{"entity":{"id":"dota-chelation","kind":"technology","name":"DOTA chelation","aka":["DOTA","1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid"],"tldr":"DOTA is a small ring-shaped molecule that grips a radioactive metal atom tightly inside its cage, so the metal stays attached to the drug instead of drifting off into the body.","summary":"DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) is a twelve-membered tetraaza macrocycle with four pendant carboxylate arms that together provide an octadentate (four nitrogen, four oxygen) cage for trivalent and some divalent radiometals. Complex formation proceeds through a diprotonated intermediate in which the metal sits outside the macrocyclic cavity, coordinated only to the four acetate arms; the rate-determining step is loss of the last ring-nitrogen proton, which lets the metal drop into the fully encapsulated, kinetically inert 'in-cage' geometry. Once formed at room temperature the complex does not revert, but formation itself is slow and usually needs heating (often 80-95°C) and, for large ions such as Ac3+, is inefficient because DOTA's cavity is sized for smaller lanthanide-like ions.\n\nThis chemistry underpins the majority of clinically used radiometal agents: 68Ga- and 177Lu-DOTATATE/DOTATOC, 90Y- and 177Lu-DOTA-conjugated peptides, and experimental 225Ac and 213Bi constructs. Its main practical strengths are extreme in vivo kinetic inertness (once formed, the metal essentially never leaves under physiological conditions) and a very large body of manufacturing and regulatory precedent. Its main limitations are the elevated temperature and time needed for labelling, which complicates heat-sensitive biomolecules such as antibodies, and its comparatively poor match to large ions like Ac3+, which has driven the search for alternative chelators such as macropa.","asOf":"2026-09-22","links":[{"label":"Price & Orvig, Chem Soc Rev 2014: Matching chelators to radiometals for radiopharmaceuticals","url":"https://doi.org/10.1039/C3CS60304K"},{"label":"One ring to bind them all? Review on DOTA complexes with medically relevant radiometals","url":"https://www.research.unipd.it/handle/11577/3611078"},{"label":"Mechanism and energetics of 90Y-DOTA complexation (J. Am. Chem. Soc. 1999)","url":"https://pubs.acs.org/doi/10.1021/ja983706q"},{"label":"Metal Chelating Agents for Medicinal Radionuclides (UBC open thesis, background on DOTA kinetics)","url":"https://open.library.ubc.ca/media/stream/pdf/24/1.0392203/4"}],"tags":["chemistry","chelator"],"related":["macropa-chelation","sarcophagine-chelation","radioligand-dosimetry","prrt","targeted-alpha-therapy","ga-68","lu-177","ac-225","y-90","bi-213"],"indications":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":["cyclotron-isotope-production","radiopharmacy-network"],"notes":[],"principle":"A twelve-membered tetraaza macrocycle with four pendant carboxylate arms wraps around a metal ion, first binding it loosely outside the ring cavity, then, as the last ring-nitrogen proton is lost, letting the metal drop fully inside the cage to form an octadentate, kinetically inert complex that does not release the metal under physiological conditions.","strengths":[],"limitations":[],"since":"1980s (macrocyclic chelator chemistry); adapted to radiometals through the 1990s-2000s"},"route":"/technologies/dota-chelation/","neighbours":{"technology":[{"id":"albumin-binder-ligands","kind":"technology","name":"Albumin-binder ligands","route":"/technologies/albumin-binder-ligands/"},{"id":"cyclotron-isotope-production","kind":"technology","name":"Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211)","route":"/technologies/cyclotron-isotope-production/"},{"id":"macropa-chelation","kind":"technology","name":"Macropa chelation","route":"/technologies/macropa-chelation/"},{"id":"prrt","kind":"technology","name":"Peptide receptor radionuclide therapy (PRRT)","route":"/technologies/prrt/"},{"id":"radiohybrid-chemistry","kind":"technology","name":"Radiohybrid (rh) chemistry","route":"/technologies/radiohybrid-chemistry/"},{"id":"radioligand-dosimetry","kind":"technology","name":"Radioligand dosimetry","route":"/technologies/radioligand-dosimetry/"},{"id":"radiopharmacy-network","kind":"technology","name":"Radiopharmacy and cyclotron networks","route":"/technologies/radiopharmacy-network/"},{"id":"sarcophagine-chelation","kind":"technology","name":"Sarcophagine chelation","route":"/technologies/sarcophagine-chelation/"},{"id":"targeted-alpha-therapy","kind":"technology","name":"Targeted alpha therapy","route":"/technologies/targeted-alpha-therapy/"}],"isotope":[{"id":"ac-225","kind":"isotope","name":"Actinium-225","route":"/isotopes/ac-225/"},{"id":"bi-213","kind":"isotope","name":"Bismuth-213","route":"/isotopes/bi-213/"},{"id":"ga-68","kind":"isotope","name":"Gallium-68","route":"/isotopes/ga-68/"},{"id":"lu-177","kind":"isotope","name":"Lutetium-177","route":"/isotopes/lu-177/"},{"id":"y-90","kind":"isotope","name":"Yttrium-90","route":"/isotopes/y-90/"}]}}