Keshavarzi Fatemeh, Zajforoushan Moghaddam Saeed, Barré Pedersen Malene, Østergaard Knudsen Nina, Jafarzadeh Shadi, Thormann Esben
Department of Chemistry, Technical University of Denmark, Lyngby, Denmark.
Riemann A/S, Orkla, Denmark.
Skin Res Technol. 2021 Mar;27(2):153-162. doi: 10.1111/srt.12926. Epub 2020 Jul 17.
Covering the skin by topical films affects the skin hydration and transepidermal water loss (TEWL). In vivo studies to investigate the water vapor permeation through topical films are complicated, expensive, ethically not preferred, and time- and labor-consuming. The objective of this study was to introduce an in vitro and subject-independent alternative evaluation method to predict the breathability of topical formulations.
In this study, we developed an in vitro setup to simulate the TEWL values of human skin and investigated the breathability of five polymeric film formers used in topical formulations. Furthermore, a comparative in vivo TEWL study was performed on ten human volunteers with defined areas of skin covered with films of two selected polymers possessing different barrier properties.
By employing the in vitro setup, a vinylpyrrolidone/acrylates/lauryl methacrylate copolymer was determined to form the most breathable film, whereas acrylates/octylacrylamide copolymer and shellac films showed the highest barrier properties. The in vivo TEWL study demonstrated the same relative barrier properties for the acrylates/octylacrylamide and polyurethane-64 films, despite a more complex driving force for water vapor permeation due to moisture accumulation on the covered skin surfaces.
We obtained a good correlation between the in vitro and in vivo results, demonstrating that our model can categorize different polymeric film formers based on their breathability when applied to human skin. This information can aid in selecting suitable film-forming polymers for topical formulations with either breathable or occluding functionalities.
局部用薄膜覆盖皮肤会影响皮肤水合作用及经表皮水分流失（TEWL）。研究局部用薄膜的水蒸气透过率的体内研究复杂、昂贵，在伦理上不受青睐，且耗时费力。本研究的目的是引入一种体外且与受试者无关的替代评估方法，以预测局部用制剂的透气性。
在本研究中，我们开发了一种体外装置来模拟人体皮肤的TEWL值，并研究了用于局部用制剂的五种聚合物成膜剂的透气性。此外，对十名人类志愿者进行了一项比较性体内TEWL研究，在其特定面积的皮肤上覆盖具有不同阻隔性能的两种选定聚合物的薄膜。
通过使用该体外装置，确定乙烯基吡咯烷酮/丙烯酸酯/甲基丙烯酸月桂酯共聚物形成的薄膜透气性最佳，而丙烯酸酯/辛基丙烯酰胺共聚物和虫胶薄膜表现出最高的阻隔性能。体内TEWL研究表明，丙烯酸酯/辛基丙烯酰胺薄膜和聚氨酯-64薄膜具有相同的相对阻隔性能，尽管由于覆盖皮肤表面的水分积聚，水蒸气渗透的驱动力更为复杂。
我们在体外和体内结果之间获得了良好的相关性，表明当应用于人体皮肤时，我们的模型可以根据不同聚合物成膜剂的透气性对其进行分类。这些信息有助于为具有透气或封闭功能的局部用制剂选择合适的成膜聚合物。
