The idea of increasing the performance of sunscreens without adding more UV-filters is very attractive. Early studies reported an influence of solvents on the absorbing properties of UV-absorbers which was shown to be connected to the solvent polarity. However, the polarity differed a lot between tested solvents and most were unsuitable UV-filter solubilizers. The aim of the present study was to focus exclusively on emollients pertinent for sunscreens and investigate their impact on the performance of UV-filter combinations. The UV absorbance of Bis-ethylhexyloxyphenol Methoxyphenyl Triazine, Ethylhexyl Triazone, Diethylamino Hydroxybenzoyl Hexyl Benzoate, and Ethylhexyl Methoxycinnamate was measured in suncare relevant emollients comprising C12-15 Alkyl Benzoate, Dibutyl Adipate, Caprylic/Capric Triglyceride, Coco-caprylate, Isopropyl Myristate, Dicaprylyl Carbonate. The wavelength of maximum absorbance (λmax) and specific extinction at λmax (E1,1 (λmax)) were assessed for each UV-filter - emollient system. The performance of market relevant UV-filter combinations based on the studied UV-filters was simulated for each emollient with a computational method using the absorbance values measured for each UV-filter - emollient system. The difference in polarity of emollients led to a 2-3 nm bathochromic shift and a variation of the E1,1 (λmax) ranging from 4 to 20% for tested UV-filters. The emollient type showed nearly no influence on the sun protection factor (SPF) of market relevant UV-filter combinations probably due to a different influence an emollient shows on the UVB filters resulting in cancelling of the corresponding effect. Conversely, for all UV-filter combinations the UVA protection decreased with a decrease in the emollient polarity. Whilst the SPF was not impacted by standardly used cosmetic oils, the results advocate to use polar emollients to optimize the UVA protection. This is of advantage since polar emollients better dissolve crystalline UV-filters. From tested emollients, Dibutyl Adipate performed the best for both SPF and PPD factors.

中文翻译：

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润肤剂对紫外线滤光片吸收和防晒功效的影响。

在不添加更多紫外线过滤剂的情况下提高防晒剂性能的想法非常有吸引力。早期的研究报道了溶剂对紫外线吸收剂吸收性能的影响，这与溶剂的极性有关。但是，测试溶剂之间的极性差异很大，大多数是不合适的紫外线过滤增溶剂。本研究的目的是专门研究与防晒霜有关的润肤剂，并研究其对紫外线过滤组合物性能的影响。在与防晒有关的润肤剂中测量了双乙基己氧基苯酚甲氧基苯基三嗪，乙基己基三氮杂,、二乙基氨基羟基苯甲酰基己基己酸酯和乙基己基甲氧基肉桂酸酯的紫外线吸收，所述润肤剂包括C12-15烷基苯甲酸酯，己二酸二丁酯，辛酸/癸酸癸酸三甘油酯 碳酸二辛酯。对每个紫外线过滤器-润肤剂系统评估了最大吸收波长（λmax）和在λmax处的比消光（E1,1（λmax））。使用每种紫外线过滤剂-润肤剂系统测得的吸光度值，采用计算方法，针对每种润肤剂，对基于研究的紫外线过滤剂的与市场相关的紫外线过滤剂组合的性能进行了仿真。对于测试的紫外线过滤剂，润肤剂极性的差异导致2-3 nm的红移和E1,1（λmax）的变化范围为4％至20％。润肤剂类型对市场相关的紫外线过滤剂组合的防晒系数（SPF）几乎没有影响，这可能是由于润肤剂在UVB过滤器上表现出的不同影响导致相应效果的抵消。反过来，对于所有紫外线过滤剂组合，随着润肤剂极性的降低，紫外线防护能力下降。虽然SPF不受标准使用的化妆品油的影响，但结果主张使用极性润肤剂来优化UVA防护。这是有利的，因为极性润肤剂可以更好地溶解结晶紫外线过滤剂。从测试的润肤剂来看，己二酸二丁酯对SPF和PPD因子均表现最佳。