Marty J-P
Laboratoire de Dermopharmacologie et Cosmétologie, Faculté de Pharmacie, 5, rue J.-B. Clément, 92296 Châtenay-Malabry Cedex.
Ann Dermatol Venereol. 2002 Jan;129(1 Pt 2):131-6.
In the stratum corneum, the water binds to the intracellular hygroscopic and hydrosoluble substances called "natural moisturizing factors" or NMF. These "natural moisturizing factors" contained in the corneocytes are formed during epidermal differentiation and may represent up to 10 p. cent of the corneocyte mass. They are principally amino acids, carboxylic pyrrolidone acid, lactic acid, urea, glucose and mineral ions. Keratinization plays an important part in the formation of NMF that exhibit strong osmotic potential attracting the water molecules. The binding of water to NMF is the static aspect of cutaneous hydration. The second, dynamic, aspect is related to the selective permeability of the stratum corneum and to its lipid barrier properties, the permeability of which depends on the integrity and nature of the inter-corneocyte lipids and their lamellar organization between the cells. In these conditions, hydration cosmetics rely on two concepts that can be isolated or associated: the supply of hydrophilic substances to the stratum corneum, capable of attracting and retaining water (moisturizer) or capable of restoring the barrier in order to restore normal water loss or of protecting it against aggression (occlusive).
在角质层中，水与细胞内称为“天然保湿因子”（NMF）的吸湿和水溶性物质结合。角质形成细胞中所含的这些“天然保湿因子”在表皮分化过程中形成，可能占角质形成细胞质量的10%。它们主要是氨基酸、吡咯烷酮羧酸、乳酸、尿素、葡萄糖和矿物质离子。角质化在具有强大渗透潜能吸引水分子的天然保湿因子的形成中起重要作用。水与天然保湿因子的结合是皮肤水合作用的静态方面。第二个动态方面与角质层的选择性通透性及其脂质屏障特性有关，其通透性取决于角质形成细胞间脂质的完整性和性质以及它们在细胞间的层状组织。在这些情况下，保湿化妆品依赖于两个可分离或关联的概念：向角质层供应亲水性物质，能够吸引和保留水分（保湿剂），或者能够恢复屏障以恢复正常的水分流失或保护其免受侵害（封闭剂）。
