ADCs combine the high specificity of monoclonal antibodies and potent cytotoxic drugs connected by a cleavable or non-cleavable linker for targeted drug payload delivery . Presently, 15 ADCs have obtained approval from Food and Drug Administration (FDA) or European Medicines Agency (EMA) . ADCs are typically designed to stay intact while in circulation and release their drug payload upon target-mediated internalization into tumor cells, maximizing therapeutic index (TI). The linker design plays a major role in modulating the timing and location of drug release . However, biotransformation of ADCs, such as payload deconjugation or modification to the antibody, drug or linker can impact their in vivo stability . Hence, in-depth characterization of ADC biotransformations would aid in their chemical optimization influencing in vivo stability.