Used in the synthesis of antibody-drug conjugates (ADCs), this compound serves as a linker that connects cytotoxic drugs to monoclonal antibodies. Its structure allows for stable attachment in circulation while enabling selective release of the active drug inside target cells, particularly in cancer therapy. The valine-citrulline (Val-Cit) dipeptide core is cleavable by cathepsin B, an enzyme overexpressed in tumor tissues, ensuring targeted drug delivery. The propionyl group enhances stability and modulates the rate of drug release, improving the therapeutic index of ADCs. Widely applied in oncology drug development, it contributes to the efficacy and safety of next-generation biopharmaceuticals.