Shelf-life/long-term stability

Enzyme-based optical sensor applications will be further described in this book. They are still the most widespread optical biosensors but work is needed to overcome limitations such as shelf life, long term stability, in situ measurements, miniaturization, and the marketing of competitive devices. 

Important steps during RM production are the control of properties that determine the quality of the final product and its long-term stability (see the overview of techniques in Table 2.4). As some of the methods discussed below, for example determination of homogeneity, stability and shelf life (expiry date) are also mentioned in other Chapters and in the interest of brevity the reader is referred to them for further details. 

These examples illustrate that, for many materials, the water content can be relatively high without leading to any material instability dmring shelf life, which depends on the water-bonding capacity of the material. When water is strongly retained, the water activity and thus the amount of free water will be low. It must be mentioned that this is quite contradictory to some former and still presently reported assumptions that the water content of CRMs should generally not exceed a rather low value, e.g. around 3 % for long-term stability of RMs. 

LONG-TERM STABILITY ANALYSIS 615 Therefore, the shelf life that should be applied to future batches is min 24 23 17 = 17 months. 

Drug products intended for storage below -20°C should be treated on a case-by-case basis. When available long-term stability data on primary batches do not cover the proposed shelf life granted at the time of approval, a commitment should be made to continue the stability studies postapproval to firmly establish the shelf life. 

Where the submission includes long-term stability data from three production batches covering the proposed shelf life, a postapproval commitment is considered unnecessary. Otherwise, one of the following commitments should be made ... 

If the submission includes data from stability studies on fewer than three production batches, a commitment should be made to continue the long-term studies through the proposed shelf life and the accelerated studies for 6 months and to place at least three additional production batches on long-term stability studies through... 

The term food colloids can be applied to all edible multi-phase systems such as foams, gels, dispersions and emulsions. Therefore, most manufactured foodstuffs can be classified as food colloids, and some natural ones also (notably milk). One of the key features of such systems is that they require the addition of a combination of surface-active molecules and thickeners for control of their texture and shelf-life. To achieve the requirements of consumers and food technologists, various combinations of proteins and polysaccharides are routinely used. The structures formed by these biopolymers in the bulk aqueous phase and at the surface of droplets and bubbles determine the long-term stability and rheological properties of food colloids. These structures are determined by the nature of the various kinds of biopolymer-biopolymer interactions, as well as by the interactions of the biopolymers with other food ingredients such as low-molecular-weight surfactants (emulsifiers). 

Residual moisture is the low level of water, usually in the range of less than 1-3% (wt/wt), remaining in a freeze-dried product after the freeze-drying (vacuum sublimation) process [1-5] is complete. Nail [6] has described in-process methods to monitor the endpoint of freeze-drying using residual gas analysis, pressure rise, comparative pressure measurement, and product temperature measurement. Roy and Pikal [7] used an electronic moisture sensor inside the lyophilization chamber. Residual moisture [8] content is important in the final freeze-dried product because it affects the potency of the product, its long-term stability, and the official shelf life of the product. 

Commercialization of ODTs have to go through the final evaluation of long-term stability of the tablet matrix and packaging components per International Conference on Harmonisation guidelines. As the majority of ODT dosage forms on the market are sensitive to moisture, evaluation of moisture vapor transmission rate is an important parameter for assessing the shelf life of the product. 

The actual glucose sensor (a platinum electrode covered by three membranes ceUulose acetate, nylon net with covalently Unked GOD, and a polycarbonate protective membrane) is located in a miniaturized waU-jet cell. The sensor exhibits excellent performance, with a linear range extending up to 27 mM, thanks to the microdialysis dilution effect which was estimated to be 1 10 for the probe length used and for the flow rate set by the instrumentation. Long-term stability tests revealed that the biosensor stiU maintains its initial activity after incubations of 4 weeks at 45°C, 11 weeks at 37°C, and 32 weeks at room temperature (see Table 12.2). From these results, a shelf life of more than 2 years at 2-8°C can be extrapolated [119]. 

Long shelf life, long operation life, and long term stability. Day-to-day reproducibility. 

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