Abstract-Spectroscopic Analysis of Melatonin in the Terahertz Frequency Range

Uroš Puc, Andreja Abina, Anton Jeglič, Aleksander Zidanšek, Irmantas Kašalynas, Rimvydas Venckevičius,  Gintaras Valušis,

https://www.mdpi.com/search?article_type=&authors=&journal=sensors&q=terahertz&search=Search&section=&special_issue=

There is a need for fast and reliable quality and authenticity control tools of pharmaceutical ingredients. Among others, hormone containing drugs and foods are subject to scrutiny. In this study, terahertz (THz) spectroscopy and THz imaging are applied for the first time to analyze melatonin and its pharmaceutical product Circadin. Melatonin is a hormone found naturally in the human body, which is responsible for the regulation of sleep-wake cycles. In the THz frequency region between 1.5 THz and 4.5 THz, characteristic melatonin spectral features at 3.21 THz, and a weaker one at 4.20 THz, are observed allowing for a quantitative analysis within the final products. Spectroscopic THz imaging of different concentrations of Circadin and melatonin as an active pharmaceutical ingredient in prepared pellets is also performed, which permits spatial recognition of these different substances. These results indicate that THz spectroscopy and imaging can be an indispensable tool, complementing Raman and Fourier transform infrared spectroscopies, in order to provide quality control of dietary supplements and other pharmaceutical product

Abstract-Investigation of pharmaceutical drugs and caffeine-containing foods using Fourier and terahertz time-domain spectroscopy

Mindaugas Karaliūnas; Rimvydas Venckevičius; Irmantas Kašalynas; Uroš Puc; Andreja Abina; Anton Jeglič; Aleksander Zidanšek; Gintaras Valušis

http://spie.org/Publications/Proceedings/Paper/10.1117/12.2188015

Several pharmaceutical drugs, such as alprazolam, ibuprofen, acetaminophen, activated carbon and others, and caffeine-containing foods were tested using terahertz (THz) time domain spectroscopy in the range from 0.3 to 2 THz. The dry powder of pharmaceutical drugs was mixed with HDPE and pressed into the pellets using hydraulic press. The coffee grounds were also pressed into the pellets after ball-milling and mixing with HDPE. The caffeine containing liquid foods were dried out on the paper strips of various stacking. Experiments allow one to determine characteristic spectral signatures of the investigated substances within THz range caused by active pharmaceutical ingredients, like in the case of caffeine, as well as supporting pharmaceutical ingredients. Spectroscopic THz imaging approach is considered as a possible option to identify packaged pharmaceutical drugs. The caffeine spectral features in the tested caffeine containing foods are difficult to observed due to the low caffeine concentration and complex caffeine chemical surrounding.