Ga-Glutathione radio-complex as a new diagnostic probe for targeting colon cancer in rats.

Objective: Glutathione (GSH) plays an important role in a horde of cellular events that include cell proliferation and apoptosis.The present study describes the radio-synthesis and characterization of gallium-68 (Ga)-labelled glutathione for its application in radionuclide imaging of cancer.

Subject And Methods: The radio-synthesis of radio-complex Ga-GSH was performed by the direct labeling method. The developed radio-complex was subjected to quality control tests. Colon tumors were developed in healthy male Sprague Dawley (S.D) rats by giving subcutaneous injections of dimethylhydrazine (DMH) in order to monitor the uptake of Ga-GSH radio-complex.

Results: Gallium-68-labelled glutathione was synthesized with a labeling efficiency of 73.5%±1%. Percentage plasma protein binding and log Po/w values for the radio-complex were found to be 20%-30% and -0.223±0.12, respectively. A significantly higher percentage specific uptake value of newly developed Ga-GSH complex was observed in colon tumor in comparison to soft tissue at 90 minutes post administration thereby exhibiting specificity for cancerous cells, which was also witnessed significantly increased overtime from the ratio of colon tumor uptake to normal colon uptake (P≤0.05).

Conclusion: Therefore, Ga-labelled glutathione can further be exploited for radionuclide imaging and assessment of tumor drug resistance in patients.