Commentary: Considerations in the Measurement of Glass Transition Temperatures of Pharmaceutical Amorphous Solids

An increased interest in using amorphous solid forms in pharmaceutical applications to increase solubility, dissolution, and bioavailability has generated a need for better characterization of key properties, such as the glass transition (T_g) temperature. Although many laboratories measure and report this value, the details around these measurements are often vague or misunderstood. In this article, we attempt to highlight and compare various aspects of the two most common methods used to measure pharmaceutical T_g values, conventional and modulated differential scanning calorimetry (DSC). Issues that directly impact the T_g, such as instrumental parameters, sample preparation methods, data analysis, and "wet" vs. "dry" measurements, are discussed.