• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.3
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• pp.189-199
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• 2015

In this study, we have investigated the stability of sunscreens based on the solubility of organic UV absorbers in the oil and sun protection efficacy of the products composed of a combination of organic UV absorbers to develop more stable and efficient sunscreen products. Results showed that the solubility of the organic UV absorber and stability were varied depending on the type, storage conditions and concentration of oil. It was also observed from the products in the emulsion type. Various UV absorbances were determined to the products composed of the combination of organic UV absorbers. In some combinations, a synergistic effect was observed to make an increase in absorbance compared to a single component. In other cases, specific synergistic effect was displayed only when combined with the particular component. In addition, the storage condition also affected the sunscreen efficacy. In conclusion, this study confirmed that there are various factors which could affect the UV-blocking efficiency of sunscreen products.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.1
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• pp.63-66
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• 2008

Sunscreen is usually used by people when they are at the beach or outdoor swimming pools. Since the existing methods of and standards for measuring the effects of blocking ultra violet rays do not employ water resistance test methods, the establishment of a water resistance SPF test method is required. In this study, to standardize the SPF evaluation methods for a water resistant sunscreen, proposed measurement methods in this study were compared with those of foreign countries. Selected water resistance SPF experiments confirmed the product's suitability and a verification test was then conducted by establishing the variables of water resistance SPF measurement methods. In the comparative experiment on water resistance SPF given a water temperature of $23{\sim}32$ degrees centigrade showed that temperature did not have any statistically significant effect on water resistance SPF. The changing water flow also did not have any statistically significant effect on the water resistance SPF. Therefore, continuous 20 min water circulation is deemed appropriate as an alternative to the subject's usual activity.

• 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.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.1
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• pp.1-10
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• 2024

In this study, a quercetin benton gel (QUERPLEX) that stabilized quercetin was prepared using organo hectorite, and its efficacy was confirmed. In addition, a comparative study was conducted on the stability and effectiveness of applying this to sunscreen cosmetics. It was confirmed that QUERPLEX remained stable without showing crystal precipitation and growth for 4 weeks. As a result of measuring antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), it showed antioxidant activity depending on the concentration, and showed a radical elimination ability of 70% or more at a concentration of 2,500 ppm or more, confirming a significant effect. Anti-inflammatory activity experiments using RAW 264.7 cells confirmed that NO production decreased in a concentration-dependent manner by reducing NO production by 8% at 25 ㎍/mL, 23% at 50 ㎍/mL, and 84% at 100 ㎍/mL. As a result of confirming the stability of the formulation according to the method of quercetin in the sunscreen formulation, the stability of the formulation was improved when quercetin was added directly to the formulation. It also improved the UV protection index on in vitro and in vivo, which is expected to have the potential as a component that can have a new boosting effect on UV protection. These results suggest that organo hectorite is very effective as a quercetin carrier and that it can be applied in cosmetic formulations by not only expressing the efficacy of quercetin but also bringing about additional effects.

• Journal of Photoscience
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• v.10 no.2
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• pp.215-216
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• 2003

SPEX SkinSkan is a newly developed spectrofluorometer that can calculate transmission of UVA on the surface of human skin as a non-invasive method. We have investigated UVA protection factors of Japanese over-the-counter sunscreens using SPEX SkinSkan. This non-invasive method is useful to know UVA protection of sunscreens in vivo.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.123-123
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• 2004

• Journal of Photoscience
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• v.9 no.2
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• pp.236-239
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• 2002

Sunscreens have been advocated as an important means of preventing skin cancer. UV-induced immunosuppression is important for skin cancer development, yet the effectiveness of sunscreens in protecting the human immune system from UV radiation is unclear. The only currently accepted method of sunscreen rating is the Sun Protection Factor (SPF) based on prevention of erythema. We developed an in vivo non-invasive method for evaluating protection of the human immune system from UV radiation based on recall contact sensitivity to nickel, a common allergen. Using this system we showed that broad-spectrum sunscreens provide greater protection to the immune system than sunscreens which protect from UVB only. UVA was found to be immunosuppressive. We developed this technique to enable the study of solar simulated UV radiation dose responses and determined Immune Protection Factors (IPFs) for six commercially available sunscreens based on limits of protection from the dose response data. We found that the IPF did not correlate with the SPF and that protection from erythema therefore cannot be used to predict protection of the immune system. However, IPF was significantly correlated to the UVA protective capability of the sunscreens, indicating that sunscreen protection from UVA is important for prevention of immunosuppression. We recommend that sunscreens should be rated against their immune protective capability to provide a better indication of their ability to protect against skin cancer.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.3
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• pp.171-184
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• 2002

The present study was undertaken to develop the in vitro sunprotection factor(SPF) measurement method having good correlation with in vivo method. As in vitro method, 8% homomentyl salicylate, P3 reference standard and sunscreens on market were measured using SPF 290 analyzer and were compared the SPF with labed value. In vitro SPF of 8% HMS and P3 reference standard were 4.59 $\pm$ 0.12 and 14.94 $\pm$ 0.83. There are good correlation, correlation factor were 0.9506 and 0.9769 respectively, between the in vitro and in vivo SPF for the sunscreen creams and lotions examined. Correlation factors of makeup base & liquid goundation, lotion labled with “shake before use”, compact powder were 0.8812, 0.8632 and 0.5984. The best sample applied method of compact powder was 1:0.8 mixture with cream base. These results suggest that the in vitro test method could be used as an alternative method for SPF.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.4
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• pp.219-225
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• 2007

Bis-ethylhexyloxyphenolmethoxyphenyltrizine (BEMT) is one of the most widely used chemical UVA+UVB double absorbers in sunscreen products. But topical application of BEMT is restricted due to its defects in product. The purpose of this study is to adopt the sunscreen product of solid lipid nano-particles containing BEMT (BEMT-SLN). The particle diameters, the encapsulation efficiencies and the crystallization index (C.I.) are about 330nm, 93.3 % and the 4.3 %. As a result, in vitro penetration and release of BEMT were generally higher in O/W emulsion than the SLN formulation. However in vivo study, it was shown that the rate of release could be decreased by 80 % in the SLN formulation. The sun protection factor (SPF) of the SLN formulation increased by 100 % in the in vitro UV protection test. Therefore, SLN formulation potentiated the UV-blocking power of BEMT. This study suggest that SLN can be used for the encapsulation of BEMT.

• Safety and Health at Work
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• v.7 no.3
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• pp.208-212
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• 2016

Background: Outdoor workers are at risk of high ultraviolet radiation exposure, and may have difficulty using sun protection. The objectives were to determine the prevalence of sun protection behaviors in a sample of outdoor construction workers, and to assess which factors predict better sun protection practices. Methods: Participants were recruited via construction unions. Workers answered a questionnaire on demographics, skin cancer risk, sun protection behaviors, and job. Sun protection behavior scores (from questions on sunscreen use, sleeved shirt, hat, shade seeking, sunglasses) were calculated by converting Likert-scale answers to scores from 0 to 4, and taking the mean (separately for work and leisure). Determinants of sun protection behavior scores were examined for work and leisure using generalized linear models. Results: Seventy-seven workers had complete questionnaire data (participation 98%). Sun protection behaviors used most often were hats (79% often/always) and sleeved shirts (82% often/always); least prevalent were shade-seeking (8% often/always) and sunscreen (29% often/always). For both work and leisure scores, the strongest predictor was skin type, with fairer-skinned individuals having higher sun protection behavior scores. Workers had higher scores at work than on weekends. Workplaces that required hats and sleeved shirts for safety purposes had higher protection behavior scores. Conclusion: This high-participation rate cohort helps characterize sun protection behaviors among outdoor workers. Workers practiced better sun protection at work than on weekends, suggesting that workplace policies supportive of sun protection could be useful for skin cancer prevention in the construction industry.