- 著者
- Hidetomo Yokoo Seiji Tanaka Eiichi Yamamoto Genichiro Tsuji Yosuke Demizu Nahoko Uchiyama
- 出版者
- The Pharmaceutical Society of Japan
- 雑誌
- Chemical and Pharmaceutical Bulletin (ISSN:00092363)
- 巻号頁・発行日
- vol.71, no.1, pp.58-63, 2023-01-01 (Released:2023-01-01)
- 参考文献数
- 33
- 被引用文献数
- 1
Understanding the characteristics of crystal polymorphism of active pharmaceutical ingredients and analyzing them with high sensitivity is important for quality of drug products, appropriate characterization strategies, and appropriate screening and selection processes. However, there are few methods to measure intra- and intermolecular correlations in crystals other than X-ray crystallography, for which it is sometimes difficult to obtain suitable single crystals. Recently, solid-state NMR has been recognized as a straightforward method for measuring molecular correlations. In this study, we selected ranitidine hydrochloride, which is known to exist in two forms, 1 and 2, as the model drug and investigated each form using solid-state NMR. In conducting the analysis, rotating the sample tube, which had a 1-mm inner diameter, increased the solid-state NMR resolution at 70 kHz. The 1H–14N dipolar-based heteronuclear multiple quantum coherence (D-HMQC) analysis revealed the intermolecular correlation of Form 1 between the N atom of the nitro group and a proton of the furan moiety, which were closer than those of the intramolecular correlation reported using single X-ray crystal analysis. Thus, 1H–14N D-HMQC analysis could be useful for characterizing intermolecular interaction in ranitidine hydrochloride crystals. In addition, we reassigned the 13C solid-state NMR signals of ranitidine hydrochloride according to the liquid-state and multiple solid-state NMR experiments.
- 著者
- Seiji Tanaka Koutaro Maeno Sid'Ahmed Ould Mohamed Sidi Ould Ely Mohamed Abdallahi Babah Ebbe
- 出版者
- JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY
- 雑誌
- Applied Entomology and Zoology (ISSN:00036862)
- 巻号頁・発行日
- vol.45, no.4, pp.641-652, 2010-11-25 (Released:2010-11-30)
- 参考文献数
- 48
- 被引用文献数
- 13 16
A short excursion was made to the western part of Mauritania to investigate increasing populations of the desert locust, Schistocerca gregaria, in October 2009. The size of locust populations observed ranged from <1 to >20 individuals per 25 m2. Adults from low- and high-density populations were similar in morphometric ratios of F/C and E/F (F, hind femur length; C, maximum head width; E, fore wing length) and the ratios were similar to those reported for solitarious forms. However, locusts from high-density populations were mostly yellow, while those from low-density populations were brown or whitish. The former were observed ovipositing in groups. These observations, together with the fact that some of the females from high-density populations had ovarian eggs significantly larger than those found in females from low-density populations, suggested that gregarization might have occurred after adult emergence. Aggregations of nymphs were observed at many sites, and nymphs with black patterns typically observed in transient and gregarious populations were found together with those with solitarious body coloration, i.e. green or brown. A prompt action of locust control by National Locust Control Center was likely to have contributed to prevent further upsurges in the locust populations in the following seasons.