The ends of the molecular chain of Benzyl-PEG-Glycol are benzyl and glycol, respectively. It is a PEG linker with a benzyl protective group and a reactive primary alcohol. Hydrophilic PEG joints increase the water solubility of the compounds in aqueous media. PEG modification can form a spatial barrier around the drug, reduce enzymatic hydrolysis of the drug, avoid rapid elimination of kidney metabolism.