FTIR Spectroscopic Imaging of Dissolution of a Solid Dispersion of Nifedipine in Poly(ethylene glycol)

Abstract
FTIR imaging was applied to study solid dispersions of a poorly water-soluble drug in poly(ethylene glycol) (PEG) and dissolution in water. It has been shown that initially amorphous nifedipine crystallizes within PEG-8000 for formulations with a drug loading of at least 10 wt %. The formation of a significant amount of crystalline drug within the polymer matrix reduces the rate of dissolution of the drug. This FTIR spectroscopic imaging in the ATR mode provides novel insight into the mechanism of dissolution of nifedipine from solid dispersions in water-soluble polymers, which is valuable in optimization of manufacturing these formulations. Keywords: FT-IR imaging; spectroscopy; crystallization; poly(ethylene glycol); drug dissolution