Assessment of test method variables for in vitro skin irritation testing of medical device extracts

Abstract

Skin irritation is an important component of the biological safety evaluation of medical devices. This testing has typically been performed using in vivo models. However, in an effort to reduce the need for in vivo testing, alternative methods for assessing skin irritation potential in vitro have been developed using a Reconstructed Human Epidermis (RhE) model. During the development of the protocol for the round robin validation of in vitro irritation testing for medical device extracts, it became clear that there were three points in the procedure where different options may be validated within each laboratory for routine testing: sample exposure time (18 vs 24h), SDS positive control concentration, and cytokine (IL-1α) release testing. The goal of our study was to evaluate the effect of these variables. EpiDerm™ tissues were exposed to extracts of three plain polymer samples, and four polymers embedded with known irritant chemicals. Exposures were performed for 18 and 24h. Resulting tissue viability was assessed by MTT reduction and IL-1α release was assessed by ELISA. Testing was also performed using various concentrations of SDS ranging from 0.5 to 1% (w/v). Overall, results were similar for samples tested and 18 and 24h, but the 18h exposure time has the potential to have an impact on the results of some sample types. IL-1α testing was shown to be useful to clarify conflicting tissue viability results. Use of a lower concentration of SDS as a positive control can help prevent issues that arise from excessive tissue damage often caused by 1% SDS.

In vitro biocompatibility study approaches to evaluate the safety profile of electrolyzed water for skin and eye

“…Measurement of IL-1a was described as additional data, which helps to ensure the correct classification of the tested material. 27 EpiDerm-SIT results are consistent with that of cell viability assay. Since the two-fold increase or greater compared to the NC was considered a positive irritation response according to the test protocol, StAEW samples were considered to have no potential for irritation.…”

“…Since the twofold increase or greater, compared to the NC, was considered a positive irritation response, the EAWs samples were considered to have no potential for irritation. 27 The PC was found to be significantly higher compared to all tested EAWs and NC ( Figure 6).…”

“…The concentration of IL-1a for each sample was calculated and a two-fold increase or greater, compared to the NC, was considered a positive irritation response according to EpiDerm-skin irritation test (SIT) protocol. 27 Results represent the mean + SD of three individual IL-1a released from the RhE tissues.…”

Skin irritation potential of graphene-based materials using a non-animal test

“…23 Accordingly, irritant treatments, either with SDS or SDBS, significantly increase IL-1α release, in line with literature data. [23][24][25][26][27] More importantly, FLG-SDS and FLG-SDBS induced a significant release of IL-1α, at levels comparable to those released by the relevant positive controls. This observation strengthens the conclusion that these materials can be considered as skin irritants and further supports the hypothesis that, for these materials, skin irritation may be due to the surfactant residues.…”

Efficacy Evaluation of Skin Care ProductsUsing PhabrOmeter

“…The huge variability discussed above and virtually lacking supply of human skin however call for substitutes. Without a consistent substrate, it is too difficult to extract meaningful analysis from across all the skin research efforts.Vitro-skin ® , manufactured by IMS, Inc., is a gelatin and protein based synthetic skin substrate designed to mimic the surface properties of human skin, and has been applied as a test substrate for the testing of sunscreen sun protectant factor (SPF), UVA and UVB protection, emollient and spreading etc [21][22][23] [24]…”