Iodine-125

(pen-tetate)

💊 Chemical information

Iodo 125.
CAS — 14158-31-7.
ATC — V09CX03 (sodium iotalamate ( 125 I)); V09GB01 (fibrinogen ( 125 I)); V09GB02 (iodinated human albumin ( 125 I)); V09IX03 (iodine CC49 monoclonal antibody ( 125 I)).
ATC Vet — QV09CX03 (sodium iotalamate ( 125 I)); QV09GB01 (fibrinogen ( 125 I)); QV09GB02 (iodinated human albumin ( 125 I)); QV09IX03 (iodine CC49 monoclonal antibody ( 125 I)).
HALF-LIFE. 60.1 days.

💊 Profile

Iodine-125 has similar adverse effects and precautions to those of iodine-131 (see below). Iodine-125 is not very suitable for the external counting of radioactivity in the thyroid gland because its gamma-energy is weak and tissue absorption is high. However, it is very suitable for radio-immunoassays in vitro and because it has a long half-life it is preferred as a label for many compounds to detect and estimate drugs and hormones in body fluids. Iodine-125 has been used orally as sodium iodide (125I) in the diagnosis of thyroid disorders. Sodium iotalamate (125I) has been used intravenously in the determination of glomerular filtration rate and sodium iodohippurate (125I) intravenously for the measurement of effective renal plasma flow. Iodine-125, as iodinated (125I) human fibrinogen, has been used intravenously to demonstrate and locate deep-vein thrombosis of the leg. Iodinated (125I) fibrinogen has also been used in the measurement of fibrinogen metabolism in certain disturbances of blood coagulation. Human albumin iodinated with iodine-125 has been used for the determination of blood or plasma volume. Iodine-125 implants have been used for the local treatment of cancers (brachytherapy). Titanium capsules containing iodine125 adsorbed onto a silver rod have been used in the treatment of cancers of the head and neck, lung, pancreas, and prostate. Brain tumours have been treated with titanium capsules containing iodine-125 adsorbed onto anion exchange resin spheres.

Breast feeding.

The American Academy of Pediatrics has stated1 that temporary cessation of breast feeding is required after exposure to iodine-125 since radioactivity has been reported to be present in breast milk for 12 days.
1. American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 2001; 108: 776–89. Correction. ibid.; 1029. Also available at: http://aappolicy.aappublications.org/cgi/content/full/ pediatrics%3b108/3/776 (accessed 01/07/04)

💊 Preparations

Ph. Eur.: Human Albumin Injection, Iodinated ( I); USP 31: Iodinated I 125 Albumin Injection; Iothalamate Sodium I 125 Injection.

Proprietary Preparations

Austral.: OncoSeeds; Rapid Strand; USA: Glofil.
Published October 30, 2018.