Abstract
Application of near-infrared spectroscopy to the analysis of freeze-dried pharmaceutical formulation was studied. Diffuse-reflection measurement from the bottom of glass vials allowed non-destructive analysis of component crystallinity and residual water in freeze-dried solids. Transmission NIR spectra of amorphous sorbitol solid showed reduction of intermolecular hydrogen-bonding OH groups at elevated temperatures. Second-derivative NIR spectra of proteins in aqueous solutions and freeze-dried solids suggested dehydration-induced perturbation of the secondary structures.
