Barium- and Bismuth-Loaded Clinoptilolite Micro- and Nano-Particles as Proposed New Efficient Contrast Agents

AIM AND OBJECTIVE: Clinoptilolite is one of the natural zeolites. Clinoptilolite particles have high surface area, negative surface charge, cation adsorption and exchange capacities. Barium sulfate (BaSO4) and bismuth subnitrate (Bi5H9N4O22) suspensions have been used for upper and lower gastrointestinal imaging but Ba2+ and Bi3+ ions are toxic. In the present study feasibility of application of Ba2+- and Bi3+-loaded clinoptilolite micro- and nano-particles in medical imaging was investigated. MATERIALS AND METHODS: Nanoparticles and microparticles of natural clinoptilolite were loaded with Ba2+ and Bi3+ ions. Radiopacities of loaded particles were measured and compared with those of BaSO4 and Bi5H9N4O22. RESULTS: Ba2+- and Bi3+-loaded clinoptilolite nanoparticles and microparticles showed more intense X-ray opacities than BaSO4 and Bi5H9N4O22 with equimolar concentrations. Moreover, Ba2+- and Bi3+-loaded clinoptilolite nanoparticles more intensely absorbed X-ray than respective loaded microparticles. CONCLUSION: The present study proposes Ba2+- and Bi3+-loaded clinoptilolite nanoparticles and microparticles as new, safe, efficient, and inexpensive contrast agents.