The importance of amorphous forms

This is clearly an area where the combination of thermodynamic, kinetic and structural information potentially can lead to successful strategies for controlling the polymorphic form obtained, in specific instances a metastable form, and as the means for obtaining these data become more sophisticated the approaches described here are sure to be developed and expanded (see also Section 3.7). 

Byrn et al. 1999 Yu 2001). One increasingly used method to stabilize the amorphous form is to disperse it in a polymer matrix such as polyvinylpyrrolidone, although there is still the possibility that crystalline material will crystallize out (Kimura et al. 2000). 

The evolution in calorimetry technology has also led to the development of protocols for quantitative analysis (Buckton and Darcy 1999). Fiebich and Mutz (1999) determined the amorphous content of desferal using both isothermal microcalorimetry and water vapour sorption gravimetry with a level of detection of less than 1 per cent amorphous material. The heat capacity jump associated with the glass transition of amorphous materials MTDSC was used to quantify the amorphous content of a micronised drag substance with a limit of detection of 3 per cent w/w of amorphous 

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