Solid State Crystallinity, Amorphous State, and Its Implications in the Pharmaceutical Process

Many drugs exist in crystalline solid form due to reasons of stability and ease of handling during the various stages of drug development. Crystalline solids can exist in the form of polymorphs, solvates or hydrates. Phase transitions such as polymorph inter-conversion, formation of hydrates, desolvation of solvates, and conversion of the crystalline to amorphous form may occur during various pharmaceutical processes. This could change the dissolution rate and transport characteristics of the drug. The current focus of research in the area is to understand the origins of polymorphism at the molecular level, and to predict and prepare the most stable polymorph of the drug. The aim of this review is to understand the recent development in the area of solid state crystallinity, amorphous state and to address the current challenges faced by pharmaceutical formulation, process development scientists and to anticipate future developments.