Used in drug delivery systems to enhance the stability and circulation time of therapeutic agents. Its cholesterol component allows for integration into lipid membranes, making it useful in liposome and nanoparticle formulations. The PEG 600 chain provides hydrophilic properties that reduce immune recognition and prevent rapid clearance from the bloodstream. Commonly applied in targeted cancer therapies and gene delivery due to its ability to improve cellular uptake and bioavailability of drugs. Also utilized in diagnostic imaging agents to prolong in vivo half-life.