Used primarily in the field of drug delivery and targeted therapy, particularly in the development of antibody-drug conjugates (ADCs). It serves as a linker molecule that connects a cytotoxic drug to a monoclonal antibody, enabling precise delivery of the drug to cancer cells. The structure includes a self-immolative para-aminobenzyl (PAB) group, which allows for the controlled release of the drug upon cleavage by specific enzymes, such as cathepsin B, found in tumor cells. The Boc group provides protection during synthesis, while the Val-Cit dipeptide sequence enhances stability in circulation. This chemical is critical for improving the efficacy and reducing the off-target toxicity of cancer treatments.