Assessment of cytotoxicity, skin and oral irritation of medical devices with hydrating properties: A case study

Ensuring the biocompatibility of medical devices (MDs) is essential for regulatory compliance and user safety. Under the evolving requirements of the European Medical Device Regulation (EU MDR 2017/745), products that come into contact with mucosal surfaces – such as those intended for oral use – must be supported by robust biocompatibility data. This study evaluated the in vitro cytotoxicity and irritation potential of the medical device hydropastilky in comparison with a benchmark product of similar composition and intended use, following ISO 10993 guidelines. Hydropastilky are designed to moisturise, protect, and support the regeneration of the oral and throat mucosa. Cytotoxicity was assessed using the Neutral Red Uptake (NRU) assay (ISO 10993-5). Hydro pastilky maintained cell viability above 50% at an extract concentration of up to 34.5%. Cytotoxic effects observed at higher concentrations were attributed to the strong hydrating and water-binding properties of the product, which posed challenges during extract preparation and likely impacted cell osmolarity as well. The benchmark product yielded comparable results. To generate more physiologically relevant data, irritation testing was performed using 3D reconstructed human epidermal (EpiDerm™) and oral mucosal (EpiOral™) models (ISO 10993-23). Both products demonstrated tissue viabilities above 50%, with most values exceeding 75%, confirming their non-irritant classification after prolonged exposure of 18 hours. These findings support the biocompatibility as well as biosimilarity of hydropastilky and the benchmark product and highlight the role of new approach methodologies (NAMs) in meeting modern regulatory expectations.