Abstract Irbesartan (IBS) is an inhibitor of angiotensin II receptor. In order to study the thermal stability and the thermal decomposition mechanism of IBS, the thermal decomposition processes of IBS in nitrogen and in air atmospheres were studied by means of thermogravimetry (TG) and differential scanning calorimetry (DSC), the evolved gaseous products from thermal decomposition were identified with thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR), and the residues of thermal decomposition at various temperatures were analyzed with infrared spectra, high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC–MS). The molecular bond orders were calculated by GAMESS program of quantum chemistry, and the thermal decomposition mechanism of IBS was discussed. The results indicated that the thermal decomposition of IBS is a three-stage process and the initial temperatures of the decomposition are 204.7 and 201.0 °C in nitrogen and in air, respectively. The initial step of the decomposition is the partial decomposition of imidazolone and tetrazol sections. The thermal stability of IBS is quite good in the routine temperature.

中文翻译：

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厄贝沙坦的热分解机理

摘要 厄贝沙坦 (IBS) 是血管紧张素 II 受体抑制剂。为研究IBS的热稳定性和热分解机理，利用热重法（TG）和差示扫描量热法（DSC）研究了IBS在氮气和空气中的热分解过程，热分解产生的气态产物。用热重结合傅里叶变换红外光谱 (TG-FTIR) 鉴定分解，并用红外光谱、高效液相色谱 (HPLC) 和液相色谱-质谱 (LC-MS) 分析不同温度下的热分解残留物）。采用量子化学GAMESS程序计算分子键序，讨论IBS的热分解机理。结果表明，IBS 的热分解过程为三阶段，在氮气和空气中，分解的初始温度分别为 204.7 和 201.0 ℃。分解的第一步是咪唑酮和四唑部分的部分分解。IBS在常温下的热稳定性相当好。