ABSTRACT
This chapter discusses the theoretical basis for the development of solid dispersions and various practical approaches to the formulation of solid dispersions for poorly water-soluble drugs. Solid dispersion formulations, by stabilizing amorphous drugs, can provide significant advantages. Compared to conventional tablet and capsule dosage forms, solid dispersion formulations are relatively complex drug delivery systems, requiring a substantially greater commitment of time, effort, and resources for development. A solid dispersion, on the other hand, is a physical mixture that undergoes, either partly or completely, a molecular-level mixing during its formation. Knowledge of the structure of solid dispersion and, particularly, how the drug exists in a carrier matrix, is of critical importance in understanding the performance of solid dispersions. A crystalline solid dispersion is formed when the rate at which drug crystallizes from drug– polymer miscible mixture is greater than the rate at which drug– polymer fluid mixture solidifies. Solid solution is a solid dispersion that is miscible in its fluid.
