Evaluating the Irritant Factors of Silicone and Hydrocolloid Skin Contact Adhesives Using Trans-Epidermal Water Loss, Protein Stripping, Erythema, and Ease of Removal

Abstract

A composite silicone skin adhesive material was designed to improve its water vapor permeability to offer advantages to wearer comfort compared to existing skin adhesive dressings available (including perforated silicone and hydrocolloid products). The chemical and mechanical properties of this novel dressing were analyzed to show that it has a high creep compliance, offering anisotropic elasticity that is likely to place less stress on the skin. A participant study was carried out in which 31 participants wore a novel silicone skin adhesive (Sil2) and a hydrocolloid competitor and were monitored for physiological response to the dressings. Trans-epidermal water loss (TEWL) was measured pre- and postwear to determine impairment of skin barrier function. Sil2 exhibited a higher vapor permeability than the hydrocolloid dressings during wear. Peel strength measurements and dye counter staining of the removed dressings showed that the hydrocolloid had a higher adhesion to the participants' skin, resulting in a greater removal of proteins from the stratum corneum and a higher pain rating from participants on removal. Once the dressings were removed, TEWL of the participants skin beneath the Sil2 was close to normal in comparison to the hydrocolloid dressings that showed an increase in skin TEWL, indicating that the skin had been highly occluded. Analysis of the skin immediately after removal showed a higher incidence of erythema following application of hydrocolloid dressings (>60%) compared to Sil2, (<30%). In summary, this modified silicone formulation demonstrates superior skin protection properties compared to hydrocolloid dressings and is more suitable for use as a skin adhesive.

Keywords: TEWL; adhesive; peel strength; silicone; skin contact; vapor permeability.

Figure 1

Wound dressing composition. Depiction of overall adhesive structure (top), adhesive surface comparison via scanning electron (middle), and surface elemental distribution analysis (bottom) microscopy of adhesive surfaces of (A) Sil2, (B) Mepilex, (C) Salts hydrocolloid, and (D) Eurotek hydrocolloid. Silica distribution is shown in blue, and carbon distribution is shown in red.

Figure 2

(A) DMA tensile creep test of Sil2 at 28, 32.5, and 37 °C. (B) DMA tensile creep test of the Eurotek hydrocolloid layer at 28, 32.5, and 37 °C.

Figure 3

(A) Parallel plate shear creep test of Sil2 at 28, 32.5, and 37 °C. (B) Parallel plate amplitude sweep of Sil2 at 32.5 °C.

Figure 4

Peak peel (left) and steady-state (right) adhesion between Sil2 (n = 6), Mepilex (n = 7), Salts hydrocolloid (n = 7), and Eurotek hydrocolloid (n = 7/5) measured against participant forearm skin.

Figure 5

Box and Whisker summary of TEWL data of participant trial showing data for all participants (top row, n = 31), or just 6 h (middle row, n = 18) or 24 h (bottom row, n = 13). Each graph contains four sets of data each at onset of wear after dressing is applied, at end of wear before the patch is removed, and skin measurement after patch removal. Data is presented in groups of left arm (LA), right arm (RA), left torso (LT), and right torso (RT). Graphs show data for silicone patches (left column), hydrocolloid patches (middle column), and control group of skin (right column).

Figure 6

Top: TEWL of the skin beneath adhesive dressings of silicone, hydrocolloid, and control skin measurement of the left arm (LA), right arm (RA), left torso (LT), and right torso (RT). Bottom: participant response to question about ease of removal.

Figure 7

Top: typical stained protein images were measured under a light microscope to compare protein staining of Sil2 (left) and Eurotek (right) dressings compared to background controls. Bottom: mean intensity of protein adhered to the hydrocolloid and silicon dressings.

Figure 8

Left: image shows the right arm of a male participant. Blue box represents the area of skin where the silicone dressing was applied and removed from. Orange box represents where the hydrocolloid was applied and removed from. Right: the left torso of the same participant. Orange box represents where hydrocolloid was removed, and the blue box represents where silicone was removed from.

Figure 9

Top left: comparison of skin before and after patches were applied showed erythema. Top right: comparisons of skin before and after patches were applied showed skin stripping (detexturization). Bottom left: box and Whisker plots show interquartile ranges of skin response when grouped by body sites. Bottom right: Box and whisker plots showing interquartile ranges of skin response when grouped by participants.

Figure 10

Increase in skin TEWL beneath dressing over 6 and 24 h wear; error bars show standard error.