This document provides general principles for the systematic evaluation of the potential and observed degradation of medical devices through the design and performance of in vitro degradation studies. Information obtained from these studies can be used in the biological evaluation described in the ISO 10993- series. This document considers both materials designed to degrade in the body as well as materials that are not intended to degrade. This document is not applicable to: a) evaluation of degradation which occurs by purely mechanical processes; methodologies for the production of this type of degradation product are described in specific product standards, where available; NOTE Purely mechanical degradation causes mostly particulate matter. Although this is excluded from the scope of this document, such degradation products can evoke a biological response and thus need to undergo biological evaluation as described in other parts of ISO 10993. b) leachable components which are not degradation products; c) medical devices or components that do not contact the patient's body directly or indirectly.