Shielded Corneosurfametry and Corneoxenometry: Novel Bioassays for the Assessment of Skin Barrier Products

Abstract

Objectives: One of the most frequent occupational and environmental insults to the skin is linked to chronic exposure to weak irritants. There is a need for new predictive tests assessing the efficacy of barrier creams. Methods: Shielded variants of corneosurfametry and corneoxenometry are introduced as novel ex vivo bioassays applicable for comparing protection to surfactants and organic solvents. Results: Both bioassays showed good reproducibility for each offending agent and skin-protective products. Significant differences in efficacy were indicated between the presumptive barrier products. Conclusions: Shielded corneosurfametry and corneoxenometry may be convenient bioassays to compare the protection afforded by topical products against specific offending compounds to the skin. They avoid animal testing and toxicological hazards in human testing. In addition, they are cheap, rapid and reproducible.

Penetration Enhancers Assessed by Corneoxenometry

“…After placing the samples on a white reference tile, reflectance colorimetry (Chroma Meter CR200 Minolta) was used to derive the L* and Chroma C* values. The colorimetric index of mildness (CIM) was calculated as previously defined [2][3][4][5] following CIM = L* -Chroma C*. The relative index of irritancy (RII) was calculated following RII = 1 -[(CIM product) (CIM water) -1 ].…”

“…There is a need for accurate assessments of the stratum corneum alterations because when the effect of penetration enhancers can be measured, safe, reliable and effective formulations can be made. 0 0 0 B 1 0 2 0 0 0 C 1 0 0 0 2 0 D 1 0 1 0 1 0 0 E 10 0 10 10 F 1 0 1 5 5 0 G 1 0 0 5 1 5 H 1 0 1 0 0 1 0 I 1 0 5 1 0 5 J 10 7.5 5 7.5 Corneoxenometry, named after corneocyte, xenobiotic and metry, was designed for testing chemicals harmful to the stratum corneum [2][3][4][5]. The bioassay entails collection of cyanoacrylate skin surface strippings (CSSS) from normal human skin.…”

Dynamics of Skin Barrier Repair following Topical Applications of Miconazole Nitrate

“…These topical products tend to guarantee partial occlusion. The real level of clinical effi cacy of barrier creams is disputed [17,18] . Other topical formulations and some ions can help in correcting the excess of TEWL after damaging the SC [3,[19][20][21][22][23][24] .…”

Skin compatibility of cyclodextrins and their derivatives: a comparative assessment using a corneoxenometry bioassay

“…Any disruption in the lipid bilayers of the SC and any protein denaturation of the corneocytes, a process that may reduce the barrier function of the SC and may induce irritation, is revealed by controlled colorimetric means. The effect of organic solvents, penetration enhancers and barrier creams were tested by corneoxenometry with relevant predictive value [4,6,7]. In this study, the corneoxenometry suggested that all tested CD are globally well tolerated by the skin because CIM medians values were above the threshold value of 30 for skin mildness (Fig.…”

“…The CIM water value (mildness reference) is around 64 while that of sodium laurylsulfate, a reference irritating product, may be as low as 5-15 [8]. Results obtained by corneoxenometry or corneosurfametry show good correlations with those of other in vitro tests and in vivo studies [6].…”