Mesalamine was labelled with technetium-99m ( 99m Tc) in high radiolabelling yield (*98.4 %), in vitro stability (*4 h) and in serum persistence (*24 h). Optimum labelling conditions were investigated. The structure of the complex was confirmed using in silico analysis. Molecular docking was performed to evaluate the complex binding to its biochemical target, the PPARc receptor. Biodistribution and clearance studies were performed in normal and ulcerative colitis models in mice. The tracer's localization was highest (*65.2 %) in microbial model compared to chemical model (*42.4 %) and normal mice (*22.1 %) at 60 min post injection. All data supported the usefulness of 99m Tc-mesalamine as a radiotracer for ulcerative colitis.

Lung imaging radiopharmaceuticals are helpful agents for measuring pulmonary blood flow and allow detection of pulmonary embolism and lung cancer. The goal of this study was to develop a novel potential radiopharmaceutical for lung imaging. Zolmitriptan (a selective serotonin receptor agonist) was successfully labeled with Tc via direct labeling method under reductive conditions studying different factors affecting the labeling efficiency.Tc-zolmitriptan was obtained with a maximum labeling yield of 92.5 ± 0.61 % and in vitro stability up to 24 h. Molecular modeling was done to predict the structure of Tc-zolmitriptan and ensure that radiolabeling did not affect binding ability of zolmitriptan to its receptor. Biodistribution studies showed that maximum lung uptake ofTc-zolmitriptan was 23.89 ± 1.2 % injected dose/g tissue at 15 min post-injection and retention in lungs remained high up to 1 h, whereas the clearance from mice appeared to proceed mainly via the renal pathway. Scintigraphic images confirmed the biodistribution results showing a high resolution lung image with low accumulation of radioactivity in other organs except kidneys and urinary bladder. Tc-zolmitriptan is not a blood product and so it is more safe than the currently availableTc-MAA, and its lung uptake is higher than that of the recently discovered I-IPMPD,Tc(CO)I and Tc-DHPM. So,Tc-zolmitriptan could be used as a hopeful radiopharmaceutical for lung scintigraphic imaging.

Famotidine was labeled with iodine-125 to obtain

Nizatidine has been labeled using [ I] with chloramine-T as oxidizing agent. Factors such as the amount of oxidizing agent, amount of substrate, pH, reaction temperature, and reaction time have been systematically studied to optimize the iodination. Biodistribution studies indicate the suitability of radioiodinated nizatidine as a novel tracer to image stomach ulcer. Radioiodinated nizatidine may be considered a highly selective radiotracer for peptic ulcer imaging.

Irbesartan was labeled using 125I or 131I with N-bromosuccinimide (NBS) as an oxidizing agent. A lot of operators such as, quantity of substrate, the quantity of oxidizing agent, reaction temperature, reaction time, and pH of reaction medium were studied to optimize high radiochemical yield of [125I]IodoIrbesartan ([125I]Irb.). The preclinical evaluation of IodoIrbesartan in experimental mice indicated high accumulation in target organ of heart with a high heart/blood ratio of 12.85 at 30 min post-injection. This study indicates the suitability of [125I]IodoIrbesartan ([125I]Irb.) for cardiac imaging.