Macromolecular MRI contrast agents with small dendrimers: Pharmacokinetic differences between sizes and cores

Hisataka Kobayashi, Satomi Kawamoto, Sang Kyung Jo, Henry L. Bryant, Martin W. Brechbiel, Robert A. Star

    Research output: Contribution to journalArticlepeer-review

    247 Citations (Scopus)


    Large macromolecular MRI contrast agents with albumin or dendrimer cores are useful for imaging blood vessels. However, their prolonged retention is a major limitation for clinical use. Although smaller dendrimer-based MRI contrast agents are more quickly excreted by the kidneys, they are also able to visualize vascular structures better than Gd-DTPA due to less extravasation. Additionally, unlike Gd-DTPA, they transiently accumulate in renal tubules and thus also can be used to visualize renal structural and functional damage. However, these dendrimer agents are retained in the body for a prolonged time. The purpose of this study was to obtain information from which a macromolecular dendrimer-based MRI contrast agents feasible for use in further clinical studies could be chosen. Six small dendrimer-based MRI contrast agents were synthesized, and their pharmacokinetics, whole-body retention, and dynamic MRI were evaluated in mice to determine an optimal agent in comparison to Gd-[DTPA]-dimeglumine. Diaminobutane (DAB) dendrimer-based agents cleared more rapidly from the body than polyamidoamine (PAMAM) dendrimer-based agents with the same numbers of branches. Smaller dendrimer conjugates were more rapidly excreted from the body than the larger dendrimer conjugates. Since PAMAM-G2, DAB-G3, and DAB-G2 dendrimer-based contrast agents showed relatively rapid excretion, these three conjugates might be acceptable for use in further clinical applications.

    Original languageEnglish
    Pages (from-to)388-394
    Number of pages7
    JournalBioconjugate Chemistry
    Issue number2
    Publication statusPublished - 2003 Mar

    ASJC Scopus subject areas

    • Biotechnology
    • Bioengineering
    • Biomedical Engineering
    • Pharmacology
    • Pharmaceutical Science
    • Organic Chemistry


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