Toward Accurate and Robust Liquid Chromatography–Mass Spectrometry-Based Quantification of Antibody Biotherapeutics in Tissues

protein recovery from tissues of dosed animals; with this method, we found mAb biotherapeutics present in free-(49.3-75.4%) and bound-forms (24.6-50.7%) in tissues, even without a target; therefore, a denaturing detergent buffer is necessary for exhaustive extraction (recovery>90%); third, overnight-incubation of calibration samples after spiking mAb to tissue was found to improve quantitative accuracy, especially for nondenaturing buffer extraction. These investigations established the critical parameters and optimal protocols that can be universally applied to achieve accurate and robust quantification of biotherapeutics/targets in tissues. As a proof of concept, we conducted the first-ever extensive pharmacokinetics measurement of mAb in major tissues with a LC-MS-based method, where interesting features of mAb tissue disposition were observed.