Polymorphism is the ability of a material to exist in more than one crystal structure.
Characteristics:
Multiple Structures: A single chemical compound can form different crystalline arrangements, each with distinct properties.
Phase Transitions: Polymorphs can transform from one form to another under certain conditions such as temperature and pressure changes.
Types of Polymorphs:
Enantiotropic Polymorphs:
Different forms can be interconverted reversibly by changing temperature or pressure.
Monotropic Polymorphs:
One form is stable, and the others are metastable, transforming irreversibly to the stable form over time or under specific conditions.
Importance in Pharmaceuticals:
Drug Formulation: Different polymorphs of a drug can have varying solubility, stability, and bioavailability, impacting effectiveness and shelf-life.
Regulation: Proper characterization and control of polymorphic forms are essential for consistent drug performance.
Examples of Polymorphism:
Carbon: Exists as diamond and graphite, with vastly different properties.
Calcium Carbonate: Exists as calcite and aragonite, with applications in construction and industry.