Polyethylene glycol (PEG)-lipids have been the polymer-lipid conjugate of choice for lipid formulations for decades. PEG-lipids are used increase systemic circulation times, mediate indirect targeting capabilities, promote LNP self-assembly, control size and aid in storage stability. Particles containing PEG-lipids are able to bypass the reticulo-endothelial system, giving them their nickname - “stealth agents”. The DMPE lipid anchor has 2 saturated 14-carbon chains and an ethanolamine headgroup.
Functions include:
- Increased half life when administered systemically
- Aids in storage ability
- Helps obtain small particle sizes.