What is the difference between accelerated aging and real-time aging?

Ⅰ. Accelerated Aging Testing

Accelerated aging testing simulates the long-term aging process of a product under natural conditions by increasing environmental factors such as temperature and humidity. Because elevated temperatures accelerate chemical reactions, products undergoing normal storage conditions will more rapidly exhibit changes in high-temperature environments. The purpose of accelerated aging testing is to assess a product's long-term stability in a shorter timeframe.

Advantages: A product's performance over its entire lifecycle can be determined in a short period of time, making it particularly suitable for products with a quick time to market.

Common Applications: Medical devices, pharmaceuticals, and electronics, especially when demonstrating product stability to meet regulatory requirements.

When is accelerated aging testing alone necessary?

Although real-time aging can provide more reliable long-term data, accelerated aging is still the only option in many cases, particularly in the following scenarios:

Quick Time to Market: During the development of certain products, market demands for faster time to market may force manufacturers to rely solely on accelerated aging data to save time.

Short-Term Use Products: For products with a short lifespan (such as some disposable medical devices), accelerated aging testing may be sufficient.

Regulatory Permission: Some regulations allow the use of only accelerated aging data under specific conditions, particularly for low-risk products.

Ⅱ. Real-Time Aging Testing

Different from accelerated aging, real-time aging testing is a long-term test conducted under normal storage conditions. This type of testing simulates the aging process a product would experience in actual use or storage. Real-time aging testing typically takes a longer time because the product is evaluated under conditions that closely resemble real-world conditions.

Advantages: It provides true performance data over the product's actual lifespan and is particularly suitable for products that are sensitive to external factors such as temperature and humidity.

Common Applications: Products subject to regulatory constraints, such as medical devices and pharmaceuticals, are particularly sensitive to environmental changes.

When is Real-Time Aging Testing Required?

Real-time aging testing is essential for certain high-risk medical products, particularly those requiring long-term storage and use, especially in the following situations:

Long Product Lifespan: For products with a design lifespan of more than three years, real-time aging testing can provide more accurate lifespan predictions.

High Product Sensitivity: For products that are extremely sensitive to environmental changes, such as pharmaceuticals and certain specialized medical devices, real-time aging can ensure their stability throughout their lifespan.

Regulatory Requirements: For example, the FDA requires real-time aging data for certain high-risk devices and pharmaceuticals.

Ⅲ. Why Both Accelerated and Real-Time Aging Are Performed?

In many cases, regulations and standards require simultaneous accelerated and real-time aging to ensure product stability throughout its lifecycle. Here are several key reasons for performing both types of aging tests:

1. Meeting Regulatory Requirements

Many international and national regulations, such as the FDA and ISO 13485. require dual validation of accelerated and real-time aging for certain high-risk medical devices and pharmaceuticals. This is to ensure product safety and effectiveness during long-term storage and use.

2. Providing Comprehensive Product Performance Data

Accelerated aging can provide a quick prediction of a product's long-term performance, but this is only based on extrapolation from models and accelerated conditions. Real-time aging verifies a product's long-term performance under real-world conditions. Combining the two provides more comprehensive data support for a product's long-term stability.

3. Addressing Unforeseen Aging Effects

Accelerated aging primarily models the effects of temperature. However, in real-world environments, other factors such as humidity, light, and oxygen also affect the aging process. Therefore, real-time aging can capture influencing factors that may be missed in accelerated aging.

IV. Combined Accelerated and Real-Time Aging Testing Process

Combining accelerated and real-time aging tests can provide the most comprehensive aging assessment for a product. The typical testing process is as follows:

1. Selecting Test Samples

Based on the product batch and specifications, select a sufficient number of test samples to ensure representativeness. Use some samples for accelerated aging and some for real-time aging.

2. Setting Accelerated Aging Conditions

According to the product characteristics, set the accelerated aging environmental conditions (typically high temperature and high humidity). Ensure that the conditions adequately simulate actual aging conditions.

3. Conducting Real-Time Aging Simultaneously

Under normal storage conditions, conduct real-time aging tests simultaneously, and record changes in product performance at different time points.

4. Data Recording and Analysis

Regularly check the product's physical, chemical, and functional properties, and compare the accelerated and real-time aging data to ensure that the results are consistent or within expectations.

Ⅴ.Differences Between Accelerated Aging And Real-time Aging Testing

1. Test Cycle and Cost

Accelerated aging testing:

The test cycle is relatively short, allowing test results to be obtained in a shorter time.

Due to the more demanding test conditions, this may result in higher testing costs.

Real-time aging testing:

The test cycle is longer because long-term observation is required under conditions close to real-world conditions.

The testing cost is relatively lower because the test conditions are simpler and no additional enhancement factors are required.

2. Reliability of Test Results

Accelerated aging testing:

Test results may be affected by the accelerated conditions, requiring appropriate post-test correction and verification.

Due to the shorter test cycle, it may not capture all details and changes during the long-term aging process.

Real-time aging testing:

Test results are closer to the product's actual performance in use, resulting in higher reliability.

It can capture details and changes during the long-term aging process, providing more comprehensive data support for the product's long-term stability.

3. Application Scenarios

Accelerated aging testing:

Suitable for products that need to be quickly put to market, such as medical devices, pharmaceuticals, and electronic products. This is particularly useful when demonstrating product stability to meet regulatory requirements.

Real-time aging testing:

Applicable to products sensitive to external factors such as temperature and humidity, such as certain medical devices and pharmaceuticals.

Applicable to products requiring long-term storage and use to assess their safety and effectiveness during such storage and use.