The comparison of seven different methods to quantify the amorphous content of spray dried lactose

The purpose of this work was to verify the usefulness, advantages and disadvantages of seven methods that are widely used to detect, and quantify the amorphous contents in pharmaceutical solids. Here, StepScan DSC, a type of modulated temperature calorimetry method, was applied for the first time to quantify amorphicity. The comparison of the analytical methods was undertaken with real (non-artificial) test samples, i.e. spray-dried lactose samples with various degrees of crystallinity. In these samples, it was essential that the amorphous and the crystalline portions are not present as separate particles, which is the case when physical (artificial) mixtures of totally amorphous and totall…