Disclosed are nanoparticles comprising an end-modified poly(β-amino ester) and an additive that is a sugar or sugar derivative, such as a sugar, a sugar alcohol or chitosan. The nanoparticles may be used in any field where polymers have been found useful, including in medical fields, particularly in drug delivery. The polymers are useful in delivering a polynucleotide such as DNA, RNA or siRNA, a small molecule or a protein. Also disclosed are compositions comprising said nanoparticles and an active agent, methods for preparing said nanoparticles, said nanoparticles and compositions for use in medicine, and in vitro methods using said nanoparticles and compositions本發明揭示奈米粒子,其包含末端修飾之聚(β-胺基酯)及添加劑,其為糖或糖衍生物(例如糖、糖醇或幾丁聚糖)。該等奈米粒子可用於任何適合使用該聚合物之領域,包括醫療領域,特定言之,用於藥物傳送。該等聚合物可用於傳送聚核苷酸(如:DNA、RNA或siRNA)、小分子或蛋白質。本發明亦揭示包含該等奈米粒子及活性劑之組合物、製備該等奈米粒子之方法、用於醫藥之該等奈米粒子及組合物、及使用該等奈米粒子及組合物之活體外方法。
