Stability testing of Herbal Drugs evaluates the physical, chemical, and microbiological properties over time under different storage conditions.
The primary goal is to determine the shelf life and ensure the drug maintains its quality throughout its intended duration.
Objectives of Stability Testing
To determine the shelf-life of herbal formulations.
To assess changes in physical, chemical, and biological properties over time.
To recommend appropriate storage conditions.
Types of Stability Testing
Real-Time Stability Testing
Conducted under normal storage conditions for an extended period (e.g., 12-24 months).
Helps determine actual shelf-life.
Accelerated Stability Testing
Conducted at elevated temperature and humidity (e.g., 40°C & 75% RH) to simulate long-term degradation.
Used to predict shelf-life in a shorter time.
Stress Testing
Exposes the drug to extreme conditions such as heat, light, oxygen, and pH variations.
Identifies potential degradation pathways.
Stability Testing Process of Herbal Drugs
Selection of Batches
At least three batches of the drug, manufactured using the same process, are selected.
Storage Conditions
The drug is stored under different temperature and humidity conditions and tested at regular intervals.
Example: 25°C ± 2°C, 60% RH ± 5% RH for 12+ months (long-term study).
Stress Testing
Subjects the drug to extreme conditions (e.g., high heat, humidity, light exposure) to assess its stability.
Accelerated Stability Testing
Uses more severe conditions (e.g., 40°C ± 2°C, 75% RH ± 5% RH) to predict shelf life faster.
Photostability Testing
Assesses how light exposure affects the drug’s stability.
Parameters Tested
Physical: Color, odor, texture, and appearance.
Chemical: Active ingredient content, degradation products.
Microbiological: Contamination by bacteria, fungi, or yeast.
Packaging Considerations
Stability testing is conducted on the product in its intended marketing packaging to check for potential interactions.
Data Evaluation
Based on the collected data, the shelf life and optimal storage conditions are determined.
Stability Testing Conditions as per ICH & WHO
ICH Guidelines
Long-term:
25°C ± 2°C / 60% RH ± 5% RH OR 30°C ± 2°C / 65% RH ± 5% RH
Intermediate:
30°C ± 2°C / 65% RH ± 5% RH
Accelerated:
40°C ± 2°C / 75% RH ± 5% RH
For storage in a refrigerator:
Long-term: 5°C ± 3°C
Accelerated: 25°C ± 2°C / 60% RH ± 5% RH
For storage in a freezer:
Long-term: -20°C ± 5°C
No accelerated testing conditions.
WHO Guidelines
Long-term:
30°C ± 2°C / 75% RH ± 5% RH
Accelerated:
40°C ± 2°C / 75% RH ± 5% RH
Additional condition:
30°C ± 2°C / 65% RH ± 5% RH
Note: Stability testing conditions vary based on the climatic zones where the drug will be marketed.
Guideline | Testing | Standard Conditions | For Storage in a Refrigerator | For Storage in a Freezer | Additional Condition |
ICH | Long-term | 25°C ± 2°C / 60% RH ± 5% RH or 30°C ± 2°C / 65% RH ± 5% RH | 5°C ± 3°C | -20°C ± 5°C | - |
ICH | Intermediate | 30°C ± 2°C / 65% RH ± 5% RH | - | - | - |
ICH | Accelerated | 40°C ± 2°C / 75% RH ± 5% RH | 25°C ± 2°C / 60% RH ± 5% RH | No specific conditions | - |
WHO | Long-term | 30°C ± 2°C / 75% RH ± 5% RH | - | - | - |
WHO | Accelerated | 40°C ± 2°C / 75% RH ± 5% RH | - | - | 30°C ± 2°C / 65% RH ± 5% RH |
