Round robin study to evaluate the reconstructed human epidermis (RhE) model as an in vitro skin irritation test for detection of irritant activity in medical device extracts

Assessment of skin irritation is an essential component of the safety evaluation of medical devices. OECD Test Guideline 439 describes the use of reconstructed human epidermis (RhE) as an in vitro test system for classification of skin irritation by neat chemicals. An international round robin study was conducted to evaluate the RhE method for determination of skin irritant potential of medical device extracts. Four irritant polymers and three non-irritant controls were obtained or developed that had demonstrated their suitability to act as positive or negative test samples. The RhE tissues (EpiDerm™ and SkinEthic™ RHE) were dosed with 100 μL aliquots of either saline or sesame oil extract. Incubation times were 18 h (EpiDerm™) and 24 h (SkinEthic™ RHE). Cell viability reduction > 50% was indicative of skin irritation. Both the EpiDerm™ and SkinEthic™ RHE tissues were able to correctly identify virtually all of the irritant polymer samples either in the saline, sesame oil or both solvent extracts. Our results indicate that RhE tissue models can detect the presence of strong skin irritants at low levels in dilute medical device polymer extracts. Therefore, these models may be suitable replacements for the rabbit skin irritation test to support the biological evaluation of medical devices.