Coleman, Kelly P; Grailer, Thomas P; McNamara, Lori R; Rollins, Beau L; Christiano, Nicholas J; Kandárová, Helena; De Jong, Wim H (2018-02-02)
A round robin study using reconstructed human epidermis (RhE) tissues was conducted to test medical device polymer extracts for skin irritation potential. Test samples were four irritant and three non-irritant medical device polymers. Five of these polymer samples were developed and two were obtained commercially. The three non-irritant samples were comprised of 100% 80A polyurethane, one-part silicone, and polyvinyl chloride (PVC). The polyurethane samples were made using a hot-melt process, while the silicone samples were created by mixing and casting. The PVC samples were commercially produced sheets. The four irritant samples were comprised of one-part silicone and 25% heptanoic acid (HA), two-part silicone and 15% sodium dodecyl sulfate (SDS), PVC and 4% Genapol® X-100, and PVC and 5.8% Genapol® X-080. The HA, SDS, and Genapol® X-100 samples were produced using the mixing and casting method, while the Genapol® X-080 sheet samples were obtained commercially. During development, irritant polymer samples were extracted using polar and non-polar solvents that were subsequently analyzed chemically. Samples with sufficient levels of extracted irritants were tested on RhE tissues to confirm their irritation potential. Polymers that passed this screening test were used in the round robin study described elsewhere in this special edition.
Kandarova, Helena; Willoughby, Jamin A; De Jong, Wim H; Letasiova, Silvia; Milasova, Tatiana; Bachelor, Michael A; Breyfogle, Bridget; Handa, Yuki; De la Fonteyne, Liset; Coleman, Kelly P (2018-02-10)
Assessment of dermal irritation is an essential component of the safety evaluation of medical devices. Reconstructed human epidermis (RhE) models have replaced rabbit skin irritation testing for neat chemicals and their mixtures (OECD Test Guideline 439). However, this guideline cannot be directly applied to the area of medical devices (MD) since their non-toxicity assessment is largely based on the testing of MD extracts that may have very low irritation potential. Therefore, the RhE-methods previously validated with neat chemicals needed to be modified to reflect the needs for detection of low levels of potential irritants. A protocol employing RhE EpiDerm was optimized in 2013 using known irritants and spiked polymers (Casas et al., 2013, TIV). In 2014 and 2015 MatTek In Vitro Life Science Laboratories (IVLSL) and RIVM assessed the transferability of the assay. After the successful transfer and standardization of the protocol, 17 laboratories were trained in the use of the protocol in the preparation for the validation. Laboratories produced data with 98% agreement of predictions for the selected references and controls. We conclude that a modified RhE skin irritation test has the potential to address the skin irritation potential of the medical devices. Standardization and focus on the technical issues is essential for accurate prediction.
Kandárová, Helena; Bendova, Hana; Letasiova, Silvia; Coleman, Kelly P; De Jong, Wim H; Jírova, Dagmar (2018-02-17)
Several irritants were used in the in vitro irritation medical device round robin. The objective of this study was to verify their irritation potential using the human patch test (HPT), an in vitro assay, and in vivo data. The irritants were lactic acid (LA), heptanoic acid (HA), sodium dodecyl sulfate (SDS), Genapol® X-80 (GP), and Y-4 polymer. Dilute saline and sesame seed oil (SSO) solutions of each were evaluated using a 4 and 18 h HPT and the EpiDerm™ SIT-MD RhE assay; results were then compared to existing rabbit skin irritation test data. Results from the 4 h HPT were negative in most cases except for GP and SDS, while the 18 h HPT also identified some LA, HA, and GP samples as irritants. EpiDerm™ SIT-MD correctly identified all irritants except GP in SSO due to limited solubility. Data from cutaneous rabbit irritation tests were negative, while all intracutaneous results were strongly or weakly positive except for the most dilute GP solutions. These findings indicate that EpiDerm™ SIT-MD results correlate with those from the rabbit intracutaneous test and confirm that RhE assays are suitable replacements for animals in evaluating the tissue irritation potential of medical devices.
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