Eurofins’ commitment to alternative methods for Medical Device Testing

Paolo Pescio, Technical Referent, Eurofins Medical Device Testing Italy, PaoloPescio@eurofins.com

Skin irritation is considered an essential endpoint for the biological evaluation of medical devices. Reconstructed human epidermis (RhE) are widely used to assess skin effects for chemical and cosmetic products while the current version of ISO 10993-10 “Biological evaluation of medical devices - Part 10: Tests for irritation and skin sensitisation” still includes in vivo tests.

Two Eurofins Medical Device Testing laboratories in Milano and Munich, along with 17 other laboratories were involved in an international Round Robin Study aimed to evaluate the RhE method for determination of skin irritant potential of medical device extracts.

Two models (MatTek EpiDerm™ and SkinEthic™ RHE) were used during this study.

Four irritant and three non-irritant polymers were specifically prepared and used as positive and negative samples. The samples were extracted according to ISO 10993-12 “Biological evaluation of medical devices - Part 12: Sample preparation and reference materials,” using a surface/volume ratio of 3cm2/ml or weight/ volume ratio of 0,2g/ml, at a temperature of 37±1°C for 72±2 hours under agitation with saline and sesame oil. 100μL of these extracts were dosed on the tissues.

After 18 hours (EpiDerm™) and 24 hours (SkinEthic™ RHE) of incubation at 37°C, 5% CO2, 95% humidified atmosphere, the viability of the tissues was determined. The viability was based on cellular reduction of MTT (methylthiazolyldiphenyl-tetrazolium bromide) and subsequent conversion to a purple formazan salt that is quantitatively measured by a spectrophotometer.

The cell viability reduction was calculated comparing treated tissue with negative control tissue. A sample was considered irritant in case of a cell viability reduction greater than 50%. All data showed that both the two RhE models were able to correctly identify irritant materials.

The results indicate that RhE tissue models can detect strong skin irritants at low levels in extracts of medical devices and these models are suitable replacements for in vivo irritation tests.

For more information, visit: www.eurofins.com/medical-device/