Shelf-life estimation temperature storage

Shelf Life Estimation for Drug Substances or Drug Products Intended for Room Temperature Storage... 

In temperature-accelerated studies, shelf life at a storage temperature 7 , is estimated from the shelf life at an elevated temperature T2, according to... 

Storage Charts of time and temperature of storage are important to control the increased levels of degradedness [6], Shelf life is defined as the amount of time in storage that a product can maintain quality and is equivalent to the time taken to reach 90% of the composition claim or have 10% degradation. The availability of an expiration date is assumed under specified conditions of temperature. Based on zero- and first-order reaction calculations, Connors et al. [45] show the estimation methods to determine the shelf life of a drug product at temperatures different from the one specified under standard conditions. 

The criterion for establishing oil deterioration was the rejection of an oil sample by a panel of trained consumers. The corresponding shelf-lives were estimated for the three temperatures (35, 45, and 60°C). These values were used to extrapolate shelf-life at 20°C (taken as room temperature). Storage temperature was found to have a marked influence on oil deterioration, even when bottled under inert nitrogen atmosphere. For example, an oil stored in the absence of light at 45°C is rejected by consumers after 102 days, compared with 1140 days estimated for oils stored at 20°C. 

It will be useful to estimate how far from the glass transition temperature an amorphous material can be stored to ensure that the material is kinetically stable over the duration of shelf life. Several rules of thumb have been proposed, of which probably the best known is the Tg - 50 rule for estimating the required storage temperature (Hancock et al. 1995). If this temperature is far below room temperature, storage of the amorphous dmg at that temperature will not be practical, and alternative means of stabilizing the amorphous drug will be needed. (It should be noted that the Tg - 50 rule is a generalization based on concepts such as those detailed above. While many materials do not follow this rule, it is still a useful concept.)... 

Elevated temperature is often used to estimate the in-can stability of adhesives and sealant formulations. This is usually applied by a simple rule of thumb that says the reaction rate of the degradation mechanisms involved doubles for every 10°C increase in temperature, and therefore 1 week storage at 50°C approximates to 8 weeks at room temperature (20°C). Application of this rule will likely be conservative in the prediction of shelf life and must be verified by real-time validation testing conducted at room temperature for the targeted shelf life. 

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