The invention relates to that is obtainable by reacting distearoylphosphatidylethanolamine-polyethylene glycol-maleimide (DSPE-PEG-MAL) with a ligand for a glutathione receptor having a maleimide-reactive thiol group and to liposome comprising such conjugates. The conjugates and liposomes are used for targeted drug delivery of drugs to intracellular target sites within cells, tissues and organs, in particular to target sites within the central nervous system (CNS), into and across the blood-brain barrier, by targeting to internalizing uptake receptors present on these cells, tissues and organs.
