Spectroscopy of several drugs in the terahertz region

We use terahertz time-domain spectroscopy (THz-TDS) to measure the absorption spectra of six drugs, atenolol, furosemide, tropicamide, lobeline hydrochloride, propranolol hydrochloride, and promethazine hydrochloride, in the frequency range of 0.3 THz to 2.0 THz. Furosemide, tropicamide, and promethazine hydrochloride show distinct absorption features, whereas atenolol, lobeline hydrochloride, and propranolol hydrochloride exhibit no obvious absorption peaks. The use of THz-TDS makes it possible to rapidly distinguish the drugs with characteristic absorption peaks. Our results demonstrate that THz-TDS is highly sensitive to the structure and spatial arrangement of molecules. As a result, THz-TDS will have potential exploitation in pharmaceutical fields.