Hexavalent lactoside labeled with [ 18 F]AlF for PET imaging of asialoglycoprotein receptor.

Several methods have been developed to label compounds with 18F. However, in general these are laborious and require a multistep synthesis. A method based on the chelation of 18F-aluminum fluoride ([18F]AlF) by 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) was developed recently. The present work was aimed to radiolabel hexavalent lactoside (NOTA-HL) by [18F]AlF method for PET imaging of asialoglycoprotein receptor (ASGPR). Methods: hexavalent lactoside was conjugated with the NOTA chelate and labeled with 18F in a one-pot method. The labeling procedure was investigated with different amounts of NOTA-HL and aluminum concentration. Radiochemical yield and radiochemical purity were determined by radio-TLC and radio-HPLC respectively. In vitro stability study of [18F]AlF-HL were carried out. PET/CT imaging of normal mice injected with [18F]AlF-NOTA-HL was performed. Results: The Radiochemical yield of [18F]AlF-NOTA-HL was higher with more precursor and optimal Al+ concentration. The radiochemical purity of labeled product was >95% after purified by Sep-Pak cartridge to remove unbound [18F]AlF. The radiolabeling, including purification, was performed in 30 min [18F]AlF-NOTA-HL exhibited good in vitro stability. PET studies in normal mice revealed high specific accumulation of activity in the liver. Conclusion: NOTA-HL could be labeled rapidly and efficiently with aqueous 18F using AlF method. [18F]AlF-NOTA-HL would provide another efficient approach for PET imaging of ASGPR.