- 著者
-
Nahoko Uchiyama
Junko Hosoe
Naoki Sugimoto
Kyoko Ishizuki
Tatsuo Koide
Mika Murabayashi
Naoto Miyashita
Kengo Kobayashi
Yoshinori Fujimine
Toshiyuki Yokose
Katsuya Ofuji
Hitoshi Shimizu
Takashi Hasebe
Yumi Asai
Eri Ena
Junko Kikuchi
Kohei Kiyota
Kazuhiro Fujita
Yoshinobu Makino
Naoko Yasobu
Yuko Yamada
Yoshiaki Iwamoto
Toru Miura
Koji Mizui
Katsuo Asakura
Takako Suematsu
Ai Kohama
Yukihiro Goda
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Chemical and Pharmaceutical Bulletin (ISSN:00092363)
- 巻号頁・発行日
- vol.69, no.1, pp.118-123, 2021-01-01 (Released:2021-01-01)
- 参考文献数
- 11
- 被引用文献数
-
10
Quantitative NMR (qNMR) is applied to determine the absolute quantitative value of analytical standards for HPLC-based quantification. We have previously reported the optimal and reproducible sample preparation method for qNMR of hygroscopic reagents, such as saikosaponin a, which is used as an analytical standard in the assay of crude drug section of Japanese Pharmacopoeia (JP). In this study, we examined the absolute purity determination of a hygroscopic substance, indocyanine green (ICG), listed in the Japanese Pharmaceutical Codex 2002, using qNMR for standardization by focusing on the adaptation of ICG to JP. The purity of ICG, as an official non-Pharmacopoeial reference standard (non-PRS), had high variation (86.12 ± 2.70%) when preparing qNMR samples under non-controlled humidity (a conventional method). Additionally, residual ethanol (0.26 ± 0.11%) was observed in the non-PRS ICG. Next, the purity of non-PRS ICG was determined via qNMR when preparing samples under controlled humidity using a saturated sodium bromide solution. The purity was 84.19 ± 0.47% with a lower variation than that under non-controlled humidity. Moreover, ethanol signal almost disappeared. We estimated that residual ethanol in non-PRS ICG was replaced with water under controlled humidity. Subsequently, qNMR analysis was performed when preparing samples under controlled humidity in a constant temperature and humidity box. It showed excellent results with the lowest variation (82.26 ± 0.19%). As the use of a constant temperature and humidity box resulted in the lowest variability, it is recommended to use the control box if the reference ICG standard is needed for JP assays.