverse effects that raise consumers' concern. The organic agents often cause irritation and may penetrate into human body while the inorganic agents raise aesthetic issues because they often turn opaque. Organic agents with high molecular weights and nano-sized inorganic agents have been developed respectively to minimize transdermal intrusion into human body and suppress turning opaque. Recently, we reported preparation of powdery UV-screening agents made of polysilsesquioxane, an organic-inorganic hybrid material. Powders would not penetrate into epidermis and organic-inorganic hybrid nature would suppress the opaqueness problem. In this study, we continued our research on this powdery polysilsesquioxane UV-screening agent, SESQUV, regarding its chemical composition, its synergic UV-screening effects when mixed with other organic agents, and its applicability in practical formulation. Results showed SESQUV was promising UV-screening agents useful in sunscreen formulation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.2
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• pp.159-167
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• 2023

Titanium dioxide (TiO₂) is commonly used in sunscreen formulations to protect the skin surface and prevent the penetration of harmful ultraviolet (UV) rays by the physical scattering action of light. However, a disadvantage of using TiO₂ is that it can cause white turbidity when used on skin due to its inactive mineral ingredient. In addition, when TiO₂ particles are reduced to nanosize to eliminate opacity, they can increase the transmittance of visible light and reduce whitening, but may lead to serious skin problems, such as allergic inflammation. To overcome these issues, the bandgap of TiO₂ was controlled by adjusting the amount of oxygen defect and nitrogen amount, resulting in color TiO₂ tailored to the skin. This innovative technology can reduce the whitening phenomenon and effectively block blue light, which is known to cause skin aging by inducing active oxygen. The bandgap controlled TiO₂ compounds proposed in this study are hypoallergenic, broad-spectrum, and environmentally friendly. Furthermore, these compounds have been shown to significantly enhance sun protection factor (SPF) of sunscreens, demonstrating their compatibility with blue light blocking products.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.167-177
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• 2019

The jadeite powder has a disadvantage affecting the stability of the formulation due to the agglomeration of the powder when applied to cosmetic formulations. To overcome this problem, a new composite powder was prepared by modifying the surface of jadeite powder and applied to foundation pact and sun stick. In this study, a triethoxycaprylylsilane among various surface modifiers was selected as an optimum component, and applied to each formulation by making the jadeite powder composite. As a result, the foundation pact maintained the clarity of the product color, and the sun stick gave about 30% higher UV blocking effect in the UVB area compared with that of the blank. In the user sensory evaluation, the formulation containing the jadeite powder composite showed a high score for the overall indicator. The stability evaluation of the formulation was also confirmed that it was stable against discoloration, detachment and hardness. In conclusion, the jadeite powder composite is stable as an inorganic pigment which is applicable to cosmetics as a multifunctional material while maintaining the color clarity of the product and acting as a booster for sunscreen agents.

• Economic and Environmental Geology
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• v.48 no.3
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• pp.247-253
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• 2015

Natural halloysite is mostly found in the form of a tubular structure with a 15-125 nm internal lumen. This kaolin clay can be used for encapsulating a liquid ingredient of cosmetics and for immobilizing an inorganic solid-phase ingredient. In this paper, the encapsulation and immobilization procedures are introduced and two example applications are reviewed to demonstrate the usefulness of halloysite as a cosmetics substrate. It may help attract more interest in cosmetic applications of halloysite and thus spur more research on the utilization of natural clays.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.246-252
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• 2002

In recent years, the safety of sunscreens has been challenged based on the reports of their adverse effect on users; dermatitis, allergic contact dermatitis and photo allergic contact dermatitis. The unscientific idea that higher SPF sunsreen is good for health mealeads many users to tend to prefer higher SPF sunscreen. In the toxicological aspect, the need to investigate the safety of sunscreens is steadily increasing. However, there were few studies on the correlation between sun protection factor (SPF) and the safety of sunscreens. The objective of this study was to assess whether there was a correlation between SPF and the safety of sunscreens. We measured in vitro SPF index using homosalate as a standard and examined the toxicity tests such as primary skin irritation tests, ocular irritation test and skin sensitization test. Homosalate (HS), octyl methoxycinnamate (OMC), octyl salicylate (OS), octocrylene (OC) as UVB organic filter and benzophenone-3 (BP3), butyl methoxy dibenzoil methane (BMDM) as UVA organic filter, and titanium dioxide (TD), zinc oxide (ZO) as inorganic filters were used. The skin irritation indexes in rabbits treated with HS, OMC, OS, BP3, and BMDM were significantly increased as SPF indices were increased. Neither ocular irritation in rabbits nor skin sensitization in guinea pigs were increased. It suggests that there might be a good correlation between SPF and the skin irritation indices of organic UV filters and skin irritation might be one of most sensitive index to assess the safety of sunscreens.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1197-1205
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• 2018

UV protection cosmetics belong to functional cosmetics and contain organic or inorganic UV blocking pigments. The inorganic UV blocking pigments are mainly zinc oxide and titanium dioxide. It is known that inorganic UV blocking pigment has a diameter of 60 to 100 nm and has good blocking ability of UVA and UVB. Also, it has high inactivity against sunlight including UV and is excellent in safety. In addition, it is not absorbed or accumulated on the skin like organic pigments and does not cause skin irritation or allergy. In this study, mica, a plate-shaped inorganic pigment, nanosized titanium dioxide, an UV blocking material, and hydrophobic silica were surface-treated with surfactants. And then, titanium dioxide nanoparticles and silica were physically adsorbed on the mica by non-chemical mutual attraction due to differences in charge. Thereafter, the mica complex was surface-treated with silane to prepare a hydrophobic UV blocking pigment complex. The plate-shaped UV blocking composite improves the cohesiveness of a general nanoparticle material titanium dioxide, enhances UV blocking effect due to uniform dispersion, and can greatly improve dispersion stability in cosmetic formulations by surface treatment with hydrophobic property. The surface charge of the pigment was evaluated by zeta potential. The properties of the UV blocking pigment complex were evaluated by FE-SEM, XRD, FT-IR and UV-VIS.