2-Octadecyleicosanoic Acid Methyl-d3 Ester is labelled 2-Octadecyleicosanoic Acid Methyl Ester (O235970), the Methyl Ester of 2-Octadecyleicosanoic acid (O235960) which is used as a reagent to synthesize Lipid Oligonucleitide Conjugates, compounds that act as a “drug delivery” system to mutated/infected cells.