Wesolowski Marek, Leyk Edyta
Department of Analytical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk, Poland.
Pharmaceutics. 2023 May 25;15(6):1596. doi: 10.3390/pharmaceutics15061596.
Reliable interpretation of the changes occurring in the samples during their heating is ensured by using more than one measurement technique. This is related to the necessity of eliminating the uncertainty resulting from the interpretation of data obtained by two or more single techniques based on the study of several samples analyzed at different times. Accordingly, the purpose of this paper is to briefly characterize thermal analysis techniques coupled to non-thermal techniques, most often spectroscopic or chromatographic. The design of coupled thermogravimetry (TG) with Fourier transform infrared spectroscopy (FTIR), TG with mass spectrometry (MS) and TG with gas chromatography/mass spectrometry (GC/MS) systems and the principles of measurement are discussed. Using medicinal substances as examples, the key importance of coupled techniques in pharmaceutical technology is pointed out. They make it possible not only to know precisely the behavior of medicinal substances during heating and to identify volatile degradation products, but also to determine the mechanism of thermal decomposition. The data obtained make it possible to predict the behavior of medicinal substances during the manufacture of pharmaceutical preparations and determine their shelf life and storage conditions. Additionally, characterized are design solutions that support the interpretation of differential scanning calorimetry (DSC) curves based on observation of the samples during heating or based on simultaneous registration of FTIR spectra and X-ray diffractograms (XRD). This is important because DSC is an inherently non-specific technique. For this reason, individual phase transitions cannot be distinguished from each other based on DSC curves, and supporting techniques are required to interpret them correctly.
通过使用多种测量技术，可以确保对样品在加热过程中发生的变化进行可靠的解释。这与消除因基于对不同时间分析的多个样品的研究，通过两种或更多单一技术获得的数据解释所产生的不确定性的必要性有关。因此，本文的目的是简要描述与非热技术（最常见的是光谱或色谱技术）相结合的热分析技术。讨论了热重分析法（TG）与傅里叶变换红外光谱法（FTIR）、TG与质谱法（MS）以及TG与气相色谱/质谱联用（GC/MS）系统的联用设计和测量原理。以药用物质为例，指出了联用技术在制药技术中的关键重要性。它们不仅能够精确了解药用物质在加热过程中的行为并鉴定挥发性降解产物，还能确定热分解的机理。所获得的数据使得预测药用物质在药物制剂生产过程中的行为并确定其保质期和储存条件成为可能。此外，还介绍了基于加热过程中对样品的观察或基于FTIR光谱和X射线衍射图（XRD）的同步记录来支持差示扫描量热法（DSC）曲线解释的设计方案。这很重要，因为DSC本质上是一种非特异性技术。因此，基于DSC曲线无法区分各个相变，需要辅助技术来正确解释它们。
