‘Apparent melting’: A new approach to characterizing crystalline structure in pharmaceutical materials

Differential Scanning Calorimetry (DSC) is widely used to detect and quantify crystalline content in pharmaceuticals, foods, polymers, and other materials. In a DSC experiment, crystalline structures typically appear as an endothermic peak during heating, with the peak temperature and area helping to identify and measure the amount of crystallinity present. While such peaks are often interpreted as evidence of thermodynamic, or ‘true’, melting, this assumption is not always accurate.

In this application note, TA Instruments defines melting in a universally accepted way and demonstrates that loss of crystalline structure can also result from chemical processes other than true melting, referred to in this paper as ‘apparent melting’.