Prediction of stabilities

Calculations of mutual locations of poles and zeros for these TF models allow to trace dynamics of moving of the parameters (poles and zeros) under increasing loads. Their location regarding to the unit circle could be used for prediction of stability of the system (material behavior) or the process stationary state (absence of AE burst ) [7]. 

Garrett, E. R. (1956), Prediction of stability in pharmaceutical preparations III. Comparison of vitamin stabilities in different multivitamin preparations. /. Am. Pharm. Assoc. Sci. Ed., 45,470-473. 

However, its high ash content and its high quantity of inert materials put it in a category of coals where predictions of stability are difficult. A comparison of the FSI values (Table II) for the +1% inch material (point 5 in Figure 5) with the 1% x Vi inch coal (point 6) suggests that the stability factor of the first-mentioned coal should be lower. This comparison substantiates to some degree the predictions made concerning the +1% inch coal. It is possible that the pitted or mylonitized component, because of its open porous structure, is more susceptible to oxidation than is the more normally textured vitrinite, and this could explain the apparently deleterious effect that this material has on coke quality. 

Garrett, E.R. Prediction of stability in pharmaceutical preparation MHm. Pharm. Assoc. Sci. Ed. 

An important aspect of the prediction of stabilities by molecular mechanics calculations is that all possible isomers and conformers have to be considered. With mac-... 

Stress testing is an important tool for the prediction of stability-related problems. The results of stress testing can be useful to many areas of pharmaceutical research and development beyond the obvious areas of analytical, formulation, and packaging development. Well-designed stress-test-... 

In this chapter, considerations are described for conducting comparative stress stability studies. Examples are presented to illustrate considerations and approaches for using stress conditions to compare sample stability. Finally, a statistical modeling approach is described, whereby the stability of a labile compound is modeled as a function of moisture and temperature. While requiring more time than some stress condition studies, this approach allows prediction of stability behavior over a wide range of conditions and ultimately saves time by eliminating the need for additional studies. 

A practical rule of thumb is that the rate of change doubles with every 10° rise in temperature. However, stability tests are rarely run at temperatures exceeding 50°C, since too drastic deviations from normal storage conditions cause distortions in the predictions of stability. 

Garrett ER, Carper RF. Prediction of stability in pharmaceutical preparations color stability in a liquid multisulfa preparation. JAPhA 1955 44 515-518. 

Garrett ER, Prediction of stability in pharmaceutical preparations, vitamin stability in liquid multivitamin preparations. JAPhA 1956 45 171-178. 

Wang, M. Ueda, H. Nagai, T. Simple prediction of stability constants for inclusion complexes of P-cyclodextrin with various drug molecules using P-cyclodextrin bonded phases (Cyclobond 1 Column). Drug Dev. Ind. Pharm. 1990,16 (4), 571-579. 

A number of silicone polyether copolymers were studied. These are detailed in Table 1 and are listed in order of increasing stability. To provide a tool for prediction of stability, 80% unhydrolyzed material was chosen as the stability limit A summary of these times is shown in Table 2 and Fig. 4. 

B. Y. Simkin, V. I. Minkin, and L. E. Nivorozhkin, Photo- and thermochromic spirans. IX. Predicting of stability of spiropyran structures and electron absorption spectra of their photo- and thermochromic isomers, Khim. Geterotsikl. Soedin. 1978, 1180-1192. 

Determination or prediction of stability in vivo (esp. of particle diameter)... 

Braiuca, R, Buthe, A., Ebert, C., Linda, R, Gardossi, L. Volsurf computational method applied to the prediction of stability of thermostable enzymes. Biotechnol. J. 2007, 2, 214—220. 

As mentioned at the beginning of the chapter, it is not feasible to cover all aspects of the pharmaceutical uses of DSC in the space available hence, emphasis has been placed on what are probably the most important applications of the technique. Clearly, DSC may be used as a simple screening method, for example, in the identification of polymorphs or glass transitions. However, there are numerous ways in which the approach can yield a more sophisticated analysis with comparatively little additional effort. Examples outlined here include the predictability of the thermodynamic parameters associated with polymorphic transitions and the assessment of the relaxation behavior of glassy pharmaceuticals. Both these examples have very tangible practical implications for the prediction of stability hence, such studies are not simply academic exercises but may be of considerable benefit in formulation optimization. 

E. R. Garrett, Prediction of stability in pharmaceutical preparations X. Alkaline hydrolysis of hydrocortisone hemisuccinate, J. Pharm. Sci. 51, 445-450 (1962). 

N. Okusa, Prediction of stability of drugs. III. Application of Weibull probability paper to prediction of stability, Chem. Pharm. Bull. 23, 794-802 (1975). 

H. Seki, T. Hayashi, and N. Okusa, An application of weighted least-squares analysis to Weibull probability paper for prediction of stability of drug products [in Japanese], Yakuzaigaku 40,201-207 (1980). 

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