Crystal polymorphism in chemical process development.

Polymorphism in molecular crystals is a prevalent phenomenon and is of great interest to the pharmaceutical community. The solid-state form is a key quality attribute of a crystalline product. Inconsistencies in the solid phase produced during the manufacturing and storage of drug substances and drug products may have severe consequences. It is essential to understand the solid-state behavior of the drug and to judiciously select the optimal solid form for development. This review highlights the pervasiveness and relevance of polymorphism and describes solid form screening and selection processes. Moreover, case studies on controlling polymorphs from a chemical development perspective are provided.