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A liposomal MRI contrast agent: Phosphatid ylethanolamine‐DTPA
Author(s) -
Grant Chris W. M.,
Karlik Stephen,
Florio Eugene
Publication year - 1989
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910110211
Subject(s) - liposome , phosphatidylethanolamine , chelation , chemistry , sonication , vesicle , phospholipid , gadolinium , bilayer , amphiphile , sialic acid , phosphatidylcholine , biochemistry , chromatography , organic chemistry , membrane , copolymer , polymer
The chelating agent, diethylenetriaminepentaacetic acid (DTPA), was attached via one‐COOH group to the amino headgroup of phosphatidylethanolamine to produce a phospholipid which is also a powerful chelating agent. It readily assembles into the walls of lipid bilayer structures as a liposome‐associated camer of cations for MR contrast or radioisotope studies. Freeze‐etch electron microscopy showed that phosphatidylethanolamine‐DTPA formed satisfactory sonicated vesicles when mixed with natural phospholipids at up to 50 wt%. The resultant structures with bound gadolinium effectively shortened T 1 and T 2 of surrounding water protons. When sonicated liposomes bearing chelating agent with bound 111 In 3+ were injected intravenously into rats, uptake was primarily by liver and spleen. By 24 h postinjection there was biliary excretion of this material. Phosphatidylethanolamine‐DTPA may have some general utility as an amphiphilic liposomal chelating agent for polyvalent cations.