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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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Tansirikongkol 2006-07: The last work on vernix caseosa synthetic analogues from the University of Cincinnati was conducted by Tansirikongkol14, 26 and focused on high internal phase emulsions—i.e., w/o emulsions with an internal aqueous phase, as high as 78% (see Figure 8). This work aimed to simulate the water/lipid ratio and water-handling properties of native vernix caseosa by combining the slow water release profile of w/o emulsions with the high water content of o/w-emulsions. Initially the oil phase contained conventional, non-vernix caseosa-like lipids but later, more vernix caseosa-like lipids were used.
Preparations with vernix caseosa-like lipids demonstrated water release profiles closer to that of native vernix caseosa than those with conventional lipids. The remainder of Tansirikongkol’s work focused more on the protective function of vernix caseosa against the enzymes present in the amniotic fluid, such as the chymotryptic enzyme, and excrements21 than on the development of synthetic analogues of vernix caseosa.
Erdal and Araman, Bouwstra, Hennink 2007: The children’s hospital and university in Cincinnati were not the only groups working on vernix caseosa imitations. Erdal and Araman from Istanbul University, for instance, suggested to be working on the same but results were not provided.40 As indicated above, Gunt had already identified that the total composition was important, not just the vernix caseosa lipids.25 However, it was when Bouwstra, PhD, of the University of Leiden, Netherlands, and Hennink, PhD, of the University of Utrecht, Netherlands, began to collaborate that a fundamentally different approach to vernix caseosa imitation emerged based on creating “cell-like” structures containing water in a lipid base formation rather than an o/w or w/o emulsion.
While Rissmann, PhD, worked with Bouwstra and Ponec, PhD, to characterize the lipids in vernix caseosa to study their packing and structure, Oudshoorn, PhD, worked with Hennink, on mimicking the vernix caseosa corneocytes. All literature cited until now has stated that water is present in the vernix caseosa corneocytes, and that vernix caseosa is different in that it can take up water at high relative humidities, but apart from the cubosomes, no formulation was capable of mimicking this.
Methacrylated hyperbranched polyglycerol microparticles with uniform sizes and shapes were prepared using photolithography, resulting in a size range of 30 μm to 1,400 μm.41 For the synthetic variant of vernix caseosa corneocytes, hexagons with a diameter of 30 μm were prepared, similar to the size of human corneocytes, which were loaded with FITC-dextran and coated with lipids (see Figure 9). Next, a lipid mixture mimicking the intercellular lipid composition and organization of vernix caseosa was prepared—similar to that reported in Table 1 for vernix caseosa, from Rissmann et al.15—and mixed in different ratios with the microparticles. Subsequently, the water-handling properties were measured gravimetrically and compared to native vernix caseosa in a dehydration study over P2O5. The result of this experiment is shown in Figure 10.28