Whole blood stability testing is one of the most important in vitro tests to evaluate ADC stability, and can be run in high-throughput screening mode. The whole blood stability assay incubates antibody-drug conjugates (ADCs) in various animal and human whole blood at 37°C of varying length of time to simulate the in vivo condition. A critical criteria for ADC assessment is the stability profile and integrity of the molecule to carry the payload to the site of the targeted tissue/cell. During the discovery phase, the potential liabilities on ADC stability can be evaluated in vitro, as the surrogate test of expensive and time-consuming in vivo animal test to sift out less stable ADC.

At NovaBioAssays, we provide the workflow to evaluate ADC stability in whole blood from different species including mouse, rat, monkey and human. Briefly, the workflow involves automated steps for immunoprecipitation of the ADC from blood, UPLC or microHPLC separation of the ADC, intact MS analysis and calculation for Drug to Antibody (DAR) ratio. All those steps are critical to have a clean MS spectra of the ADC after incubation with blood. Our extensive experience on bioanalysis and analytical chemistry enabled us to not only conduct the DAR calculation but also identify minor peaks representing degradant species. The information can be used to evaluate and decide which conjugation method (site specific or non-specific), or which linker-payload combination is more stable in blood, as well as making decisions to trouble-shoot the degradation problems.