1-Accelerated studies:
- Purpose: using stress conditions to:
1- Identify weakness of an active ingredient or a formulation
2- Prediction of decomposition rate
3- Predict effects of storage and transport extreme conditions on the product
- Stress Conditions:
- Using temp. within the range (40-80 ºC)
- Temp. increased in 10 ºC steps: starting from (21, 25, 30 ºC), then 40, 50, 60, 70 or 80 ºC.
At least three temperatures are used
- -15 ºC, 2-8, freeze-thaw cycle can be used according to the product
- Humidity conditions and light should be considered
- High correlation between results of accelerated stability and long-term shelf studies are necessary.
- Special precautions for certain dosage forms
Solid dosage forms: stored in ovens in open containers until equilib. Is reached. And two more stress conditions cab be applied (21 ºC/45 % R.H, 25 ºC/60 %, 25 ºC/75%, 30 ºC/70 % or 40 ºC/75 % R.H).
Semi-solids: studies at temp. (4 -40 ºC). Freeze and 25 ºC is used if cold storage is required.
Liquid dosage forms: 10 ºC over room temp. and stored laying down and upside down to test compatibility with closure.
Frequency of testing: 0, 1, 2, 3 months or 6 months when possible.
2-climatic zones stability testing
- At climatic zones mentioned earlier
- Frequency: 0, 6,12, 24, 36, 48 and 60 months
- Most studies are carried out at 25 ºC/60 % R.H& 30 ºC/70 % R.H.
3-Long term study (Real time or shelf stability):
- Products are kept on shelves at room temperature (at normal storage conditions in practice).
- Samples taken for analysis every: 0, 3, 6, 12 months and 2, 3, 4 and 5 years.
- At least results of 6 months are required at the time of registeration.
4-Ongoing stability studies:
Samples are tested less frequently: e.g. every 6 or 12 months intervals for well established products.