Temperature of storage

Storage of specimens at near in-place temperatures (2°C-5°C) to prevent the growth of bacteria and chemical changes is recommended by most workers (Richards and Parker, 1968 Lee and Clausner, 1979 Lambert et al., 1981 Rau and Chaney, 1987). Comparative 

10-20 days Approximately 20% change in strength and maximum past pressure Arman and McManis (1976) 

5 months No change in shear strength for samples stored under water Hagerty (1974) 

1 year 10% loss in strength with 37-mm end plug Broms (1980) 

3 years No change in strength and Atterberg limits for samples wrapped in plastic sheets dipped in wax La Rochelle et al. (1986) 

---

The reaction rates are also dependent on the rate constants for the reactions at the temperatures of storage and curiug. 

One of the factors that will affect the stability data is the temperature of storage the higher the temperature, the shorter the time that will elapse before the fat becomes rancid. 

Lisiewska, Z., Kmiecik, W., and Shnpski, J., Contents of chlorophylls and carotenoids in frozen dill effect of nsahle part and pre-treatment on the content of chlorophylls and carotenoids in frozen diU (Anethum graveolens L.), depending on the time and temperature of storage. Food Chem., 84, 511, 2004. 

Many of the coagulation factors measured by global coagulation tests have limited stability, and the time and temperature of storage of sample will affect their measurements. Concepts of analyte stability and half-life in plasma extend to markers measured by immunoassay. Markers of platelet activation are affected by artifactual activation in vitro upon collection of the blood specimen. This section will highlight some of the nonanalytical variables that, if uncontrolled, can lead to spurious results and thus affect the interpretation of laboratory data. 

When talking about temperature control, what do we mean An example from everyday life is the storage of frozen food like pizza, ice cream, vegetables or others. In many cases, the package indicates the maximum storage time depending on the temperature of storage. If the food is not kept below a certain temperature it often has to be eaten at the day of purchase. 

Tstart = temperature of storage at the beginning of the time horizon... 

The reaction of neomycin with many compounds has been described in Section 3, hence numerous reports of neomycin incompatibility may be expected. Dale and Rundman have extensively reviewed the compatibility of neomycin with substances that may be encountered by the formulation pharmacist. Kudalker et al 03 have described the incompatibility of the antibiotic with rancid oils, and the incompatibility with bentonite, a montomorill-onite clay, has been reported by Danti and Guth306. The incompatibility with lactose, causing a discoloration of the mixture has been studied by Hammouda and Salakawy- 0 . The amount of browning produced was shown to be dependant on the initial pH of the solution. The rate of discoloration of the lactose/neomycin powder was directly related to the temperature of storage and the relative humidity of the atmosphere. Discoloration was overcome by addition of sodium bisulphite. 

For epidemic prevention and public health, rendering plants are bound by law to accept all perished animals and parts of animals in any stage of decomposition. Due to the nature of this raw material, containing fat and protein, its biological decomposition increases with time and temperature of storage, and very odoriferous compounds are produced. 

When stored at 10-20 °C, solutions of III had their greatest stabilities at an initial pH of 6. 33 When the temperature of storage was 30°C or more, the initial pH that provided the greatest stability of the oxime in an aqueous solution was 5. With that initial pH, the estimated half-life of III in solutions stored at 40°C was 9.6 yr. The half-life of I in solutions at the pH of greatest stability, initially 4, for storage at 40°C was estimated to be 9 yr. In a solution containing also atropine and benactyzine at a pH of 2.8, 1.42 of the protective potency due to III was lost after 1 yr at 25°C.134... 

Temperature of storage It has been established by a number of investigators notably Will [24], Robertson [25], Farmer [26-28] and Hinshelwood [29] that all explosives undergo a thermal decomposition at temperatures far below those at which spontaneous explosion occurs. Therefore, decomposition reactions are of considerable importance in determining stability of explosives and it can be determined by measuring their rate of decomposition at elevated temperatures. 

A detailed account of the compatibility and stability of explosives-definition, implications and effect of various parameters such as temperature of storage, chemical constitution of explosive vis-a-vis other ingredients, sunlight and electrostatic discharge etc has already been given in Chapter 1 (Section 1.4.1). In this section, the test methods used to determine compatibility and stability are discussed. 

Analytical methods for the determination of malonaldehyde are particularly well developed. 2-Thiobarbituric acid in the presence of trifluoroacetic acid reacts with malonaldehyde to give a product whose absorption at 530 nm is proportional to the irradiation dose up to 400 rads. This reaction is proposed as a test for determining the absorbed dose, provided that the humidity of the sample, date of irradiation, and the temperature of storage are known.152 168 173 An alternative method is the reaction of malonaldehyde with 2-methylindole.174 The same reaction has also been used for the determination of deoxy sugars, but this requires oxidation with periodate to give malonaldehyde.175,176... 

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. 

Transfer of substances will also depend on the time and temperature of storage and/or processing or heating of food in 2° packaging. For a given substance, the lower the temperature, the lower the rate of transfer will be and, conversely, the higher the temperature, the higher the rate of transfer. 

Moisture retained within the stopper could effuse out and enter the lyophilized plug, thus increasing its residual moisture over time. It is reasonable to suppose that the temperature of storage might influence the rate of effusion. As mentioned in Section 3.3, elevated temperatures are often used to screen formulations and predict their shelf lives based on potency and other physicochemical stability parameters. It is therefore important to know whether the residual moisture of the lyophilized product stored at higher temperatures is comparable to that for the same product under the regular storage conditions. 

We monitored the residual moisture of a protein product at different temperatures to evaluate its dependence on the temperature of storage. The stoppers were prepared by our normal manufacturing process, which had previously been optimized for occluded water removal. The product was placed at 5°C, the normal storage condition, and 25°C, an accelerated stability condition. Residual moisture in the 5°C samples was monitored for 36 months in the 25°C samples, for 12 months. The data are plotted in Figure 2. Residual moisture increased slowly in the 5°C samples from the initial value of 0.5% to about 1.0% in 36 months. In contrast, residual moisture rose much more rapidly at 25°C, attaining a value of 1.8% in 12 months. The data were fitted to a straight line and the slopes of the curves were calculated. Whereas the slope of moisture uptake at 5°C was only 0.02% per month, that at 25°C was 0.11 % per month. In other experiments (data not shown), we have found that moisture is gained at an even faster rate at 37°C (approximately 0.50% per month). 

Temperature of storage is important in maintaining the ascorbic acid content of potatoes. In general, potatoes are stored at relatively high temperatures (40-50°F), which results in better ascorbic acid retention as well as better quality (67). 

---