Context: Apertured polyethylene films (AF) have been used as a surface for sanitary pads for decades because they are compatible with the skin and keep the pad surface drier. A modified film (AF-plus) with improved fluid handling and a smoother, suppler texture has been developed. We hypothesized that these changes would improve both performance and skin compatibility. However, distinguishing the skin effects of materials that are inherently mild is a challenge.
Objectives: (i) To compare the skin irritation potential of pads with AF-plus modified film relative to the standard AF film and (ii) to assess the potential for the AF-plus film to induce delayed contact hypersensitivity.
Materials and methods: Pads bearing the AF-plus film were compared to pads with the standard AF film in a behind-the-knee (BTK) test, which assesses the combination of chemical irritation and frictional effects of materials applied to the popliteal fossa under a semi-occlusive bandage. Erythema on the skin surface was scored with the naked eye and subsurface tissue erythema was visualized and scored using cross-polarized illumination. Skin dryness was scored with the naked eye only. One-sided statistical evaluations were performed to test the hypothesis of AF-plus film superiority. The potential of the AF-plus film to induce delayed contact hypersensitivity was assessed by a human repeat insult patch test (HRIPT).
Results: Pads with the AF-plus surface were significantly milder to skin in the BTK test, producing lower levels of both surface and subsurface tissue erythema. Moreover, subjects with preexisting erythema on the skin surface at study start developed comparatively less erythema over the course of the study overall with the AF-plus pad compared to the AF pad. No significant difference in skin dryness was observed between product groups. The AF-plus pad showed no evidence of inducing delayed contact hypersensitivity.
Conclusions: The AF-plus pad was superior to the AF pad in terms of skin mildness as discerned by objectively scored surface and subsurface tissue erythema. In subjects with preexisting erythema, the AF-plus pad appeared to contribute less to the further development of inflammation under the test conditions. Given the compositional similarities in the two films, the results could point to more limited contribution of the AF-plus film to skin friction, one of the factors simulated by the BTK test protocol.