ASTM D1980 is also know as the Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical Devices. It offers multiple aging protocols to determine the effects of time on the sterile integrity of the packaging as well as the physical properties of the latter. While this guide does evaluate the sterile barrier system shelf life, it does not address the barrier system material and device interaction compatibility. Micom offers ASTM F1980 as part of its Medical devices testing services.
Use and factors to be considered
The aging of products or materials refers to the variation of their properties over time. The properties of interest are those related to safety and efficacy. An aging study is a procedure that seeks the determination of the behavior of a device under normal-usage conditions over a relatively long time by exposing the material for a short period of time to an external stress, which is more severe or more frequently applied than normal environmental stresses. Many accelerated aging techniques used for the qualification testing of polymer medical devices are based on the assumption that the chemical reactions involved in the deterioration of materials follows the Arrhenius’ law. According to the latter, aging processes increase as a function of the ambient temperature. This function states that any chemical reaction will double its rate with each 10 oC increase. This ideal case would correspond to curve Q10=2 below. However, the value of the Q10 is not always “2”; using the Arrhenius reaction rate function with Q10 equal to two is a common and conservative way of calculating the aging factor. For additional information about Arrhenius law, please see; Heat Aging Testing.
Medical devices need to be able to be stored for an extended period without any decrease in performance that may influence safety and efficacy when used. The ability of product designers to predict in a precise way the changes in polymer properties is therefore crucial and this standard guide provides sufficient evidence for claimed expiry date until data from real time aging studies are available. The loss of sterile barrier system integrity can be the result of the deterioration of physical properties of the materials, the degradation of adhesive or cohesive bonds as well as the subsequent dynamic events during shipping and handling. Furthermore, a given polymer may have many functional chemical groups organized in various ways (glass, amorphous, crystalline) as well as additives, processing agents, catalyst, lubricants, residual solvents, corrosive gases and fillers. These elements combined with variations in end-use conditions and storage environment influence the degradation chemistry. However, ISO 11607-1:2006 states that «the packaging system must provide physical protection, maintain sterile conditions and integrity of the sterile barrier system to the point of use or until the expire date.»
Typical experimental parameters for ASTM F1980 testing
- Number of specimens/product: to be specified
- Room or ambient temperature: Must represent the actual product storage and use conditions. Typically between 20 oC and 25 oC.
- Accelerated aging temperature: To be specified, but typically below 60 oC since higher temperature may induce nonlinear changes.
- Accelerated aging factor: To be specified. It is calculated by the following equation:
TAA: Accelerated aging temperature (oC)
TRT: Ambient temperature (oC)
Q10: Rate of the chemical reaction, typically 2
- Humidity conditions: Although we consider this parameter to have an impact on the aging process, ASTM D1980 considers that moisture «is not related to aging of the materials».
The sterile barrier system that have been subjected to aging are evaluated for both physical properties and integrity to assess whether or not product properties were modified or adversely compromised compared to the unexposed one. Mechanical tests such as tensile properties and other physical tests tailored to your specific needs should be considered at different time intervals during the accelerated aging process.
Other test methods related to ASTM F1980:
Should you need guidance in deciding which test conditions should be used for your specific needs, please feel free to contact us.