Summary
Lactose is a widely used excipient, used as carrier in dry powder inhalation (DPI) and filler/binder in oral solid dosage (OSD). The presence of amorphous material in commercially available excipients such as lactose may affect the performance of the final drug product. To understand the impact of amorphous lactose on the performance of the drug, it is essential to accurately measure amorphous content. Developing a suitable method is particularly challenging as various types of amorphous lactose can be generated by different processing techniques. These different amorphous types often behave differently, making it more difficult to develop a method that can be used to measure all types of amorphous lactose. This study evaluates the potential of calorimetric methods (differential scanning calorimetry, DSC, and solution calorimetry, Sol Cal) and a gravimetric method (dynamic vapor sorption, DVS) for developing a comprehensive method to determine all types of amorphous content. The findings suggest that calorimetric methods are more suitable than gravimetric methods.