Raman spectroscopy analysis for monitoring of chemical composition of aspirin after exposure to plasma flame

Introduction Further details about the degradation structure of pharmaceutical products are required to improve their stability and determine whether the degradation products and impurities have any toxicity.1–4 Temperature is an important component in much of our lives, not least in the climate system, and plays a key role in the chemical change of compounds. Some pharmaceutical compounds are damaged or toxic chemicals produced due to exposure at plasma flame temperatures.5 Exposure to these temperatures has been shown to be related to adverse effects in human health both directly and indirectly. Therefore, these rapid changes are having a serious effect on the environmental and biological impacts of chemical compounds.6 Various analytical techniques such as near infrared (NIR), Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) and high-performance liquid chromatography (HPLC) have been used to analyse pharmaceutical solid compounds.7 Recently, investigators have examined the effects of temperature on the stability of pharmaceutical samples. The thermal stability of aspirin samples after treatment at 40 °C and exposure to a 300 W UV-A lamp for 12 h was studied by Al-Maydama et al. and found to be lower to that of the untreated samples using HPLC, photocatalytic, X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods.8 In the study by Acharya and co-workers, IR, mass spectrometry and 1H NMR methods were successfully applied for analysis of the thermal degradation product obtained from the interaction of aspirin and salicylic acid. This study confirmed that the structure of the new thermal degradation product is different to those of aspirin and salicylic acid.9 The chemical composition of artepillin C and p-coumaric acid was investigated using HPLC after exposure to high temperature and it showed that the stability of these compounds was affected.10 However, HPLC is expensive, has long run times and consumes solvents. In the study by Johnsiani et al., several techniques such as NMR, quadruple time-of-flight mass spectrometry (Q-TOF/MS) and electrospray ionisation collision-induced dissociation tandem mass spectrometry (ESI-CID-MS/MS) were used to study the degradation of sorafenib tosylate after exposure to different stress conditions including temperature.11 Vishnuvardhan and co-workers have shown there was significant degradation of the drug DOI: 10.1255/sew.2022.a15