99mTc-exorphin C: A new peptide radiopharmaceutical for tumor imaging

The aim of this study was to label exorphin C with 99mTc and to examine its usefulness as opioid receptor binding radiopharmaceutical in Albino Wistar rats. Exorphin C, which is a peptide with 5 aminoacids, was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Labeling efficiency was higher than 98%. The compound was stable for at least 5 hours at room temperature. Mammary tumor bearing Albino Wistar rats were imaged using gamma-camera. Biodistribution studies were also performed. Results demonstrated that 99mTc-glucoheptonate-exorphin C ( 99mTc-GE) analogs may be useful as a new class of receptor-binding peptides for the diagnosis and therapy of some cancer diseases related with opioid receptor-expressing tissues. © 2005 Akadémiai Kiadó.Parts of the study were presented in 2004 at the 6th International Congress of Nuclear Oncology, ÇeOme, Turkey. The authors thank for the financial supports of the Ege University Scientific Research Fund. -