Polymorph

Polymorph, from poly- meaning many and morph meaning form, is a term used across several disciplines to describe an entity that exists in more than one distinct form or structure. The common thread is a shared composition or identity with alternative arrangements or expressions.

In chemistry and materials science, a polymorph is one of several crystalline forms that a compound can adopt. The forms have the same chemical formula but different crystal lattices, resulting in different physical properties such as melting point, solubility, hardness, and stability. Polymorphism is distinct from allotropy, which describes different forms of an element. Common examples include pharmaceutical polymorphs of a drug and the silica polymorphs quartz, cristobalite, and tridymite. Polymorphs are identified and characterized by techniques such as X-ray diffraction, differential scanning calorimetry, and infrared spectroscopy. Control of polymorph formation is important in manufacturing, as different forms can affect processing, shelf life, and performance.

In pharmacology, polymorphs of an active pharmaceutical ingredient can differ in dissolution rate and bioavailability. Regulatory agencies require thorough characterization and screening for potential polymorphs during drug development, and processes are designed to produce and maintain a desired form to ensure consistent efficacy and safety.

In biology, polymorphism refers to the occurrence of two or more distinct phenotypes or genotypes within a population. This can include color morphs, body size variants, or alternative life-history strategies. Polymorphism is often maintained by evolutionary forces such as balancing selection, frequency-dependent selection, or environmental heterogeneity.