iodinated

Iodinated describes a molecule that contains iodine atoms either through substitution of hydrogen or other groups, or by incorporating iodine into its structure. In organic chemistry, iodination refers to the process of introducing iodine into a substrate, often by electrophilic substitution or nucleophilic displacement, using reagents such as I2 with an oxidant or N-iodosuccinimide (NIS).

Common end products include iodoaromatic compounds (for example iodobenzene) and a range of iodinated alkanes and alkenes. Iodination can influence properties such as reactivity, polarity, and biological activity, and is a routine step in synthesis of pharmaceuticals, dyes, and specialty materials.

Medical uses are dominated by iodinated substances. Iodinated contrast agents (for example iohexol, iopamidol) are widely used in radiology because iodine's high atomic number yields strong X-ray attenuation. Radiolabeled iodinated compounds, using isotopes such as iodine‑123, iodine‑125, iodine‑131, or iodine‑124, are employed in diagnostic imaging and targeted radiotherapy, particularly for thyroid disorders and certain cancers.

Examples include the historical antiseptic iodoform; iodinated aromatic compounds; and various iodinated pharmaceuticals. Iodination can also occur biologically, for example during the enzymatic iodination of tyrosine residues in proteins, and in the thyroid's uptake and metabolism of iodine.

Safety and regulation relate to iodine content and radioactivity. Excess iodine can disrupt thyroid function; allergic reactions to iodinated contrast can occur; radiolabeled compounds require careful dosing and shielding to minimize radiation exposure.