Tetraethylene glycol monotosylate is a cleavable and acylhydrazone-based ADC linker used in the synthesis of antibody-drug conjugates (ADCs). Tetraethylene glycol monotosylate also can be used as a PROTAC linker that can be used in the synthesis of PROTACs.In Vitro: ADCs are comprised of an antibody to which is attached an ADC cytotoxin through an ADC linker.