Coexistence effect of <scp>UVA</scp> absorbers to increase their solubility and stability of supersaturation

Endo, Mikiko; Mukawa, Tsubasa; Sato, Nobumasa; Maezawa, Daisuke; Ohtsu, Yutaka; Kuroda, Akihiro; Wakabayashi, M.; Asakura, Kouichi

doi:10.1111/ics.12154

Cited by 5 publications

(11 citation statements)

References 12 publications

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“…DHHB and EHMC were purchased from BASF Japan Ltd., and BMDM was purchased from DSM Nutrition Japan K. K. Acryl silicone resin, Silicone Acrylates KP‐541, was supplied from Shin‐Etsu Chemical Co., Ltd. iso ‐Propanol was purchased from Kanto Chemical Co., Inc. A cosmetic oil, 2‐ethylhexyl ester of the oligomer of hydroxystearic acid (EH‐O‐HAS) exhibiting a hydroxyl value of 29.26 mg KOH g −1 [which indicated its degree of oligomerization was 6.33 ], was supplied from National Mimatsu Co., Ltd. According to our recent finding of the strong coexistence effects of DHHB and BMDM on their solubility in EHMC in the presence of EH‐O‐HAS , DHHB, BMDM and EH‐O‐HAS were dissolved in EHMC to prepare a UV absorbers solution in which the weight ratio was DHHB:BMDM:EHMC:EH‐O‐HAS = 0.220:0.214:0.470:0.096. It was dissolved in a iso ‐propanol solution of the acryl silicone resin to prepare two types of pseudosunscreen solutions having the weight ratio of UV absorbers solution: acryl silicone resin: iso ‐propanol = 0.030:0.485:0.485 ( A ) and 0.050:0.475:0.475 ( B ).…”

Section: Methodsmentioning

confidence: 99%

“…The linear motor coater used in our previous studies was used for the application of the pseudosunscreen solutions. To analyze the pure influence of the geometric factor generated by the viscous fingering on the UV transmission, no roughened PMMA plate for the current in vitro measurements was used, but a flat square quartz plate of 10 cm × 10 cm and a thickness of 3.1 mm was employed as a substrate.…”

Section: Methodsmentioning

confidence: 99%

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Problems on the Evaluation of the Critical Wavelength of Sunscreens for “Broad Spectrum” Approval Brought on by Viscous Fingering During Sunscreen Application

Wakabayashi

Okano

Mukawa³

et al. 2016

Photochem & Photobiology

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When a viscous liquid is applied to a solid substrate, a patterned liquid layer is usually formed by the phenomenon called viscous fingering, since the moving liquid surface is in far-from-equilibrium conditions to let the morphological fluctuation to grow. Pseudosunscreen solutions were prepared and applied on a flat quartz plate. A spatially periodic stripe pattern was formed on the pseudosunscreen layer when a block applicator was used, whereas a flat surface layer was formed when a four-sided applicator was used. UV absorbance of the patterned layer was lower than that of the flat layer having the same average thickness. In addition, a larger decrease in the UV absorbance by the pattern formation was observed at wavelengths at which the UV absorbance of the flat layer was large, which was consistent with theoretical simulations. In 2011, US FDA introduced a new rule using the term "Broad Spectrum" for labeling the sunscreens. The different decrease in the UV absorbance at each wavelength was found to change the critical wavelength, which is a criterion for sunscreens to be labeled as "Broad Spectrum" protection. The result of this study makes the problem on the evaluation of the critical wavelength come to the surface.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Problems on the Evaluation of the Critical Wavelength of Sunscreens for “Broad Spectrum” Approval Brought on by Viscous Fingering During Sunscreen Application

Wakabayashi

Okano

Mukawa³

et al. 2016

Photochem & Photobiology

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“…UV absorbers, diethylamino hydroxybenzoyl hexyl benzoate DHHB and 2-ethylhexyl methoxycinnamate EHMC , were purchased from BASF Japan Ltd., and butyl methoxydibenzoylmethane BMDM was purchased from DSM Nutrition Japan K. K. A cosmetic oil, 2-ethylhexyl ester of oligomer of hydroxystearic acid EH-O-HAS 23 , exhibiting a hydroxyl value 24 of 29.26 mg KOH/1g of oil, indicating that its degree of oligomerizaion was 6.33 25 , was supplied by National Mimatsu Co., Ltd. According to our recent finding of the strong coexistence effects of DHHB and BMDM on their solubility in EHMC in the presence of EH-O-HAS 26 , DHHB, BMDM, and EH-O-HAS were dissolved in EHMC to prepare a UV absorber solution in which the weight ratio was DHHB : BMDM : EHMC : EH-O-HAS 0.220 : 0.217 : 0.470 : 0.096. It was subsequently dissolved in a hexane solution of ASR to prepare three types of pseudo-sunscreen solutions 1, 2, and 3 Table 1 .…”

Section: Methodsmentioning

confidence: 99%

Surface Structures of Cosmetic Standard Poly Methyl Methacrylate UV Evaluation Plates and their Influence on the <i>in vitro</i> Evaluation of UV Protection Abilities of Cosmetic Sunscreens

Kuroda

Sakai²,

Yahagi³

et al. 2019

J. Oleo Sci.

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for the Broad-spectrum approval by US FDA s Final Sunscreen Rule 10 , roughened cosmetic standard poly methyl methacrylate PMMA UV evaluation plates are used 11 13. In our previous studies, it was shown that spontaneous pattern formation by viscous fingering 14 18 on the sunscreen layer during the process of its application onto a flat Abstract: Cosmetic standard poly methyl methacrylate (PMMA) UV evaluation plates, i.e., roughened PMMA plates, are used in the EU and the US for the in vitro evaluation of UV protection abilities of sunscreen, such as in vitro UVA-PF and critical wavelength for the Broad-spectrum approval. In our previous studies, inhomogeneity in the thickness of a pseudo-sunscreen layer applied on a flat quartz plate was observed to alter UV transmission. Thus, the surface roughness of the standard plates should have a significant influence on the in vitro evaluation. In the present study, we have analyzed the surface structures of three cosmetic standard PMMA UV evaluation plates: Helioplates HD6 (Sa = 6 µm) and ISO plates (Ra = 2 and 5 µm). A decamethylcyclopentasiloxane and 2-propanol-mixed solvent solution of acrylsilicone resin was prepared, and the solution was added dropwise onto the plates. After the evaporation of the solvents, the plates were cut and the cross section was analyzed using SEM-EDS. The distribution of silicon atoms at the cross-section suggested that the maximum depth of penetrating of acrylsilicone resin was larger than Ra for all the standard plates, and the surface structure was significantly different for each standard plate. In addition, cracks into which the acrylsilicone resin deeply penetrated were observed on the surface of some plates. Clear-solution-type pseudo-sunscreen samples in which UV absorbers and acrylsilicone resin were dissolved were deposited on the standard roughened PMMA plates. It was observed that the addition of acrylsilicone resin drastically changed the net UV transmission. The degree to which the hollows of the roughened surface were filled with the pseudo-sunscreen samples determined the variation of UV transmittance.

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“…Solubilizers are referred herein as solvents with the particular ability of increasing the solubility of UV filters in a system or phase by adding high-affinity solvophillic functional groups as well as inhibiting their nucleation. 4 2.3. Recrystallization in Sunscreens.…”

Section: Theorymentioning

confidence: 99%

“…Recrystallization is one of the possible consequences of these environmental factors. 4,[6][7][8]13 Therefore, it is important to confirm the stability of these products under such conditions to ensure efficacy.…”

Section: Theorymentioning

confidence: 99%

Efficient UV Filter Solubilizers Prevent Recrystallization Favoring Accurate and Safe Sun Protection

Souza

Berkowitz

Chea

et al. 2018

ACS Appl. Mater. Interfaces

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Sun protection is a global concern, and maximizing sunscreen stability and efficacy depends partially on the prevention of UV filters recrystallization. We aimed to study the efficacy of hydrophobic solubilizers in preventing the recrystallization of solid hydrophobic UV filters in predissolutions, sunscreen formulations, and during simulated human use. Recrystallization of UV filters induced by ultrasonication, temperature variation, or simulated human application was analyzed by different methods. Maximum solubility of UV filters in solubilizers was determined. Surprisingly, the best solubilizer was not necessarily the best solvent to prevent recrystallization, suggesting there are different forces controlling these phenomena. Hydrophobic solubilizers tend to perform better than ethanol in predissolutions, but the presence of other components in final products may change their performance. Results suggest that some UV filters tend to form liquid clusters, which may behave as crystals and affect the desired even distribution of UV filters on the skin. UV filters were also found to respond differently to Hansen Solubility Parameters. Scanning electron microscopy supports the fact that recrystallization upon sunscreen application is an issue to be tested during development. A timesaving method to predict recrystallization of UV filters in clear systems was developed and is presented as a tool to enhance the efficacy of sunscreens.

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Coexistence effect of UVA absorbers to increase their solubility and stability of supersaturation

Abstract: The solution type composite having the highest concentrations of DHHB and BMDM prepared in this study exhibited critical wavelength at 368 nm that was just below the border for sunscreens being qualified as 'Broad Spectrum' protection under the new rule launched by US FDA.

Cited by 5 publications

References 12 publications

Problems on the Evaluation of the Critical Wavelength of Sunscreens for “Broad Spectrum” Approval Brought on by Viscous Fingering During Sunscreen Application

Problems on the Evaluation of the Critical Wavelength of Sunscreens for “Broad Spectrum” Approval Brought on by Viscous Fingering During Sunscreen Application

Surface Structures of Cosmetic Standard Poly Methyl Methacrylate UV Evaluation Plates and their Influence on the <i>in vitro</i> Evaluation of UV Protection Abilities of Cosmetic Sunscreens

Efficient UV Filter Solubilizers Prevent Recrystallization Favoring Accurate and Safe Sun Protection

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