Evaluation of (99m)Tc-labeled photosan-3, a hematoporphyrin derivative, as a potential radiopharmaceutical for tumor scintigraphy.

Abstract

A quick and reproducible method for radiolabeling of Photosan-3(R), a photosensitizer used worldwide for photodynamic therapy (PDT) of cancer, with radioisotope of technetium ((99m)Tc) was developed. The radiotracer was evaluated for radiochemical purity, stability, and tissue distribution in a murine tumor model. The (99m)Tc-Photosan-3, which was prepared by using (99m)Tc-pertechnetate in place of reduced (99m)Tc, demonstrated better labeling efficiency (>90%) and reproducibility. The procedure also minimized radiation exposure to the radiochemist because handling time was considerably reduced. Due to the commercial availability of Photosan-3, the risk of batch-to-batch variation in the in situ synthesis of hematoporphyrin derivative, which is a complex mixture of at least five compounds, was also significantly reduced. The biodistribution studies and tumor scintigraphy confirmed that (99m)Tc-labeled Photosan-3 was preferentially taken up by the neoplastic tissue similar to the parent compound. In addition to its applications in tumor imaging, (99m)Tc-Photosan-3 could also be used for estimating tumor uptake of Photosan-3 as may be required for individualization of clinical protocols of PDT.

• Authors: A K Babbar, A K Singh, H C Goel, U P Chauhan, R K Sharma
• Journal: Nuclear medicine and biology (Nucl Med Biol) Vol. 27 Issue 4 Pg. 419-26 (May 2000) ISSN: 0969-8051 [Print] United States
• PMID: 10938479 (Publication Type: Journal Article)

Chemical References

• Hematoporphyrins
• Photosensitizing Agents
• Radiopharmaceuticals
• photosan III
• Technetium

Topics

• Animals
• Arboviruses
• Drug Stability
• Hematoporphyrins
• Isotope Labeling
• Neoplasms, Experimental (diagnostic imaging)
• Photosensitizing Agents (chemistry, pharmacokinetics)
• Protein Binding
• Rabbits
• Radionuclide Imaging
• Radiopharmaceuticals
• Technetium
• Tissue Distribution