Drug Stability Test
The effectiveness and safety of drugs have attracted much attention, and it is also a livelihood issue that the country and the government attach great importance to. The stability of drugs will affect the efficacy and safety. In order to ensure the quality of drugs and storage containers, stability tests should be performed to determine their effective time and storage state. Stability test mainly studies whether the quality of drugs is affected by environmental factors such as temperature, humidity and light, and whether it changes with time and the correlation between them, and studies the degradation curve of drugs, according to which the effective period is presumed to ensure the effectiveness and safety of drugs when used. This article collects the standard information and test methods required for various stability tests for customers' reference.
First, drug stability test criteria
Storage conditions of drugs:
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Storage conditions (Note 2) |
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Long-term experiment |
25℃±2℃ / 60%±5%RH or 30℃±2℃ /65%±5% RH |
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Accelerated test |
40℃±2℃ / 75%±5%RH |
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Middle test (Note 1) |
30℃±2℃ / 65%±5%RH |
Note 1: If the long-term test condition has been set at 30℃±2℃/65% ±5%RH, there is no middle test; if the long-term storage condition is 25℃±2℃/ 60% ±5%RH, and there is a significant change in the accelerated test, then middle test should be added. And should be assessed against the criteria of "significant change".
Note 2: Sealed impervious containers such as glass ampoules can be exempted from humidity conditions. Unless otherwise determined, all tests shall be carried out in accordance with the stability test plan in the interim test.
The accelerated test data should be available for six months. The minimum duration of the stability test is 12 months for the middle test and the long-term test.
Store in refrigerator:
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Storage conditions |
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Long-term experiment |
5℃±3℃ |
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Accelerated test |
25℃±2℃ / 60%±5%RH |
Stored in freezer:
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Storage conditions |
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Long-term experiment |
-20℃±5℃ |
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Accelerated test |
5℃±3℃ |
If the product containing water or solvents that may be subject to solvent loss is packaged in a semi-permeable container, the stability assessment should be conducted under low relative humidity for a long period of time, or an middle test of 12 months, and an accelerated test of 6 months, in order to prove that the drug placed in the semi-permeable container can withstand the low relative humidity environment.
Containing water or solvents
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Storage conditions |
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Long-term experiment |
25℃±2℃ / 40%±5%RH or 30℃±2℃ /35%±5% RH |
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Accelerated test |
40℃±2℃;≤25%RH |
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Middle test (Note 1) |
30℃±2℃ / 35%RH±5%RH |
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Note 1: If the long-term test condition is 30℃±2℃ / 35%±5%RH, there is no middle test. |
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The calculation of the relative water loss rate at a constant temperature of 40℃ is as follows:
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Substituted relative humidity (A) |
Control relative humidity (R) |
Water loss rate ratio ([1-R]/[1-A]) |
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60%RH |
25%RH |
1.9 |
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60%RH |
40%RH |
1.5 |
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65%RH |
35%RH |
1.9 |
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75%RH |
25%RH |
3.0 |
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Illustration: For aqueous drugs placed in semi-permeable containers, the water loss rate at 25%RH is three times that of 75%RH. |
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Second, Drug stability solutions
Common drug stability test criteria
(Source: Food and Drug Administration, Ministry of Health and Welfare)
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Item |
Storage conditions |
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Long-term experiment |
25°C /60% RH |
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Accelerated test |
40°C /75%RH |
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Middle test |
30°C/65%RH |
(1) Wide temperature range test
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Item |
Storage conditions |
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Long-term experiment |
Low or sub-zero temperature conditions |
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Accelerated test |
Room temperature and humidity or low temperature conditions |
(2) Test equipment
1. Constant temperature and humidity test chamber
2. Drug stability test chamber
