Formulation storage test

Note All formulations should be subjected to storage tests under various temperature and humidity conditions. 

Although accelerated storage testing has proved invaluable in the development of stable formulations, it is important that we consider some of the limitations of this technique. We must take care that the order of reaction is not different at the higher temperatures from that which occurs at room temperature. There are several cases where this might be so. For example, with complex... 

The detonation velocity of nitrate-o-ethylbenzene explosives is stable at low temperature (dry ice frozen to -30 °C, velocity was 7,070 m/s at glass tube with inner diameter 19 mm and wall thickness 1.5 mm), and the velocity will not change after 1 month storage (tests were conducted in a glass mbe with 10 mm inner diameter and 1 mm wall thickness, and the detonation velocities were measured as 6,840 and 6,770 m/s). The formulations of nitrate-o-ethylbenzene and their brisance are given in Fig. 7.3. 

After the first RCM, the participants formulated individual test plans specific to their spent fuel storage basins. A general test protocol for conducting the programme was provided by the IAEA. This protocol included instructions for preassembly, assembly and immersion of the corrosion racks in the storage basin, exposure intervals, and removal and examination. 

The suspension stability of the formulation was tested over the course of 2 months using particle size as the main indicator (Fig. 15.3). Storage in the presence of 2% albumin, or in buffer after a single antoclave cycle of 20 min, had no adverse effect on stabihty of the particle suspension. 

The main physico-chemical characteristics that need to be controlled in cosmetic emulsions are their formation and stability on storage as well as their rheology, which controls spreadability and skin feel. Most cosmetic and toiletry brands have a relatively short life span (3-5 years) and hence development of the product should be rapid. Consequently, accelerated storage testing is needed to predict stability and change of rheology with time. These accelerated tests represent a challenge to the formulation chemist. 

The B-series of silica samples were also blended with rubber and the compound formulation is shown in Table 17.6. The uncured gums were then tested according to ISO 5794-2 1998. The uncured samples were tested using a Mooney viscometer and an RPA, which measures the dynamic mechanical properties as the samples cure. Figure 17.7 shows the results of these two tests for the Mooney viscosity at 100°C, storage modulus, loss modulus, and tan 8. 

A reference substance can be either the formulated test substance suspended in water or the technical or analytical grade active ingredient of the test substance dissolved in a solvent. The reference substance is normally used to fortify field matrices to develop information on the field storage stability of the active ingredient. Reference substances should be prepared at the analytical facility where the matrix samples are to be analyzed. Methods to prepare reference substances for field use will be discussed later. 

Once the optimal formulation and processing method have been determined and the most suitable packaging configuration decided, product stability tests may be commenced. The aim is to determine a shelf life and provide data that demonstrate the product s continued quality under the conditions of manufacture, storage. 

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