Amino-PEG-benzyl ester is a class of molecules that belongs to the PEGylation family. It is a PEG-based polymer with a benzyl ester functional group at one end and an amine functional group at the other end. This type of molecule is widely used in pharmaceutical research and development due to its unique properties, which make it an excellent candidate for drug delivery systems. The amino group can be used for conjugation with various active molecules, while the PEG chain provides increased solubility, improved biocompatibility, and extended circulation time. Furthermore, the benzyl ester group can be easily cleaved under mild conditions, enabling controlled drug release.