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Updated: Dec 23, 2025

Coherent anti-Stokes Raman Scattering CARS Microscopy Visualizes Pharmaceutical Tablets During Dissolution
Published on: July 4, 2014
Fate and behaviour of acetaminophen, 17α-ethynylestradiol and carbamazepine in aqueous solution
Albano Joel Moreira Santos1, Cláudia Sofia Gomes Cardoso1, Albertina Alice Ribeiro Mota1
1Centro de Investigação em Química da Universidade do Porto (CIQUP), Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
Abstract:
Pharmaceuticals are invaluable tools for the prevention and treatment of human and animal diseases. Human evolution led to the increase of life expectancy, which promoted the increase of consumption of pharmaceuticals. These compounds are consistently detected in superficial waters, and whilst degradation processes are expected to mitigate their levels, they also induce the formation of potentially harmful by-products. The compounds studied in this work were acetaminophen, 17α-ethynylestradiol and carbamazepine. High-performance liquid chromatography coupled with ultraviolet diode-array detection was used to follow the degradation reactions, whilst liquid chromatography associated with ultraviolet diode-array detection and mass spectrometry was applied in the determination of by-products. Ethynylestradiol proved to be the most reactive (t1/2 = 38.6 ± 1.9 seconds) and carbamazepine the least reactive (t1/2 = 481.4 ± 16.7 minutes) when exposed to active chlorine. In relation to disinfection by-products, two monochlorinated analogues were detected for acetaminophen, one monochlorinated for carbamazepine, and one mono- and one trichlorinated for ethynylestradiol. Chlorine levels and water pH proved to be the most influential variables on the degradation of the compounds, with and without dissolved organic matter in solution. All pharmaceuticals displayed significant photostability towards artificial solar radiation, with acetaminophen being slightly more stable.
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