Radiosynthesis and biodistribution studies of [62Zn/62Cu]-plerixafor complex as a novel in vivo PET generator for chemokine receptor imaging

In order to develop a possible C-X-C chemokine receptor type 4 (CXCR4) imaging agent for oncological scintigraphy, [Zn-62]labeled 1,1'-[1,4-phenylenebis(methylene)]bis-1,4,8,11-tetraazacyclotetradecane ([Zn-62]-AMD3100) was prepared using in-house made [Zn-62]ZnCl2 and AMD-3100 for 1 h at 50 degrees C (radiochemical purity: >97 % ITLC, >96 % HPLC, specific activity: 20-22 GBq/mmol) in acetate buffer. The complex showed highly hydrophilic properties (log P = -1.114). Stability of the complex was checked in presence of human serum (37 degrees C) and in final formulation for 1 day. The biodistribution of the labeled compound in vital organs of wild-type Sprague-Dawdley rats were determined and compared with that of free Zn2+ cation up to 6 h. Co-incidence imaging of the complex was consistent with the distribution data up to 3 h. The complex can be a possible in vivo generator compound for PET imaging in CXCR4 positive tumors.