Stability testing purpose

The purpose of stability testing is to assess the effects of temperature, humidity, light, and other environmental factors on the quality of a drug substance or product. The data produced are used to establish storage conditions, retest periods, shelf loss, and to justify overages included in products for stability reasons. The most useful equation relating temperature and reaction rate is the Arrhenius equation. This equation (27) may be integrated and rewritten as Eqs. (31) and (32). 

It should be emphasized that the results from RSST experiments use simplified calculation methods and give estimated values for stability and vent sizing. For large scale purposes, more dedicated and accurate measuring techniques may be needed for further hazard evaluation determinations. Due to the relatively recent development of this apparatus, comparison with other stability test methods is not yet comprehensive. 

In applications for static purpose, phosphoric add fuel cells have been constructed on a large scale for mainly test purposes. They have shown commerdal level performance and stability. More advanced types of fuel cells like molten carbonate fuel cells and solid oxide fuel cells are also under development for this purpose but are %t to reach that level. 

In Ref 3 is also described on pp 29-31 the so-called Reactivity Test. The purpose of this test is to determine which materials might cause deterioration, or even hazard, when brought in contact (ot stored together) with the explosive to test. The test involves the same procedure and apparatus as the vacuum stability test at 100°. A detailed description of the procedure is given on pp 30-31 of Ref 3... 

New Molecular Entity — An active pharmaceutical substance not previously contained in any drug product registered with the national or regional authority concerned. A new salt, ester, or noncovalent bond derivative of an approved drug substance is considered a new molecular entity for the purpose of stability testing under this guidance. 

The dibasic calcium phosphate dihydrate example discussed above is probably an extreme example of the instability of an excipient relating to the release of water. But many excipients exist in a hydrated state, and heating them for the purposes of compatibility studies, or accelerated stability testing, can cause any free water, and sometimes other types of water, to be released, which can then influence any potential interaction, or even interact itself with the drug. 

Devel Section Rept No 8 (1957) (Storage stability tests of colloidal LA for use in low energy electric detonators) 19)Purchase Description X-PA-PD-1217(1957) (Tentative spec for Type I and Type II LA s used in the US for military purposes) 20)K.J.Holloway, G.W.C. Taylor A.T. Thomas, ERDE Rept No 7/R/58(l958) (Prepn and props of RD-1343 lead azide) 21)R.L.Wagner, PicArsn... 

There are many other variations of the heat test.101 They are sometimes called stability tests, but most of them, it will be noted, involve the self-catalyzed decomposition of the sample in an atmosphere of air or of red fumes. They indicate the comparative stability only 6f materials which are physically alike. True indications of the stability of nitric esters are to be secured only by studying the decomposition of the substances in vacuum. For this purpose the 120° vacuum stability test is most generally preferred. 

According to the ICH guideline on stability testing, the purpose of stress testing is twofold [45]. First, it can be used to predict the stability of the molecule and from the degradation products establish degradation pathways. Second, it can validate the stability-indicating capability of the analytical... 

More often we are not interested so much in the exact rate of decomposition as we are in how a particular explosive compares to others in its storage life. For that purpose, much simpler tests are run, such as the thermal stability tests. 

This is a useful guide to the physical stability of suspensions. If freeze—thaw cycling or elevated temperature exposures are chosen for physical stability testing, companion samples of a closely related marketed suspension should be included in the testing protocol for comparison purpose because pharmaceutical suspensions are not normally designed to withstand temperature extremes during storage (15-30°C optimum). 

Stability testing is required by the FDA as part of the NDA for bulk drug substance and drug product. The purpose of stability testing is to establish a shelf life for the drug product, the period during which it is therapeutically useful. The decrease in potency must not exceed 10% over the shelf life [24]. A preferred shelf life is two years [24,25]. 

The ICH Guideline on Stability Testing of New Drug Substances and Products provides some guidance on stress testing or purposeful degradation ... 

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