Radiolabeling optimization and characterization of 68Ga labeled DOTA-polyamido-amine dendrimer conjugate - Animal biodistribution and PET imaging results

Aanchal Ghai, Baljinder Singh, Puja Panwar Hazari, Michael K. Schultz, Ambika Parmar, Pardeep Kumar, Sarika Sharma, Devinder Dhawan, Anil Kumar Mishra

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

The present study describes the optimization of 68Ga radiolabeling with PAMAM dendrimer-DOTA conjugate. A conjugate (PAMAM-DOTA) concentration of 11.69μM, provided best radiolabeling efficiency of more than 93.0% at pH 4.0, incubation time of 30.0min and reaction temperature ranging between 90 and 100°C. The decay corrected radiochemical yield was found to be 79.4±0.01%. The radiolabeled preparation ([68Ga]-DOTA-PAMAM-D) remained stable (radiolabeling efficiency of 96.0%) at room temperature and in serum for up to 4-h. The plasma protein binding was observed to be 21.0%. After intravenous administration, 50.0% of the tracer cleared from the blood circulation by 30-min and less than 1.0% of the injected activity remained in blood by 1.0h. The animal biodistribution studies demonstrated that the tracer excretes through the kidneys and about 0.33% of the %ID/g accumulated in the tumor at 1h post injection. The animal organ's biodistribution data was supported by animal PET imaging showing good 'non-specific' tracer uptake in tumor and excretion is primarily through kidneys. Additionally, DOTA-PAMAM-D conjugation with αVβ3 receptors targeting peptides and drug loading on the dendrimers may improve the specificity of the 68Ga labeled product for imaging and treating angiogenesis respectively.

Original languageEnglish (US)
Pages (from-to)40-46
Number of pages7
JournalApplied Radiation and Isotopes
Volume105
DOIs
StatePublished - 2015
Externally publishedYes

Keywords

  • Angiogenesis
  • DOTA-NHS
  • Gallium-68 complexes
  • Nanoparticles
  • PAMAM conjugates
  • Radiolabeling

ASJC Scopus subject areas

  • Radiation

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