2020 Volume 10 Issue 2 Pages 69-78
Medical devices that come into contact with human body need to be evaluated for the biological safety according to ISO 10993 series. Although the ISO 10993 series defines several biological safety tests including cytotoxicity, irritation and sensitization tests, ISO 10993-1 “Evaluation and testing within a risk management process” requires that information on the chemical properties of biomaterials must be collected before conducting tests. The scheme for chemical characterization of biomaterials and the concept of toxicological threshold of concern (TTC) that may be able to promote animal welfare and reduce the testing costs are newly specified in ISO 10993-18 and ISO/TS 21736, respectively, and hence, chemical analysis for biological safety assessment is expected to be increasingly used in the near future. Chemical analysis is very useful for assessing elution amounts from medical devices and the exposure amounts to human when the target chemical is known. On the other hand, since raw material suppliers do not disclose all compositions including impurities, available information for chemical analysis is limited. Therefore, TTC approach is used for comprehensive qualitative and quantitative analyses for medical devices, but there are several and critical problems in current extractables and leachables (E & L) analysis using for the approach. In this section, the problems of the current E & L analysis are introduced, such as the concept of hazard analysis, sensitivity for detection, analysis method and so on. In addition, we propose a strategic analysis package that is different from current E & L analysis and available as alternative for genotoxicity and sensitization tests, according to TTC approach and the novel concept for dermal sensitization threshold (DST).
