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以还原胺化法合成了半乳糖多聚－Ｌ－赖氨酸（ＧａｌＰＬＬ），并首次利用放射性示踪实验测定了ＧａｌＰＬＬ在小鼠体内的肝靶向特征．结果表明，ＧａｌＰＬＬ具有较高的肝靶向性，其在体内的分布形式与肝细胞去唾液酸糖蛋白受体（ＡＳＧＰＲ）的内源性配体去唾液酸胎球蛋白（ＡＳＦ）相似．１２５Ｉ标记的ＧａｌＰＬＬ经静脉注入小鼠体内后，主要被肝脏吸收，在注射后５ｍｉｎ时肝脏的最大吸收为注射总量的３８．９％，比人血清白蛋白高５．７倍．肝脏对ＧａｌＰＬＬ的吸收可特异地被ＡＳＦ及非标记的ＧａｌＰＬＬ抑制，但不能被未半乳糖基化的多聚－Ｌ－赖氨酸抑制，证明ＧａｌＰＬＬ是通过肝细胞ＡＳＧＰＲ介导的内吞作用特异地被肝脏吸收的．由于ＧａｌＰＬＬ不但具有较高的肝靶向性，而且与ＡＳＧＰＲ的天然配体相比在合成和应用方面均具有许多优势，因此有望成为进行药物或基因肝靶向运送的良好载体．
Galactose-poly-L-lysine (GalPLL) was synthesized by reductive amination, and the liver targeting characteristics of GalPLL in mice were determined by radioactive tracing assay for the first time. The results show that GalPLL has a high degree of liver targeting and its distribution in vivo is similar to that of aspartate fetuin (ASF), an endogenous ligand of the asialoglycoprotein receptor (ASGPR) of hepatocytes. 125I-labeled GalPLL was mainly absorbed by the liver after intravenous injection into the body. The maximum absorption of the liver at 5 min after injection was 38.9% of the injected volume and 5.7-fold higher than that of the human serum albumin. Absorption of GalPLL by the liver can be specifically inhibited by ASF and non-labeled GalPLL but not by non-galactosylated poly-L-lysine, demonstrating that GalPLL is specific for endocytosis mediated by hepatocyte ASGPR Absorbed by the liver. GalPLL is expected to be a good carrier for drug or gene-targeted liver delivery as it not only has high liver targeting but also has many advantages in synthesis and application as compared with the natural ligand of ASGPR.