ASTM Standards and Testing of Flexible Materials Used in Healthcare

The ASTM (formerly the American Society for Testing Materials, currently ASTM International) is an organization that develops and publishes consensus technical standards for a broad range of materials, products, services, and systems. Today over 12,000 ASTM standards operate globally, helping to improve millions of lives every day. 

The Six Types of ASTM International Standards

Test Method   A procedure that produces a test result

Classification  An arrangement or division of materials, products, systems, or services into groups based on characteristics such as origin, composition, properties, or use

Terminology  Definitions of terms; explanations of symbols, abbreviations, or acronyms

Guide  A compendium of information or series of options that does not recommend a specific course of action

Specification  A requirement to be satisfied by a material, product, system, or service

Practice  Instructions for performing specific operations that do not produce a test result

ASTM Standards and Testing of Flexible Materials Used in Healthcare

Guidance for the industry involved in the production of flexible materials and adhesives provided by ASTM assures high quality and defines acceptable standards for each category tested.

An ASTM test method represents a consensus as to the best currently available test procedure for the use intended. It is supported by experience and adequate data obtained from cooperative tests. Test methods undergo periodic review to determine whether revisions are needed due to technological advances in manufacturing, testing, and use requirements.

Some examples of ASTM standards and testing related to single-use disposable medical devices and healthcare include:

Adhesive Strength - ASTM F2256 Strength Properties of Tissue Adhesives by T-Peel Testing

This test is to determine the adhesive strength of products used for tissue applications such as bandages, secondary dressings, wound closure, and surgical sealants. Before use in the clinical setting, the adhesive strength must be clearly defined.

If the adhesive is not strong enough the product may not provide adequate protection, leading to infection or poor healing. On the other hand, if the adhesive is too strong, the underlying tissue may be damaged when the product is removed.

Soft tissue substrates must be tested under conditions similar to that of the human body. This may involve submersion in a liquid bath or within a chamber or temperature-controlled enclosure set to body temperature (37C). The test is performed using pneumatic grips, controlled with a foot pedal, which ensures accurate results. 

Other ASTM standards for testing adhesive strength are ASTM F2255, ASTM 2258, and ASTM F2458.

Seal Strength - ASTM F88 Standard Test Method for Seal Strength of Flexible Barrier Materials

The disposable packaging of single-use sterile medical devices is preferred as they eliminate the need for sterilization and improve patient safety. However, package integrity and shelf-life are critical factors when considering whether to purchase, store, and employ these products.

ASTM F88 standard test method can be used to evaluate seal strength by testing different combinations of packaging materials and adhesives.

Tensile Testing - ASTM D882-12 Tensile Testing of Thin Plastic Sheeting

Thin films and plastics are versatile and cost-effective materials used in a variety of healthcare applications, such as:

• drug delivery
• implantable devices
• IV bags
• catheters
• tubing
• blister packs
• tapes and dressings

Tensile properties of thin plastic sheeting include tensile strength, yield strength, yield strain, strain at break, and modulus of elasticity. Challenges encountered when testing to standard include:

• accurate strain measurement
• specimen gripping
• reporting calculations in compliance with the standard

Watch our video series about biomedical innovation.

Penetration Resistance Testing - ASTM F1306 Slow Rate Penetration Resistance of Flexible Barrier Films and Laminates

This test relies on the ability to characterize penetration resistance, which is critical for products and applications that depend on certain levels of barrier integrity. This is especially crucial in the healthcare setting, where every care must be taken to prevent infection or contamination.

Burst Testing - ASTM F2054/F2054M-13 Burst Testing of Flexible Package Seals

The purpose of this test is to evaluate tendencies for package seal failure when exposed to a pressure differential, such as may occur during the processes of sterilization, transportation, or other handling. It is also used to test package seal strength during manufacturing and along the various stages of the package's life cycle.

In addition, ASTM International's committee on primary barrier packaging (F02) has approved a new guide that will help validate test methods for packaging of medical devices. The new standard (F3263) will provide guidance for pass/fail validation and variable packaging test methods. They have planned a presentation on this topic at the F02 committee meeting October 3-4, 2018, in Nice, France.

Conclusion

With the aim of "Helping our world work better," ASTM International sets the standards that enhance performance and give people confidence in the things they buy and use. Omnexus' article on stress, strain, and elastic modulus is an excellent resource specific to polymers for those wishing to gain a more comprehensive understanding of the underlying principles behind the tests mentioned above.