Types of stability:
1-Chemical: chemical integrity and labeled potency
2-Physical: appearance, palatability, dissolution …etc
3-Microbiological: sterility
4-Therapeutic: activity remain unchanged
5-Toxicological: no increase in toxicity
Chemical stability:
Importance:
1-Selection of storage conditions: (temp. light, humidity)
2-Selection of proper container
3-Interaction when drugs are mixed together or with excipientsin the final dosage form.
Stability and expiration dating:
Most decomposition reactions are zero and first order reactions
Types of stability studies: depend on manufacturing phase and final use:
I-In the development phase: accelerated stability testing is carried out to predict shelf life and storage conditions. Real time studies should be started for confirmation.
II-In the registration process: results from both accelerated and real time studies should be submitted to the drug regulatory authority. World wide climatic zone studies can be done.
III-In the post-registration period: real time stability studies and those at climatic zones are used to approve expiry date and storage conditions.
