ASTATINE-211-LABELED BIOTIN CONJUGATES RESISTANT TO BIOTINIDASE FOR USE IN PRETARGETED RADIOIMMUNOTHERAPY

We report herein the preparation and biological evaluation of two radi oastatinated biotin conjugates, (3-[At-211]astatobenzoyl)norbiotinamid e and At-211]astato-3-pyridinyl)carbonyl)norbiotinamide. Both conjugat es were stable in the presence of human serum and cerebrospinal fluid as well as murine serum, indicating a resistance to degradation to bio tinidase. The normal tissue clearance of (3-[At-211]astatobenzoyl)norb iotinamide and [At-211]astato-3-pyridinyl)carbonyl)norbiotinamide was rapid, as observed previously with their iodo analogues. Also reported are the first syntheses of N-succinimidyl 5-[At-211]astato-3-pyridine carboxylate and 3-[At-211]astatoaniline, two reagents of potential uti lity for labeling proteins and peptides with At-211. (C) 1998 Elsevier Science Inc.