Radiochemical and Biological Characterization of some Radiolabeled Drugs for Nuclear Medicine Applications

Abstract

This study aimed to take advantages from drugs that are able to cross the blood-brain barrier for the development of potential radiopharmaceuticals for non-invasive brain imaging. Tizanidine hydrochloride, quetiapine fumarate and cyclobenzaprine hydrochloride were successfully labeled with radioactive iodine (125I) using chloramine-T via an electrophilic substitution reaction.125I-tizanidine, 125I-quetiapine and 125I-cyclobenzaprine gave maximum labeling yields of 92.8 % ± 0.1, 94.5 % ± 1.5 and 91.7 % ± 0.6, respectively. Biodistribution studies showed that the maximum uptake of radioiodinated tizanidine and quetiapine by the brain of mice was 5.2 % and 3.5 %, respectively, at 120 min post injection while the maximum uptake of radioiodinated cyclobenzaprine was 2.9 % at 240 min post injection. The SPECT imaging confirmed the results of biodistribution studies.