Amorphous solid dispersions: a robust platform to address bioavailability challenges

Amorphous solid dispersions (ASDs) are being used with increasing frequency for poorly soluble pharmaceutical compounds in development. These systems consist of an amorphous active pharmaceutical ingredient stabilized by a polymer to produce a system with improved physical and solution stability. ASDs are commonly considered as a means of improving the apparent solubility of an active pharmaceutical ingredient. This review will discuss methods of preparation and characterization of ASDs with an emphasis on understanding and predicting stability. Theoretical understanding of supersaturation and predicting in vivo performance will be stressed. Additionally, a summary of preclinical and clinical development efforts will be presented to give the reader an understanding of risks and key pitfalls when developing an ASD.