Mass Spectrometry Detection and Imaging of a Non‐Covalent Protein–Drug Complex in Tissue from Orally Dosed Rats

Here, we demonstrate detection by mass spectrometry of an intact protein–drug complex directly from liver tissue rats that had been orally dosed with the drug. The comprised fatty acid binding protein 1, FABP1, non-covalently bound to small molecule therapeutic bezafibrate. Moreover, spatial mapping [FABP1+bezafibrate] across a thin section targeted imaging. This work is first demonstration in situ analysis non-covalent formed vivo and has implications for early stage drug discovery providing route target-drug characterization physiological environment.