Iophenoxic acid, an iodinated marker, and a radiocontrast agent used to investigate the feeding behavior of bait-consuming animals. This compound has high-affinity binding to the human albumin and has a long half-life in the body that is why this drug as withdrawn from the clinical use.

Iotroxic acid (INN), also known as meglumine iotroxate (BAN) (Biliscopin) for infusion is indicated for radiological examination of the hepatic and biliary ducts and gallbladder when examination by oral technique is unsuccessful or inappropriate. Following intravenous administration Biliscopin is rapidly excreted, mainly by the liver into the bile. Visualisation of the hepatic and common bile ducts and the gallbladder can, therefore, be achieved. Visualisation of the biliary ducts is usually possible 30-60 minutes after completion of administration. In vitro meglumine iotroxate binds to plasma proteins to the extent of 60-90% depending on concentration. In animals it crosses the placental barrier. This agent is the single intravenous cholangiographic agent, which is currently available in Australia.

Iodine-labeled ioglycamic acid (Bilivistan or Biligram) has been used as a contrast medium for intravenous cholangiocystography.

Ioxitalamic acid is a contrast media, which was used as a meglumine salt under the name Telebrix for intravenous urography; computed tomography; digital angiography; angiocardiography (ventriculography, coronary angiography). The drug is no longer available on the market.

Perfluorobutane (PFB) is an inert, high-density colorless gas used as a replacement for Halon 1301 in fire extinguishers, as well as the gas component for newer generation microbubble ultrasound contrast agents. Perflubutane has been used in clinical trials for the diagnostic of Liver Mass, Liver Diseases, Liver Metastasis, Portal Hypertension, and Peripheral Artery Disease. Perflubutane perfusion echocardiography has the potential to be a cost-effective and convenient alternative to nuclear perfusion imaging. Ultrasound enhanced with Perflubutane was able to image myocardial perfusion and obtain information that appears comparable to nuclear imaging.

Ioglicinate, contrast agent, is used in computed tomography.

Iodoalphionic acid is the contrast medium, which was used for gallbladder examination. It is rarely appeared in the colon and, therefore, rarely masked the gallbladder. The density of the shadow produced by Iodoalphionic acid was greater than that produced by iodophthalein. It was reliable peroral cholecystographic medium, which was less objectionable to take and seldom causes vomiting. Diarrhoea occurred in some cases, but not more often than with tetraiodophenolphthalein. The ingestion of Iodoalphionic acid resulted in low thyroidal radioiodine accumulation for periods ranging from a few weeks to many months.

Lidofenin is ligand for a coordination complex consisting of the radioisotope technetium-99m. Technetium Lidofenin is a nontoxic radiopharmaceutical that is used in radionuclide imaging for the clinical evaluation of hepatobiliary disorders in humans. Technetium lidofenin is indicated as a hepatobiliary imaging agent for the evaluation of hepatobiliary tract patency to differentiate jaundice resulting from hepatocellular causes from jaundice resulting from partial or complete biliary obstruction; to differentiate extrahepatic biliary atresia from neonatal hepatitis; to detect cystic duct obstruction associated with acute cholecystitis nd to detect bile leaks. Also, technetium Tc 99m lidofenin may be useful to detect intrahepatic cholestasis and to distinguish it from other hepatobiliary diseases, which involve hepatocyte damage. Following intravenous administration, technetium Tc 99m–labeled IDA derivatives, such as lidofenin, become bound to plasma proteins (mainly albumin). In the liver, in the space of Disse, technetium Tc 99m lidofenin becomes dissociated from the proteins and enters the hepatocyte by a mechanism similar to that of serum bilirubin. Technetium Tc 99m lidofenin traverses through the hepatocyte unmetabolized and enters the bile canaliculi. Flow beyond the canaliculi is influenced to a large extent by the tone of the sphincter of Oddi and the patency of the bile ducts. Clear visualization of the gallbladder and intestines, usually within 15 to 30 minutes of administration, demonstrates hepatobiliary tract patency.

Amogastrin [INN, JAN] is a pseudopeptide which acts as a Cholecystokinin receptor agonist(CCKs or. 'gastrin receptor'), and a gastric acid secretion stimulant. Is used as a diagnostic agent.

Iobenguane, mainly use as a radiopharmaceutical, used in a scintigraphy method called MIBG scan. Synthetic guanethidine derivative that locates phaeochromocytomas and neuroblastomas. The radioisotope used can either be iodine-123 for imaging or iodine-131 for destruction of tissues that metabolize noradrenaline. Iodine 123 is a cyclotron-produced radionuclide that decays to Te 123 by electron capture. Images are produced by a I123 MIBG scintigraphy. It localizes to adrenergic tissue and thus can be used to identify the location of tumors such as pheochromocytomas and neuroblastomas. With I-131 it can also be used to eradicate tumor cells that take up and metabolize norepinephrine. The radioactive iodine component is responsible for its imaging properties. Iobenguane and guanethidine are substrates for the norepinephrine transporter (NET) and accumulate by the uptake mechanism into presynaptic nerve endings. Unlike norepinephrine, these drugs are protonated under physiologic conditions; therefore, they do not cross the blood–brain barrier and in vivo uptake is limited primarily to systemic neuronal tissue. The accumulation of iobenguane in myocardial tissue is also dictated by the high fraction of aortic blood flow that enters the coronary arteries. This physiology constitutes an ideal molecular targeting mechanism for diagnosis of various cardiac diseases, including heart failure, heart transplant rejection, ischemic heart disease, dysautonomia, and drug-induced cardiotoxicity, as well as cardiac neuropathy related to diabetes mellitus and Parkinson disease