Accelerated Aging Manufacturers of medical products must demonstrate
that the product, in combination with its packaging components, performs efficiently,
safely and effectively throughout its intended shelf life. Accelerated aging should
be performed prior to distribution of the product.
Determining the
effects of aging on a package/product in real time is a lengthy process
that would severely delay market introduction of new products. Therefore, a standardized
test methodology was developed to accurately evaluate the environmental effect
of storage on a package/product during its expected usable shelf life.
Accelerated
aging, which subjects samples to elevated temperatures for specific periods of
time, is used to simulate the effects of real-time aging and provides data which
allows the manufacturer to accurately predict the effect of real-time aging on
his package/product. A product can be released to market based upon successful
accelerated aging of the package/product that simulates the period claimed for
product expiration. (1 year, 2 years, etc.) Concurrent with the accelerated aging
process, the manufacturer should still conduct real-time studies in order to substantiate
the data generated during the accelerated aging process.
Standard Test
Method: ASTM F1980; Accelerated Aging of Sterile Medical Device Packages
Methodology: Accelerated aging techniques are based on the assumptions
that the chemical reactions involved in the deterioration of materials follow
the Arrhenius reaction rate function. This function states that a 10° C increase
or decrease in the temperature of a homogenous process, results in approximately
a two times or ½ time change in the rate of a chemical reaction.
NOTE:
Accelerated aging is independent of humidity levels. Medical packages do not need
to be tested for the long-term effects of exposure to humidity. LONG-TERM exposure
to high or low humidity is not a requirement for accelerated aging unless the
packaging is known or suspected of being detrimentally affected by environmental
humidity. Routine environmental conditioning of packages per ASTM D4332, prior
to distribution simulation testing or prior to package testing will simulate the
effects of humidity on the packaging materials.
Definition
of variables
AAR | Accelerated Aging Rate |
AATD | Accelerated Aging Time Duration |
DRTA | Desired Real Time Aging |
AAT | Accelerated Aging Temperature |
AT | Ambient Temperature |
Q10 | Accelerated
Aging Factor |
| | Q10 = 2 - industry standard
Q10 = 1.8 - more conservative option |
Equations:
Step 1. AAR = Q10^ ((AAT – AT) /10)
Step
2. AATD = DRTA / AAR
Example: Time duration calculation
for accelerated aging of a medical product:
One
year shelf study at 55° C, where ambient temperature is 22° C and Q10=
2
Equation | Sample
Data |
| AAR = Q10 ^ ((AAT –AT) /10) | AAR
= 2 ^ ((55 - 22 / 10) = 9.85 |
| | DRTA = 1 year x 365 =
365 days |
| AATD = DRTA / AAR | AATD = 365 / 9.85 = 38 days
|
NOTE: 55° C and Q10 =2 are
the most commonly used factors for medical devices and medical packaging components.
- Pre-calculated heat aging table for different shelf life testing periods based
upon the above example:
