Influence of Structure on the Spectroscopic Properties of the Polymorphs of Piroxicam
Influence of Structure on the Spectroscopic Properties of the Polymorphs of Piroxicam
复制标题
结构对吡罗昔康多晶型物光谱性质的影响
DOI：
10.1021/jp1084444
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Dybowski, Cecil
中科院分区：
文献类型：
--
作者：
Liu, Wei;Wang, Wei David;Wang, Wei;Bai, Shi;Dybowski, Cecil
本文报道了镇痛药吡罗昔康的两种多晶型（PI和PII）和一水合物（PM）的碳位的完全~（13）C NMR化学位移张量。核磁共振参数（各向同性化学位移，化学屏蔽各向异性和不对称性，偶极耦合），X射线粉末衍射，和密度泛函计算吡罗昔康的氢键和结构进行了分析。所有数据的整合给出了多晶型物的局部固态结构的改进模型。特别是，固态NMR光谱表明，一水合物的不对称单元，PM，含有两个两性离子吡罗昔康分子。
The complete13C NMR chemical-shift tensors for the carbon sites of the two polymorphic forms (PIandPII) and the monohydrate form (PM) of the analgesic drug, piroxicam, are reported. The NMR parameters (isotropic chemical shifts, chemical-shielding anisotropies and asymmetries, and dipolar couplings), X-ray powder diffraction, and density functional calculations of piroxicam are analyzed in terms of hydrogen bonding and structure. The integration of all the data gives an improved model of the local solid-state structures of the polymorphs. In particular, the solid-state NMR spectra demonstrate that the asymmetric unit of the monohydrate,PM, contains two zwitterionic piroxicam molecules.