ASTM F604-94

1.1 This specification covers silicone elastomers intended for use as materials of construction for fabrication of medical devices.

1.2 Variations in ingredients, processing, and vulcanization (crosslinking/cure) systems of silicone elastomer are necessary to achieve the properties required in specific medical device applications.

1.2.1 An alphabetical/numerical code abbreviation is defined in this specification as what may be used to specify ingredients, crosslinking systems, processing conditions, and physical properties of many silicone elastomers used in medical device applications by a standard, abbreviated designation.

1.3 In all cases where the provisions of this specification are in conflict with those of the detailed specifications for a particular product, the latter shall take precedence.

1.3.1 When silicone elastomers are used in medical device applications where the materials requirements cannot be completely achieved by the technology prescribed in this specification, it may be necessary to adjust ingredients, processing, or cure systems to a greater extent to obtain the properties needed in these specific medical device applications.

1.3.1.1 When silicone elastomers are adjusted more extensively than prescribed in this specification, such adjustments shall be completely described and controlled in specifications for each specific material.

1.3.1.2 All sections of this specification that contain requirements pertinent to safety and effectiveness apply to all silicone elastomers used as materials of construction for medical devices, including those adjusted more broadly than defined in this specification.

1.4 While silicone elastomers have demonstrated excellent biocompatibility in medical device applications, the biocompatibility of silicone elastomers as a generic class has not been established. Many compositions and formulations are possible. Manufacturing practices, facilities, controls, process validation, and other considerations that ensure batch-to-batch duplication, assurance of identity, and quality of ingredients, as well as freedom from contamination or cross-contamination may vary widely within the silicone elastomer industry. Medical device manufacturers must ensure safety and effectiveness of each specific composition or formulation from each supplier in its intended applications. Historic, clinical, and biocompatibility data are pertinent prospectively only when all compounding, formulating, and fabrication are done in accordance with the provisions of Good Manufacturing Practice Regulations, which help ensure medical materials and devices are reasonably duplicated each time they are manufactured.

1.5 This specification is intended to assist in the development of specifications for formulated silicone elastomer compounds. It is also recommended for use in materials and finished device labeling to specify the type or types of silicone elastomers contained.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.