Toxicological Assessment of Mask Adhesive with Respect to Skin Contact
Mask adhesive is a polymeric adhesive intended to be used in medical devices with skin contact. According to the International Organization for Standardization (ISO) 10993-1, there are three main toxicological endpoints in the case of skin contact which need to be assessed: cytotoxicity, skin irritation (or intracutaneous reactivity) and sensitization. We have not conducted animal testing with Mask adhesive itself in order to assess its toxicological properties and suitability for skin contact applications. Instead, this assessment is based on safety testing results obtained with dry films of different adhesives (Formulation A and B) which are considered representative for Mask adhesive. Furthermore, a human irritation study was conducted with Mask adhesive. The test polymeric adhesive A is a solvent based adhesive which requires a drying step at elevated temperatures leading to the evaporation of solvent. Therefore the resulting polymeric adhesive is similar in composition to Mask adhesive and was tested for skin irritation and sensitization. The differences are not considered toxicologically relevant. Cytotoxicity was performed with Formulation B, an almost identical formulation to Mask adhesive with differences in ingredient concentration <1% and data are summarized below.
The cytotoxicity of an almost identical formulation refer to as Formulation B, where differences were not considered toxicologically relevant, was tested in accordance with ISO 10993-5 and applying an elution approach. The elution was carried out for 24 hours at 37˚C using Minimal Essential Medium (MEM). The undiluted extract of the representative formulation when applied to confluent monolayers of L-929 mouse fibroblast cells for 48 hours did not cause any cell lysis or cell toxicity while positive and negative controls performed as expected. Thus, it can be concluded from this test that the polymeric adhesive is not cytotoxic.