A Look at the Recrystallization of Drug out of Supersaturated Amorphous Dispersions

70% of new drug candidates discovered in recent years show a lack of bioavailability due to poor water solubility. While new drug candidates are normally in the crystalline form due to that form’s greater stability, the amorphous form has shown between 1.1 to 1000 times greater solubility. In order to stabilize the amorphous form and capture its solubility advantage, the drug can be suspended in a polymer to create an amorphous solid dispersion (ASD). While some factors have been identified that would lead to recrystallization of drug in an ASD, such as exposure to atmospheric H2O or sustained exposure to temperatures above the glass transition temperature, the behavior of a drug in an ASD remains a topic for research. This study looks at the behavior of a supersaturated ASD composed of Indomethacin (IMC) and PVP K12 as it is heated at temperatures where crystallization occurs. The data suggest that regardless of the initial amount of IMC in PVPK12, the IMC crashes out of the supersaturated solution to a consistent level based upon the amount of PVP K12 available to hold IMC. The data also suggest that as the annealing temperature increases the solubility of IMC in PVP K12 increases

Research Supported by the National Science Foundation REU Program #EED-1460486