The present invention belongs to technical field of
medicine, and relates to the preparing of cleavable
polyethylene glycol (PEG) lipid derivative and an application thereof in the liquid particle preparation. The general formula is as follows: CH3O(CH2CH2O)n-R-O-R, n=5-5000. The molecular weight of PEG is 300-30000. R represents one group selected from hemisuccinate group and carbomethoxy. The liposoluble fragment represented by R comprises one component selected from
cholesterol, sitosterol, alpha-
tocopherol. According to the invention,
polyethylene glycol are connected with lipoid derivatives such as
cholesterol, alpha-
tocopherol, etc. through ester linkage. The cleavable
PEG lipid derivative can be applied to the modification of liquid particle preparation. On one hand, the
PEG lipid derivative has appropriate
adhesive force of the surface of liquid particle preparation and guarantees enough
holding time of
PEG lipid derivative in blood. On the other hand, the PEG lipid derivative can gradually break away from the surface of preparation in the circulation process. The particle preparation which only comprises a few
polyethylene glycol on the surface can combine and phagocytose the
pathological cell. The
medicine is delivered into the
cell and therefore has the function of selectively killing the
pathological cell.