Isothermal stability

In a further study in isothermal stability testing, Wollmann et al. [86] indicated that the water of crystallization (5.53%) of niclosamide had no effect on stability, and the half-life claimed can be extended to 10 years. 

K. Ellstrom and H. Nyqvist, Non-isothermal stability testing of drug substances in the solid state, Acta Pharm. Sueu. 24, 115-122(1987). 

Table 16.19. Isothermal stability of carbazole-anhydride and poly-(N-vinylearbazole)-anhydride eo-polyeondensates. Adapted from J.Appl.Polym.Sci. 42, 1989 (1991), with permission of John Wiley Sons, Chichester...

When a metal reacts with a gas containing more than one oxidant, a number of different phases may form depending on both thermodynamic and kinetic considerations. Isothermal stability diagrams, usually constructed with the logarithmic values of the activities or partial pressures of the two non-metallic components as... 

Experiments were carried out in a 250 cm autoclave equipped with a magnetically driven impeller, a cooling coil and a pressure transducer. Induction heating of the reactor allows heating rate up to 1.5 K.s and isothermal stability better than 0.5 K. 

Table X. Isothermal Stability of Carbazole Anhydride and Poly(Af-viitylcaibazole)anhydride Copolycondensates...

Figure 2-3. Schematic isothermal stability diagram for a gas consisting of two compounds X2 and Y2 A is the metal, AX and AY are the respective reaction products.

We have recently tried to challenge the correlation and reduce the scatter that arises from the uncertain extraction of enthalpies from equilibrium measurements by measuring the enthalpy directly in calorimeters, notably combined DSC/TG instruments where the water exchange and associated enthalpy can be recorded simultaneously. It has so far turned out that combination instruments lack the isothermal stability to obtain significant results. 

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