Comparative Assessment of Skin Protectant Barrier Performance Using an in vitro Test Methodology

Introduction: Proper skin management requires appropriate abatement of exudate and other caustic fluids, while simultaneously supporting proper hydration levels.^1,2 Skin protectants are designed to occlude deleterious external liquids in order to maintain healthy conditions.³ Reducing percutaneous absorption of cytotoxic fluids is essential for efficient skin maintenance.⁴ The objective of this controlled study was to compare the barrier performance of various commercially available skin protectants.

Methods: A series of 2.5cm² circles were tattooed on swine skin flaps. Small 2.5cm² Reston™ foam squares were dipped in methylene blue (1%w/v), allowed to drain, and gently compressed onto randomly assigned control circles until trace liquid was visible around the foam margin. Then, 1mL of six different topical skin protectants was applied randomly to the remaining circles. Methylene blue was applied in the same manner previously described to all test groups. The circles were then photographed and quantified for mean gray value (MGV), a measure of optical density, to compare the permeability of competing skin protectant products.

Results: The control group presented an MGV of 18.32±3.7. Product A had a significantly greater MGV than Products B, C, D, E, and F (80.01±15.7 versus 33.36±12.6, 44.07±20.1, 36.41±14.5, 22.88±6.3, and 37.73±11.7, respectively; ANOVA p<0.0001). Product E was not significantly different from the control (ANOVA p = 0.0978).

Conclusion: Products A, B, C, D, and F exhibited higher MGV values than the control (application of no protective product at all), so all of these products were seen to have some protective value, but overall, Product A demonstrated significantly greater occlusive properties than all other competitive products. No significant difference was seen between Product E and the control, which may indicate a lack of protective properties. Further studies are warranted to demonstrate whether the observations made on porcine skin translate to human skin.