The solid state

Many active pharmaceutical ingredients (APIs) can exist in more than one solid-state form, including crystalline polymorphs, solvates, salts, cocrystals, and noncrystalline or amorphous solids (Fig. 1; Table 1). Hence, assessment and control of the solid-state structure of APIs is necessary to ensure efficient and reproducible processing, manufacturing, and storage; to satisfy regulatory authorities; to protect intellectual property; and ultimately to deliver safe, effective, and high-quality medicinal products. This section introduces key practical aspects of solid-state pharmaceuticals, with a specific emphasis on crystalline solids and their preparation, handling, and analysis, particularly in the context of preclinical drug development and pharmaceutical manufacture.