Effects of polyvinylpyrrolidone on the crystallization of amorphous griseofulvin: fracture and molecular mobility

Abstract

This study aims to investigate the fracture, molecular mobility and crystallization behaviors of amorphous griseofulvin (GSF) in the presence of polyvinylpyrrolidone (PVP). In the presence of 10%(w/w) PVP K90, the fracture resistance of griseofulvin was greatly improved. Compared with the pure GSF system, the average fracture temperature of the griseofulvin–PVP K90 system was decreased to approximately −6.1°C. More importantly, a statistical study revealed that the direct connection between fracture and nucleation of griseofulvin was weakened in the presence of PVP K90. This study also explored the effects of PVP K90 on the molecular dynamics and crystallization behaviors of amorphous GSF. In the presence of PVP K90, the crystal growth kinetics and molecular dynamics were both slowed down. Interestingly, needle-like crystal growth was observed, exhibiting approximately the same rates as the bubble-induced process. These findings are important for understanding the complex mechanisms of physical stability of polymer-based amorphous solid dispersions.