A simple method for iodination of heterocyclic compounds using HIO4/NaCl/silica gel/H2SO4 in water

Radiosynthesis and in silico bioevaluation of 131 I-Sulfasalazine as a highly selective radiotracer for imaging of ulcerative colitis

This study demonstrated the tracking of ulcerative colitis, which is considered a stressful immune disease. Although there are many ways to test for this disease including dependence on gases, dyes, and painful anal endoscopy, these treatment modalities have many disadvantages. Hence, it is the utmost need of time to discover new methods to detect this chronic immune disease and to avoid the defects of traditional methodologies. Sulfasalazine (SSD) was labeled with iodine-131 (half-life: 8 days, Energy: 971 keV) under optimum reaction conditions including the amount of reducing agent, pH factor, chloramine-T (Ch-T) amount, and incubation period. Characterization was performed using ¹ H/ ¹³ C-NMR, ESI-MS, and HPLC (UV/ Radio) techniques. The biodistribution study was performed in normal and ulcerative mice models, and in silico molecular docking study was performed to evaluate the possible mechanism of action to target peroxisome proliferator-activated receptor gamma (PPARγ). The high radiolabeling yield of [¹³¹ I]-sulfasalazine ([¹³¹ I]-SSD) was achieved ≥90% through the direct labeling method with radioactive iodine-131 in the presence of chloramine-T (100 μg). The radiotracer [¹³¹ I]-SSD was observed to be stable in normal saline and freshly eluted serum up to 12 hr at ambient temperature (37℃ ± 2℃). The radiotracer [¹³¹ I]-SSD showed the highest uptake in the targeted organ (i.e., ulcerative colon) which was observed to be ≥75% injected dose per gram (% ID/g) organ for 24 hr postinjection (p.i). Furthermore, in silico data collected from molecular modeling analysis of SSD and [¹³¹ I]-SSD with antimicrobial protein (PDB code: 3KEG) and peroxisome proliferator-activated receptor gamma (PPARγ) (PDB code: 4XTA) showed azoreductase activity and high binding potential for PPAR-γ site, respectively. The results of biological studies obtained in this study enlighten the usefulness of radiotracer [¹³¹ I]-SSD as a potential imaging agent for ulcerative colitis.

In silico and in vivo study of radio-iodinated nefiracetam as a radiotracer for brain imaging in mice

This study presents development and characterization of a radiotracer, [125I]iodonefiracetam ([125I]iodoNEF). Labeling with high yield and radiochemical purity was achieved through the formation of a [125I]iodoNEF radiotracer after investigating many factors like oxidizing agent content (chloramines-T (Ch-T)), substrate amount (Nefiracetam (NEF)), pH of reaction mixture, reaction time and temperature. Nefiracetam (NEF) is known as nootropic agent, acting as N-methyl-d-aspartic acid receptor ligand (NMDA). The radiolabeled compound was stable, and exhibited the logarithm of the partition coefficient (log p) value of [125I]iodonefiracetam as 1.85 (lipophilic). Biodistribution studies in normal mice confirmed the suitability of the [125I]iodoNEF radiotracer as a novel tracer for brain imaging. High uptake of 8.61 ± 0.14 percent injected dose/g organ was observed in mice

Radioiodinated celiprolol as a new highly selective radiotracer for β1-adrenoceptor-myocardial perfusion imaging

The present study was oriented to synthesis radioiodinated celiprolol (Cel) for a potential cardiac imaging. Celiprolol has been labeled using 125I with chloramine-T (Ch-T) as an oxidizing agent. The key effective factors such as amount of oxidizing agent, amount of substrate, pH, reaction temperature and reaction time, have been systematically studied to optimize the iodination. The biological distribution indicates the suitability of radioiodinated Cel as a novel tracer to image heart.

Radioiodination of olmesartan medoxomil and biological evaluation of the product as a tracer for cardiac imaging

The present study is oriented to synthesis of radioiodinated olmesartan medoxomil (OM) for potential cardiac imaging. Olmesartan medoxomil has been labeled with [125/131I] using chloramine-T (Ch-T) as an oxidizing agent. The key effective factors such as amount of oxidizing agent, amount of substrate, pH, reaction temperature and reaction time, have been systematically studied to get high radiochemical yield of the [125I]olmesartan medoxomil reaching values of 98.5%. The labeled compound was separated and purified using thin layer chromatography (TLC), paper electrophoresis and high performance liquid chromatography (HPLC). The biological distribution indicates the suitability of [125I]olmesartan medoxomil as a novel tracer to image heart with high heart/blood ratio within 30 min which was detected by gamma camera.

Radioiodination and biological evaluation of nizatidine as a new highly selective radiotracer for peptic ulcer disorder detection

Nizatidine has been labeled using [¹²⁵ 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.

Radioiodinated famotidine as a new highly selective radiotracer for peptic ulcer disorder detection, diagnostic nuclear imaging and biodistribution

Famotidine was labeled with iodine-125 to obtain 125I-famotidine (125I-fam) as an agent for ulcer imaging. The radiochemical yield of 125I-famotidine reached approximately 98.5 ± 0.23% at optimum conditions of pH, oxidizing agent, reaction time and the amount of substrate. 125I-fam was stable for 48 h. Different chromatographic techniques were used to determine the radiochemical yield and purity. Intravenous biodistribution studies of 125I-fam revealed high concentration in the stomach ulcer, reaching about 65.9 ± 0.28% of the total injected dose at 30 min post injection. This concentration of 125I-fam in stomach ulcer makes this agent promising for stomach ulcer imaging.