Crystalline Polymorphism
The ability of a drug substance to exist in more than one crystalline form (polymorph), each with distinct molecular packing arrangements in the solid state. Different polymorphs can have significantly different solubility, dissolution rate, stability, and bioavailability, even though they are chemically identical. Polymorph screening and selection are critical steps in pharmaceutical development and patent strategy.
示例
- Ritonavir: unexpected conversion to a less soluble polymorph (Form II) caused product recall in 1998
- Chloramphenicol palmitate: polymorph A is therapeutically inactive due to poor dissolution vs. polymorph B
- Carbamazepine: four known polymorphs with different dissolution rates affecting bioequivalence
您知道吗？
The ability of a drug substance to exist in more than one crystalline form (polymorph), each with distinct molecular packing arrangements in the solid state. Different polymorphs can have significantly …