Water-handling properties of vernix caseosa and a synthetic analogue

Abstract

A naturally occurring barrier cream, vernix caseosa, is the viscous material synthesized by the sebaceous glands in the late gestational human fetus. Vernix functions as a moisturizer by increasing the skin hydration and water-holding capacity of treated skin. Vernix films are semi-permeable, i.e., in the range that facilitates barrier repair. Antioxidant, disinfectant, and skin cleansing functions are also present. Premature infants have a markedly immature epidermal barrier and the excessive water loss can lead to fluid and electrolyte imbalances, along with high evaporative heat loss. Application of petrolatum-based, low-water creams on these infants has decreased TEWL and improved the skin condition. However, in infants of 500-750 g, this treatment was associated with an increased incidence of late-onset nosocomial infection, and questions regarding efficacy and safety have been raised. The water-handling properties, semi-permeability and multi-functionality, suggest that application of vernix may promote the development and restoration of premature or other compromised skin. The present study focuses on the development of barrier creams to simulate the water-handling properties of native vernix. Barrier creams were prepared as high-water-phase emulsions containing various lipid mixtures. Several stable creams with high water content exhibited slow water release and water vapor transport rates in the range to facilitate barrier repair. The results showed the importance of emulsion type in preventing water release. Preparations with vernix-like lipids demonstrated water release profiles closer to the native vernix benchmark than those with conventional lipids. The work resulted in a synthetic vernix barrier cream prototype for evaluation on skin and to which additional functionality, e.g., anti-infective and antioxidant activity, could be added.