Quantitative imaging of tyrosine kinase inhibitor distribution in live cells and tissues

Intracellular drug target validation and target engagement quantification have proven to be challenging, and all drugs have some degree of non-specific accumulation due to variable drug affinity, biodistribution, pharmacokinetics, and metabolism. Quantification of available drug targets necessitates accounting for both the drug that binds to its target as well as the drug that accumulates in the cells and tissues in a non-specific manner. We have developed a dynamic, fluorescence-based, three-compartment model termed intracellular paired-agent imaging that utilizes fluorophore labeled small molecule therapeutics as imaging agents to measure drug target availability in live cells and tissues.