Stability shelf life extension

It was felt that, in addition to the rigidity of the partially cyclized backbone, the extensive hydrogen bonding capability of the quinacridone segments would have to be modified if soluble systems which could be processed were to be obtained. Other considerations included preventing the evolution of volatile byproducts with suitably chosen cure chemistry and stability (shelf life) of the intermediate polymer. 

Where a large pack size is provided, it might be necessary to undertake more extensive in-use testing and/ or to restrict the in-use shelf life once the container has been opened. In addition to preservative efficacy testing the chemical stability of antimicrobial preservatives should also be investigated over the unopened and in-use shelf lives of the product. 

An extension of an expiration dating period based on (1) data obtained under a new or revised stability testing protocol that has not been approved in the application or (2) full shelf life data on pilot scale batches using an approved protocol. 

A projection of shelf life should be included to document the recommendation for the expiration date. Although accelerated stability data are frequently used to support expiration dating for up to 24 months, extension of dating beyond 24 months is based on real-time test results. 

Emulsions are used extensively in the food, pharmaceutical, and cosmetics industries, where their most important properties include stability (both physical and qualitative), rheology, reactivity, shelf life, texture, appearance, and flavor. All of these properties are affected by droplet size and/or size distribution [107,108], which in turn are functions of the method of production. Because emulsions are thermodynamically unstable, they require energy input for production and usually rely on a stabilizing agent (emulsifier, surfactant) to remain stable over long periods [109]. 

Products containing less stable active ingredients and formulations not suitable for experimental studies on storage at elevated temperature (e.g., suppositories) will need more extensive realtime stability studies. The proposed shelf-life should then not exceed twice the period covered by the real-time studies. 

Thermogravimetry (or thermogravimetic analysis, TGA) is one of the oldest thermo-analytical procedures and has been used extensively in the study of polymeric systems. The technique involves monitoring the weight loss of the sample in a chosen atmosphere (usually nitrogen or air) as a function of temperature. It is a popular technique for the evaluation of the thermal decomposition kinetics of polymeric materials and hence provides information on thermal stability and shelf life. However, it is well known for its ability to provide information on the bulk composition of polymer compounds. 

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