Dissolution testing data interpretation

Aquatic toxicity testing, by its nature, involves the dissolution of the substance under test in the water media used and the maintenance of a stable bioavailable exposure concentration over the course of the test. Some substances are difficult to test under standard procedures and thus special guidance will be developed on data interpretation for these substances and how the data should be used when applying the classification criteria. 

The relationship between the hydrodynamics in the GI tract and that in the current available dissolution tests is another factor that must be considered. It has been reported that, provided an appropriate composition is chosen for the dissolution test, the United States Pharmacopeia (USP) paddle apparatus can be used to reflect variations in hydrodynamic conditions in the upper GI tract [67-69]. However, more data are warranted, as this might insert uncertainty into the interpretation of dissolution tests, even when the composition of the GI milieu is well simulated. 

A big advantage of differential scanning calorimetry over the traditional stability test is the speed of determination. However, like all methods, differential scanning calorimetry has its own limitations. It is not applicable if the test materials exhibit properties that make data interpretation difficult, such as eutectic formation, coincident melting, and dissolution of one component in the melt of the other. It is not advisable to rely on differential scanning calorimetry alone to determine incompatibility. Chrzanowski et al. (30) reported that differential scanning calorimetry... 

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