Keratin and associated bound water

Keratin and associated bound water represent the primary structural and functional unit of the stratum corneum, the outermost layer of the skin. Keratins are fibrous intermediate filament proteins that provide mechanical resilience, while the associated bound water is essential for maintaining the flexibility and enzymatic activity required for healthy skin desquamation (Source: PubMed, PMID: 10849128). In a healthy state, water molecules are chemically bound to the polar side chains of keratin, preventing the skin from becoming brittle and cracked. This complex is a major therapeutic target in dermatology, particularly for treating xerosis and hyperkeratotic disorders. Drugs such as urea act as humectants by increasing the hydration of this keratin matrix, effectively 'softening' the tissue and restoring barrier function (Source: StatPearls, NBK544231). Conversely, keratolytic agents target the structural integrity of the keratin-water complex to promote the removal of excess scales in conditions like psoriasis. Understanding the biophysical interaction between keratin and water is crucial for the development of topical formulations aimed at skin barrier repair and maintenance.

Other names

Stratum corneum hydration complexKeratin-water matrixHydrated keratinSoft keratin complex

Humectants like urea and glycerin increase the water-binding capacity of keratin by creating hydrogen bonds and unfolding protein structures to expose more water-binding sites. Keratolytic agents like salicylic acid reduce the cohesion between keratinocytes by disrupting the keratin matrix and intercellular lipids, facilitating the shedding of the stratum corneum. Occlusives like petrolatum indirectly affect this target by preventing the evaporation of bound water from the keratin matrix.