Analytical Sciences

Application of Terahertz Absorption Spectroscopy to Evaluation of Aging Variation of Medicine

Masaya KAWASE,*1,*2 Tadashi SAITO,*2 Masafumi OGAWA,*3 Hideki UEJIMA,*3 Yasutoshi HATSUDA,*3 Sonoyo KAWANISHI,*3 Yoshihiko HIROTANI,*3 Michiaki MYOTOKU,*3 Kenji IKEDA,*3 Hiroki KONISHI,*3 Ikumi IGA,*3 Junji YAMAKAWA,*4 Seizi NISHIZAWA,*5 Kohji YAMAMOTO,*6 and Masahiko TANI*6

*1 Nagahama Institute of Bio-science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
*2 Radioisotope Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
*3 Faculty of Pharmaceutical Sciences, Osaka Ohtani University, 3-11-1 Nishikiorikita, Tondabayashi, Osaka 584-8540, Japan
*4 Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita, Okayama 700-8530, Japan
*5 Advanced Infrared Spectroscopy, 3-17-16 Sennin, Hachioji, Tokyo 193-0835, Japan
*6 Research Center for Development of Far-Infrared Region, University of Fukui, 3-9-1 Bunkyo, Fukui 901-8507, Japan

The absorption spectra of three kinds of medicines both before and after the expiration date: Amlodin OD^® (5 mg), Basen OD^® (0.2 mg) and Gaster D^® (10 mg) have been measured by terahertz time domain spectroscopy (THz-TDS). All the medicines show some differences in the THz absorption spectra between medicines before and after the expiration dates. X-Ray powder diffraction (XRD) studies of all medicines suggest that the polymorph of the main effective compound is not changed before and after the expiration date. Therefore, the differences in the THz spectra between medicines before and after the expiration dates arise from aging variation of diluting agents and/or from modifications of intermolecular interaction between the effective compounds and diluting agents.

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