• Korean Journal of Materials Research
• /
• v.34 no.2
• /
• pp.95-104
• /
• 2024

Nanoparticles are commonly used to avoid the opaque white color of TiO₂ based sunscreen. However, a dispersing agent is typically required because of the tendency of the nanoparticles (NPs) to agglomerate. Stearic acid is one kind of dispersing agent often used for sunscreen products. However, according to the MSDS data sheet on stearic acid, stearic acid is highly hazardous to aquatic life and causes irritation on human skin. To avoid this problem, in this study a safer organic dispersing agent extracted from Korean seaweed has been studied to disperse TiO₂ nanoparticles, and further use as an active agent in sunscreen products. The presence of phytochemicals in seaweed extract, especially alginate, can disperse TiO₂ nanoparticles and improve TiO₂ dispersion properties. Results show that seaweed extract can improve the dispersion properties of TiO₂ nanoparticles and sunscreen products. Reducing the agglomeration of TiO₂ nanoparticles improves sunscreen properties, by making it less opaque white in color, and increasing UV protection value. It was also confirmed that adding seaweed extract into sunscreen products had no irritating effects on the human skin, making it more desirable for cosmetics application.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.37 no.3
• /
• pp.227-236
• /
• 2011

The new sunscreen agent, methoxycinnamidopropyl polysilsesquioxane, is manufactured as polymeric particles with an organic/inorganic hybrid composition. We have already reported the manufacturing method, physical properties, and sunprotection effects of methoxycinnamidopropyl polysilsesquioxane. In this study, we evaluated the photochemical properties and photostabilities of methoxycinnamidopropyl polysilsesquioxane that has the same functional group as a typical organic sunscreen agent, ethylhexyl methoxycinnamate (EHMC). Using the correlation of UV absorbance and fluorescence, we studied photostabilizers to enhance the photostability of methoxycinnamidopropyl polysilsesquioxane. Finally, we confirmed that octocrylene, ethylhexyl methoxycrylene, and bis-ethylhexyloxyphenol methoxyphenyl triazine were good photostabilizers for methoxycinnamidopropyl polysilsesquioxane.

• Proceedings of the SCSK Conference
• /
• 2003.09a
• /
• pp.97-97
• /
• 2003

Chemists must take into consideration more factors to formulate with inorganic sunscreens than many other active ingredients including organic sunscreens. Because the UV radiation attenuation grade particles of Titanium Dioxide and Zinc Oxide are in the nanometer range, the state of their dispersion in the product film on the skin governs their efficacy and aesthetics.(omitted)

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.47 no.4
• /
• pp.289-296
• /
• 2021

In this study, 27 inorganic sunscreens and 23 sunscreens for children were collected to investigate the use and incorporation of 17 types of sunscreen agents, 13 types of preservatives, and 5 types of heavy metals. As a result, sunscreen agents were detected in the order of titanium dioxide (41 cases), zinc oxide (29 cases), bis-ethylhexyloxyphenyltriazine (10 cases), ethylhexyl salicylate (8 cases), and ethylhexylmethoxynamate (8 cases), and preservatives were detected in order of phenoxyethanol (6 cases), benzoic acid (1 case), and dihydroacetic acid(1 case). All of the identified sunscreen agents were suitable for labeling, but phenoxyethanol, a preservative component other than labeling, was detected at a concentration of 0.1%. Heavy metals such as lead, cadmium, arsenic, antimony, and nickel were not detected or were detected at various concentrations of less than 3.6 ㎍/g. All the detected UV filters, preservatives, and heavy metals were less than the allowed maximum amount stipulated by the Regulations on Cosmetic Safety Standards in Korea.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.985-1001
• /
• 2018

In this study, we tried the various experiments using the emulsifier, electrolyte, stabilizer and gelling agent in order to improve a stability of low viscosity W/O emulsion. As a result, when we used polyglyceryl-4 diisostearate/polyhydroxystearate/sebacate as a main emulsifier, PEG-30 dipolyhydroxystearate and cetyl PEG/PPG-10/1 dimethicone as a co-emulsifier for stable emulsification system, 0.5 % sodium chloride as an electrolyte, 1 % distearyldimonium chloride as a stabilizer, 0.5 % glyceryl behenate/eicosadioate as an oil gelling agent, emulsion particle is the best. Also, we got the stable and low viscosity W/O emulsion maintained at a constant viscosity at 2,000 cps or less. In addition, we were able to examine the possibility of development of low viscosity fluids type sunscreens with excellent feeling and stability through the application of inorganic sunscreen agents.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.49 no.3
• /
• pp.247-258
• /
• 2023

This study aims to investigate the enhancement of water resistance and improvement in adhesion to the skin by combining dextrin palmitate and isopropyl titanium triisostearate coating materials with titanium dioxide. Due to the recent increase in consumers who enjoy outdoor activities, the demand for sunscreen with excellent water resistance is increasing. Prior research was conducted with O/W, Pickering, and W/O/W multiple formulations, but there was a limit to water resistance. The purpose of this study is to develop a complex inorganic powder that can improve water resistance and increase adhesion to the skin to solve this problem. First, we combined dextrin palmitate and isopropyl titanium triisostearate coating materials to form a composite with titanium dioxide. The coating of the inorganic powder was confirmed using FE-SEM and FT-IR analysis. The composite exhibited significantly higher in vitro water resistance compared to other formulations. The hydrophobicity of the coated inorganic powder was compared by measuring the contact angles. When the coated inorganic powder was applied to the W/O sunscreen formulation and the non-coated inorganic powder was applied to the W/O sunscreen formulation as a control, the SPF of the sunscreen containing the coated inorganic powder was higher. These results were the same when observed with a UV camera. Finally the adhesion of the coated inorganic powder to the skin was assessed by applying it to a foundation product. In vivo study, it was observed that the product formulated with the coated powder exhibited less smudging compared to the foundation product formulated with the non-coated powder. The developed inorganic powder in this study demonstrated excellent adhesion to the skin, providing a superior sensory experience, as well as enhanced hydrophobicity and remarkable water resistance effects. In the future, the result of this study is expected to help develop various sunscreen products to improve water resistance.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.23 no.3
• /
• pp.134-146
• /
• 1997

Consumers have recently preferred to purchase extensive UV intercepting products, which are waterproof and free from side effects on skin. Testing Cytoroxicity in SR method, cell survivial ratio of UV-B interceptors decreased above 0.08W/V%, and so did that of UV-A interceptors above 0.06W/V%. Also, Patch-test of inorganic UV interceptors resulted in no skin irritation even below 10.0 and 11.25. UV interceptors in the sunlight showed yellowish discoloration in 5 to 14 days. In absorption curves, UV-B was most suitable for Octyl methoxycinnamate and UV-A for Butyl methoxy dibenzoylmethane. Fro this reason, Nylonpoly UVA/UVB the material of OMC and BMDM coated with Nylon & polyethylene, was used as the organic UV interceptor. And zinc oxide and titanium dioxide was used as inorganic UV ibterceptors. The appropriate mixture ratio of ZnO and TiO2 was 6 to 4.6% of ZnO, 4% of TiO2 and 5% of Nylonpoly UVA/UVB were all combined with our sunscreen cream. The SPF value of in-vivo applied to a guinea pig was 34.9 and that of in-vivo was 38.5. Cyclomerhicone and dimerthicone were used in water-in-Silicone system. Ceryl diverhicone and sorbitan sesquioleate were used as emulsifiers and MgSO4, 7H2O, Mg-stearate/Mg-Al-stearate copolymer as emulsification stabilizers. In practical application, each SPF duration of O/W type and W/S type containing sunscreen cream of the same content showed that W/S type of sunscreen cream was 5 times as durable as the other. This product is fit for using in swimming, climbing or skiing. This research is to minimize skin trouble used by UV interceptors and to make one with proper softness, skin safety and UV intercepting efficiency.

• Journal of Pharmaceutical Investigation
• /
• v.35 no.6
• /
• pp.411-416
• /
• 2005

The aim of the present work was to prepare the nanosuspension of inorganic pigment which shows light reflection and scattering as efficient sunscreen. The zinc oxide (ZnO) was chosen as an inorganic pigment, and high pressure homogenizer and bead mill have been used for the preparation of nanosuspension. The ZnO nanosuspensions were characterized by particle size, in vitro sun protection factor (SPF) and UV transmittance. ZnO nanosuspension prepared by bead mill showed the average diameter of $119{\pm}4\;nm$, resulting in the high value of SPF $(28.74{\pm}2.06,\;n=20)$, while that prepared by high pressure homogenizer showed the average diameter of $751{\pm}32\;nm$ with the relative lower value of SPF $(21.38{\pm}1.94\;n=20)$. In addition, the film of ZnO nanosuspension prepared by bead mill was showed a high visible ray (VIS) transmittance, indicating a high transparency. In conclusion, a physically stable ZnO nanosuspension in cyclomethicone was successfully prepared using bead mill for the suitable sunscreen preparations.

• Analytical Science and Technology
• /
• v.11 no.2
• /
• pp.79-87
• /
• 1998

Consumers have recently preferred to purchase extensive UV intercepting products, which are waterproof and free from side effects on skin. During the testing of cytotoxicity (in-vitro) in neutral red (NR) method, cell survival ratio of UV-B interceptors decreased to just above 0.08 w/v%, and it was observed that the UV-A interceptors the ratio also decreased to just above 0.06 w/v%. In addition patch-tests of inorganic UV interceptors resulted in no skin irritation even below 10.0 and 11.25. In absorption curves, UV-B was most suitable for octyl methoxycinnamate (OMC) and UV-A for butyl methoxy dibenzoylmethane (BMDM). For this reason, $Nylonpoly^{TM}$ UVA/UVB the material of OMC and BMDM coated with Nylon & polyethylene, was used as the organic UV interceptor. Zinc oxide (ZnO) and titanium dioxide ($TiO_2$) was used as inorganic UV interceptors. The appropriate mixture ratio of ZnO and $TiO_2$ was 6 to 4:6% of ZnO, 4% of $TiO_2$ and 5% of $Nylonpoly^{TM}$ UVA/UVB were all combined and added to our sunscreen cream. The SPF value of in-vitro was 38.9. In practical application, each sun protection factor (SPF) duration of oil-in-water (O/W) emulsion and water-in-silicone (W/S) emulsion containing sunscreen cream of the same content showed that W/S type of sunscreen cream was 5 times as durable as the other. Therefore, this product is fit for use in swimming, climbing or skiing. This research is to minimize skin trouble caused by UV interceptors and to make one with proper softness, skin safety and UV intercepting efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.5
• /
• pp.3312-3318
• /
• 2014

For the sunscreen development from natural resources, a possible usage of microalgal extracts or mycosporine-like amino acids (MAAs) was investigated. Sunscreens containing 7% of microalgal extracts or MAAs derived from microalgae, Chlamydomonas hedleyi, were prepared and they were applied to human research. Through this clinical research, the values of Sun Protection Factors, Sun Protector Factor (SPF) and Protection Factor of UVA (PFA), of sunscreen containing microalgal extracts or MAAs were determined: SPF values of microalgal extracts and MAAs indicated 9.07 and 9.42, respectively, while PFA ones did 2.43 and 2.41. Due to more than 2 of PFA value in both sunscreens, they can be classified into [PA+]. Taken together, although sunscreen containing microalgae-derived extracts or MAAs does not effectively protect UV irradiation, its capacity can be satisfied if inorganic UV-protecting compounds are added.