Proof of concept testing of a positive reference material for in vivo and in vitro skin irritation testing

Abstract

In vivo and in vitro irritation testing is important for evaluating the biological safety of medical devices. Here, the performance of positive reference materials for skin irritation testing was evaluated. Four reference standards, referred to as Y-series materials, were analyzed: a polyvinyl chloride (PVC) sheet spiked with 0 (Y-1), 1.0 (Y-2), 1.5 (Y-3), or 10 (Y-4) parts of Genapol X-080 per 100 parts of PVC by weight. Y-1, Y-2, and Y-3 did not induce skin irritation responses in an in vitro reconstructed human epidermis (RhE) tissue model, as measured by tissue viability or interleukin-1α release, or in an in vivo intracutaneous response test using rabbits. In contrast, Y-4 extracts prepared with saline or sesame oil at 37°C and 50°C clearly elicited positive irritation responses, including reduced viability (< 50%) and significantly higher interleukin-1α release compared with the solvent alone group, in the RhE tissue model and an intracutaneous response test, where substantial necrosis was observed by histopathology. The positive skin irritation responses induced in vitro under various extraction conditions, as well as those elicited in vivo, indicate that Y-4 is an effective extractable positive control material for in vivo and in vitro skin irritation tests of medical devices. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2807-2814, 2018.

Characteristics to consider when selecting a positive control material for an in vitro assay

“…It may be that a single positive control material is not dissolvable in this range of solvent types, in which case it may be necessary to have more than one positive control material for an assay. For testing medical devices, it may be possible to have a single positive control material, such as a polymer, that can undergo chemical extraction using different solvents (Nomura et al, 2018;Coleman et al, 2018).…”

Proof of concept testing of a positive reference material for in vivo and in vitro sensitization testing of medical devices

“…ISO 10993‐12 and the Japanese guidelines list polyurethane (PU) films containing 0.1% zinc diethyldithiocarbamate and 0.25% zinc dibutyldithiocarbamate as positive controls for cytotoxicity studies. In a previous study, we evaluated positive reference materials for in vivo and in vitro skin irritation testing 11 . Additionally, 2,4‐dinitrochlorobenzene (DNCB, CAS No.…”

“…In a previous study, we evaluated positive reference materials for in vivo and in vitro skin irritation testing. 11 Additionally, 2,4-dinitrochlorobenzene (DNCB, CAS No. 97-00-7) has been used as a positive control (logP = 2.27, EC3 = 0.04 w/v% in LLNAs) for sensitization testing.…”