Polymorphism is a fundamental phenomenon observed in lipid materials, encompassing a diverse group of biomolecules such as fats, oils, and phospholipids. This phenomenon refers to the ability of lipids to exist in multiple structurally distinct states of crystallinity. Polymorphism in lipid materials has significant implications, e.g. in pharmaceutical and industrial applications. Controlling lipid polymorphism can be of paramount importance in the development of lipid-based drug delivery systems.
Polymorphism results in different crystal structures with distinct physical properties. For lipids, this includes variations in melting point, density, hardness and optical characteristics. Different polymorphs of the same lipid thereby influence the release rate and bioavailability of drug products.
Understanding this property and how a lipid excipient transitions between different states of crystallinity plays a crucial role in lipid-based drug delivery systems.