6–10 Jul 2026
University of the Western Cape
Africa/Johannesburg timezone
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Photostability analysis of Aspirin tablets using Raman spectroscopy: A detection method for screening substandard and falsified medication.

7 Jul 2026, 15:40
20m
Lecture Hall DL1 (University of the Western Cape)

Lecture Hall DL1

University of the Western Cape

Oral Presentation Track C - Photonics Photonics

Speaker

Dr Lebogang Thobakgale (CSIR Biophotonics Photonics Centre Council for Scientific and Industrial Research)

Description

Substandard and falsified (SF) medications pose a growing public health and regulatory challenge in South Africa, with serious implications for patient safety and healthcare systems. Continuous development of rapid screening methods is essential to detect SF products effectively. This study evaluates the stability of aspirin tablets using Raman spectroscopy combined with partial least squares (PLS) analysis before and after ultraviolet (UV) irradiation. Degradation of the active ingredient was monitored through changes in its molecular Raman fingerprint over time (0-90 minutes). Spectral bands associated with the carboxylic acid, ester, phenol and hydroxyl bonds were selected for evaluation because they represent areas where structural changes are likely to occur in response to irradiation. The PLS analysis showed linearity of >98% from the calibration curves derived from the Raman intensities of the functional groups. Secondly, calculations show that structural degradation can be detected between 3.48 to 17 minutes using the hydroxyl and phenol degradation products respectively. Thirdly, accuracy tests at 15, 45, and 70 minutes exposure times yielded responses of 97-103%, while repeatability, expressed as relative standard deviation (RSD), was within 0.1 - 4.9% across the functional groups. This approach offers a rapid, non-destructive method for assessing medication integrity, demonstrating strong potential application in SF drug detection and quality control of pharmaceutical products.

Author

Dr Lebogang Thobakgale (CSIR Biophotonics Photonics Centre Council for Scientific and Industrial Research)

Co-authors

Lungile Nomcebo Thwala (CSIR) Saturnin Ombinda-Lemboumba (CSIR) Dr Kelvin Mpofu (CSIR Biophotonics Photonics Centre Council for Scientific and Industrial Research) Masixole Lugongolo (CSIR) Sello Lebohang Manoto (CSIR)

Presentation materials