中文摘要：

以氢氯噻嗪（ HCT）作为药物活性成分（ API），以烟酰胺、烟酸作为共晶形成物（ CCF），在室温条件下制得2种药物共晶HCT·NCA（1）、HCT·NNA（2）。通过X-射线单晶衍射测定了它们的晶体结构，并进行了元素分析、红外光谱、X-射线粉末衍射表征。此外，利用Gausian 03W程序，在B3LYP/6-31G（ d）水平上对2种化合物进行了结构全优化，对其分子轨道能量、前线分子轨道、自然键轨道（ NBO）等进行了量子化学计算分析。

英文摘要：

With hydrochlorothiazide as the active pharmaceutical ingredient（ API）,nicotinamide and nicotinic acid as the cocrystal former（CCF）,two pharmaceutical cocrystals HCT·NCA（1）,HCT·NNA（2）were successfully synthesized at room temperature,respectively. The crystal structures were determined by single-crystal X-ray diffrac-tion,and they were further characterized by elemental analysis,infrared spectroscopy and powder X-ray diffraction. In addition,based on the B3LYP/6-31G（d）level with Gaussian 03W program,the full geometry optimization,the orbital energies,the frontier molecular orbital and the natural bond orbital of the two compounds have been investi-gated.