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Vernix Caseosa: The Ultimate Natural Cosmetic?
By: Johann W. Wiechers, PhD, JW Solutions; and Bernard Gabard, PhD, Iderma
Posted: August 31, 2009, from the September 2009 issue of Cosmetics & Toiletries.
- Figure 1. Vernix caseosa covers newborn infants
- Figure 2. Lipid, free lipid extract and ceramide analyses
- Figure 3. Water loss profiles
- Figure 4. Water loss profiles of vernix caseosa films as a function of relative humidity
- Figure 5. Equilibrium water sorption-desorption curves
- Figure 6. Percent barrier recovery after tape stripping versus film permeability
- Figure 7. Moisture accumulation assessment
- Figure 8. Water release profiles
- Figure 9. Microgels and coating lipids
- Figure 10. Water release profiles of native VC and various biofilms
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“In utero, its rheological properties are modified by extracutaneous secretions such as pulmonary surfactant. Detached vernix is swallowed by the fetus. Vernix contributes to the electrical isolation of the fetus and has osmoregulatory capability. At the time of birth, its water content precisely matches the cube of the golden section ratio. Following tactile spreading, polygonal vernix corneocytes orient parallel to the skin surface. The hydrophilic (intracorneocyte) and hydrophobic (external lipid) domains of vernix contain a plethora of biologically active, small molecules in a complex, structured array.
“Cleansing studies6 support ready entry of applied vernix into surface pores such as hair follicles. Vernix has a nongreasy feel and its physical properties hypothetically contribute to the panoply of sensory cues, which attract caregivers to the skin of the newborn. The possibility that vernix contains pheromones, like mother’s milk, is open to investigation. Vernix facilitates acid mantle formation and presumably contributes to optimal bacterial colonization of newborn skin after birth.” Imagine getting such a product brief from marketing!
From all of the above, it is clear that a synthetic analogue of vernix caseosa cannot simply mimic all its biological and physical characteristics. Formulators have therefore focused on a few main points, including the water-holding capacity and the water vapor transport rate; more recently, the skin barrier effect has become another focus. Papers describing synthetic analogues of vernix caseosa include the following, discussed in chronological order of publication:
Sumida 1998: Sumida et al.12 were (one of) the first to describe a pseudo vernix caseosa formulation and found that the skin’s hygroscopicity and water-holding ability markedly improved after application of a test cream, even after washing with water. The authors suggested that the liquid crystalline structure of both the vernix caseosa and pseudo vernix caseosa formulation contributed water-absorption ability to these lipid mixtures.
The next six publications describing synthetic analogues for vernix caseosa all come from the University of Cincinnati School of Pharmacy, or the Skin Science Institute at the Cincinnati Children’s Hospital Research Foundation, which clearly made this into a research theme for almost a decade. It started with a poster of Bautista et al.22 in which vernix caseosa was compared with a petrolatum and mineral oil-based ointmentd and petrolatum. Initially, the comparisons were only conducted with oil-based formulations but over the course of approximately seven years, more complex formulations were studied.