1,2-Distearoyl-d70-sn-glycero-3-phosphocholine is a deuterated phospholipid primarily used in the formulation of liposomes for drug delivery systems, including targeted cancer therapies. The saturated stearoyl chains provide high stability to liposomal bilayers, enabling controlled release of encapsulated drugs. It is commonly incorporated into stealth liposomes (often with PEGylation) to reduce immune recognition, prolong circulation time in the bloodstream, and enhance tumor accumulation via the enhanced permeability and retention (EPR) effect, thereby improving pharmacokinetics. The deuterium labeling (d70) is particularly valuable in research for studying membrane dynamics, lipid behavior in bilayers, and molecular interactions using techniques such as NMR spectroscopy or mass spectrometry, due to its well-defined structure and lack of proton interference.