In the pharmaceutical processes like milling, wet granulation, drying, re-crystallization as well as compaction, there is a possibility of generating disorder in the form of crystal defects or amorphous phase [1]. The amorphous phase generated may need to be quantified using sensitive analytical tools. In the envisaged study, amorphous content in crystalline form of carvedilol drug substance and its formulation was studied by different analytical techniques like Modulated Differential scanning colorimetry (MDSC) and Powder X-Ray diffraction (PXRD). The characteristic glass transition (Tg) of amorphous carvedilol is exhibited at about 35°C. Different concentrations of amorphous content in crystalline drug substance and its formulation have been prepared and analysed. The method was developed based on the fact that the change in the specific heat at the glass transition is linearly proportional to the amorphous content. The linearity of amorphous content was established for drug substance using both MDSC and PXRD. as well as for drug product using MDSC. Superiority of the MDSC has been justified over PXRD in terms of detection of low level of amorphous content in formulation which could be of immense help to the formulator.
