Polymorphism of pharmaceutical molecules: perspectives on nucleation

Abstract

Polymorphism is a widespread phenomenon observed in more than half of all drug substances. Various polymorphs frequently possess different physical, chemical, mechanical and thermal properties that can profoundly affect the bioavailability, stability and other performance characteristics of the drug. Accordingly, the elucidation of the relationship between the particular polymorph of a pharmaceutical molecule and its functional properties is crucial to select the most suitable polymorph of the pharmaceutical molecule for development into a drug product. This review briefly introduces recent advances in the discovery and control of the polymorphs of pharmaceutical molecules, in terms of the enhancement of the selective nucleation of a particular polymorph. In the light of this, some cases discussed in the following is to be considered controversial.