Shelf-life, analysis

Donahue DW, Canitez N, Bushway AA. 2004. UV inactivation of coli 0157 H7 in apple cider quality, sensory and shelf-life analysis. J Food Process Preserv 28 368-387. 

Measurements were performed by using Besthorn s Hydrazone method which includes spectrophotometric analysis of quinones produced by enzyme. Enzyme electrodes were characterized in terms of maximum reaction rate (V ax) and Michaelis-Menten constant (KJ. In addition to kinetic parameters, stability of enzyme electrodes towards environmental conditions such as pH and temperature was investigated. Usage stability and shelf-life analysis were also examined. 

The Ru(II)-BINAP complex,2 [Et2NH2]+[Ru2Cl5(BINAP)2]-,3 is prepared as a toluene solvate in nearly pure form by this procedure. Typical crystallized product shows no other signals in the phosphorus NMR and gives a good combustion analysis. The material is quite stable and can be routinely handled in air. Storage under nitrogen will extend its shelf life, however. 

All reagents are traceable to certificates of analysis, are used within the posted shelf-life, and are from known suppliers. 

Stability is then considered as known and defined when Rf Uj is not significantly different from one. However the uncertainty calculated for the ratio RT based on the sum of CVs of two measurements carried out at two temperatures is a CV and not a confidence interval. In fact it does not consider the number of measurements carried out at the two temperatures and the use of this combined CV is not correct. In many cases it is an underestimation, as usually only two or three replicates are made. However, stability should be determined on the basis of a trend analysis, which is of importance also for any shelf life quantification see below. 

Most matrix reference materials are regarded stable for their application within a certain time frame see also Section 2.2. They are usually produced in large batches designed to ensure that the same material is available for a number of years as well as to spread the high cost of production over as many units as is possible. The stability is closely monitored from initial production by the producer lot numbers or even individual unit numbers are allocated and the producers closely monitor, by regular analysis, the condition and quality of their reference materials over time. Because of such careful control, and to minimize waste, the tendency has been for producers to give a usable life from receipt to the customer, commonly 12-24 months. However, the producers can give this shelf life expectancy only for unopened units. 

Johnson B., Headspace analysis and shelf life, Cereal Foods World 1997 42 752-754. 

Analysis Bottle material Bottle size Reagents in bottle Shelf life Notes... 

Isoelectric focusing also finds application in analysing the stability of biopharmaceuticals over the course of their shelf life. Repeat analysis of samples over time will detect deamidation or other degradative processes that alter protein charge characteristics. 

It has now been established beyond any reasonable doubt that quality of a drug product cannot simply be ensured by inspection or analysis, but a control system has to be built into, from the very beginning of manufacture of a drug. Besides effective quality control measures exercised in every aspects of production including environment, screening of raw materials, process controls, intermediate shelf-life of finished products the most important aspect is to assess the bioavailability of the active principle. 

An approach for analyzing data of a quantitative attribute that is expected to change with time is to determine the time at which the 95% one-sided confidence limit for the mean curve intersects the acceptance criterion. If analysis shows that the batch-to-batch variability is small, it is advantageous to combine the data into one overall estimate by applying appropriate statistical tests (e.g., p-values for level of significance of rejection of more than 0.25) to the slopes of the regression lines and zero-time intercepts for individual batches. If it is inappropriate to combine data from several batches, the overall shelf life should be based on the minimum time a batch can be expected to remain within the acceptance criteria. 

Long-Term and Accelerated Stability Data Show Little Change over Time and/or Variability Under this scenario, the proposed retest period or shelf life can be up to one and a half times as long as but not more than six months beyond the period covered by long-term data without the support of statistical analysis. 

The shelf life for a single batch is usually computed based on regression techniques. An appropriate approach to shelf life estimation when using regression analysis is by calculating the earliest time at which the 95% confidence limit for the mean intersects the proposed acceptance criterion [8]. A detailed description of shelf life calculations is provided in Sections 7.2.3 and 7.2.4. 

Data for which statistical analysis does not apply The proposed shelf life can be up to 1.5 times but should not be more than 6 months beyond the period covered in the stabihty study for the long-term data. This will require relevant supporting data to show that the drug product will meet all attribute acceptance criteria by the end of the proposed shelf life period. 

If significant change at any time during the six-month period of the accelerated (short-term) condition is observed, then extrapolation is not considered appropriate. If the long-term data show variability, the proposed shelf life can be verified by statistical analysis. 

This section considers the stability analysis of the long-term studies. The purpose of this section is to provide a set of fundamental statistical tools to calculate the shelf life for single and multiple packages and strengths. The statistical methods will be... 

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