Used in pharmaceutical synthesis as a linker in antibody-drug conjugates (ADCs), enabling targeted delivery of cytotoxic agents to cancer cells. Its polyether backbone provides water solubility and flexibility, while the terminal carboxylic acid allows for conjugation to antibodies or drugs. The structure includes cleavable bonds that can be designed to release the active drug under specific biological conditions, such as in the acidic environment of tumors or inside lysosomes. Also employed in bioconjugation research due to its biocompatibility and ease of modification.