Department of Physics, University of Warwick, Coventry CV4 7AL, UK; Analytical and Quality Evaluation Research Laboratories, Daiichi Sankyo Co. Ltd., 1-12-1, Shinomiya, Hiratsuka-shi, Kanagawa 254-0014, Japan.
Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
J Pharm Sci. 2017 Nov;106(11):3372-3377. doi: 10.1016/j.xphs.2017.07.014. Epub 2017 Jul 25.
The lower detection limit for 2 distinct crystalline phases by H magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) is investigated for a minority amount of cimetidine (anhydrous polymorph A) in a physical mixture with the anhydrous HCl salt of cimetidine. Specifically, 2-dimensional H double-quantum (DQ) MAS NMR spectra of polymorph A and the anhydrous HCl salt constitute fingerprints for the presence of each of these solid forms. For solid-state NMR data recorded at a H Larmor frequency of 850 MHz and a MAS frequency of 30 kHz on ∼10 mg of sample, it is shown that, by following the pair of cross-peaks at a H DQ frequency of 7.4 + 11.6 = 19.0 ppm that are unique to polymorph A, the level of detection for polymorph A in a physical mixture with the anhydrous HCl salt is a concentration of 1% w/w.
通过高磁场魔角旋转（MAS）固态核磁共振（NMR）研究了两种不同晶相的下限检测限，其中包含少量西咪替丁（无水多晶型 A）与西咪替丁无水盐酸盐的物理混合物。具体来说，多晶型 A 和无水 HCl 盐的二维 H 双量子（DQ）MAS NMR 图谱构成了每种固体形式存在的指纹。在 H 拉莫尔频率为 850 MHz 和 MAS 频率为 30 kHz 的固态 NMR 数据记录在约 10 毫克的样品上，结果表明，通过跟踪在 H DQ 频率为 7.4 + 11.6 = 19.0 ppm 处特有的多晶型 A 的交叉峰对，可以检测到无水 HCl 盐与多晶型 A 的物理混合物中多晶型 A 的检测限为 1% w/w。
