Sharma Anu, Kumar Abhishek, Li Changning, Sharma Rakesh Kumar, Swihart Mark T
Department of Chemistry, University of Delhi India
Department of Chemical and Biological Engineering, University at Buffalo (SUNY) USA
RSC Adv. 2020 Sep 15;10(56):34254-34260. doi: 10.1039/d0ra05828a. eCollection 2020 Sep 10.
Sunscreens play a vital role in protecting human skin from photodamage upon UV exposure, but their effectiveness is limited by degradation and phototoxicity. Photoactivation of UV filters in sunscreen can generate reactive oxygen species, with accompanying cytotoxicity. Herein, we report stable, safe, fluorescent, and long-lasting sunscreens produced by microencapsulation of organic UV filters octylmethoxycinnamate (OMC) and butyl-methoxydibenzoylmethane (BMDM), alone and together, into a microporous zeolitic imidazole framework (ZIF-8). The visibly transparent OMC + BMDM@ZIF-8 sunscreens displayed complete broad-spectrum photoprotection against UV light even after 24 hours. Photostability testing of the sunscreens demonstrated the photo-protective nature of microporous ZIF-8 for stabilizing these UV filters. The sun protection factor (SPF) values for lotions containing 10% (w/w) OMC@ZIF-8, BMDM@ZIF-8 and OMC + BMDM@ZIF-8 sunscreens decreased from 29.8 to 26.0, 32.5 to 26.4, and 62.1 to 53.0, respectively, upon 24 hours of intense UV exposure. No release of the UV filters from the encapsulated formulations was observed. The ZIF-8 particles are too large to be transported across the stratum corneum. Thus, our findings suggest that zeolitic framework-encapsulated sunscreens could provide prolonged UV-protection efficacy and ultra-high SPF with reduced potential for degradation, phototoxicity, and transport across the skin.
防晒霜在保护人体皮肤免受紫外线照射引起的光损伤方面起着至关重要的作用，但其有效性受到降解和光毒性的限制。防晒霜中紫外线过滤剂的光活化会产生活性氧，并伴有细胞毒性。在此，我们报告了通过将有机紫外线过滤剂甲氧基肉桂酸辛酯（OMC）和丁基甲氧基二苯甲酰甲烷（BMDM）单独或一起微囊化到微孔沸石咪唑框架（ZIF-8）中而制备的稳定、安全、荧光且持久的防晒霜。即使在24小时后，可见透明的OMC + BMDM@ZIF-8防晒霜仍能对紫外线提供完整的广谱光保护。防晒霜的光稳定性测试证明了微孔ZIF-8对稳定这些紫外线过滤剂的光保护性质。含有10%（w/w）OMC@ZIF-8、BMDM@ZIF-8和OMC + BMDM@ZIF-8防晒霜的乳液在强烈紫外线照射24小时后，其防晒系数（SPF）值分别从29.8降至26.0、32.5降至26.4和62.1降至53.0。未观察到紫外线过滤剂从包封制剂中释放。ZIF-8颗粒太大，无法穿过角质层。因此，我们的研究结果表明，沸石框架包封的防晒霜可以提供延长的紫外线防护效果和超高的SPF，同时降低降解、光毒性和透过皮肤转运的可能性。
