Physical characterization of pharmaceutical excipients is not only a requirement but can also provide data that can be predictive in nature regarding the performance of final dosage forms including tablets, capsules, inhaled dosage forms, transdermals, and others. Manufacturers generally provide some of this physical testing data, such as particle size. In the case of particle size data, the manufacturer’s specification may be wider than is actually acceptable for a particular process or product. Additionally, other tests may not be reported such as surface area, density, or porosity. In some cases, this data may provide insight into how a particular material will behave in a given process (flow, blending, compression) or final dosage form (disintegration, dissolution, bioavailability).