Disclosed are compounds represented by formula (1), or their tautomers, meso compounds, racemic compounds, enantiomers, diastereomers, mixtures thereof, or pharmaceutically acceptable salts, prodrugs, or solvates thereof. The structure of formula (1) is shown below. By introducing strongly hydrophilic
sulfonic acid inner salts and / or
phosphate inner salt side chains at the polypeptide (VC, VA, AAA, etc.)-PAB (self-destructing group) position of the
linker, the compounds significantly improve the
druggability (including hydrophilicity and stability) of the
antibody-
drug conjugates corresponding to the compounds, reduce
drug clearance in the body, and enhance tumor therapeutic effects.
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