Bismuth chelate as a contrast agent for X-ray computed tomography

Area of Science:

• Radiology and Imaging
• Nanomedicine
• Biomaterials

Background:

• Iodinated contrast agents for X-ray computed tomography (CT) imaging can cause adverse side effects, necessitating the development of novel alternatives.
• Heavy metal nanoparticles (e.g., gold, bismuth) offer advantages like long circulation and tumor targeting but may present toxicity and complex preparation challenges.

Purpose of the Study:

• To investigate a small molecular bismuth chelate as a potential CT contrast agent.
• To evaluate the efficacy, safety, and pharmacokinetic profile of the novel bismuth agent.

Main Methods:

• Synthesis of a small molecular bismuth chelate using diethylenetriaminepentaacetic acid (DPTA).
• Evaluation of CT imaging performance for the kidney compared to iohexol.
• In vitro cytotoxicity assays on L02 cells and hemolysis tests.
• In vivo toxicity assessment in mice via repeated high-dose intravenous administration.
• Pharmacokinetic studies to determine elimination kinetics and half-life.

Main Results:

• The bismuth agent demonstrated superior CT imaging enhancement in the kidney compared to iohexol, indicated by improved CT values.
• Negligible toxicity was observed in L02 cells and minimal hemolysis up to 500 µM.
• No detectable organ morphology changes occurred in mice after high-dose repeated administration.
• The agent exhibited first-order elimination kinetics with a short half-life of 0.602 h, indicating rapid clearance and good biocompatibility.

Conclusions:

• The developed bismuth agent is easily prepared, cost-effective, and exhibits excellent biocompatibility.
• Its superior imaging performance and safety profile suggest it is a strong candidate for novel CT contrast agents in clinical settings.