摘要:
New multi-valent, carbohydrate ligands that contain terminal N-acetylgalactosamine (GalNAc) or lactose (Lac) were prepared using a nitrilotriacetic acid (NTA) derivative of L-lysine as scaffold. Tri-valent structures were prepared by attaching an x-amino glycoside of GalNAc or Lac to each of the three carboxyl groups of N-epsilon-protected N-alpha-dicarboxymethyl-L-lysine. In addition, a hexa-valent lactoside was synthesized by attaching N-epsilon-deprotected trivalent lactoside to each of the carboxyl group of N-alpha-(trifluoroacetamido) hexanoyl L-aspartic acid. Tri-valent GalNAc glycosides and the hexa-valent lactoside had high affinity (dissociation constants approaching nM) for rat hepatocytes. The hexa-valent lactoside, after de-Ne-protection, was modified with a chelator, diethylenetriaminepentaacetic acid (DTPA), through which a fluorescent or radioactive tag, such as europium or indium, can be firmly attached. Intravenous infusion of (111)Indium-tagged hexa-valent lactoside to rats and mice resulted in nearly exclusive accumulation of radioactivity in the liver.(C) 2011 Elsevier Ltd. All rights reserved.