Accelerated Aging, Real Time Aging, & Stability Testing
Accelerated aging is performed on materials, products and packaging systems including packaged medical devices to provide atheoretical equivalent to real time shelf life. Real time aging is performed in parallel with accelerated aging in order to support and verify accelerated aging conclusions. It is recognized that in some cases products are technologically obsolete before a real time aging project can be completed.
The FDA provides guidance regarding medical device shelf lifedetermination and advises manufacturers to consider several parameters including chemical and physical parameters. The European Medical Device Directive (MDD) requires all sterile medical devices to have an expiration date. Documented shelf life evidence must exist to substantiate shelf life claims made by the manufacturer.
DDL carries out both accelerated aging and real time aging at both its Minnesota and California laboratories.
Van't Hoff's Theory for Accelerated Aging Testing
Accelerated aging testing is based on a thermodynamic temperature coefficient formulated by J.H. Van't Hoff that states "for every ten degree Celsius rise in temperature the rate of chemical reaction will double." However, since this formula is based on rate kinetics of a single chemical reaction, not on packages made up of various materials, the direct extrapolation of this theory to the aging of packaging materials must be used with caution.
The FDA and the package testing industry believe Van’t Hoff’s theory is useful in defining and justifying accelerated aging testing services. Temperature selection for an accelerated aging study should be determined by the temperature that avoids unrealistic failure conditions such as deformation due to melting. Real time aging must be performed in conjunction with any accelerated aging study to correlate the results found during accelerated aging.
The use of Van't Hoff's Theory for medical device products and packaging materials is supported by the following references:
- Hemmerich, Karl J., "General Aging Theory and Simplified Protocol for Accelerated Aging of Medical Devices" Proceedings MDM-West, January, 1997
- Clark, Geoffrey, "Shelf Life of Medical Devices" Guidance Document, Division of Small Manufacturers Assistance, CDRH, FDA, April 1991
You can also call us at 1-800-229-4235.
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