Sodium-2-[(3-butanoylamino-2,4,6-triiodo-phenyl)methyl]butanoate

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Cheng KT

Sodium-2-[(3-butanoylamino-2,4,6-triiodo-phenyl)methyl]butanoate

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PubMed ID

20641974 [ View in PubMed

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Abstract

Sodium-2-[(3-butanoylamino-2,4,6-triiodo-phenyl)methyl]butanoate (tyropanoate sodium) is an oral X-ray cholecystographic agent used to aid the radiographic visualization of the gallbladder for detecting the presence of gallstones in cholelithiasis patients (1-4). Clinically, this technique is largely superseded by ultrasound, computed tomography (CT; without contrast), and nuclear medicine techniques and is used only for selected patients (5-7). Studies in 1999-2000 reported that it might be feasible to use this class of agents with helical CT cholangiography (8). Radiographic imaging of the gallbladder depends on the opacification of the gallbladder with an oral cholecystographic agent. Solubilization in the intestinal lumen, absorption across the intestinal mucosa, transport in the blood, uptake and excretion by the liver and final concentration of the agent in the gallbladder allow X-ray imaging of the gallbladder and the biliary tree (9-12). Cholecystographic agents are generally weak organic acids that contain a tri-iodinated benzene ring with iodine at positions 2, 4 and 6 (2, 7, 13-16). This class of compounds includes iocetamic acid, iopanoic acid, bunamiodyl sodium and ipodate. Their major chemical differences are the different substituents at positions 1 and 3 on the aromatic ring. The hydrophobic and hydrophilic properties of these substituents determine the aqueous and lipid solubility of the compound, and it must be sufficiently lipophilic to pass through the gastrointestinal mucosa. The absence of a substituent at position 5 allows the compound to bind to serum albumin and facilitates preferential hepatocyte uptake. The exact hepatic uptake mechanism is not entirely known. The agent is then metabolized by glucuronide conjugation in the same pathway as bilirubin (17-19). These glucuronide-conjugated compounds are readily excreted into the bile, follow the bile flow to fill up the gallbladder, and then are excreted by the biliary system in the feces. Tyropanoate sodium was first synthesized in1962 as a modification of an earlier cholecystographic agent, iopanoic acid, in an effort to decrease its toxicity (1, 15, 20). Based on the fact that aromatic amino compounds are detoxified in vivo by acetylamino groups, tyropanoate sodium was developed and was different from iopanoic acid, chiefly in the butyrylation of the amine group. Whereas iopanoic acid is insoluble in water, tyropanoate sodium as a salt is soluble in water. The greater aqueous solubility of tyropanoate sodium and the lack of effect of bile acids on its hepatic excretion favor its oral absorption in the fasting state (21). The commercial formulation of tyropanoate sodium contains approximately 57.4% iodine for producing the necessary X-ray attenuation and organ opacification (1, 2, 4). It is no longer marketed in the United States.

DrugBank Data that Cites this Article

Drugs

Iopodic acid

Drug Carriers

Drug	Carrier	Kind	Organism	Pharmacological Action	Actions
Iopodic acid	Serum albumin	Protein	Humans	No	Substrate	Details