ASTM F2743-11

The shedding of the coating from a vascular stent can alter its clinical safety and/or therapeutic benefit. Clinical performance (for example, drug elution) may be affected by particulate generation from the coated stent system and coating defects. This document provides guidance for coating inspection and acute particulate characterization of drug eluting vascular stents. Information about the potential for shedding can be gained during bench testing. The general guidelines presented here may be used for writing detailed protocols for specific products at the various stages of the product development process. Such testing may be performed during device development, design validation testing, lot-release testing, and/or stability testing although different requirements may apply at each stage. These suggested methods may represent a reasonable simulation of clinical usage. When establishing the coating inspection and acute particulate characterization testing conditions, the current clinical usage/practice (for example, post-dilation, overlapping stents) and the instructions for use (IFU), as applicable, should be considered. While methods for chronic particulate characterization and coating inspection have not been established, these suggested methods may be helpful in the development of chronic methods. Testing in accordance with recommendations in this guide will generate data that may lead to further improvements in the method and its validation, as well as possible advancements in device design and performance. See also FDA Guidance for Industry and FDA Staff and AAMI TIR42:2010.

1.1 This guide describes recommended in vitro test procedures for coating inspection and acute particulate characterization of coated drug-eluting vascular (balloon-expandable and self-expanding) stent systems.

1.2 Recommended practices for coating inspection and acute particulate characterization include baseline (deployment) testing and simulated use testing. This guide describes the capture and analysis of particulates. This guide describes the inspection of the coated stent surface. This guide was developed for characterization and not intended for production release testing of coated drug-eluting vascular stent systems although some sections may be appropriate.

1.3 Chronic particulate characterization and coating inspection are not included herein.

1.4 Coating systems specifically designed to degrade or otherwise intentionally separate themselves from the permanent stent structure may not be fully addressed herein.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.