Review of Pharmaceutical Solid Polymorphism: Preparation, Characterization and Influence on Performance of Drugs

Abstract

When the crystalline structure of the same chemical compound (and atomic formula) exhibits two or more patterns of the repeated unit cells, these crystalline structures are called polymorphs and the phenomena is referred to as polymorphism. Active pharmaceutical ingredient (API) can have a variety of polymorph. These different Polymorphic forms of drug substance exhibits different physical and chemical properties, including melting point, chemical reactivity, apparent solubility, dissolution rate, optical and mechanical properties, vapor pressure and density. Polymorphism properties of API can have a direct effect on the ability to process and/or manufacture the API and the drug product. More importantly, polymorphisms of API directly affect drug product stability, dissolution and bioavailability. Hence, quality, safety and efficacy of the drug product can be directly affected by polymorphism. This review will discuss briefly the polymorphism preparation, characterization and their importance on drug substance and drug product.