Henkel AG & Co. KGaA, Düsseldorf, Germany.
Int J Cosmet Sci. 2021 Apr;43(2):181-190. doi: 10.1111/ics.12679. Epub 2021 Jan 1.
Axillary wetness represents an unwanted effect of the physiologically vital sweating mechanism, especially when it becomes excessive. Cosmetic products reducing sweat secretion rely on aluminium salts as the active ingredient acting by physically blocking the sweat gland. Driven by the interest to better understand the sweat mechanism and to develop alternative technologies against excessive sweating a search for an effective testing approach started as up to now, cost- and time-consuming in vivo studies represent the standard procedure for testing and identifying these alternatives.
The herein described in vitro test system is based on the measurement of intracellular changes of the ion equilibrium in cultured eccrine sweat gland cells. Subsequently, in vivo studies on the back of volunteers were conducted to verify the sweat-reducing effect of in vitro newly discovered substance.
In this study, we describe an effective cell-based in vitro method as a potent tool for a more targeted screening of alternatives to aluminium salts. Testing the commonly used aluminium chlorohydrate as one example of an aluminium-based active in this screening procedure, we discovered a distinct influence on the ion equilibrium: Intracellular levels of sodium ions were decreased while those of chloride increased. Screening of various substances revealed a polyethyleneimine, adjusted to pH 3.5 with hydrochloric acid, to evoke the same alterations in the ion equilibrium as aluminium chlorohydrate. Subsequent in vivo studies showed its substantial antiperspirant action and confirmed the high efficiency of the polyethyleneimine solution in vivo. Further, specific investigations connecting the chloride content of the tested substances with the resulting sweat reduction pointed towards a substantial impact of the chloride ions on sweating.
The newly described in vitro cell-based screening method represents an effective means for identifying new antiperspirant actives and suggests an additional biological mechanism of action of sweat-reducing ingredients which is directed towards unbalancing of the ion equilibrium inside eccrine sweat gland cells.
腋窝潮湿代表生理上重要的出汗机制的一种不良影响，尤其是当它变得过度时。减少汗液分泌的化妆品产品依赖于作为活性成分的铝盐，通过物理方式阻止汗腺。由于有兴趣更好地了解出汗机制并开发针对过度出汗的替代技术，因此开始寻找一种有效的测试方法，到目前为止，成本高且耗时的体内研究是测试和识别这些替代物的标准程序。
本文所述的体外测试系统基于培养的大汗腺细胞中离子平衡的细胞内变化的测量。随后，在志愿者的背部进行了体内研究，以验证体外新发现物质的减少出汗效果。
在这项研究中，我们描述了一种有效的基于细胞的体外方法，作为一种针对铝盐替代物进行更有针对性筛选的有效工具。在这种筛选过程中，测试了常用的氯化铝作为基于铝的活性物质的一个例子，我们发现它对离子平衡有明显的影响：细胞内钠离子水平降低，而氯离子水平升高。对各种物质的筛选显示，一种经过盐酸调节至 pH3.5 的聚乙烯亚胺会引起与氯化铝相同的离子平衡变化。随后的体内研究表明它具有实质性的止汗作用，并证实了体内聚乙烯亚胺溶液的高效性。此外，将测试物质的氯化物含量与产生的汗液减少联系起来的具体研究表明，氯化物离子对出汗有实质性的影响。
新描述的基于细胞的体外筛选方法是识别新的止汗活性物质的有效手段，并提出了一种针对减少汗液成分的生物作用机制的建议，该机制针对的是大汗腺细胞内离子平衡的失衡。
