Stability studies store the product under defined temperature and humidity conditions to set its shelf life. Under ICH Q1A(R2), the general case uses long-term storage at 25 °C/60% RH or 30 °C/65% RH and accelerated storage at 40 °C/75% RH. Products for hot and very humid regions such as India (climatic Zone IVb) use 30 °C/75% RH for long-term storage.
Storage conditions for the general case
| Study | Storage condition | Minimum period at submission |
|---|---|---|
| Long-term | 25 °C ± 2 °C / 60% RH ± 5% RH, or 30 °C ± 2 °C / 65% RH ± 5% RH | 12 months |
| Intermediate | 30 °C ± 2 °C / 65% RH ± 5% RH | 6 months |
| Accelerated | 40 °C ± 2 °C / 75% RH ± 5% RH | 6 months |
The intermediate study is needed when long-term storage is at 25 °C and a significant change occurs under accelerated conditions.
Climatic zones
Long-term conditions depend on where the product will be marketed. India falls in Zone IVb (hot and very humid), where long-term testing is at 30 °C ± 2 °C / 75% RH ± 5% RH. Always confirm the conditions required by the regulator of each market.
Other storage categories
- Refrigerated products: long-term at 5 °C ± 3 °C, accelerated at 25 °C/60% RH.
- Frozen products: long-term at −20 °C ± 5 °C.
- Semi-permeable containers: tested at lower humidity to assess water loss.
Testing frequency
For a proposed shelf life of at least 12 months, long-term samples are usually tested every 3 months in the first year, every 6 months in the second year, and yearly after that. Accelerated studies usually include at least three points, such as 0, 3 and 6 months.
What to test
Attributes likely to change and to affect quality: appearance, assay, degradation products, dissolution, water content, and microbial quality where relevant. Use validated stability-indicating methods.
A consolidated revision of the ICH Q1 stability guidelines is in progress. Check the current version before designing a regulatory study.
Frequently asked questions
What are accelerated stability conditions?
40 °C ± 2 °C and 75% RH ± 5% RH, usually for 6 months.
Which climatic zone is India?
Zone IVb, hot and very humid. Long-term stability testing uses 30 °C/75% RH.
How many batches are needed for stability studies?
Formal studies for registration usually use at least three primary batches of the drug product.
Related
Need help with your project?
Book a free 20-minute consultation. We reply within 1 working day.
More in Formulation & lab
How to calculate the f2 similarity factor: a worked example
The f2 similarity factor compares two dissolution profiles on a scale where 100 means identical. An f2 between 50 and 100 means the profiles are…
Formulation & labSetting up a formulation R&D lab: equipment checklist
A formulation R&D lab needs equipment in six groups: dispensing, processing for your dosage forms, physical testing, analytical instruments,…