In this paper the structural characterization of terfenadine crystallized from ethanol-water, ethanol and methanol is performed
by infrared spectroscopy. The OH stretching vibration, composed of three markedly overlapped bands, is analyzed by peak fitting.
The assignment of the hydrogen bonds was conducted making use of band parameters, spectroscopic data for CCl4 solutions, and molecular dynamics calculations from dimeric systems. Terfenadine just precipitated from solvents is never
in the highest crystalline state. This state is reached when the samples are heated at a temperature above 100C. Some amorphous
solid is coprecipitated with the crystalline phase, particularly in methanol.