Entrapment of gadolinium-DTPA in liposomes characterization of vesicles by P-31 nmr spectroscopy

J. M. Devoisselle, J. Vion-Dury, J. P. Galons, S. Confort-Gouny, D. Coustaut, P. Canioni, P. J. Cozzone

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The use of paramagnetic ion chelates to enhance contrast between pathologic and surrounding parenchyma is extensively documented in the magnetic resonance imaging (MRI) literature. Liposomes can be used to increase chelate concentration in the pathologic area, thereby enhancing the efficiency of paramagnetic compounds as contrast agents. Liposomes (50 ± 20 nm) were prepared by sonicating a solution of dipalmitoylphosphatidylcho- line and cholesterol containing 16.5 mM Gadolinium-DTPA (Gd- DTPA) in pharmaceutical formulation (Schering Laboratories, France) and 25 mM inorganic phosphate (Pi). The solutions were dialyzed against 0.9% NaCi before analysis by phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy. Spectra of liposomes displayed a sharp resonance ascribed to Pi and a broad signal arising from the phosphate groups of the phospholipid bilayer. The content of Gd-DTPA in liposomes was directly esti- mated, based on specific modifications of the longitudinal relaxation rate of intraliposomal Pi. Entrapment ratio was estimated by P-31 NMR spectroscopy and atomic absorption spectroscopy to represent 2.5% to 5% of the initial Gd-DTPA content in the solution. This work illustrates the usefulness of NMR spectroscopy in the characterization of liposomes to be used for MRI applications.

Original languageEnglish (US)
Pages (from-to)719-724
Number of pages6
JournalInvestigative Radiology
Issue number10
StatePublished - Oct 1988


  • Gadolinium-DTPA
  • Liposomes
  • MRI contrast agent
  • P-31 NMR

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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