APPLICATION NOTE Authors: Paul Gabbott PerkinElmer Thermal Analysis Paul Clarke PerkinElmer Thermal Analysis Tim Mann PerkinElmer Thermal Analysis Paul Royall King's College School of Pharmacy Sukhraj Shergill King's College School of Pharmacy PerkinElmer, Inc. United Kingdom Introduction The study of the amorphous content of pharmaceutical materials has been of great interest for many years. However, it has often been difficult to quantify very low levels of amorphous content using differential scanning calorimetry (DSC) because of the small energy changes associated with the measurement of the glass transition (Tg) at these low levels. As a consequence, other techniques have been preferred for this measurement, such as moisture sorption and solution calorimetry. The disadvantage of these techniques is their time-consuming nature 1 . Recently, a DSC technique has been shown to give greatly increased sensitivity of DSC measurement. HyperDSC™ (PerkinElmer, Shelton, CT) allows the clear characterization of weak transitions such as the Tg of the type found in materials of low amorphous content. Examples of this type of analysis on glass transitions can be found in the work of Pijpers and Mathot 2 . In addition, because of the very fast scan rates used in HyperDSC, analyses are made in very short time periods, often less than 30 seconds. The ability to measure these difficult transitions in a very short time gives significant benefits to the pharmaceutical and polymer industries. A High-Sensitivity, High-Speed DSC Technique: Measurement of Amorphous Lactose Differential Scanning Calorimetry