31-15 Effect of Residual Chlorine on the Stability of Gadolinium-Based Contrast Agent Gadobutrol (Gadavist) and Its Behavior in Simulated Gastric Fluid

Session: Environmental Geochemistry and Health (Posters)

Poster Booth No.: 41

Presenting Author:

Malsha Kanaththage

Authors:

Kanaththage, Malsha Indeewari¹, Coyte, Rachel Marylee², Rubasinghege, Gayan³

(1) Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM, USA, (2) Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NM, , (3) Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM, USA,

Abstract:

Gadolinium-based contrast agents (GBCAs) are increasingly detected in aquatic environments due to their widespread clinical use and persistence during wastewater treatment. Understanding the stability of these compounds under environmentally relevant conditions is essential for assessing their potential transformation and health implications. This study evaluated the stability of the macrocyclic GBCA, Gadobutrol (Gadavist), in the presence of residual chlorine and its subsequent behavior under simulated gastric conditions. Gadavist (10 ppm) was [RC1] incubated with sodium hypochlorite, and residual chlorine was monitored daily to represent residual chlorine (2- 0.5 ppm) in drinking water at 25 °C for seven days under dark and simulated sunlight conditions, along with the control. Following incubation, samples were analyzed using ion chromatography coupled with inductively coupled plasma mass spectrometry (IC-ICP-MS). Preliminary chromatographic results showed greater changes in gadolinium speciation in chlorine-treated samples than in the untreated control, with sunlight exposure producing more pronounced alterations than dark storage. To evaluate the potential implications of these transformations following ingestion, chlorine-treated samples were exposed to simulated gastric fluid (SGF) and compared with untreated GBCAs. Initial IC-ICP-MS results suggest that residual chlorine may alter the chemical behavior of Gadavist and influence its stability under gastric conditions.

These preliminary findings indicate that residual chlorine, particularly when combined with sunlight exposure, may compromise the environmental stability of Gadavist despite [RC2] its macrocyclic structure. Ongoing work will verify GBCA concentrations and determine the implications of chlorine-induced transformations for human exposure through drinking water.

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