Preclinical evaluation of 99mTc labeled gefitinib as a potential scintigraphic probe for the detection of tumors expressing epidermal growth factor receptors

•Gefitinib – an epidermal growth factor receptor inhibitor was successfully radiolabeled with 99mTc and the resultant radiolabel 99mTc-gefitinib had high radiolabeling efficiency and in vitro stability.•The radiotracer cleared from blood bi-exponentially.•Animal organ biodistribution data demonstrated hepato-renal excretion of the radiotracer.•Gamma camera imaging in tumor bearing mice demonstrated that the radiotracer accumulated in the tumor site with high target to non target ratio.•The diagnostic efficacy of 99mTc-gefitinib needs clinical validation in tumors expressing high EGFR density.

In the present study, we successfully radiolabeled gefitinib with 99mTc by direct labeling method. The radio-ligand had radiolabeling efficiency of >95.0% and in vitro stability of >80.0% at 24 h. The radiotracer cleared from blood bi-exponentially. Animal organ biodistribution data indicated hepato-renal excretion of the radiotracer. Scintigraphy carried out in tumor bearing mice (induced by EGFR expressing EAT cell lines) demonstrated that the radiotracer accumulated in the tumor site with T/NT ratio of 3.3±0.2 at 1 h.