For the first biotransformation case, involving the topoisomerase I inhibitor-conjugated ADC, plasma samples (post-dose timepoints = 1, 24, 72, 120, 168, and 336 h) from cynomolgus monkey (n=1) dosed with ADC1 (a DAR8 ADC containing a topoisomerase I inhibitor-AZ14170132) at 15 mg/kg were subjected to immunocapture with SMART IA streptavidin magnetic beads coupled with anti-human Fc, washed extensively with PBS and water. Approximately 1 µg of enriched ADC was eluted with 1 % (v/v) formic acid (FA). The eluate was subjected to chromatography separation with Waters BioResolve RP mAb polyphenyl column (PN186009017; 1% FA, 0.01 % TFA in water/ACN as mobile phases) followed by mass spectrometry analysis on SCIEX 7600 Zeno TOF.