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:
|
