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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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Bautista 1999: In the first poster from Bautista et al.,22 three test creams were applied to the volar skin surface of adult volunteers following cleansing; these contained vernix caseosa, a petrolatum- and mineral oil-based ointmentd and petrolatum. Results indicated an increase in skin surface hydration on the sites where barrier creams had been applied—but not on the vernix caseosa-treated control sites. The researchers concluded that there are major differences between vernix caseosa and the o/o ointments.
Youssef, Bautista 2000: Youssef et al.24 compared the in vitro tritiated water flux through layers of varying thickness of vernix caseosa, a petrolatum- and mineral oil-based ointmentd and petrolatum, and found that the permeability coefficient of water through a film of vernix caseosa with a thickness of 20 μm was significantly higher than that through both the petrolatum and mineral oil ointment (2-fold) and petrolatum alone (25-fold). This supported the hypothesis that vernix caseosa does not act as a totally occlusive biofilm in utero but rather forms a semi-occlusive barrier overlaying the developing SC.
Also in 2000, Bautista et al.23 published the first full paper on the comparison between vernix caseosa and standard oil-based ointments, of which the conclusions were, as might be expected, similar to the 1999 poster. In this paper, a petrolatum-, mineral oil- and lanolin alcohol-based w/o emulsione also was included. Given the lipid constituents of vernix caseosa, the researchers anticipated that it would function as a hydrophobic barrier to prevent water loss and thereby act in a similar manner to hydrophobic ointments.
Surface electrical capacitance and TEWL experiments were conducted as indices of surface hydration. Sorption-desorption profiles were taken to determine skin surface hydrophobicity and immediately after the application of vernix caseosa, an increase in the rate of water loss from the skin surface was noted. Relative to control skin and the skin treated with the ointments and w/o emulsions, the application of vernix caseosa to freshly bathed human skin resulted in a unique profile of temporal change in baseline surface hydration, moisture accumulation and water-holding capacity (see Figure 7). These results, however, indicated major differences between human vernix caseosa, standard ointments and w/o emulsions, especially in their time profiles.23
Gunt 2002: The next publication was a thesis from Gunt.25 Apart from studying fundamentals such as the influence of film thickness and relative humidity (see Figure 4), Gunt was the first to measure the water loss profiles of: vernix caseosa; the w/o emulsiona; o/w emulsionb (see Figure 3); and cubosomes. Cubosomes, or cubic liquid crystalline nanoparticles, have a bicontinuous liquid phase structure wherein both the water and lipid domains are continuous.