Polymorphism describes the fact that some materials with the same composition can exist in more than one crystalline form, characterized by different molecular packing. The ability to identify, understand, and control the polymorphic form of a material is important to multiple technical fields but is of special relevance to the field of pharmaceuticals.
Most pharmaceutical products are administered as solids (e.g. tablets, capsules and inhalation materials) and the polymorphic form of the Active Pharmaceutical Ingredient (API) is of direct interest because it can influence the dissolution behaviour of the product in-vivo, and therefore the bioavailability.
In turn, the polymorphic form of the API can be affected by processing, formulation and storage conditions so it is often important to carry out checks during API synthesis route development, formulation development, storage and manufacture etc.
It is possible that an API can exist in multiple different polymorphic forms, and the determination of form or of the combination of forms, in a specific sample can be technologically challenging, especially when there are other important factors affecting the overall picture such as the existence of solvates, hydrates and also amorphous material. Thus, the analytical challenges can be difficult, and multiple methods are typically used across the industry.