Drug substances stability study conditions

If stability samples have been put into the intermediate condition but have not been tested, these samples may be tested as soon as the accelerated study shows significant change in the drug substance. Alternatively, studies in the intermediate condition would be started from the initial time point. 

Drug substance stability is also addressed in analytical methods development validation studies that require a demonstration of selectivity as part of specificity testing. These results are included in CMC submissions in support of the analytical methods. In this testing, drug substance is commonly stressed with acid, base, oxidation, air, heat, light and other conditions to give rise to products that can be separated from the parent compound. 

Data to demonstrate the stability characteristics of both the drug substance and the drug product must be collected. Studies using three different batches of both substance and product in their respective containers/packaging must be conducted. Real-time data should be collected under conditions of temperature and relative humidity in line with the recommended storage. Conditions in different world climatic zones must be taken into consideration for cases where normal environmental... 

The storage conditions and the length of the studies should be sufficient to cover storage, shipment, and subsequent use. Both drug substances and products should be evaluated under storage conditions that test for thermal stability (temperature effect) and moisture sensitivity (humidity tolerance). 

Long-term testing Stability studies under the recommended storage condition for the retest period or shelf life proposed (or approved) are performed with several drug substance batches in the stipulate packaging. In the general case, the storage condition is at a temperature of 25°C and 60% relative humidity. 

Studies undertaken to elucidate the intrinsic stability of the drug substance. Such testing is part of the development strategy and is normally carried out under more severe conditions than those used for accelerated testing. 

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